Cold-rolled steel sheet

Information

  • Patent Grant
  • 9567658
  • Patent Number
    9,567,658
  • Date Filed
    Thursday, May 24, 2012
    12 years ago
  • Date Issued
    Tuesday, February 14, 2017
    7 years ago
Abstract
A cold-rolled steel sheet satisfies that an average pole density of an orientation group of {100}<011> to {223}<110> is 1.0 to 5.0, a pole density of a crystal orientation {332}<113> is 1.0 to 4.0, a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50, and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50. Moreover, the cold-rolled steel sheet includes, as a metallographic structure, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.
Description
TECHNICAL FIELD

The present invention relates to a high-strength cold-rolled steel sheet which is excellent in uniform deformability contributing to stretchability, drawability, or the like and is excellent in local deformability contributing to bendability, stretch flangeability, burring formability, or the like, and relates to a method for producing the same. Particularly, the present invention relates to a steel sheet including a Dual Phase (DP) structure.


This application is a national stage application of International Application No. PCT/JP2012/063261, filed May 24, 2012, which claims priority to Japanese Patent Application No. 2011-117432, filed on May 25, 2011, and the content of which is incorporated herein by reference.


BACKGROUND OF INVENTION

In order to suppress emission of carbon dioxide gas from a vehicle, a weight reduction of an automobile body has been attempted by utilization of a high-strength steel sheet. Moreover, from a viewpoint of ensuring safety of a passenger, the utilization of the high-strength steel sheet for the automobile body has been attempted in addition to a mild steel sheet. However, in order to further improve the weight reduction of the automobile body in future, a usable strength level of the high-strength steel sheet should be increased as compared with that of conventional one. Moreover, in order to utilize the high-strength steel sheet for suspension parts or the like of the automobile body, the local deformability contributing to the burring formability or the like should also be improved in addition to the uniform deformability.


However, in general, when the strength of steel sheet is increased, the formability (deformability) is decreased. For example, uniform elongation which is important for drawing or stretching is decreased. In respect to the above, Non-Patent Document 1 discloses a method which secures the uniform elongation by retaining austenite in the steel sheet. Moreover, Non-Patent Document 2 discloses a method which secures the uniform elongation by compositing metallographic structure of the steel sheet even when the strength is the same.


In addition, Non-Patent Document 3 discloses a metallographic structure control method which improves local ductility representing the bendability, hole expansibility, or the burring formability by controlling inclusions, controlling the microstructure to single phase, and decreasing hardness difference between microstructures. In the Non-Patent Document 3, the microstructure of the steel sheet is controlled to the single phase by microstructure control, and the hardness difference is decreased between the microstructures. As a result, the local deformability contributing to the hole expansibility or the like is improved. However, in order to control the microstructure to the single phase, a heat treatment from an austenite single phase is a basis producing method as described in Non-Patent Document 4.


In addition, the Non-Patent Document 4 discloses a technique which satisfies both the strength and the ductility of the steel sheet by controlling a cooling after a hot-rolling in order to control the metallographic structure, specifically, in order to obtain intended morphologies of precipitates and transformation structures and to obtain an appropriate fraction of ferrite and bainite. However, all techniques as described above are the improvement methods for the local deformability which rely on the microstructure control, and are largely influenced by a microstructure formation of a base.


Also, a method, which improves material properties of the steel sheet by increasing reduction at a continuous hot-rolling in order to refine grains, is known as a related art. For example, Non-Patent Document 5 discloses a technique which improves the strength and toughness of the steel sheet by conducting a large reduction rolling in a comparatively lower temperature range within an austenite range in order to refine the grains of ferrite which is a primary phase of a product by transforming non-recrystallized austenite into the ferrite. However, in Non-Patent Document 5, a method for improving the local deformability to be solved by the present invention is not considered at all, and a method which is applied to the cold-rolled steel sheet is not also described.


RELATED ART DOCUMENTS
Non-Patent Documents



  • [Non-Patent Document 1] Takahashi: Nippon Steel Technical Report No. 378 (2003), p. 7.

  • [Non-Patent Document 2] O. Matsumura et al: Trans. ISIJ vol. 27 (1987), p. 570.

  • [Non-Patent Document 3] Katoh et al: Steel-manufacturing studies vol. 312 (1984), p. 41.

  • [Non-Patent Document 4] K. Sugimoto et al: ISIJ International, vol. 40 (2000), p. 920.

  • [Non-Patent Document 5] NFG product introduction of NAKAYAMA STEEL WORKS, LTD.



SUMMARY OF INVENTION
Technical Problem

As described above, it is the fact that the technique, which simultaneously satisfies the high-strength and both properties of the uniform deformability and the local deformability, is not found. For example, in order to improve the local deformability of the high-strength steel sheet, it is necessary to conduct the microstructure control including the inclusions. However, since the improvement relies on the microstructure control, it is necessary to control the fraction or the morphology of the microstructure such as the precipitates, the ferrite, or the bainite, and therefore the metallographic structure of the base is limited. Since the metallographic structure of the base is restricted, it is difficult not only to improve the local deformability but also to simultaneously improve the strength and the local deformability.


An object of the present invention is to provide a cold-rolled steel sheet which has the high-strength, the excellent uniform deformability, the excellent local deformability, and small orientation dependence (anisotropy) of formability by controlling texture and by controlling the size or the morphology of the grains in addition to the metallographic structure of the base, and is to provide a method for producing the same. Herein, in the present invention, the strength mainly represents tensile strength, and the high-strength indicates the strength of 440 MPa or more in the tensile strength. In addition, in the present invention, satisfaction of the high-strength, the excellent uniform deformability, and the excellent local deformability indicates a case of simultaneously satisfying all conditions of TS≧440 (unit: MPa), TS×u-EL≧7000 (unit: MPa·%), TS×λ≧30000 (unit: MPa·%), and d/RmC≧1 (no unit) by using characteristic values of the tensile strength (TS), the uniform elongation (u-EL), hole expansion ratio (λ), and d/RmC which is a ratio of thickness d to minimum radius RmC of bending to a C-direction.


Solution to Problem

In the related arts, as described above, the improvement in the local deformability contributing to the hole expansibility, the bendability, or the like has been attempted by controlling the inclusions, by refining the precipitates, by homogenizing the microstructure, by controlling the microstructure to the single phase, by decreasing the hardness difference between the microstructures, or the like. However, only by the above-described techniques, main constituent of the microstructure must be restricted. In addition, when an element largely contributing to an increase in the strength, such as representatively Nb or Ti, is added for high-strengthening, the anisotropy may be significantly increased. Accordingly, other factors for the formability must be abandoned or directions to take a blank before forming must be limited, and as a result, the application is restricted. On the other hand, the uniform deformability can be improved by dispersing hard phases such as martensite in the metallographic structure.


In order to obtain the high-strength and to improve both the uniform deformability contributing to the stretchability or the like and the local deformability contributing to the hole expansibility, the bendability, or the like, the inventors have newly focused influences of the texture of the steel sheet in addition to the control of the fraction or the morphology of the metallographic structures of the steel sheet, and have investigated and researched the operation and the effect thereof in detail. As a result, the inventors have found that, by controlling a chemical composition, the metallographic structure, and the texture represented by pole densities of each orientation of a specific crystal orientation group of the steel sheet, the high-strength is obtained, the local deformability is remarkably improved due to a balance of Lankford-values (r values) in a rolling direction, in a direction (C-direction) making an angle of 90° with the rolling direction, in a direction making an angle of 30° with the rolling direction, or in a direction making an angle of 60° with the rolling direction, and the uniform deformability is also secured due to the dispersion of the hard phases such as the martensite.


An aspect of the present invention employs the following.


(1) A cold-rolled steel sheet according to an aspect of the present invention includes, as a chemical composition of the steel sheet, by mass %, C: 0.01% to 0.4%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, Al: 0.001% to 2.0%, P: limited to 0.15% or less, S: limited to 0.03% or less, N: limited to 0.01% or less, 0: limited to 0.01% or less, and a balance consisting of Fe and unavoidable impurities, wherein: an average pole density of an orientation group of {100}<011> to {223}<110>, which is a pole density represented by an arithmetic average of pole densities of each crystal orientation {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110>, is 1.0 to 5.0 and a pole density of a crystal orientation {332}<113> is 1.0 to 4.0 in a thickness central portion which is a thickness range of ⅝ to ⅜ based on a surface of the steel sheet; a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50 and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50; and the steel sheet includes, as a metallographic structure, plural grains, and includes, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.


(2) The cold-rolled steel sheet according to (1) may further includes, as the chemical composition of the steel sheet, by mass %, at least one selected from the group consisting of Ti: 0.001% to 0.2%, Nb: 0.001% to 0.2%, B: 0.0001% to 0.005%, Mg: 0.0001% to 0.01%, Rare Earth Metal: 0.0001% to 0.1%, Ca: 0.0001% to 0.01%, Mo: 0.001% to 1.0%, Cr: 0.001% to 2.0%, V: 0.001% to 1.0%, Ni: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Zr: 0.0001% to 0.2%, W: 0.001% to 1.0%, As: 0.0001% to 0.5%, Co: 0.0001% to 1.0%, Sn: 0.0001% to 0.2%, Pb: 0.0001% to 0.2%, Y: 0.001% to 0.2%, and Hf: 0.001% to 0.2%.


(3) In the cold-rolled steel sheet according to (1) or (2), a volume average diameter of the grains may be 5 μm to 30 μm.


(4) In the cold-rolled steel sheet according to (1) or (2), the average pole density of the orientation group of {100}<011> to {223}<110> may be 1.0 to 4.0, and the pole density of the crystal orientation {332}<113> may be 1.0 to 3.0.


(5) In the cold-rolled steel sheet according to any one of (1) to (4), a Lankford-value rL in the rolling direction may be 0.70 to 1.50, and a Lankford-value r60 in a direction making an angle of 60° with the rolling direction may be 0.70 to 1.50.


(6) In the cold-rolled steel sheet according to any one of (1) to (5), when an area fraction of the martensite is defined as fM in unit of area %, an average size of the martensite is defined as dia in unit of μm, an average distance between the martensite is defined as dis in unit of μm, and a tensile strength of the steel sheet is defined as TS in unit of MPa, a following Expression 1 and a following Expression 2 may be satisfied.

dia≦13 μm  (Expression 1)
TS/fM×dis/dia≧500  (Expression 2)


(7) In the cold-rolled steel sheet according to any one of (1) to (6), when an area fraction of the martensite is defined as fM in unit of area %, a major axis of the martensite is defined as La, and a minor axis of the martensite is defined as Lb, an area fraction of the martensite satisfying a following Expression 3 may be 50% to 100% as compared with the area fraction fM of the martensite.

La/Lb≦5.0  (Expression 3)


(8) In the cold-rolled steel sheet according to any one of (1) to (7), the steel sheet may include, as the metallographic structure, by area %, the bainite of 5% to 80%.


(9) In the cold-rolled steel sheet according to any one of (1) to (8), the steel sheet may include a tempered martensite in the martensite.


(10) In the cold-rolled steel sheet according to any one of (1) to (9), an area fraction of coarse grain having grain size of more than 35 μm may be 0% to 10% among the grains in the metallographic structure of the steel sheet.


(11) In the cold-rolled steel sheet according to any one of (1) to (10), when a hardness of the ferrite or the bainite which is a primary phase is measured at 100 points or more, a value dividing a standard deviation of the hardness by an average of the hardness may be 0.2 or less.


(12) In the cold-rolled steel sheet according to any one of (1) to (11), a galvanized layer or a galvannealed layer may be arranged on the surface of the steel sheet.


(13) A method for producing a cold-rolled steel sheet according to an aspect of the present invention includes: first-hot-rolling a steel in a temperature range of 1000° C. to 1200° C. under conditions such that at least one pass whose reduction is 40% or more is included so as to control an average grain size of an austenite in the steel to 200 μm or less, wherein the steel includes, as a chemical composition, by mass %, C: 0.01% to 0.4%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, Al: 0.001% to 2.0%, P: limited to 0.15% or less, S: limited to 0.03% or less, N: limited to 0.01% or less, 0: limited to 0.01% or less, and a balance consisting of Fe and unavoidable impurities; second-hot-rolling the steel under conditions such that, when a temperature calculated by a following Expression 4 is defined as T1 in unit of ° C. and a ferritic transformation temperature calculated by a following Expression 5 is defined as Ar3 in unit of ° C., a large reduction pass whose reduction is 30% or more in a temperature range of T1+30° C. to T1+200° C. is included, a cumulative reduction in the temperature range of T1+30° C. to T1+200° C. is 50% or more, a cumulative reduction in a temperature range of Ar3 to lower than T1+30° C. is limited to 30% or less, and a rolling finish temperature is Ar3 or higher; first-cooling the steel under conditions such that, when a waiting time from a finish of a final pass in the large reduction pass to a cooling start is defined as t in unit of second, the waiting time t satisfies a following Expression 6, an average cooling rate is 50° C./second or faster, a cooling temperature change which is a difference between a steel temperature at the cooling start and a steel temperature at a cooling finish is 40° C. to 140° C., and the steel temperature at the cooling finish is T1+100° C. or lower; second-cooling the steel to a temperature range of a room temperature to 600° C. after finishing the second-hot-rolling; coiling the steel in the temperature range of the room temperature to 600° C.; pickling the steel; cold-rolling the steel under a reduction of 30% to 70%; heating-and-holding the steel in a temperature range of 750° C. to 900° C. for 1 second to 1000 seconds; third-cooling the steel to a temperature range of 580° C. to 720° C. under an average cooling rate of 1° C./second to 12° C./second; fourth-cooling the steel to a temperature range of 200° C. to 600° C. under an average cooling rate of 4° C./second to 300° C./second; and holding the steel as an overageing treatment under conditions such that, when an overageing temperature is defined as T2 in unit of ° C. and an overageing holding time dependent on the overageing temperature T2 is defined as t2 in unit of second, the overageing temperature T2 is within a temperature range of 200° C. to 600° C. and the overageing holding time t2 satisfies a following Expression 8.

T1=850+10×([C]+[N])×[Mn]  (Expression 4)


here, [C], [N], and [Mn] represent mass percentages of C, N, and Mn respectively.

Ar3=879.4−516.1×[C]−65.7×[Mn]+38.0×[Si]+274.7×[P]   (Expression 5)


here, in Expression 5, [C], [Mn], [Si] and [P] represent mass percentages of C, Mn, Si, and P respectively.

t≦2.5×t1  (Expression 6)


here, t1 is represented by a following Expression 7.

t1=0.001×((Tf−T1)×P1/100)2−0.109×((Tf−T1)×P1/100)+3.1   (Expression 7)


here, Tf represents a celcius temperature of the steel at the finish of the final pass, and P1 represents a percentage of a reduction at the final pass.

log(t2)≦0.0002×(T2−425)2+1.18  (Expression 8)


(14) In the method for producing the cold-rolled steel sheet according to (13), the steel may further includes, as the chemical composition, by mass %, at least one selected from the group consisting of Ti: 0.001% to 0.2%, Nb: 0.001% to 0.2%, B: 0.0001% to 0.005%, Mg: 0.0001% to 0.01%, Rare Earth Metal: 0.0001% to 0.1%, Ca: 0.0001% to 0.01%, Mo: 0.001% to 1.0%, Cr: 0.001% to 2.0%, V: 0.001% to 1.0%, Ni: 0.001% to 2.0%, Cu: 0.001% to 2.0%, Zr: 0.0001% to 0.2%, W: 0.001% to 1.0%, As: 0.0001% to 0.5%, Co: 0.0001% to 1.0%, Sn: 0.0001% to 0.2%, Pb: 0.0001% to 0.2%, Y: 0.001% to 0.2%, and HP 0.001% to 0.2%, and a temperature calculated by a following Expression 9 may be substituted for the temperature calculated by the Expression 4 as T1.

T1=850+10×([C]+[N])×[Mn]+350×[Nb]+250×[Ti]+40×[B]+10×[Cr]+100×[Mo]+100×[V]  (Expression 9)


here, [C], [N], [Mn], [Nb], [Ti], [B], [Cr], [Mo], and [V] represent mass percentages of C, N, Mn, Nb, Ti, B, Cr, Mo, and V respectively.


(15) In the method for producing the cold-rolled steel sheet according to (13) or (14), the waiting time t may further satisfy a following Expression 10.

0≦t<t1  (Expression 10)


(16) In the method for producing the cold-rolled steel sheet according to (13) or (14), the waiting time t may further satisfy a following Expression 11.

t1≦t≦t1×2.5  (Expression 11)


(17) In the method for producing the cold-rolled steel sheet according to any one of (13) to (16), in the first-hot-rolling, at least two times of rollings whose reduction is 40% or more may be conducted, and the average grain size of the austenite may be controlled to 100 μm or less.


(18) In the method for producing the cold-rolled steel sheet according to any one of (13) to (17), the second-cooling may start within 3 seconds after finishing the second-hot-rolling.


(19) In the method for producing the cold-rolled steel sheet according to any one of (13) to (18), in the second-hot-rolling, a temperature rise of the steel between passes may be 18° C. or lower.


(20) In the method for producing the cold-rolled steel sheet according to any one of (13) to (19), the first-cooling may be conducted at an interval between rolling stands.


(21) In the method for producing the cold-rolled steel sheet according to any one of (13) to (20), a final pass of rollings in the temperature range of T1+30° C. to T1+200° C. may be the large reduction pass.


(22) In the method for producing the cold-rolled steel sheet according to any one of (13) to (21), in the second-cooling, the steel may be cooled under an average cooling rate of 10° C./second to 300° C./second.


(23) In the method for producing the cold-rolled steel sheet according to any one of (13) to (22), a galvanizing may be conducted after the overageing treatment.


(24) In the method for producing the cold-rolled steel sheet according to any one of (13) to (23), a galvanizing may be conducted after the overageing treatment; and a heat treatment may be conducted in a temperature range of 450° C. to 600° C. after the galvanizing.


Advantageous Effects of Invention

According to the above aspects of the present invention, it is possible to obtain a cold-rolled steel sheet which has the high-strength, the excellent uniform deformability, the excellent local deformability, and the small anisotropy even when the element such as Nb or Ti is added.







DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, a cold-rolled steel sheet according to an embodiment of the present invention will be described in detail. First, a pole density of a crystal orientation of the cold-rolled steel sheet will be described.


Average Pole Density D1 of Crystal Orientation: 1.0 to 5.0


Pole Density D2 of Crystal Orientation: 1.0 to 4.0


In the cold-rolled steel sheet according to the embodiment, as the pole densities of two kinds of the crystal orientations, the average pole density D1 of an orientation group of {100}<011> to {223}<110> (hereinafter, referred to as “average pole density”) and the pole density D2 of a crystal orientation {332}<113> in a thickness central portion, which is a thickness range of ⅝ to ⅜ (a range which is ⅝ to ⅜ of the thickness distant from a surface of the steel sheet along a normal direction (a depth direction) of the steel sheet), are controlled in reference to a thickness-cross-section (a normal vector thereof corresponds to the normal direction) which is parallel to a rolling direction.


In the embodiment, the average pole density D1 is an especially-important characteristic (orientation integration and development degree of texture) of the texture (crystal orientation of grains in metallographic structure). Herein, the average pole density D1 is the pole density which is represented by an arithmetic average of pole densities of each crystal orientation {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110>.


A intensity ratio of electron diffraction intensity or X-ray diffraction intensity of each orientation to that of a random sample is obtained by conducting Electron Back Scattering Diffraction (EBSD) or X-ray diffraction on the above cross-section in the thickness central portion which is the thickness range of ⅝ to ⅜, and the average pole density D1 of the orientation group of {100}<011> to {223}<110> can be obtained from each intensity ratio.


When the average pole density D1 of the orientation group of {100}<011> to {223}<110> is 5.0 or less, it is satisfied that d/RmC (a parameter in which the thickness d is divided by a minimum bend radius RmC (C-direction bending)) is 1.0 or more, which is minimally-required for working suspension parts or frame parts. Particularly, the condition is a requirement in order that tensile strength TS, hole expansion ratio λ, and total elongation EL preferably satisfy TS×λ≧30000 and TS×EL≧14000 which are two conditions required for the suspension parts of the automobile body.


In addition, when the average pole density D1 is 4.0 or less, a ratio (Rm45/RmC) of a minimum bend radius Rm45 of 45°-direction bending to the minimum bend radius RmC of the C-direction bending is decreased, in which the ratio is a parameter of orientation dependence (isotropy) of formability, and the excellent local deformability which is independent of the bending direction can be secured. As described above, the average pole density D1 may be 5.0 or less, and may be preferably 4.0 or less. In a case where the further excellent hole expansibility or small critical bending properties are needed, the average pole density D1 may be more preferably less than 3.5, and may be furthermore preferably less than 3.0.


When the average pole density D1 of the orientation group of {100}<011> to {223}<110> is more than 5.0, the anisotropy of mechanical properties of the steel sheet is significantly increased. As a result, although the local deformability in only a specific direction is improved, the local deformability in a direction different from the specific direction is significantly decreased. Therefore, in the case, the steel sheet cannot satisfy d/RmC≧1.0.


On the other hand, when the average pole density D1 is less than 1.0, the local deformability may be decreased. Accordingly, preferably, the average pole density D1 may be 1.0 or more.


In addition, from the similar reasons, the pole density D2 of the crystal orientation {332}<113> in the thickness central portion which is the thickness range of ⅝ to ⅜ may be 4.0 or less. The condition is a requirement in order that the steel sheet satisfies d/RmC≧1.0, and particularly, that the tensile strength TS, the hole expansion ratio λ, and the total elongation EL preferably satisfy TS×λ≧30000 and TS×EL≧14000 which are two conditions required for the suspension parts.


Moreover, when the pole density D2 is 3.0 or less, TS×λ or d/RmC can be further improved. The pole density D2 may be preferably 2.5 or less, and may be more preferably 2.0 or less. When the pole density D2 is more than 4.0, the anisotropy of the mechanical properties of the steel sheet is significantly increased. As a result, although the local deformability in only a specific direction is improved, the local deformability in a direction different from the specific direction is significantly decreased. Therefore, in the case, the steel sheet cannot sufficiently satisfy d/RmC≧1.0.


On the other hand, when the average pole density D2 is less than 1.0, the local deformability may be decreased. Accordingly, preferably, the pole density D2 of the crystal orientation {332}<113> may be 1.0 or more.


The pole density is synonymous with an X-ray random intensity ratio. The X-ray random intensity ratio can be obtained as follows. Diffraction intensity (X-ray or electron) of a standard sample which does not have a texture to a specific orientation and diffraction intensity of a test material are measured by the X-ray diffraction method in the same conditions. The X-ray random intensity ratio is obtained by dividing the diffraction intensity of the test material by the diffraction intensity of the standard sample. The pole density can be measured by using the X-ray diffraction, the Electron Back Scattering Diffraction (EBSD), or Electron Channeling Pattern (ECP). For example, the average pole density D1 of the orientation group of {100}<011> to {223}<110> can be obtained as follows. The pole densities of each orientation {100}<110>, {116}<110>, {114}<110>, {112}<110>, and {223}<110> are obtained from a three-dimensional texture (ODF: Orientation Distribution Functions) which is calculated by a series expanding method using plural pole figures in pole figures of {110}, {100}, {211}, and {310} measured by the above methods. The average pole density D1 is obtained by calculating an arithmetic average of the pole densities.


With respect to samples which are supplied for the X-ray diffraction, the EBSD, and the ECP, the thickness of the steel sheet may be reduced to a predetermined thickness by mechanical polishing or the like, strain may be removed by chemical polishing, electrolytic polishing, or the like, the samples may be adjusted so that an appropriate surface including the thickness range of ⅝ to ⅜ is a measurement surface, and then the pole densities may be measured by the above methods. With respect to a transverse direction, it is preferable that the samples are collected in the vicinity of ¼ or ¾ position of the thickness (a position which is at ¼ of a steel sheet width distant from a side edge the steel sheet).


When the above pole densities are satisfied in many other thickness portions of the steel sheet in addition to the thickness central portion, the local deformability is further improved. However, since the texture in the thickness central portion significantly influences the anisotropy of the steel sheet, the material properties of the thickness central portion approximately represent the material properties of the entirety of the steel sheet. Accordingly, the average pole density D1 of the orientation group of {100}<011> to {223}<110> and the pole density D2 of the crystal orientation {332}<113> in the thickness central portion of ⅝ to ⅜ are prescribed.


Herein, {hkl}<uvw> indicates that the normal direction of the sheet surface is parallel to <hkl> and the rolling direction is parallel to <uvw> when the sample is collected by the above-described method. In addition, generally, in the orientation of the crystal, an orientation perpendicular to the sheet surface is represented by (hkl) or {hkl} and an orientation parallel to the rolling direction is represented by [uvw] or <uvw>. {hkl}<uvw> indicates collectively equivalent planes, and (hkl)[uvw] indicates each crystal plane. Specifically, since the embodiment targets a body centered cubic (bcc) structure, for example, (111), (−111), (1-11), (11-1), (−1−11), (−11−1), (1−1−1), and (−1−1−1) planes are equivalent and cannot be classified. In the case, the orientation is collectively called as {111}. Since the ODF expression is also used for orientation expressions of other crystal structures having low symmetry, generally, each orientation is represented by (hkl)[uvw] in the ODF expression. However, in the embodiment, {hkl}<uvw> and (hkl)[uvw] are synonymous.


Next, an r value (Lankford-value) of the steel sheet will be described.


In the embodiment, in order to further improve the local deformability, the r values of each direction (as described below, rL which is the r value in the rolling direction, r30 which is the r value in a direction making an angle of 30° with the rolling direction, r60 which is the r value in a direction making an angle of 60° with the rolling direction, and rC which is the r value in a direction perpendicular to the rolling direction) may be controlled to be a predetermined range. In the embodiment, the r values are important. As a result of investigation in detail by the inventors, it is found that the more excellent local deformability such as the hole expansibility is obtained by appropriately controlling the r values in addition to the appropriate control of each pole density as described above.


r Value in Direction Perpendicular to Rolling Direction (rC): 0.70 to 1.50


As a result of the investigation in detail by the inventors, it is found that more excellent hole expansibility is obtained by controlling the rC to 0.70 or more in addition to the control of each pole density to the above-described range. Accordingly, the rC may be 0.70 or more. In order to obtain the more excellent hole expansibility, an upper limit of the rC may be 1.50 or less. Preferably, the rC may be 1.10 or less.


r Value in Direction Making Angle of 30° with Rolling Direction (r30): 0.70 to 1.50


As a result of the investigation in detail by the inventors, it is found that more excellent hole expansibility is obtained by controlling the r30 to 1.50 or less in addition to the control of each pole density to the above-described range. Accordingly, the r30 may be 1.50 or less. Preferably, the r30 may be 1.10 or less. In order to obtain the more excellent hole expansibility, a lower limit of the r30 may be 0.70 or more.


r Value of Rolling Direction (rL): 0.70 to 1.50


r Value in Direction Making Angle of 60° with Rolling Direction (r60): 0.70 to 1.50


As a result of further investigation in detail by the inventors, it is found that more excellent TS×λ is obtained by controlling the rL and the r60 so as to satisfy rL≧0.70 and r60≦1.50 respectively, in addition to the control of the rC and the r30 to the above-described range. Accordingly, the rL may be 0.70 or more, and the r60 may be 1.50 or less. Preferably, the r60 may be 1.10 or less. In order to obtain the more excellent hole expansibility, an upper limit of the rL may be 1.50 or less, and a lower limit of the r60 may be 0.70 or more. Preferably, the rL may be 1.10 or less.


Each r value as described above is evaluated by tensile test using JIS No. 5 tensile test sample. In consideration of a general high-strength steel sheet, the r values may be evaluated within a range where tensile strain is 5% to 15% and a range which corresponds to the uniform elongation.


In addition, since the directions in which the bending is conducted differ in the parts which are bent, the direction is not particularly limited. In the cold-rolled steel sheet according to the embodiment, the similar properties can be obtained in any bending direction.


Generally, it is known that the texture and the r value have a correlation. However, in the cold-rolled steel sheet according to the embodiment, the limitation with respect to the pole densities of the crystal orientations and the limitation with respect to the r values as described above are not synonymous. Accordingly, when both limitations are simultaneously satisfied, more excellent local deformability can be obtained.


Next, a metallographic structure of the cold-rolled steel sheet according to the embodiment will be described.


A metallographic structure of the cold-rolled steel sheet according to the embodiment is fundamentally to be a Dual Phase (DP) structure which includes plural grains, includes ferrite and/or bainite as a primary phase, and includes martensite as a secondary phase. The strength and the uniform deformability can be increased by dispersing the martensite which is the secondary phase and the hard phase to the ferrite or the bainite which is the primary phase and has the excellent deformability. The improvement in the uniform deformability is derived from an increase in work hardening rate by finely dispersing the martensite which is the hard phase in the metallographic structure. Moreover, herein, the ferrite or the bainite includes polygonal ferrite and bainitic ferrite.


The cold-rolled steel sheet according to the embodiment includes residual austenite, pearlite, cementite, plural inclusions, or the like as the microstructure in addition to the ferrite, the bainite, and the martensite. It is preferable that the microstructures other than the ferrite, the bainite, and the martensite are limited to, by area %, 0% to 10%. Moreover, when the austenite is retained in the microstructure, secondary work embrittlement or delayed fracture properties deteriorates. Accordingly, except for the residual austenite of approximately 5% in area fraction which unavoidably exists, it is preferable that the residual austenite is not substantially included.


Area Fraction of Ferrite and Bainite which are Primary Phase: 30% to Less than 99%


The ferrite and the bainite which are the primary phase are comparatively soft, and have the excellent deformability. When the area fraction of the ferrite and the bainite is 30% or more in total, both properties of the uniform deformability and the local deformability of the cold-rolled steel sheet according to the embodiment are satisfied. More preferably, the ferrite and the bainite may be, by area %, 50% or more in total. On the other hand, when the area fraction of the ferrite and the bainite is 99% or more in total, the strength and the uniform deformability of the steel sheet are decreased.


Preferably, the area fraction of the bainite which is the primary phase may be 5% to 80%. By controlling the area fraction of the bainite which is comparatively excellent in the strength to 5% to 80%, it is possible to preferably increase the strength in a balance between the strength and the ductility (deformability) of the steel sheet. By increasing the area fraction of the bainite which is harder phase than the ferrite, the strength of the steel sheet is improved. In addition, the bainite, which has small hardness difference from the martensite as compared with the ferrite, suppresses initiation of voids at an interface between the soft phase and the hard phase, and improves the hole expansibility.


Alternatively, the area fraction of the ferrite which is the primary phase may be 30% to 99%. By controlling the area fraction of the ferrite which is comparatively excellent in the deformability to 30% to 99%, it is possible to preferably increase the ductility (deformability) in the balance between the strength and the ductility (deformability) of the steel sheet. Particularly, the ferrite contributes to the improvement in the uniform deformability.


Area Fraction fM of Martensite: 1% to 70%


By dispersing the martensite, which is the secondary phase and is the hard phase, in the metallographic structure, it is possible to improve the strength and the uniform deformability. When the area fraction of the martensite is less than 1%, the dispersion of the hard phase is insufficient, the work hardening rate is decreased, and the uniform deformability is decreased. Preferably, the area fraction of the martensite may be 3% or more. On the other hand, when the area fraction of the martensite is more than 70%, the area fraction of the hard phase is excessive, and the deformability of the steel sheet is significantly decreased. In accordance with the balance between the strength and the deformability, the area fraction of the martensite may be 50% or less. Preferably, the area fraction of the martensite may be 30% or less. More preferably, the area fraction of the martensite may be 20% or less.


Average Grain Size Dia of Martensite: 13 μm or Less


When the average size of the martensite is more than 13 μm, the uniform deformability of the steel sheet may be decreased, and the local deformability may be decreased. It is considered that the uniform elongation is decreased due to the fact that contribution to the work hardening is decreased when the average size of the martensite is coarse, and that the local deformability is decreased due to the fact that the voids easily initiates in the vicinity of the coarse martensite. Preferably, the average size of the martensite may be less than 10 μm. More preferably, the average size of the martensite may be 7 μm or less. Furthermore preferably, the average size of the martensite may be 5 μm or less.


Relationship of TS/fM×Dis/Dia: 500 or More


Moreover, as a result of the investigation in detail by the inventors, it is found that, when the tensile strength is defined as TS (tensile strength) in unit of MPa, the area fraction of the martensite is defined as fM (fraction of Martensite) in unit of %, an average distance between the martensite grains is defined as dis (distance) in unit of μm, and the average grain size of the martensite is defined as dia (diameter) in unit of μm, the uniform deformability of the steel sheet may be preferably improved in a case that a relationship among the TS, the fM, the dis, and the dia satisfies a following Expression 1.

TS/fM×dis/dia≧500  (Expression 1)


When the relationship of TS/fM×dis/dia is less than 500, the uniform deformability of the steel sheet may be significantly decreased. A physical meaning of the Expression 1 has not been clear. However, it is considered that the work hardening more effectively occurs as the average distance dis between the martensite grains is decreased and as the average grain size dia of the martensite is increased. Moreover, the relationship of TS/fM×dis/dia does not have particularly an upper limit. However, from an industrial standpoint, since the relationship of TS/fM×dis/dia barely exceeds 10000, the upper limit may be 10000 or less.


Fraction of Martensite Having 5.0 or Less in Ratio of Major Axis to Minor Axis: 50% or More


In addition, when a major axis of a martensite grain is defined as La in unit of μm and a minor axis of a martensite grain is defined as Lb in unit of μm, the local deformability may be preferably improved in a case that an area fraction of the martensite grain satisfying a following Expression 2 is 50% to 100% as compared with the area fraction fM of the martensite.

La/Lb≦5.0  (Expression 2)


The detail reasons why the effect is obtained has not been clear. However, it is considered that the local deformability is improved due to the fact that the shape of the martensite varies from an acicular shape to a spherical shape and that excessive stress concentration to the ferrite or the bainite near the martensite is relieved. Preferably, the area fraction of the martensite grain having La/Lb of 3.0 or less may be 50% or more as compared with the fM. More preferably, the area fraction of the martensite grain having La/Lb of 2.0 or less may be 50% or more as compared with the fM. Moreover, when the fraction of equiaxial martensite is less than 50% as compared with the fM, the local deformability may deteriorate. Moreover, a lower limit of the Expression 2 may be 1.0.


Moreover, all or part of the martensite may be a tempered martensite. When the martensite is the tempered martensite, although the strength of the steel sheet is decreased, the hole expansibility of the steel sheet is improved by a decrease in the hardness difference between the primary phase and the secondary phase. In accordance with the balance between the required strength and the required deformability, the area fraction of the tempered martensite may be controlled as compared with the area fraction fM of the martensite. Moreover, the cold-rolled steel sheet according to the embodiment may include the residual austenite of 5% or less. When the residual austenite is more than 5%, the residual austenite is transformed to excessive hard martensite after working, and the hole expansibility may deteriorate significantly.


The metallographic structure such as the ferrite, the bainite, or the martensite as described above can be observed by a Field Emission Scanning Electron Microscope (FE-SEM) in a thickness range of ⅛ to ⅜ (a thickness range in which ¼ position of the thickness is the center). The above characteristic values can be determined from micrographs which are obtained by the observation. In addition, the characteristic values can be also determined by the EBSD as described below. For the observation of the FE-SEM, samples are collected so that an observed section is the thickness-cross-section (the normal vector thereof corresponds to the normal direction) which is parallel to the rolling direction of the steel sheet, and the observed section is polished and nital-etched. Moreover, in the thickness direction, the metallographic structure (constituent) of the steel sheet may be significantly different between the vicinity of the surface of the steel sheet and the vicinity of the center of the steel sheet because of decarburization and Mn segregation. Accordingly, in the embodiment, the metallographic structure based on ¼ position of the thickness is observed.


Volume Average Diameter of Grains: 5 μm to 30 μm


Moreover, in order to further improve the deformability, size of the grains in the metallographic structure, particularly, the volume average diameter may be refined. Moreover, fatigue properties (fatigue limit ratio) required for an automobile steel sheet or the like are also improved by refining the volume average diameter. Since the number of coarse grains significantly influences the deformability as compared with the number of fine grains, the deformability significantly correlates with the volume average diameter calculated by the weighted average of the volume as compared with a number average diameter. Accordingly, in order to obtain the above effects, the volume average diameter may be 5 μm to 30 μm, may be more preferably 5 μm to 20 μm, and may be furthermore preferably 5 μm to 10 μm.


Moreover, it is considered that, when the volume average diameter is decreased, local strain concentration occurred in micro-order is suppressed, the strain can be dispersed during local deformation, and the elongation, particularly, the uniform elongation is improved. In addition, when the volume average diameter is decreased, a grain boundary which acts as a barrier of dislocation motion may be appropriately controlled, the grain boundary may affect repetitive plastic deformation (fatigue phenomenon) derived from the dislocation motion, and thus, the fatigue properties may be improved.


Moreover, as described below, the diameter of each grain (grain unit) can be determined. The pearlite is identified through a metallographic observation by an optical microscope. In addition, the grain units of the ferrite, the austenite, the bainite, and the martensite are identified by the EBSD. If crystal structure of an area measured by the EBSD is a face centered cubic structure (fcc structure), the area is regarded as the austenite. Moreover, if crystal structure of an area measured by the EBSD is the body centered cubic structure (bcc structure), the area is regarded as the any one of the ferrite, the bainite, and the martensite. The ferrite, the bainite, and the martensite can be identified by using a Kernel Average Misorientation (KAM) method which is added in an Electron Back Scatter Diffraction Pattern-Orientation Image Microscopy (EBSP-OIM, Registered Trademark). In the KAM method, with respect to a first approximation (total 7 pixels) using a regular hexagonal pixel (central pixel) in measurement data and 6 pixels adjacent to the central pixel, a second approximation (total 19 pixels) using 12 pixels further outside the above 6 pixels, or a third approximation (total 37 pixels) using 18 pixels further outside the above 12 pixels, an misorientation between each pixel is averaged, the obtained average is regarded as the value of the central pixel, and the above operation is performed on all pixels. The calculation by the KAM method is performed so as not to exceed the grain boundary, and a map representing intragranular crystal rotation can be obtained. The map shows strain distribution based on the intragranular local crystal rotation.


In the embodiment, the misorientation between adjacent pixels is calculated by using the third approximation in the EBSP-OIM (registered trademark). For example, the above-described orientation measurement is conducted by a measurement step of 0.5 μm or less at a magnification of 1500-fold, a position in which the misorientation between the adjacent measurement points is more than 15° is regarded as a grain border (the grain border is not always a general grain boundary), the circle equivalent diameter is calculated, and thus, the grain sizes of the ferrite, the bainite, the martensite, and the austenite are obtained. When the pearlite is included in the metallographic structure, the grain size of the pearlite can be calculated by applying an image processing method such as binarization processing or an intercept method to the micrograph obtained by the optical microscope.


In the grain (grain unit) defined as described above, when a circle equivalent radius (a half value of the circle equivalent diameter) is defined as r, the volume of each grain is obtained by 4×π×r3/3, and the volume average diameter can be obtained by the weighted average of the volume. In addition, an area fraction of coarse grains described below can be obtained by dividing area of the coarse grains obtained using the method by measured area. Moreover, except for the volume average diameter, the circle equivalent diameter or the grain size obtained by the binarization processing, the intercept method, or the like is used, for example, as the average grain size dia of the martensite.


The average distance dis between the martensite grains may be determined by using the border between the martensite grain and the grain other than the martensite obtained by the EBSD method (however, FE-SEM in which the EBSD can be conducted) in addition to the FE-SEM observation method.


Area Fraction of Coarse Grains Having Grain Size of More than 35 μm: 0% to 10%


In addition, in order to further improve the local deformability, with respect to all constituents of the metallographic structure, the area fraction (the area fraction of the coarse grains) which is occupied by grains (coarse grains) having the grain size of more than 35 μm occupy per unit area may be limited to be 0% to 10%. When the grains having a large size are increased, the tensile strength may be decreased, and the local deformability may be also decreased. Accordingly, it is preferable to refine the grains. Moreover, since the local deformability is improved by straining all grains uniformly and equivalently, the local strain of the grains may be suppressed by limiting the fraction of the coarse grains.


Hardness H of Ferrite: It is Preferable to Satisfy a Following Expression 3


The ferrite which is the primary phase and the soft phase contributes to the improvement in the deformability of the steel sheet. Accordingly, it is preferable that the average hardness H of the ferrite satisfies the following Expression 3. When a ferrite which is harder than the following Expression 3 is contained, the improvement effects of the deformability of the steel sheet may not be obtained. Moreover, the average hardness H of the ferrite is obtained by measuring the hardness of the ferrite at 100 points or more under a load of 1 mN in a nano-indenter.

H<200+30×[Si]+21×[Mn]+270×[P]+78×[Nb]1/2+108×[Ti]1/2  (Expression 3)


Here, [Si], [Mn], [P], [Nb], and [Ti] represent mass percentages of Si, Mn, P, Nb, and Ti respectively.


Standard Deviation/Average of Hardness of Ferrite or Bainite: 0.2 or Less


As a result of investigation which is focused on the homogeneity of the ferrite or bainite which is the primary phase by the inventors, it is found that, when the homogeneity of the primary phase is high in the microstructure, the balance between the uniform deformability and the local deformability may be preferably improved. Specifically, when a value, in which the standard deviation of the hardness of the ferrite is divided by the average of the hardness of the ferrite, is 0.2 or less, the effects may be preferably obtained. Moreover, when a value, in which the standard deviation of the hardness of the bainite is divided by the average of the hardness of the bainite, is 0.2 or less, the effects may be preferably obtained. The homogeneity can be obtained by measuring the hardness of the ferrite or the bainite which is the primary phase at 100 points or more under the load of 1 mN in the nano-indenter and by using the obtained average and the obtained standard deviation. Specifically, the homogeneity increases with a decrease in the value of the standard deviation of the hardness/the average of the hardness, and the effects may be obtained when the value is 0.2 or less. In the nano-indenter (for example, UMIS-2000 manufactured by CSIRO corporation), by using a smaller indenter than the grain size, the hardness of a single grain which does not include the grain boundary can be measured.


Next, a chemical composition of the cold-rolled steel sheet according to the embodiment will be described.


C: 0.01% to 0.4%


C (carbon) is an element which increases the strength of the steel sheet, and is an essential element to obtain the area fraction of the martensite. A lower limit of C content is to be 0.01% in order to obtain the martensite of 1% or more, by area %. Preferably, the lower limit may be 0.03% or more. On the other hand, when the C content is more than 0.40%, the deformability of the steel sheet is decreased, and weldability of the steel sheet also deteriorates. Preferably, the C content may be 0.30% or less. The C content may be preferably 0.3% or less, and may be more preferably 0.25% or less.


Si: 0.001% to 2.5%


Si (silicon) is a deoxidizing element of the steel and is an element which is effective in an increase in the mechanical strength of the steel sheet. Moreover, Si is an element which stabilizes the ferrite during the temperature control after the hot-rolling and suppresses cementite precipitation during the bainitic transformation. However, when Si content is more than 2.5%, the deformability of the steel sheet is decreased, and surface dents tend to be made on the steel sheet. On the other hand, when the Si content is less than 0.001%, it is difficult to obtain the effects.


Mn: 0.001% to 4.0%


Mn (manganese) is an element which is effective in an increase in the mechanical strength of the steel sheet. However, when Mn content is more than 4.0%, the deformability of the steel sheet is decreased. Preferably, the Mn content may be 3.5% or less. More preferably, the Mn content may be 3.0% or less. On the other hand, when the Mn content is less than 0.001%, it is difficult to obtain the effects. In addition, Mn is also an element which suppresses cracks during the hot-rolling by fixing S (sulfur) in the steel. When elements such as Ti which suppresses occurrence of cracks due to S during the hot-rolling are not sufficiently added except for Mn, it is preferable that the Mn content and the S content satisfy Mn/S≧20 by mass %.


Al: 0.001% to 2.0%


Al (aluminum) is a deoxidizing element of the steel. Moreover, Al is an element which stabilizes the ferrite during the temperature control after the hot-rolling and suppresses the cementite precipitation during the bainitic transformation. In order to obtain the effects, Al content is to be 0.001% or more. However, when the Al content is more than 2.0%, the weldability deteriorates. In addition, although it is difficult to quantitatively show the effects, Al is an element which significantly increases a temperature Ar3 at which transformation starts from γ (austenite) to α (ferrite) at the cooling of the steel. Accordingly, Ar3 of the steel may be controlled by the Al content.


The cold-rolled steel sheet according to the embodiment includes unavoidable impurities in addition to the above described base elements. Here, the unavoidable impurities indicate elements such as P, S, N, O, Cd, Zn, or Sb which are unavoidably mixed from auxiliary raw materials such as scrap or from production processes. In the elements, P, S, N, and O are limited to the following in order to preferably obtain the effects. It is preferable that the unavoidable impurities other than P, S, N, and O are individually limited to 0.02% or less. Moreover, even when the impurities of 0.02% or less are included, the effects are not affected. The limitation range of the impurities includes 0%, however, it is industrially difficult to be stably 0%. Here, the described % is mass %.


P: 0.15% or Less


P (phosphorus) is an impurity, and an element which contributes to crack during the hot-rolling or the cold-rolling when the content in the steel is excessive. In addition, P is an element which deteriorates the ductility or the weldability of the steel sheet. Accordingly, the P content is limited to 0.15% or less. Preferably, the P content may be limited to 0.05% or less. Moreover, since P acts as a solid solution strengthening element and is unavoidably included in the steel, it is not particularly necessary to prescribe a lower limit of the P content. The lower limit of the P content may be 0%. Moreover, considering current general refining (includes secondary refining), the lower limit of the P content may be 0.0005%.


S: 0.03% or Less


S (sulfur) is an impurity, and an element which deteriorates the deformability of the steel sheet by forming MnS stretched by the hot-rolling when the content in the steel is excessive. Accordingly, the S content is limited to 0.03% or less. Moreover, since S is unavoidably included in the steel, it is not particularly necessary to prescribe a lower limit of the S content. The lower limit of the S content may be 0%. Moreover, considering the current general refining (includes the secondary refining), the lower limit of the S content may be 0.0005%.


N: 0.01% or Less


N (nitrogen) is an impurity, and an element which deteriorates the deformability of the steel sheet. Accordingly, the N content is limited to 0.01% or less. Moreover, since N is unavoidably included in the steel, it is not particularly necessary to prescribe a lower limit of the N content. The lower limit of the N content may be 0%. Moreover, considering the current general refining (includes the secondary refining), the lower limit of the N content may be 0.0005%.


O: 0.01% or Less


O (oxygen) is an impurity, and an element which deteriorates the deformability of the steel sheet. Accordingly, the O content is limited to 0.01% or less. Moreover, since O is unavoidably included in the steel, it is not particularly necessary to prescribe a lower limit of the O content. The lower limit of the O content may be 0%. Moreover, considering the current general refining (includes the secondary refining), the lower limit of the O content may be 0.0005%.


The above chemical elements are base components (base elements) of the steel in the embodiment, and the chemical composition, in which the base elements are controlled (included or limited) and the balance consists of Fe and unavoidable impurities, is a base composition of the embodiment. However, in addition to the base elements (instead of a part of Fe which is the balance), in the embodiment, the following chemical elements (optional elements) may be additionally included in the steel as necessary. Moreover, even when the optional elements are unavoidably included in the steel (for example, amount less than a lower limit of each optional element), the effects in the embodiment are not decreased.


Specifically, the cold-rolled steel sheet according to the embodiment may further include, as a optional element, at least one selected from a group consisting of Mo, Cr, Ni, Cu, B, Nb, Ti, V, W, Ca, Mg, Zr, REM, As, Co, Sn, Pb, Y, and Hf in addition to the base elements and the impurity elements. Hereinafter, numerical limitation ranges and the limitation reasons of the optional elements will be described. Here, the described % is mass %.


Ti: 0.001% to 0.2%


Nb: 0.001% to 0.2%


B: 0.001% to 0.005%


Ti (titanium), Nb (niobium), and B (boron) are the optional elements which form fine carbon-nitrides by fixing the carbon and the nitrogen in the steel, and which have the effects such as precipitation strengthening, microstructure control, or grain refinement strengthening for the steel. Accordingly, as necessary, at least one of Ti, Nb, and B may be added to the steel. In order to obtain the effects, preferably, Ti content may be 0.001% or more, Nb content may be 0.001% or more, and B content may be 0.0001% or more. More preferably, the Ti content may be 0.01% or more and the Nb content may be 0.005% or more. However, when the optional elements are excessively added to the steel, the effects may be saturated, the control of the crystal orientation may be difficult because of suppression of recrystallization after the hot-rolling, and the workability (deformability) of the steel sheet may deteriorate. Accordingly, preferably, the Ti content may be 0.2% or less, the Nb content may be 0.2% or less, and the B content may be 0.005% or less. More preferably, the B content may be 0.003% or less. Moreover, even when the optional elements having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. Moreover, since it is not necessary to add the optional elements to the steel intentionally in order to reduce costs of alloy, lower limits of amounts of the optional elements may be 0%.


Mg: 0.0001% to 0.01%


REM: 0.0001% to 0.1%


Ca: 0.0001% to 0.01%


Ma (magnesium), REM (Rare Earth Metal), and Ca (calcium) are the optional elements which are important to control inclusions to be harmless shapes and to improve the local deformability of the steel sheet. Accordingly, as necessary, at least one of Mg, REM, and Ca may be added to the steel. In order to obtain the effects, preferably, Mg content may be 0.0001% or more, REM content may be 0.0001% or more, and Ca content may be 0.0001% or more. More preferably, the Mg content may be 0.0005% or more, the REM content may be 0.001% or more, and the Ca content may be 0.0005% or more. On the other hand, when the optional elements are excessively added to the steel, inclusions having stretched shapes may be formed, and the deformability of the steel sheet may be decreased. Accordingly, preferably, the Mg content may be 0.01% or less, the REM content may be 0.1% or less, and the Ca content may be 0.01% or less. Moreover, even when the optional elements having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. Moreover, since it is not necessary to add the optional elements to the steel intentionally in order to reduce costs of alloy, lower limits of amounts of the optional elements may be 0%.


In addition, here, the REM represents collectively a total of 16 elements which are 15 elements from lanthanum with atomic number 57 to lutetium with atomic number 71 in addition to scandium with atomic number 21. In general, REM is supplied in the state of misch metal which is a mixture of the elements, and is added to the steel.


Mo: 0.001% to 1.0%


Cr: 0.001% to 2.0%


Ni: 0.001% to 2.0%


W: 0.001% to 1.0%


Zr: 0.0001% to 0.2%


As: 0.0001% to 0.5%


Mo (molybdenum), Cr (chromium), Ni (nickel), W (tungsten), Zr (zirconium), and As (arsenic) are the optional elements which increase the mechanical strength of the steel sheet. Accordingly, as necessary, at least one of Mo, Cr, Ni, W, Zr, and As may be added to the steel. In order to obtain the effects, preferably, Mo content may be 0.001% or more, Cr content may be 0.001% or more, Ni content may be 0.001% or more, W content may be 0.001% or more, Zr content may be 0.0001% or more, and As content may be 0.0001% or more. More preferably, the Mo content may be 0.01% or more, Cr content may be 0.01% or more, Ni content may be 0.05% or more, and W content is 0.01% or more. However, when the optional elements are excessively added to the steel, the deformability of the steel sheet may be decreased. Accordingly, preferably, the Mo content may be 1.0% or less, the Cr content may be 2.0% or less, the Ni content may be 2.0% or less, the W content may be 1.0% or less, the Zr content may be 0.2% or less, and the As content may be 0.5% or less. More preferably, the Zr content may be 0.05% or less. Moreover, even when the optional elements having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. Moreover, since it is not necessary to add the optional elements to the steel intentionally in order to reduce costs of alloy, lower limits of amounts of the optional elements may be 0%.


V: 0.001% 1.0%


Cu: 0.001% to 2.0%


V (vanadium) and Cu (copper) are the optional elements which is similar to Nb, Ti, or the like and which have the effect of the precipitation strengthening. In addition, a decrease in the local deformability due to addition of V and Cu is small as compared with that of addition of Nb, Ti, or the like. Accordingly, in order to obtain the high-strength and to further increase the local deformability such as the hole expansibility or the bendability, V and Cu are more effective optional elements than Nb, Ti, or the like. Therefore, as necessary, at least one of V and Cu may be added to the steel. In order to obtain the effects, preferably, V content may be 0.001% or more and Cu content may be 0.001% or more. More preferably, the contents of both optional elements may be 0.01% or more. However, the optional elements are excessively added to the steel, the deformability of the steel sheet may be decreased. Accordingly, preferably, the V content may be 1.0% or less and the Cu content may be 2.0% or less. More preferably, the V content may be 0.5% or less. Moreover, even when the optional elements having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. In addition, since it is not necessary to add the optional elements to the steel intentionally in order to reduce costs of alloy, lower limits of amounts of the optional elements may be 0%.


Co: 0.0001% to 1.0%


Although it is difficult to quantitatively show the effects, Co (cobalt) is the optional element which significantly increases the temperature Ar3 at which the transformation starts from γ (austenite) to α (ferrite) at the cooling of the steel. Accordingly, Ar3 of the steel may be controlled by the Co content. In addition, Co is the optional element which improves the strength of the steel sheet. In order to obtain the effect, preferably, the Co content may be 0.0001% or more. More preferably, the Co content may be 0.001% or more. However, when Co is excessively added to the steel, the weldability of the steel sheet may deteriorate, and the deformability of the steel sheet may be decreased. Accordingly, preferably, the Co content may be 1.0% or less. More preferably, the Co content may be 0.1% or less. Moreover, even when the optional element having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. In addition, since it is not necessary to add the optional element to the steel intentionally in order to reduce costs of alloy, a lower limit of an amount of the optional element may be 0%.


Sn: 0.0001% to 0.2%


Pb: 0.0001% to 0.2%


Sn (tin) and Pb (lead) are the optional elements which are effective in an improvement of coating wettability and coating adhesion. Accordingly, as necessary, at least one of Sn and Pb may be added to the steel. In order to obtain the effects, preferably, Sn content may be 0.0001% or more and Pb content may be 0.0001% or more. More preferably, the Sn content may be 0.001% or more. However, when the optional elements are excessively added to the steel, the cracks may occur during the hot working due to high-temperature embrittlement, and surface dents tend to be made on the steel sheet. Accordingly, preferably, the Sn content may be 0.2% or less and the Pb content may be 0.2% or less. More preferably, the contents of both optional elements may be 0.1% or less. Moreover, even when the optional elements having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. In addition, since it is not necessary to add the optional elements to the steel intentionally in order to reduce costs of alloy, lower limits of amounts of the optional elements may be 0%.


Y: 0.0001% to 0.2%


Hf: 0.0001% to 0.2%


Y (yttrium) and Hf (hafnium) are the optional elements which are effective in an improvement of corrosion resistance of the steel sheet. Accordingly, as necessary, at least one of Y and Hf may be added to the steel. In order to obtain the effect, preferably, Y content may be 0.0001% or more and Hf content may be 0.0001% or more. However, when the optional elements are excessively added to the steel, the local deformability such as the hole expansibility may be decreased. Accordingly, preferably, the Y content may be 0.20% or less and the Hf content may be 0.20% or less. Moreover, Y has the effect which forms oxides in the steel and which adsorbs hydrogen in the steel. Accordingly, diffusible hydrogen in the steel is decreased, and an improvement in hydrogen embrittlement resistance properties in the steel sheet can be expected. The effect can be also obtained within the above-described range of the Y content. More preferably, the contents of both optional elements may be 0.1% or less. Moreover, even when the optional elements having the amount less than the lower limit are included in the steel, the effects in the embodiment are not decreased. In addition, since it is not necessary to add the optional elements to the steel intentionally in order to reduce costs of alloy, lower limits of amounts of the optional elements may be 0%.


As described above, the cold-rolled steel sheet according to the embodiment has the chemical composition which includes the above-described base elements and the balance consisting of Fe and unavoidable impurities, or has the chemical composition which includes the above-described base elements, at least one selected from the group consisting of the above-described optional elements, and the balance consisting of Fe and unavoidable impurities.


Moreover, surface treatment may be conducted on the cold-rolled steel sheet according to the embodiment. For example, the surface treatment such as electro coating, hot dip coating, evaporation coating, alloying treatment after coating, organic film formation, film laminating, organic salt and inorganic salt treatment, or non-chrome treatment (non-chromate treatment) may be applied, and thus, the cold-rolled steel sheet may include various kinds of the film (film or coating). For example, a galvanized layer or a galvannealed layer may be arranged on the surface of the cold-rolled steel sheet. Even if the cold-rolled steel sheet includes the above-described coating, the steel sheet can obtain the high-strength and can sufficiently secure the uniform deformability and the local deformability.


Moreover, in the embodiment, a thickness of the cold-rolled steel sheet is not particularly limited. However, for example, the thickness may be 1.5 mm to 10 mm, and may be 2.0 mm to 10 mm. Moreover, the strength of the cold-rolled steel sheet is not particularly limited, and for example, the tensile strength may be 440 MPa to 1500 MPa.


The cold-rolled steel sheet according to the embodiment can be applied to general use for the high-strength steel sheet, and has the excellent uniform deformability and the remarkably improved local deformability such as the bending workability or the hole expansibility of the high-strength steel sheet.


Next, a method for producing the cold-rolled steel sheet according to an embodiment of the present invention will be described. In order to produce the cold-rolled steel sheet which has the high-strength, the excellent uniform deformability, and the excellent local deformability, it is important to control the chemical composition of the steel, the metallographic structure, and the texture which is represented by the pole densities of each orientation of a specific crystal orientation group. The details will be described below.


The production process prior to the hot-rolling is not particularly limited. For example, the steel (molten steel) may be obtained by conducting a smelting and a refining using a blast furnace, an electric furnace, a converter, or the like, and subsequently, by conducting various kinds of secondary refining, in order to melt the steel satisfying the chemical composition. Thereafter, in order to obtain a steel piece or a slab from the steel, for example, the steel can be cast by a casting process such as a continuous casting process, an ingot making process, or a thin slab casting process in general. In the case of the continuous casting, the steel may be subjected to the hot-rolling after the steel is cooled once to a lower temperature (for example, room temperature) and is reheated, or the steel (cast slab) may be continuously subjected to the hot-rolling just after the steel is cast. In addition, scrap may be used for a raw material of the steel (molten steel).


In order to obtain the high-strength steel sheet which has the high-strength, the excellent uniform deformability, and the excellent local deformability, the following conditions may be satisfied. Moreover, hereinafter, the “steel” and the “steel sheet” are synonymous.


First-Hot-Rolling Process


In the first-hot-rolling process, using the molten and cast steel piece, a rolling pass whose reduction is 40% or more is conducted at least once in a temperature range of 1000° C. to 1200° C. (preferably, 1150° C. or lower). By conducting the first-hot-rolling under the conditions, the average grain size of the austenite of the steel sheet after the first-hot-rolling process is controlled to 200 μm or less, which contributes to the improvement in the uniform deformability and the local deformability of the finally obtained cold-rolled steel sheet.


The austenite grains are refined with an increase in the reduction and an increase in the frequency of the rolling. For example, in the first-hot-rolling process, by conducting at least two times (two passes) of the rolling whose reduction is 40% or more per one pass, the average grain size of the austenite may be preferably controlled to 100 μm or less. In addition, in the first-hot-rolling, by limiting the reduction to 70% or less per one pass, or by limiting the frequency of the rolling (the number of times of passes) to 10 times or less, a temperature fall of the steel sheet or excessive formation of scales may can be decreased. Accordingly, in the rough rolling, the reduction per one pass may be 70% or less, and the frequency of the rolling (the number of times of passes) may be 10 times or less.


As described above, by refining the austenite grains after the first-hot-rolling process, it is preferable that the austenite grains can be further refined by the post processes, and the ferrite, the bainite, and the martensite transformed from the austenite at the post processes may be finely and uniformly dispersed. Moreover, the above is one of the conditions in order to control the Lankford-value such as rC or r30. As a result, the anisotropy and the local deformability of the steel sheet are improved due to the fact that the texture is controlled, and the uniform deformability and the local deformability (particularly, uniform deformability) of the steel sheet are improved due to the fact that the metallographic structure is refined. Moreover, it seems that the grain boundary of the austenite refined by the first-hot-rolling process acts as one of recrystallization nuclei during a second-hot-rolling process which is the post process.


In order to inspect the average grain size of the austenite after the first-hot-rolling process, it is preferable that the steel sheet after the first-hot-rolling process is rapidly cooled at a cooling rate as fast as possible. For example, the steel sheet is cooled under the average cooling rate of 10° C./second or faster. Subsequently, the cross-section of the sheet piece which is taken from the steel sheet obtained by the cooling is etched in order to make the austenite grain boundary visible, and the austenite grain boundary in the microstructure is observed by an optical microscope. At the time, visual fields of 20 or more are observed at a magnification of 50-fold or more, the grain size of the austenite is measured by the image analysis or the intercept method, and the average grain size of the austenite is obtained by averaging the austenite grain sizes measured at each of the visual fields.


After the first-hot-rolling process, sheet bars may be joined, and the second-hot-rolling process which is the post process may be continuously conducted. At the time, the sheet bars may be joined after a rough bar is temporarily coiled in a coil shape, stored in a cover having a heater as necessary, and recoiled again.


Second-Hot-Rolling Process


As the second-hot-rolling process, when a temperature calculated by a following Expression 4 is defined as T1 in unit of ° C., the steel sheet after the first-hot-rolling process is subjected to a rolling under conditions such that, a large reduction pass whose reduction is 30% or more in a temperature range of T1+30° C. to T1+200° C. is included, a cumulative reduction in the temperature range of T1+30° C. to T1+200° C. is 50% or more, a cumulative reduction in a temperature range of Ar3° C. to lower than T1+30° C. is limited to 30% or less, and a rolling finish temperature is Ar3° C. or higher.


As one of the conditions in order to control the average pole density D1 of the orientation group of {100}<011> to {223}<110> and the pole density D2 of the crystal orientation {332}<113> in the thickness central portion which is the thickness range of ⅝ to ⅜ to the above-described ranges, in the second-hot-rolling process, the rolling is controlled based on the temperature T1 (unit: ° C.) which is determined by the following Expression 4 using the chemical composition (unit: mass %) of the steel.

T1=850+10×([C]+[N])×[Mn]+350×[Nb]+250×[Ti]+40×[B]+10×[Cr]+100×[Mo]+100×[V]  (Expression 4)


In Expression 4, [C], [N], [Mn], [Nb], [Ti], [B], [Cr], [Mo], and [V] represent mass percentages of C, N, Mn, Nb, Ti, B, Cr, Mo, and V respectively.


The amount of the chemical element, which is included in Expression 4 but is not included in the steel, is regarded as 0% for the calculation. Accordingly, in the case of the chemical composition in which the steel includes only the base elements, a following Expression 5 may be used instead of the Expression 4.

T1=850+10×([C]+[N])×[Mn]  (Expression 5)


In addition, in the chemical composition in which the steel includes the optional elements, the temperature calculated by Expression 4 may be used for T1 (unit: ° C.), instead of the temperature calculated by Expression 5.


In the second-hot-rolling process, on the basis of the temperature T1 (unit: ° C.) obtained by the Expression 4 or 5, the large reduction is included in the temperature range of T1+30° C. to T1+200° C. (preferably, in a temperature range of T1+50° C. to T1+100° C.), and the reduction is limited to a small range (includes 0%) in the temperature range of Ar3° C. to lower than T1+30° C. By conducting the second-hot-rolling process in addition to the first-hot-rolling process, the uniform deformability and the local deformability of the steel sheet is preferably improved. Particularly, by including the large reduction in the temperature range of T1+30° C. to T1+200° C. and by limiting the reduction in the temperature range of Ar3° C. to lower than T1+30° C., the average pole density D1 of the orientation group of 11001<011> to {223}<110> and the pole density D2 of the crystal orientation {332}<113> in the thickness central portion which is the thickness range of ⅝ to ⅜ are sufficiently controlled, and as a result, the anisotropy and the local deformability of the steel sheet are remarkably improved.


The temperature T1 itself is empirically obtained. It is empirically found by the inventors through experiments that the temperature range in which the recrystallization in the austenite range of each steels is promoted can be determined based on the temperature T1. In order to obtain the excellent uniform deformability and the excellent local deformability, it is important to accumulate a large amount of the strain by the rolling and to obtain the fine recrystallized grains. Accordingly, the rolling having plural passes is conducted in the temperature range of T1+30° C. to T1+200° C., and the cumulative reduction is to be 50% or more. Moreover, in order to further promote the recrystallization by the strain accumulation, it is preferable that the cumulative reduction is 70% or more. Moreover, by limiting an upper limit of the cumulative reduction, a rolling temperature can be sufficiently held, and a rolling load can be further suppressed. Accordingly, the cumulative reduction may be 90% or less.


When the rolling having the plural passes is conducted in the temperature range of T1+30° C. to T1+200° C., the strain is accumulated by the rolling, and the recrystallization of the austenite is occurred at an interval between the rolling passes by a driving force derived from the accumulated strain. Specifically, by conducting the rolling having the plural passes in the temperature range of T1+30° C. to T1+200° C., the recrystallization is repeatedly occurred every pass. Accordingly, it is possible to obtain the recrystallized austenite structure which is uniform, fine, and equiaxial. In the temperature range, dynamic recrystallization is not occurred during the rolling, the strain is accumulated in the crystal, and static recrystallization is occurred at the interval between the rolling passes by the driving force derived from the accumulated strain. In general, in dynamic-recrystallized structure, the strain which introduced during the working is accumulated in the crystal thereof, and a recrystallized area and a non-crystallized area are locally mixed. Accordingly, the texture is comparatively developed, and thus, the anisotropy appears. Moreover, the metallographic structures may be a duplex grain structure. In the method for producing the cold-rolled steel sheet according to the embodiment, the austenite is recrystallized by the static recrystallization. Accordingly, it is possible to obtain the recrystallized austenite structure which is uniform, fine, and equiaxial, and in which the development of the texture is suppressed.


In order to increase the homogeneity, and to preferably increase the uniform deformability and the local deformability of the steel sheet, the second-hot-rolling is controlled so as to include at least one large reduction pass whose reduction per one pass is 30% or more in the temperature range of T1+30° C. to T1+200° C. In the second-hot-rolling, in the temperature range of T1+30° C. to T1+200° C., the rolling whose reduction per one pass is 30% or more is conducted at least once. Particularly, considering a cooling process as described below, the reduction of a final pass' in the temperature range may be preferably 25% or more, and may be more preferably 30% or more. Specifically, it is preferable that the final pass in the temperature range is the large reduction pass (the rolling pass with the reduction of 30% or more). In a case that the further excellent deformability is required in the steel sheet, it is further preferable that all reduction of first half passes are less than 30% and the reductions of the final two passes are individually 30% or more. In order to more preferably increase the homogeneity of the steel sheet, a large reduction pass whose reduction per one pass is 40% or more may be conducted. Moreover, in order to obtain a more excellent shape of the steel sheet, a large reduction pass whose reduction per one pass is 70% or less may be conducted.


Moreover, as one of conditions in order that the rL and the r60 satisfy respectively rL≧0.70 and r60≦1.50, for example, it is preferable that a temperature rise of the steel sheet between passes of the rolling in the temperature range of T1+30° C. to T1+200° C. is suppressed to 18° C. or lower, in addition to an appropriately control of a waiting time t as described below. Moreover, by the above, it is possible to preferably obtain the recrystallized austenite which is more uniform.


In order to suppress the development of the texture and to keep the equiaxial recrystallized structure, after the rolling in the temperature range of T1+30° C. to T1+200° C., an amount of working in the temperature range of Ar3° C. to lower than T1+30° C. (preferably, T1 to lower than T1+30° C.) is suppressed as small as possible. Accordingly, the cumulative reduction in the temperature range of Ar3° C. to lower than T1+30° C. is limited to 30% or less. In the temperature range, it is preferable that the cumulative reduction is 10% or more in order to obtain the excellent shape of the steel sheet, and it is preferable that the cumulative reduction is 10% or less in order to further improve the anisotropy and the local deformability. In the case, the cumulative reduction may be more preferably 0%. Specifically, in the temperature range of Ar3° C. to lower than T1+30° C., the rolling may not be conducted, and the cumulative reduction is to be 30% or less even when the rolling is conducted.


When the cumulative reduction in the temperature range of Ar3° C. to lower than T1+30° C. is large, the shape of the austenite grain recrystallized in the temperature range of T1+30° C. to T1+200° C. is not to be equiaxial due to the fact that the grain is stretched by the rolling, and the texture is developed again due to the fact that the strain is accumulated by the rolling. Specifically, as the production conditions according to the embodiment, the rolling is controlled at both of the temperature range of T1+30° C. to T1+200° C. and the temperature range of Ar3° C. to lower than T1+30° C. in the second-hot-rolling process. As a result, the austenite is recrystallized so as to be uniform, fine, and equiaxial, the texture, the metallographic structure, and the anisotropy of the steel sheet are controlled, and therefore, the uniform deformability and the local deformability can be improved. In addition, the austenite is recrystallized so as to be uniform, fine, and equiaxial, and therefore, the metallographic structure, the texture, the Lankford-value, or the like of the finally obtained cold-rolled steel sheet can be controlled.


In the second-hot-rolling process, when the rolling is conducted in the temperature range lower than Ar3° C. or the cumulative reduction in the temperature range of Ar3° C. to lower than T1+30° C. is excessive large, the texture of the austenite is developed. As a result, the finally obtained cold-rolled steel sheet does not satisfy at least one of the condition in which the average pole density D1 of the orientation group of {100}<011> to {223}<110> is 1.0 to 5.0 and the condition in which the pole density D2 of the crystal orientation {332}<113> is 1.0 to 4.0 in the thickness central portion. On the other hand, in the second-hot-rolling process, when the rolling is conducted in the temperature range higher than T1+200° C. or the cumulative reduction in the temperature range of T1+30° C. to T1+200° C. is excessive small, the recrystallization is not uniformly and finely occurred, coarse grains or mixed grains may be included in the metallographic structure, and the metallographic structure may be the duplex grain structure. Accordingly, the area fraction or the volume average diameter of the grains which is more than 35 μm is increased.


Moreover, when the second-hot-rolling is finished at a temperature lower than Ar3 (unit: ° C.), the steel is rolled in a temperature range of the rolling finish temperature to lower than Ar3 (unit: ° C.) which is a range where two phases of the austenite and the ferrite exist (two-phase temperature range). Accordingly, the texture of the steel sheet is developed, and the anisotropy and the local deformability of the steel sheet significantly deteriorate. Here, when the rolling finish temperature of the second-hot-rolling is T1 or more, the anisotropy may be further decreased by decreasing an amount of the strain in the temperature range lower than T1, and as a result, the local deformability may be further increased. Therefore, the rolling finish temperature of the second-hot-rolling may be T1 or more.


Here, the reduction can be obtained by measurements or calculations from a rolling force, a thickness, or the like. Moreover, the rolling temperature (for example, the above each temperature range) can be obtained by measurements using a thermometer between stands, by calculations using a simulation in consideration of deformation heating, line speed, the reduction, or the like, or by both (measurements and calculations). Moreover, the above reduction per one pass is a percentage of a reduced thickness per one pass (a difference between an inlet thickness before passing a rolling stand and an outlet thickness after passing the rolling stand) to the inlet thickness before passing the rolling stand. The cumulative reduction is a percentage of a cumulatively reduced thickness (a difference between an inlet thickness before a first pass in the rolling in each temperature range and an outlet thickness after a final pass in the rolling in each temperature range) to the reference which is the inlet thickness before the first pass in the rolling in each temperature range. Ar3, which is a ferritic transformation temperature from the austenite during the cooling, is obtained by a following Expression 6 in unit of ° C. Moreover, although it is difficult to quantitatively show the effects as described above, Al and Co also influence Ar3.

Ar3=879.4−516.1×[C]−65.7×[Mn]+38.0×[Si]+274.7×[P]   (Expression 6)


In the Expression 6, [C], [Mn], [Si] and [P] represent mass percentages of C, Mn, Si and P respectively.


First-Cooling Process


In the first-cooling process, after a final pass among the large reduction passes whose reduction per one pass is 30% or more in the temperature range of T1+30° C. to T1+200° C. is finished, when a waiting time from the finish of the final pass to a start of the cooling is defined as t in unit of second, the steel sheet is subjected to the cooling so that the waiting time t satisfies a following Expression 7. Here, t1 in the Expression 7 can be obtained from a following Expression 8. In the Expression 8, Tf represents a temperature (unit: ° C.) of the steel sheet at the finish of the final pass among the large reduction passes, and P1 represents a reduction (unit: %) at the final pass among the large reduction passes.

t≦2.5×t1  (Expression 7)
t1=0.001×((Tf−T1)×P1/100)2−0.109×((Tf−T1)×P1/100)+3.1   (Expression 8)


The first-cooling after the final large reduction pass significantly influences the grain size of the finally obtained cold-rolled steel sheet. Moreover, by the first-cooling, the austenite can be controlled to be a metallographic structure in which the grains are equiaxial and the coarse grains rarely are included (namely, uniform sizes). Accordingly, the finally obtained cold-rolled steel sheet has the metallographic structure in which the grains are equiaxial and the coarse grains rarely are included (namely, uniform sizes), and the texture, the Lankford-value, or the like can be controlled. In addition, the ratio of the major axis to the minor axis of the martensite, the average size of the martensite, the average distance between the martensite, and the like may be preferably controlled.


The right side value (2.5×t1) of the Expression 7 represents a time at which the recrystallization of the austenite is substantially finished. When the waiting time t is more than the right side value (2.5×t1) of the Expression 7, the recrystallized grains are significantly grown, and the grain size is increased. Accordingly, the strength, the uniform deformability, the local deformability, the fatigue properties, or the like of the steel sheet are decreased. Therefore, the waiting time t is to be 2.5×t1 seconds or less. In a case where runnability (for example, shape straightening or controllability of a second-cooling) is considered, the first-cooling may be conducted between rolling stands. Moreover, a lower limit of the waiting time t is to be 0 seconds or more.


Moreover, when the waiting time t is limited to 0 second to shorter than t1 seconds so that 0≦t<t1 is satisfied, it may be possible to significantly suppress the grain growth. In the case, the volume average diameter of the finally obtained cold-rolled steel sheet may be controlled to 30 μm or less. As a result, even if the recrystallization of the austenite does not sufficiently progress, the properties of the steel sheet, particularly, the uniform deformability, the fatigue properties, or the like may be preferably improved.


Moreover, when the waiting time t is limited to t1 seconds to 2.5×t1 seconds so that t1≦t≦2.5×t1 is satisfied, it may be possible to suppress the development of the texture. In the case, although the volume average diameter may be increased because the waiting time t is prolonged as compared with the case where the waiting time t is shorter than t1 seconds, the crystal orientation may be randomized because the recrystallization of the austenite sufficiently progresses. As a result, the r value, the anisotropy, the local deformability, or the like of the steel sheet may be preferably improved.


Moreover, the above-described first-cooling may be conducted at an interval between the rolling stands in the temperature range of T1+30° C. to T1+200° C., or may be conducted after a final rolling stand in the temperature range. Specifically, as long as the waiting time t satisfies the condition, a rolling whose reduction per one pass is 30% or less may be further conducted in the temperature range of T1+30° C. to T1+200° C. and between the finish of the final pass among the large reduction passes and the start of the first-cooling. Moreover, after the first-cooling is conducted, as long as the reduction per one pass is 30% or less, the rolling may be further conducted in the temperature range of T1+30° C. to T1+200° C. Similarly, after the first-cooling is conducted, as long as the cumulative reduction is 30% or less, the rolling may be further conducted in the temperature range of Ar3° C. to T1+30° C. (or Ar3° C. to Tf ° C.). As described above, as long as the waiting time t after the large reduction pass satisfies the condition, in order to control the metallographic structure of the finally obtained hot-rolled steel sheet, the above-described first-cooling may be conducted either at the interval between the rolling stands or after the rolling stand.


In the first-cooling, it is preferable that a cooling temperature change which is a difference between a steel sheet temperature (steel temperature) at the cooling start and a steel sheet temperature (steel temperature) at the cooling finish is 40° C. to 140° C. When the cooling temperature change is 40° C. or higher, the growth of the recrystallized austenite grains may be further suppressed. When the cooling temperature change is 140° C. or lower, the recrystallization may more sufficiently progress, and the pole density may be preferably improved. Moreover, by limiting the cooling temperature change to 140° C. or lower, in addition to the comparatively easy control of the temperature of the steel sheet, variant selection (variant limitation) may be more effectively controlled, and the development of the recrystallized texture may be preferably controlled. Accordingly, in the case, the isotropy may be further increased, and the orientation dependence of the formability may be further decreased. When the cooling temperature change is higher than 140° C., the progress of the recrystallization may be insufficient, the intended texture may not be obtained, the ferrite may not be easily obtained, and the hardness of the obtained ferrite is increased. Accordingly, the uniform deformability and the local deformability of the steel sheet may be decreased.


Moreover, it is preferable that the steel sheet temperature T2 at the first-cooling finish is T1+100° C. or lower. When the steel sheet temperature T2 at the first-cooling finish is T1+100° C. or lower, more sufficient cooling effects are obtained. By the cooling effects, the grain growth may be suppressed, and the growth of the austenite grains may be further suppressed.


Moreover, it is preferable that an average cooling rate in the first-cooling is 50° C./second or faster. When the average cooling rate in the first-cooling is 5.0° C./second or faster, the growth of the recrystallized austenite grains may be further suppressed. On the other hand, it is not particularly necessary to prescribe an upper limit of the average cooling rate. However, from a viewpoint of the sheet shape, the average cooling rate may be 200° C./second or slower.


Second-Cooling Process


In the second-cooling process, the steel sheet after the second-hot-rolling and after the first-cooling process is cooled to a temperature range of the room temperature to 600° C. Preferably, the steel sheet may be cooled to the temperature range of the room temperature to 600° C. under the average cooling rate of 10° C./second to 300° C./second. When a second-cooling stop temperature is 600° C. or higher or the average cooling rate is 10° C./second or slower, the surface qualities may deteriorate due to surface oxidation of the steel sheet. Moreover, the anisotropy of the cold-rolled steel sheet may be increased, and the local deformability may be significantly decreased. The reason why the steel sheet is cooled under the average cooling rate of 300° C./second or slower is the following. When the steel sheet is cooled under the average cooling rate of faster than 300° C./second, the martensite transformation may be promoted, the strength may be significantly increased, and the cold-rolling may not be easily conducted. Moreover, it is not particularly necessary to prescribe a lower limit of the cooling stop temperature of the second-cooling process. However, in a case where water cooling is conducted, the lower limit may be the room temperature. In addition, it is preferable to start the second-cooling within 3 seconds after finishing the second-hot-rolling or after the first-cooling process. When the second-cooling start exceeds 3 seconds, coarsening of the austenite may occur.


Coiling Process


In the coiling process, after the hot-rolled steel sheet is obtained as described above, the steel sheet is coiled in the temperature range of the room temperature to 600° C. When the steel sheet is coiled at the temperature of 600° C. or higher, the anisotropy of the steel sheet after the cold-rolling may be increased, and the local deformability may be significantly decreased. The steel sheet after the coiling process has the metallographic structure which is uniform, fine, and equiaxial, the texture which is random orientation, and the excellent Lankford-value. By producing the cold-rolled steel sheet using the steel sheet, it is possible to obtain the cold-rolled steel sheet which simultaneously has the high-strength, the excellent uniform deformability, the excellent local deformability, and the excellent Lankford-value. Moreover, the metallographic structure of the steel sheet after the coiling process mainly includes the ferrite, the bainite, the martensite, the residual austenite, or the like.


Pickling Process


In the pickling process, in order to remove surface scales of the steel sheet after the coiling process, the pickling is conducted. A pickling method is not particularly limited, and a general pickling method such as sulfuric acid, or nitric acid may be applied.


Cold-Rolling Process


In the cold-rolling process, the steel sheet after the pickling process is subjected to the cold-rolling in which the cumulative reduction is 30% to 70%. When the cumulative reduction is 30% or less, in a heating-and-holding (annealing) process which is the post process, the recrystallization is hardly occurred, the area fraction of the equiaxial grains is decreased, and the grains after the annealing are coarsened. When the cumulative reduction is 70% or more, in the heating-and-holding (annealing) process which is the post process, the texture is developed, the anisotropy of the steel sheet is increased, and the local deformability or the Lankford-value deteriorates.


After the cold-rolling process, a skin pass rolling may be conducted as necessary. By the skin pass rolling, it may be possible to suppress a stretcher strain which is formed during working of the steel sheet, or to straighten the shape of the steel sheet.


Heating-And-Holding (Annealing) Process


In the heating-and-holding (annealing) process, the steel sheet after the cold-rolling process is subjected to the heating-and-holding in a temperature range of 750° C. to 900° C. for 1 second to 1000 seconds. When the heating-and-holding of lower than 750° C. or shorter than 1 second is conducted, a reverse transformation from the ferrite to the austenite does not sufficiently progress, and the martensite which is the secondary phase cannot be obtained in the cooling process which is the post process. Accordingly, the strength and the uniform deformability of the cold-rolled steel sheet are decreased. On the other hand, when the heating-and-holding of higher than 900° C. or longer than 1000 seconds is conducted, the austenite grains are coarsened. Therefore, the area fraction of the coarse grains of the cold-rolled steel sheet is increased.


Third-Cooling Process


In the third-cooling process, the steel sheet after the heating-and-holding (annealing) process is cooled to a temperature range of 580° C. to 720° C. under an average cooling rate of 1° C./second to 12° C./second. When the average cooling rate is slower than 1° C./second or the third-cooling is finished at a temperature lower than 580° C./second, the ferritic transformation may be excessively promoted, and the intended area fractions of the bainite and the martensite may not be obtained. Moreover, the pearlite may be excessively formed. When the average cooling rate is faster than 12° C./second or the third-cooling is finished at a temperature higher than 720° C., the ferritic transformation may be insufficient. Accordingly, the area fraction of the martensite of the finally obtained cold-rolled steel sheet may be more than 70%. By decreasing the average cooling rate and decreasing the cooling stop temperature within the above-described range, the area fraction of the ferrite can be preferably increased.


Fourth-Cooling Process


In the fourth-cooling process, the steel sheet after the third-cooling process is cooled to a temperature range of 200° C. to 600° C. under an average cooling rate of 4° C./second to 300° C./second. When the average cooling rate is slower than 4° C./second or the fourth-cooling is finished at a temperature higher than 600° C./second, a large amount of the pearlite may be formed, and the martensite of 1% or more in unit of area % may not be finally obtained. When the average cooling rate is faster than 300° C./second or the fourth-cooling is finished at a temperature lower than 200° C., the area fraction of the martensite may be more than 70%. By decreasing the average cooling rate within the above-described range of the average cooling rate, the area fraction of the bainite may be increased. On the other hand, by increasing the average cooling rate within the above-described range of the average cooling rate, the area fraction of the martensite may be increased. In addition, the grain size of the bainite is also refined.


Overageing Treatment Process


In the overageing treatment, when an overageing temperature is defined as T2 in unit of ° C. and an overageing holding time dependent on the overageing temperature T2 is defined as t2 in unit of second, the steel sheet after the fourth-cooling process is held so that the overageing temperature T2 is within a temperature range of 200° C. to 600° C. and the overageing holding time t2 satisfies a following Expression 9. As a result of investigation in detail by the inventors, it is found that the balance between the strength and the ductility (deformability) of the finally obtained cold-rolled steel sheet is improved when the following Expression 9 is satisfied. The reason seems to relate to a rate of bainitic transformation. Moreover, when the Expression 9 is satisfied, the area fraction of the martensite may be preferably controlled to 1% to 70%. Moreover, the Expression 9 is a common logarithm to the base 10.

log(t2)≦0.0002×(T2−425)2+1.18  (Expression 9)


In accordance with properties required for the cold-rolled steel sheet, the area fractions of the ferrite and the bainite which are the primary phase may be controlled, and the area fraction of the martensite which is the second phase may be controlled. As described above, the ferrite can be mainly controlled in the third-cooling process, and the bainite and the martensite can be mainly controlled in the fourth-cooling process and in the overageing treatment process. In addition, the grain sizes or the morphologies of the ferrite and the bainite which are the primary phase and of the martensite which is the secondary phase significantly depend on the grain size or the morphology of the austenite at the hot-rolling. Moreover, the grain sizes or the morphologies also depend on the processes after the cold-rolling process. Accordingly, for example, the value of TS/fM×dis/dia, which is the relationship of the area fraction fM of the martensite, the average size dia of the martensite, the average distance dis between the martensite, and the tensile strength TS of the steel sheet, may be satisfied by multiply controlling the above-described production processes.


After the overageing treatment process, as necessary, the steel sheet may be coiled. As described above, the cold-rolled steel sheet according to the embodiment can be produced.


Since the cold-rolled steel sheet produced as described above has the metallographic structure which is uniform, fine, and equiaxial and has the texture which is the random orientation, the cold-rolled steel sheet simultaneously has the high-strength, the excellent uniform deformability, the excellent local deformability, and the excellent Lankford-value.


As necessary, the steel sheet after the overageing treatment process may be subjected to a galvanizing. Even if the galvanizing is conducted, the uniform deformability and the local deformability of the cold-rolled steel sheet are sufficiently maintained.


In addition, as necessary, as an alloying treatment, the steel sheet after the galvanizing may be subjected to a heat treatment in a temperature range of 450° C. to 600° C. The reason why the alloying treatment is conducted in the temperature range of 450° C. to 600° C. is the following. When the alloying treatment is conducted at a temperature lower than 450° C., the alloying may be insufficient. Moreover, when the alloying treatment is conducted at a temperature higher than 600° C., the alloying may be excessive, and the corrosion resistance deteriorates.


Moreover, the obtained cold-rolled steel sheet may be subjected to a surface treatment. For example, the surface treatment such as the electro coating, the evaporation coating, the alloying treatment after the coating, the organic film formation, the film laminating, the organic salt and inorganic salt treatment, or the non-chromate treatment may be applied to the obtained cold-rolled steel sheet. Even if the surface treatment is conducted, the uniform deformability and the local deformability are sufficiently maintained.


Moreover, as necessary, a tempering treatment may be conducted as a reheating treatment. By the treatment, the martensite may be softened as the tempered martensite. As a result, the hardness difference between the ferrite and the bainite which are the primary phase and the martensite which is the secondary phase is decreased, and the local deformability such as the hole expansibility or the bendability is improved. The effects of the reheating treatment may be also obtained by heating for the hot dip coating, the alloying treatment, or the like.


Example

Hereinafter, the technical features of the aspect of the present invention will be described in detail with reference to the following examples. However, the condition in the examples is an example condition employed to confirm the operability and the effects of the present invention, and therefore, the present invention is not limited to the example condition. The present invention can employ various conditions as long as the conditions do not depart from the scope of the present invention and can achieve the object of the present invention.


Steels S1 to S135 including chemical compositions (the balance consists of Fe and unavoidable impurities) shown in Tables 1 to 6 were examined, and the results are described. After the steels were melt and cast, or after the steels were cooled once to the room temperature, the steels were reheated to the temperature range of 900° C. to 1300° C. Thereafter, the hot-rolling, the cold-rolling, and the temperature control (cooling, heating-and-holding, or the like) were conducted under production conditions shown in Tables 7 to 16, and cold-rolled steel sheets having the thicknesses of 2 to 5 mm were obtained.


In Tables 17 to 26, the characteristics such as the metallographic structure, the texture, or the mechanical properties are shown. Moreover, in Tables, the average pole density of the orientation group of {100}<011> to {223}<110> is shown as D1 and the pole density of the crystal orientation {332}<113> is shown as D2. In addition, the area fractions of the ferrite, the bainite, the martensite, the pearlite, and the residual austenite are shown as F, B, fM, P, and γ respectively. Moreover, the average size of the martensite is shown as dia, and the average distance between the martensite is shown as dis. Moreover, in Tables, the standard deviation ratio of hardness represents a value dividing the standard deviation of the hardness by the average of the hardness with respect to the phase having higher area fraction among the ferrite and the bainite.


As a parameter of the local deformability, the hole expansion ratio λ and the critical bend radius (d/RmC) by 90° V-shape bending of the final product were used. The bending test was conducted to C-direction bending. Moreover, the tensile test (measurement of TS, u-EL and EL), the bending test, and the hole expansion test were respectively conducted based on JIS Z 2241, JIS Z 2248 (V block 90° bending test) and Japan Iron and Steel Federation Standard JFS T1001. Moreover, by using the above-described EBSD, the pole densities were measured by a measurement step of 0.5 μm in the thickness central portion which was the range of ⅝ to ⅜ of the thickness-cross-section (the normal vector thereof corresponded to the normal direction) which was parallel to the rolling direction at ¼ position of the transverse direction. Moreover, the r values (Lankford-values) of each direction were measured based on JIS Z 2254 (2008) (ISO 10113 (2006)). Moreover, the underlined value in the Tables indicates out of the range of the present invention, and the blank column indicates that no alloying element was intentionally added.


Production Nos. P1 to P30 and P112 to P214 are the examples which satisfy the conditions of the present invention. In the examples, since all conditions of TS 440 (unit: MPa), TS×u−EL≧7000 (unit: MPa·%), TS×30000 (unit: MPa·%), and d/RmC≧1 (no unit) were simultaneously satisfied, it can be said that the cold-rolled steel sheets have the high-strength, the excellent uniform deformability, and the excellent local deformability.


On the other hand, P31 to P111 are the comparative examples which do not satisfy the conditions of the present invention. In the comparative examples, at least one condition of TS≧440 (unit: MPa), TS×u−EL≧7000 (unit: MPa·%), TS×λ≧30000 (unit: MPa·%), and d/RmC≧1 (no unit) was not satisfied.










TABLE 1







STEEL
CHEMICAL COMPOSITION/mass %






















No.
C
Si
Mn
Al
P
S
N
O
Mo
Cr
Ni
Cu
B
Nb
Ti





S1
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032









S2

0.008

0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S3

0.401

0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S4
0.070

0.0009

1.300
0.040
0.015
0.004
0.0026
0.0032


S5
0.070

2.510

1.300
0.040
0.015
0.004
0.0026
0.0032


S6
0.070
0.080

0.0009

0.040
0.015
0.004
0.0026
0.0032


S7
0.070
0.080

4.010

0.040
0.015
0.004
0.0026
0.0032


S8
0.070
0.080
1.300

0.0009

0.015
0.004
0.0026

0.0110



S9
0.070
0.080
1.300

2.010

0.015
0.004
0.0026
0.0032


S10
0.070
0.080
1.300
0.040

0.151

0.004
0.0026
0.0032


S11
0.070
0.080
1.300
0.040
0.015

0.031

0.0026
0.0032


S12
0.070
0.080
1.300
0.040
0.015
0.004

0.0110

0.0032


S13
0.070
0.080
1.300
0.040
0.015
0.004
0.0026

0.0110



S14
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032

1.010



S15
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


2.010



S16
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032



2.010



S17
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032




2.010



S18
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032





0.0051



S19
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032






0.201



S20
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032







0.201



S21
0.070
0.080
1.300
0.040
0.015
0.004
0.0025
0.0032


S22
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S23
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S24
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S25
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S26
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S27
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S28
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S29
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S30
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S31
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S32
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S33
0.010
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S34
0.030
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S35
0.050
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S36
0.120
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S37
0.180
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S38
0.250
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S39
0.280
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S40
0.300
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S41
0.400
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S42
0.070
0.001
1.300
0.040
0.015
0.004
0.0026
0.0032


S43
0.070
0.050
1.300
0.040
0.015
0.004
0.0026
0.0032


S44
0.070
0.500
1.300
0.040
0.015
0.004
0.0026
0.0032


S45
0.070
1.500
1.300
0.040
0.015
0.004
0.0026
0.0032





























TABLE 2







STEEL















No.
V
W
Ca
Mg
Zr
REM
As
Co
Sn
Pb
Y
Hf
REMARKS





S1












EXAMPLE


S2












COMPARATIVE EXAMPLE


S3












COMPARATIVE EXAMPLE


S4












COMPARATIVE EXAMPLE


S5












COMPARATIVE EXAMPLE


S6












COMPARATIVE EXAMPLE


S7












COMPARATIVE EXAMPLE


S8












COMPARATIVE EXAMPLE


S9












COMPARATIVE EXAMPLE


S10












COMPARATIVE EXAMPLE


S11












COMPARATIVE EXAMPLE


S12












COMPARATIVE EXAMPLE


S13












COMPARATIVE EXAMPLE


S14












COMPARATIVE EXAMPLE


S15












COMPARATIVE EXAMPLE


S16












COMPARATIVE EXAMPLE


S17












COMPARATIVE EXAMPLE


S18












COMPARATIVE EXAMPLE


S19












COMPARATIVE EXAMPLE


S20












COMPARATIVE EXAMPLE


S21

1.010












COMPARATIVE EXAMPLE


S22


1.010











COMPARATIVE EXAMPLE


S23



0.0110










COMPARATIVE EXAMPLE


S24




0.0110









COMPARATIVE EXAMPLE


S25





0.2010








COMPARATIVE EXAMPLE


S26






0.1010







COMPARATIVE EXAMPLE


S27







0.5010






COMPARATIVE EXAMPLE


S28








1.0100





COMPARATIVE EXAMPLE


S29









0.2010




COMPARATIVE EXAMPLE


S30










0.2010



COMPARATIVE EXAMPLE


S31











0.2010


COMPARATIVE EXAMPLE


S32












0.2010

COMPARATIVE EXAMPLE


S33












EXAMPLE


S34












EXAMPLE


S35












EXAMPLE


S36












EXAMPLE


S37












EXAMPLE


S38












EXAMPLE


S39












EXAMPLE


S40












EXAMPLE


S41












EXAMPLE


S42












EXAMPLE


S43












EXAMPLE


S44












EXAMPLE


S45












EXAMPLE



















CALCULATED







VALUE OF



STEEL
T1/
Ar3/
HARDNESS



No.
° C.
° C.
OF FERRITE/—
REMARKS







S1
851
765
234
EXAMPLE



S2
850
797
234
COMPARATIVE EXAMPLE



S3
855
594
234
COMPARATIVE EXAMPLE



S4
851
762
231
COMPARATIVE EXAMPLE



S5
851
857
307
COMPARATIVE EXAMPLE



S6
850
850
206
COMPARATIVE EXAMPLE



S7
853
587
291
COMPARATIVE EXAMPLE



S8
851
765
234
COMPARATIVE EXAMPLE



S9
851
842
234
COMPARATIVE EXAMPLE



S10
851
802
270
COMPARATIVE EXAMPLE



S11
851
765
234
COMPARATIVE EXAMPLE



S12
851
765
234
COMPARATIVE EXAMPLE



S13
851
765
234
COMPARATIVE EXAMPLE



S14
952
765
234
COMPARATIVE EXAMPLE



S15
871
765
234
COMPARATIVE EXAMPLE



S16
851
765
234
COMPARATIVE EXAMPLE



S17
851
765
234
COMPARATIVE EXAMPLE



S18
851
765
234
COMPARATIVE EXAMPLE



S19
921
765
269
COMPARATIVE EXAMPLE



S20
901
765
282
COMPARATIVE EXAMPLE



S21
952
765
234
COMPARATIVE EXAMPLE



S22
851
765
234
COMPARATIVE EXAMPLE



S23
851
765
234
COMPARATIVE EXAMPLE



S24
851
765
234
COMPARATIVE EXAMPLE



S25
851
765
234
COMPARATIVE EXAMPLE



S26
851
765
234
COMPARATIVE EXAMPLE



S27
851
765
234
COMPARATIVE EXAMPLE



S28
851
842
234
COMPARATIVE EXAMPLE



S29
851
765
234
COMPARATIVE EXAMPLE



S30
851
765
234
COMPARATIVE EXAMPLE



S31
851
765
234
COMPARATIVE EXAMPLE



S32
851
765
234
COMPARATIVE EXAMPLE



S33
850
796
234
EXAMPLE



S34
850
786
234
EXAMPLE



S35
851
775
234
EXAMPLE



S36
852
739
234
EXAMPLE



S37
852
708
234
EXAMPLE



S38
853
672
234
EXAMPLE



S39
854
657
234
EXAMPLE



S40
854
646
234
EXAMPLE



S41
855
595
234
EXAMPLE



S42
851
762
231
EXAMPLE



S43
851
764
233
EXAMPLE



S44
851
781
246
EXAMPLE



S45
851
819
276
EXAMPLE


















TABLE 3







STEEL
CHEMICAL COMPOSITION/mass %






















No.
C
Si
Mn
Al
P
S
N
O
Mo
Cr
Ni
Cu
B
Nb
Ti

























S46
0.070
2.500
1.300
0.040
0.015
0.004
0.0026
0.0032









S47
0.070
0.080
0.001
0.040
0.015
0.004
0.0026
0.0032


S48
0.070
0.080
0.050
0.040
0.015
0.004
0.0026
0.0032


S49
0.070
0.080
0.500
0.040
0.015
0.004
0.0026
0.0032


S50
0.070
0.080
1.500
0.040
0.015
0.004
0.0026
0.0032


S51
0.070
0.080
2.500
0.040
0.015
0.004
0.0026
0.0032


S52
0.070
0.080
3.000
0.040
0.015
0.004
0.0026
0.0032


S53
0.070
0.080
3.300
0.040
0.015
0.004
0.0026
0.0032


S54
0.070
0.080
3.500
0.040
0.015
0.004
0.0026
0.0032


S55
0.070
0.080
4.000
0.040
0.015
0.004
0.0026
0.0032


S56
0.070
0.080
1.300
0.001
0.015
0.004
0.0026
0.0032


S57
0.070
0.080
1.300
0.050
0.015
0.004
0.0026
0.0032


S58
0.070
0.080
1.300
0.500
0.015
0.004
0.0026
0.0032


S59
0.070
0.080
1.300
1.500
0.015
0.004
0.0026
0.0032


S60
0.070
0.080
1.300
2.000
0.015
0.004
0.0026
0.0032


S61
0.070
0.080
1.300
0.040
0.0005
0.004
0.0026
0.0032


S62
0.070
0.080
1.300
0.040
0.030
0.004
0.0026
0.0032


S63
0.070
0.080
1.300
0.040
0.050
0.004
0.0026
0.0032


S64
0.070
0.080
1.300
0.040
0.100
0.004
0.0026
0.0032


S65
0.070
0.080
1.300
0.040
0.150
0.004
0.0026
0.0032


S66
0.070
0.080
1.300
0.040
0.015
0.0005
0.0026
0.0032


S67
0.070
0.080
1.300
0.040
0.015
0.010
0.0026
0.0032


S68
0.070
0.080
1.300
0.040
0.015
0.030
0.0026
0.0032


S69
0.070
0.080
1.300
0.040
0.015
0.004
0.0005
0.0032


S70
0.070
0.080
1.300
0.040
0.015
0.004
0.0050
0.0032


S71
0.070
0.080
1.300
0.040
0.015
0.004
0.0100
0.0032


S72
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0005


S73
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0050


S74
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0100


S75
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032






0.0009


S76
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032






0.003


S77
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032






0.144


S78
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032





0.0009


S79
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032





0.003


S80
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032





0.150


S81
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032




0.00009


S82
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032




0.0008


S83
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032




0.0030


S84
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032




0.0050


S85
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S86
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S87
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S88
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S89
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S90
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032





























TABLE 4







STEEL















No.
V
W
Ca
Mg
Zr
REM
As
Co
Sn
Pb
Y
Hf
REMARKS





S46












EXAMPLE


S47












EXAMPLE


S48












EXAMPLE


S49












EXAMPLE


S50












EXAMPLE


S51












EXAMPLE


S52












EXAMPLE


S53












EXAMPLE


S54












EXAMPLE


S55












EXAMPLE


S56












EXAMPLE


S57












EXAMPLE


S58












EXAMPLE


S59












EXAMPLE


S60












EXAMPLE


S61












EXAMPLE


S62












EXAMPLE


S63












EXAMPLE


S64












EXAMPLE


S65












EXAMPLE


S66












EXAMPLE


S67












EXAMPLE


S68












EXAMPLE


S69












EXAMPLE


S70












EXAMPLE


S71












EXAMPLE


S72












EXAMPLE


S73












EXAMPLE


S74












EXAMPLE


S75












EXAMPLE


S76












EXAMPLE


S77












EXAMPLE


S78












EXAMPLE


S79












EXAMPLE


S80












EXAMPLE


S81












EXAMPLE


S82












EXAMPLE


S83












EXAMPLE


S84












EXAMPLE


S85



0.00009








EXAMPLE


S86



0.0003








EXAMPLE


S87



0.0050








EXAMPLE


S88





0.00009






EXAMPLE


S89





0.0005






EXAMPLE


S90





0.0050






EXAMPLE



















CALCULATED







VALUE OF



STEEL
T1/
Ar3/
HARDNESS



No.
° C.
° C.
OF FERRITE/—
REMARKS







S46
851
857
306
EXAMPLE



S47
850
850
206
EXAMPLE



S48
850
847
208
EXAMPLE



S49
850
818
217
EXAMPLE



S50
851
752
238
EXAMPLE



S51
852
686
259
EXAMPLE



S52
852
653
269
EXAMPLE



S53
852
634
276
EXAMPLE



S54
853
620
280
EXAMPLE



S55
853
588
290
EXAMPLE



S56
851
765
234
EXAMPLE



S57
851
767
234
EXAMPLE



S58
851
784
234
EXAMPLE



S59
851
822
234
EXAMPLE



S60
851
842
234
EXAMPLE



S61
851
761
230
EXAMPLE



S62
851
769
238
EXAMPLE



S63
851
775
243
EXAMPLE



S64
851
788
257
EXAMPLE



S65
851
802
270
EXAMPLE



S66
851
765
234
EXAMPLE



S67
851
765
234
EXAMPLE



S68
851
765
234
EXAMPLE



S69
851
765
234
EXAMPLE



S70
851
765
234
EXAMPLE



S71
851
765
234
EXAMPLE



S72
851
765
234
EXAMPLE



S73
851
765
234
EXAMPLE



S74
851
765
234
EXAMPLE



S75
851
765
237
EXAMPLE



S76
852
765
240
EXAMPLE



S77
887
765
275
EXAMPLE



S78
851
765
236
EXAMPLE



S79
852
765
238
EXAMPLE



S80
903
765
264
EXAMPLE



S81
851
765
234
EXAMPLE



S82
851
765
234
EXAMPLE



S83
851
765
234
EXAMPLE



S84
851
765
234
EXAMPLE



S85
851
765
234
EXAMPLE



S86
851
765
234
EXAMPLE



S87
851
765
234
EXAMPLE



S88
851
765
234
EXAMPLE



S89
851
765
234
EXAMPLE



S90
851
765
234
EXAMPLE


















TABLE 5







STEEL
CHEMICAL COMPOSITION/mass %






















No.
C
Si
Mn
Al
P
S
N
O
Mo
Cr
Ni
Cu
B
Nb
Ti





S91
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032









S92
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S93
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S94
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032
0.0009


S95
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032
0.003


S96
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032
0.060


S97
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032

0.0009


S98
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032

0.005


S99
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032

0.499


S100
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


0.0009


S101
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


0.005


S102
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


0.500


S103
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S104
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S105
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S106
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S107
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S108
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S109
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S110
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S111
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S112
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S113
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S114
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S115
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032



0.0009


S116
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032



0.005


S117
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032



0.500


S118
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S119
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S120
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S121
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S122
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S123
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S124
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S125
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S126
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S127
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S128
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S129
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S130
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S131
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S132
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S133
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S134
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032


S135
0.070
0.080
1.300
0.040
0.015
0.004
0.0026
0.0032





























TABLE 6







STEEL















No.
V
W
Ca
Mg
Zr
REM
As
Co
Sn
Pb
Y
Hf
REMARKS





S91


0.00009









EXAMPLE


S92


0.0004









EXAMPLE


S93


0.0010









EXAMPLE


S94












EXAMPLE


S95












EXAMPLE


S96












EXAMPLE


S97












EXAMPLE


S98












EXAMPLE


S99












EXAMPLE


S100












EXAMPLE


S101












EXAMPLE


S102












EXAMPLE


S103

0.0009










EXAMPLE


S104

0.005










EXAMPLE


S105

0.500










EXAMPLE


S106




0.00009







EXAMPLE


S107




0.0100







EXAMPLE


S108




0.150 







EXAMPLE


S109






0.00009





EXAMPLE


S110






0.0010





EXAMPLE


S111
0.0009











EXAMPLE


S112
0.005











EXAMPLE


S113
0.500











EXAMPLE


S114
0.800











EXAMPLE


S115












EXAMPLE


S116












EXAMPLE


S117












EXAMPLE


S118








0.00009





EXAMPLE


S119







0.00050




EXAMPLE


S120







0.0500 




EXAMPLE


S121







0.5000 




EXAMPLE


S122









0.00009




EXAMPLE


S123








0.0100 



EXAMPLE


S124








0.1000 



EXAMPLE


S125








0.1500 



EXAMPLE


S126









0.00009


EXAMPLE


S127









0.0050


EXAMPLE


S128









0.0100


EXAMPLE


S129









0.1500


EXAMPLE


S130










0.00009

EXAMPLE


S131










0.0500

EXAMPLE


S132










0.1500

EXAMPLE


S133











0.00009
EXAMPLE


S134











0.0500
EXAMPLE


S135











0.1500
EXAMPLE



















CALCULATED







VALUE OF



STEEL
T1/
Ar3/
HARDNESS



No.
° C.
° C.
OF FERRITE/—
REMARKS







S91
851
765
234
EXAMPLE



S92
851
765
234
EXAMPLE



S93
851
765
234
EXAMPLE



S94
851
765
234
EXAMPLE



S95
851
765
234
EXAMPLE



S96
857
765
234
EXAMPLE



S97
851
765
234
EXAMPLE



S98
851
765
234
EXAMPLE



S99
856
765
234
EXAMPLE



S100
851
765
234
EXAMPLE



S101
851
765
234
EXAMPLE



S102
851
765
234
EXAMPLE



S103
851
765
234
EXAMPLE



S104
851
765
234
EXAMPLE



S105
851
765
234
EXAMPLE



S106
851
765
234
EXAMPLE



S107
851
765
234
EXAMPLE



S108
851
765
234
EXAMPLE



S109
851
765
234
EXAMPLE



S110
851
765
234
EXAMPLE



S111
851
765
234
EXAMPLE



S112
851
765
234
EXAMPLE



S113
901
765
234
EXAMPLE



S114
931
765
234
EXAMPLE



S115
851
765
234
EXAMPLE



S116
851
765
234
EXAMPLE



S117
851
765
234
EXAMPLE



S118
851
765
234
EXAMPLE



S119
851
765
234
EXAMPLE



S120
851
769
234
EXAMPLE



S121
851
803
234
EXAMPLE



S122
851
765
234
EXAMPLE



S123
851
765
234
EXAMPLE



S124
851
765
234
EXAMPLE



S125
851
765
234
EXAMPLE



S126
851
765
234
EXAMPLE



S127
851
765
234
EXAMPLE



S128
851
765
234
EXAMPLE



S129
851
765
234
EXAMPLE



S130
851
765
234
EXAMPLE



S131
851
765
234
EXAMPLE



S132
851
765
234
EXAMPLE



S133
851
765
234
EXAMPLE



S134
851
765
234
EXAMPLE



S135
851
765
234
EXAMPLE




















TABLE 7









ROLLING IN RANGE OF




1000° C. TO 1200° C.
ROLLING IN RANGE OF T1 + 30° C. to T1 + 200° C.




















FRE-








MAXIMUM




QUEN-



FRE-




OF TEM-




CY OF
EACH

CUMU-
QUENCY
FREQUENCY



PERATURE



PRO-
REDUC-
REDUC-
GRAIN
LATIVE
OF
OF



RISE



DUC-
TION
TION OF
SIZE OF
REDUC-
REDUC-
REDUCTION



BETWEEN


STEEL
TION
OF 40% OR
40% OR
AUSTENITE/
TION/
TION/
OF 30%
EACH

Tf/
PASSES/


No.
No.
MORE/—
MORE/%
μm
%

OR MORE/—
REDUCTION/%
P1/%
° C.
° C.





S1
P1
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P2
1
45
180
55
4
1
13/13/15/30
30
935
17


S1
P3
1
45
180
55
4
1
13/13/15/30
30
935
17


S1
P4
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P5
2
45/45
 90
55
4
1
13/13/15/30
30
935
17


S1
P6
2
45/45
 90
75
5
1
20/20/25/25/30
30
935
17


S1
P7
2
45/45
 90
80
6
2
20/20/20/20/30/30
30
935
17


S1
P8
2
45/45
 90
80
6
2
30/30/20/20/20/20
30
935
17


S1
P9
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P10
2
45/45
 90
80
6
2
20/20/20/20/30/30
30
935
17


S1
P11
2
45/45
 90
80
6
2
20/20/20/20/30/30
30
935
17


S1
P12
2
45/45
 90
80
6
2
30/30/20/20/20/20
30
935
17


S1
P13
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P14
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P15
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P16
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P17
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P18
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P19
2
45/45
 90
55
4
1
13/13/15/30
30
935
17


S1
P20
2
45/45
 90
75
5
1
20/20/25/25/30
30
935
17


S1
P21
2
45/45
 90
80
6
2
20/20/20/20/30/30
30
935
17


S1
P22
2
45/45
 90
80
6
2
30/30/20/20/20/20
30
935
17


S1
P23
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P24
2
45/45
 90
80
6
2
20/20/20/20/30/30
30
935
17


S1
P25
2
45/45
 90
80
6
2
20/20/20/20/30/30
30
935
17


S1
P26
2
45/45
 90
80
6
2
30/30/20/20/20/20
30
935
17


S1
P27
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P28
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P29
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P30
2
45/45
 90
80
6
2
15/15/18/20/30/40
40
915
17


S1
P31

0



250

55
4
1
13/13/15/30
30
935
20


S1
P32
1
45
180

45

4
1
7/7/8/30
30
935
20


S1
P33
1
45
180
55
4

0

12/20/20/20


20


S1
P34
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P35
1
45
180
55
4
1
13/13/15/30
30
760
20


S1
P36
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P37
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P38
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P39
1
45
180
55
4
1
13/13/15/30
30
995
20


S1
P40
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P41
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P42
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P43
1
45
180
55
4
1
13/13/15/30
30
935
20













ROLLING IN RANGE OF Ar3




TO LOWER THAN T1 + 30° C.
FIRST-COOLING




















ROLLING




AVERAGE
COOLING
TEMPERATURE



PRODUC-

FINISH




COOLING
TEMPERATURE
AT COOLING


STEEL
TION
CUMULATIVE
TEMPERATURE/




RATE/
CHANGE/
FINISH/


No.
No.
REDUCTION/%
° C.
t1/s
2.5 × t1/s
t/s
t/t1/—
° C./second
° C.
° C.





S1
P1
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P2
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P3
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P4
0
935
0.99
2.47
0.10
0.10
113
90
845


S1
P5
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P6
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P7
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P8
0
880
0.99
2.47
0.90
0.91
113
90
787


S1
P9
0
915
0.96
2.41
0.90
0.93
113
90
822


S1
P10
20 
890
0.99
2.47
0.90
0.91
113
90
797


S1
P11
8
890
0.99
2.47
0.90
0.91
113
90
797


S1
P12
0
830
0.99
2.47
0.90
0.91
113
45
782


S1
P13
0
915
0.96
2.41
0.90
0.93
113
90
822


S1
P14
0
915
0.96
2.41
0.90
0.93
113
90
822


S1
P15
0
915
0.96
2.41
0.90
0.93
113
90
822


S1
P16
0
915
0.96
2.41
0.50
0.52
113
90
824


S1
P17
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P18
0
935
0.99
2.47
2.40
2.43
113
90
838


S1
P19
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P20
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P21
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P22
0
880
0.99
2.47
1.10
1.11
113
90
787


S1
P23
0
915
0.96
2.41
1.10
1.14
113
90
822


S1
P24
20 
890
0.99
2.47
1.10
1.11
113
90
797


S1
P25
8
890
0.99
2.47
1.10
1.11
113
90
797


S1
P26
0
830
0.99
2.47
1.10
1.11
113
45
782


S1
P27
0
915
0.96
2.41
1.10
1.14
113
90
822


S1
P28
0
915
0.96
2.41
1.10
1.14
113
90
822


S1
P29
0
915
0.96
2.41
1.10
1.14
113
90
822


S1
P30
0
915
0.96
2.41
1.50
1.56
113
90
821


S1
P31
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P32
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P33
0
935


0.90

113
90
842


S1
P34

35

890
0.99
2.47
0.90
0.91
113
90
797


S1
P35
0

760

6.82
17.05 
6.20
0.91
113
45
696


S1
P36
0
935
0.99
2.47
0.90
0.91
45
90
842


S1
P37
0
935
0.99
2.47
0.90
0.91
113

35

897


S1
P38
0
935
0.99
2.47
0.90
0.91
113

145

787


S1
P39
0
995
0.26
0.64
0.24
0.91
 50
40

954



S1
P40
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P41
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P42
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P43
0
935
0.99
2.47
0.90
0.91
113
90
842



















TABLE 8









ROLLING IN RANGE OF




1000° C. TO 1200° C.
ROLLING IN RANGE OF T1 + 30° C. to T1 + 200° C.




















FREQUENCY








MAXIMUM OF




OF
EACH
GRAIN


FREQUENCY OF



TEMPERATURE RISE




REDUCTION OF
REDUCTION OF
SIZE OF

FREQUENCY
REDUCTION



BETWEEN


STEEL
PRODUCTION
40%
40%
AUSTENITE/
CUMULATIVE
OF
OF 30%
EACH

Tf/
PASSES/


No.
No.
OR MORE/—
OR MORE/%
μm
REDUCTION/%
REDUCTION/—
OR MORE/—
REDUCTION/%
P1/%
° C.
° C.





S1
P44
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P45
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P46
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P47
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P48
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P49
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P50
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P51
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P52
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P53
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P54
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P55
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P56

0



250

55
4
1
13/13/15/30
30
935
20


S1
P57
1
45
180

45

4
1
7/7/8/30
30
935
20


S1
P58
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P59
1
45
180
55
4
1
13/13/15/30
30
760
20


S1
P60
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P61
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P62
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P63
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P64
1
45
180
55
4
1
13/13/15/30
30
995
20


S1
P65
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P66
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P67
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P68
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P69
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P70
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P71
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P72
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P73
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P74
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P75
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P76
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P77
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P78
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P79
1
45
180
55
4
1
13/13/15/30
30
935
20


S1
P80
1
45
180
55
4
1
13/13/15/30
30
935
20


S2
P81
1
45
180
55
4
1
13/13/15/30
30
935
20


S3
P82
1
45
180
55
4
1
13/13/15/30
30
935
20


S4
P83
1
45
180
55
4
1
13/13/15/30
30
935
20


S5
P84
1
45
180
55
4
1
13/13/15/30
30
935
20


S6
P85
1
45
180
55
4
1
13/13/15/30
30
935
20


S7
P86
1
45
180
55
4
1
13/13/15/30
30
935
20













ROLLING IN RANGE OF Ar3




TO LOWER THAN T1 + 30° C.
FIRST-COOLING




















ROLLING




AVERAGE
COOLING
TEMPERATURE





FINISH




COOLING
TEMPERATURE
AT COOLING


STEEL
PRODUCTION
CUMULATIVE
TEMPERATURE/




RATE/
CHANGE/
FINISH/


No.
No.
REDUCTION/%
° C.
t1/s
2.5 × t1/s
t/s
t/t1/—
° C./second
° C.
° C.





S1
P44
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P45
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P46
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P47
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P48
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P49
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P50
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P51
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P52
0
935
0.99
2.47
0.99
0.91
113
90
842


S1
P53
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P54
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P55
0
935
0.99
2.47
0.90
0.91
113
90
842


S1
P56
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P57
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P58

35

890
0.99
2.47
1.10
1.11
113
90
797


S1
P59
0

760

6.82
17.05
7.60
1.11
113
45
692


S1
P60
0
935
0.99
2.47

2.50

2.53
113
90
838


S1
P61
0
935
0.99
2.47
1.10
1.11
45
90
842


S1
P62
0
935
0.99
2.47
1.10
1.11
113

35

897


S1
P63
0
935
0.99
2.47
1.10
1.11
113

145

787


S1
P64
0
995
0.26
0.64
0.29
1.11
 50
40

954



S1
P65
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P66
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P67
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P68
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P69
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P70
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P71
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P72
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P73
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P74
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P75
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P76
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P77
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P78
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P79
0
935
0.99
2.47
1.10
1.11
113
90
842


S1
P80
0
935
0.99
2.47
1.10
1.11
113
90
842


S2
P81
0
935
0.97
2.43
0.90
0.92
113
90
842


S3
P82
0
935
1.06
2.66
0.90
0.85
113
90
842


S4
P83
0
935
0.99
2.47
0.90
0.91
113
90
842


S5
P84
0
935
0.99
2.47
0.90
0.91
113
90
842


S6
P85
0
935
0.97
2.43
0.90
0.93
113
90
842


S7
P86
0
935
1.02
2.56
0.90
0.88
113
90
842



















TABLE 9









ROLLING IN RANGE OF
ROLLING IN RANGE OF T1 + 30° C. to T1 + 200° C.











1000° C. TO 1200° C.

MAXIMUM OF





























TEMPERATURE




FREQUENCY

GRAIN


FREQUENCY OF



RISE




OF REDUCTION
EACH
SIZE

FREQUENCY
REDUCTION



BETWEEN


STEEL
PRODUCTION
OF 40%
REDUCTION OF
OF AUSTENITE/
CUMULATIVE
OF
OF 30%
EACH


PASSES/


No.
No.
OR MORE/—
40% OR MORE/%
μm
REDUCTION/%
REDUCTION/—
OR MORE/—
REDUCTION/%
P1/%
Tf/° C.
° C.





S8
P87
1
45
180
55
4
1
13/13/15/30
30
935
20


S9
P88
1
45
180
55
4
1
13/13/15/30
30
935
20









S10
P89
Cracks occur during Hot rolling


















S11
P90
1
45
180
55
4
1
13/13/15/30
30
935
20


S12
P91
1
45
180
55
4
1
13/13/15/30
30
935
20


S13
P92
1
45
180
55
4
1
13/13/15/30
30
935
20


S14
P93
1
45
180
55
4
1
13/13/15/30
30
935
20


S15
P94
1
45
180
55
4
1
13/13/15/30
30
935
20


S16
P95
1
45
180
55
4
1
13/13/15/30
30
935
20


S17
P96
1
45
180
55
4
1
13/13/15/30
30
935
20


S18
P97
1
45
180
55
4
1
13/13/15/30
30
935
20


S19
P98
1
45
180
55
4
1
13/13/15/30
30
935
20


S20
P99
1
45
180
55
4
1
13/13/15/30
30
935
20


S21
P100
1
45
180
55
4
1
13/13/15/30
30
935
20


S22
P101
1
45
180
55
4
1
13/13/15/30
30
935
20


S23
P102
1
45
180
55
4
1
13/13/15/30
30
935
20


S24
P103
1
45
180
55
4
1
13/13/15/30
30
935
20


S25
P104
1
45
180
55
4
1
13/13/15/30
30
935
20


S26
P105
1
45
180
55
4
1
13/13/15/30
30
935
20


S27
P106
1
45
180
55
4
1
13/13/15/30
30
935
20


S28
P107
1
45
180
55
4
1
13/13/15/30
30
935
20









S29
P108
Cracks occur during Hot rolling


S30
P109
Cracks occur during Hot rolling


















S31
P110
1
45
180
55
4
1
13/13/15/30
30
935
20


S32
P111
1
45
180
55
4
1
13/13/15/30
30
935
20


S33
P112
1
45
180
55
4
1
13/13/15/30
30
935
20


S34
P113
1
45
180
55
4
1
13/13/15/30
30
935
20


S35
P114
1
45
180
55
4
1
13/13/15/30
30
935
20


S36
P115
1
45
180
55
4
1
13/13/15/30
30
935
20


S37
P116
1
45
180
55
4
1
13/13/15/30
30
935
20


S38
P117
1
45
180
55
4
1
13/13/15/30
30
935
20


S39
P118
1
45
180
55
4
1
13/13/15/30
30
935
20


S40
P119
1
45
180
55
4
1
13/13/15/30
30
935
20


S41
P120
1
45
180
55
4
1
13/13/15/30
30
935
20


S42
P121
1
45
180
55
4
1
13/13/15/30
30
935
20


S43
P122
1
45
180
55
4
1
13/13/15/30
30
935
20


S44
P123
1
45
180
55
4
1
13/13/15/30
30
935
20


S45
P124
1
45
180
55
4
1
13/13/15/30
30
935
20


S46
P125
1
45
180
55
4
1
13/13/15/30
30
935
20


S47
P126
1
45
180
55
4
1
13/13/15/30
30
935
20


S48
P127
1
45
180
55
4
1
13/13/15/30
30
935
20


S49
P128
1
45
180
55
4
1
13/13/15/30
30
935
20


S50
P129
1
45
180
55
4
1
13/13/15/30
30
935
20













ROLLING IN RANGE OF Ar3




TO LOWER THAN T1 + 30° C.
FIRST-COOLING






















ROLLING




AVERAGE
COOLING
TEMPERATURE






FINISH




COOLING
TEMPERATURE
AT COOLING



STEEL
PRODUCTION
CUMULATIVE
TEMPERATURE/




RATE/
CHANGE/
FINISH/



No.
No.
REDUCTION/%
° C.
t1/s
2.5 × t1/s
t/s
t/t1/—
° C./second
° C.
° C.







S8
P87
0
935
0.99
2.47
0.90
0.91
113
90
842



S9
P88
0
935
0.99
2.47
0.90
0.91
113
90
842











S10
P89
Cracks occur during Hot rolling



















S11
P90
0
935
0.99
2.47
0.90
0.91
113
90
842



S12
P91
0
935
0.99
2.47
0.90
0.91
113
90
842



S13
P92
0
935
0.99
2.47
0.90
0.91
113
90
842



S14
P93
0
935
3.68
9.20
0.90
0.24
113
90
842



S15
P94
0
935
1.38
3.44
0.90
0.65
113
90
842



S16
P95
0
935
0.99
2.47
0.90
0.91
113
90
842



S17
P96
0
935
0.99
2.47
0.90
0.91
113
90
842



S18
P97
0
935
0.99
2.48
0.90
0.91
113
90
842



S19
P98
0
935
2.67
6.67
0.90
0.34
113
90
842



S20
P99
0
935
2.10
5.24
0.90
0.43
113
90
842



S21
P100
0
935
3.68
9.20
0.90
0.24
113
90
842



S22
P101
0
935
0.99
2.47
0.90
0.91
113
90
842



S23
P102
0
935
0.99
2.47
0.90
0.91
113
90
842



S24
P103
0
935
0.99
2.47
0.90
0.91
113
90
842



S25
P104
0
935
0.99
2.47
0.90
0.91
113
90
842



S26
P105
0
935
0.99
2.47
0.90
0.91
113
90
842



S27
P106
0
935
0.99
2.47
0.90
0.91
113
90
842



S28
P107
0
935
0.99
2.47
0.90
0.91
113
90
842











S29
P108
Cracks occur during Hot rolling



S30
P109
Cracks occur during Hot rolling



















S31
P110
0
935
0.99
2.47
0.90
0.91
113
90
842



S32
P111
0
935
0.99
2.47
0.90
0.91
113
90
842



S33
P112
0
935
0.97
2.43
1.10
1.13
113
90
842



S34
P113
0
935
0.98
2.45
1.10
1.12
113
90
842



S35
P114
0
935
0.98
2.46
1.10
1.12
113
90
842



S36
P115
0
935
1.00
2.50
1.10
1.10
113
90
842



S37
P116
0
935
1.01
2.53
1.10
1.09
113
90
842



S38
P117
0
935
1.03
2.57
1.10
1.07
113
90
842



S39
P118
0
935
1.04
2.59
1.10
1.06
113
90
842



S40
P119
0
935
1.04
2.60
1.10
1.06
113
90
842



S41
P120
0
935
1.06
2.66
1.10
1.03
113
90
842



S42
R121
0
935
0.99
2.47
1.10
1.11
113
90
842



S43
P122
0
935
0.99
2.47
1.10
1.11
113
90
842



S44
P123
0
935
0.99
2.47
1.10
1.11
113
90
842



S45
P124
0
935
0.99
2.47
1.10
1.11
113
90
842



S46
P125
0
935
0.99
2.47
1.10
1.11
113
90
842



S47
P126
0
935
0.97
2.43
1.10
1.13
113
90
842



S48
P127
0
935
0.97
2.43
1.10
1.13
113
90
842



S49
P128
0
935
0.98
2.44
1.10
1.13
113
90
842



S50
P129
0
935
0.99
2.47
1.10
1.11
113
90
842




















TABLE 10









ROLLING IN RANGE OF




1000° C. TO 1200° C.
ROLLING IN RANGE OF T1 + 30° C. to T1 + 200° C.




















FREQUENCY








MAXIMUM OF




OF
EACH
GRAIN


FREQUENCY OF



TEMPERATURE RISE




REDUCTION OF
REDUCTION OF
SIZE OF

FREQUENCY
REDUCTION



BETWEEN


STEEL
PRODUCTION
40%
40%
AUSTENITE/
CUMULATIVE
OF
OF 30%
EACH

Tf/
PASSES/


No.
No.
OR MORE/—
OR MORE/%
μm
REDUCTION/%
REDUCTION/—
OR MORE/—
REDUCTION/%
P1/%
° C.
° C.





S51
P130
1
45
180
55
4
1
13/13/15/30
30
935
20


S52
P131
1
45
180
55
4
1
13/13/15/30
30
935
20


S53
P132
1
45
180
55
4
1
13/13/15/30
30
935
20


S54
P133
1
45
180
55
4
1
13/13/15/30
30
935
20


S55
P134
1
45
180
55
4
1
13/13/15/30
30
935
20


S56
P135
1
45
180
55
4
1
13/13/15/30
30
935
20


S57
P136
1
45
180
55
4
1
13/13/15/30
30
935
20


S58
P137
1
45
180
55
4
1
13/13/15/30
30
935
20


S59
P138
1
45
180
55
4
1
13/13/15/30
30
935
20


S60
P139
1
45
180
55
4
1
13/13/15/30
30
935
20


S61
P140
1
45
180
55
4
1
13/13/15/30
30
935
20


S62
P141
1
45
180
55
4
1
13/13/15/30
30
935
20


S63
P142
1
45
180
55
4
1
13/13/15/30
30
935
20


S64
P143
1
45
180
55
4
1
13/13/15/30
30
935
20


S65
P144
1
45
180
55
4
1
13/13/15/30
30
935
20


S66
P145
1
45
180
55
4
1
13/13/15/30
30
935
20


S67
P146
1
45
180
55
4
1
13/13/15/30
30
935
20


S68
P147
1
45
180
55
4
1
13/13/15/30
30
935
20


S69
P148
1
45
180
55
4
1
13/13/15/30
30
935
20


S70
P149
1
45
180
55
4
1
13/13/15/30
30
935
20


S71
P150
1
45
180
55
4
1
13/13/15/30
30
935
20


S72
P151
1
45
180
55
4
1
13/13/15/30
30
935
20


S73
P152
1
45
180
55
4
1
13/13/15/30
30
935
20


S74
P153
1
45
180
55
4
1
13/13/15/30
30
935
20


S75
P154
1
45
180
55
4
1
13/13/15/30
30
935
20


S76
P155
1
45
180
55
4
1
13/13/15/30
30
935
20


S77
P156
1
45
180
55
4
1
13/13/15/30
30
935
20


S78
P157
1
45
180
55
4
1
13/13/15/30
30
935
20


S79
P158
1
45
180
55
4
1
13/13/15/30
30
935
20


S80
P159
1
45
180
55
4
1
13/13/15/30
30
935
20


S81
P160
1
45
180
55
4
1
13/13/15/30
30
935
20


S82
P161
1
45
180
55
4
1
13/13/15/30
30
935
20


S83
P162
1
45
180
55
4
1
13/13/15/30
30
935
20


S84
P163
1
45
180
55
4
1
13/13/15/30
30
935
20


S85
P164
1
45
180
55
4
1
13/13/15/30
30
935
20


S86
P165
1
45
180
55
4
1
13/13/15/30
30
935
20


S87
P166
1
45
180
55
4
1
13/13/15/30
30
935
20


S88
P167
1
45
180
55
4
1
13/13/15/30
30
935
20


S89
P168
1
45
180
55
4
1
13/13/15/30
30
935
20


S90
P169
1
45
180
55
4
1
13/13/15/30
30
935
20


S91
P170
1
45
180
55
4
1
13/13/15/30
30
935
20


S92
P171
1
45
180
55
4
1
13/13/15/30
30
935
20


S93
P172
1
45
180
55
4
1
13/13/15/30
30
935
20













ROLLING IN RANGE OF Ar3




TO LOWER THAN T1 + 30° C.
FIRST-COOLING

























AVERAGE
COOLING
TEMPERATURE





ROLLING FINISH




COOLING
TEMPERATURE
AT COOLING


STEEL
PRODUCTION
CUMULATIVE
TEMPERATURE/




RATE/
CHANGE/
FINISH/


No.
No.
REDUCTION/%
° C.
t1/s
2.5 × t1/s
t/s
t/t1/—
° C./second
° C.
° C.





S51
P130
0
935
1.00
2.51
1.10
1.10
113
90
842


S52
P131
0
935
1.01
2.52
1.10
1.09
113
90
842


S53
P132
0
935
1.01
2.53
1.10
1.09
113
90
842


S54
P133
0
935
1.02
2.54
1.10
1.08
113
90
842


S55
P134
0
935
1.02
2.56
1.10
1.08
113
90
842


S56
P135
0
935
0.99
2.47
1.10
1.11
113
90
842


S57
P136
0
935
0.99
2.47
1.10
1.11
113
90
842


S58
P137
0
935
0.99
2.47
1.10
1.11
113
90
842


S59
P138
0
935
0.99
2.47
1.10
1.11
113
90
842


S60
P139
0
935
0.99
2.47
1.10
1.11
113
90
842


S61
P140
0
935
0.99
2.47
1.10
1.11
113
90
842


S62
P141
0
935
0.99
2.47
1.10
1.11
113
90
842


S63
P142
0
935
0.99
2.47
1.10
1.11
113
90
842


S64
P143
0
935
0.99
2.47
1.10
1.11
113
90
842


S65
P144
0
935
0.99
2.47
1.10
1.11
113
90
842


S66
P145
0
935
0.99
2.47
1.10
1.11
113
90
842


S67
P146
0
935
0.99
2.47
1.10
1.11
113
90
842


S68
P147
0
935
0.99
2.47
1.10
1.11
113
90
842


S69
P148
0
935
0.99
2.47
1.10
1.11
113
90
842


S70
P149
0
935
0.99
2.47
1.10
1.11
113
90
842


S71
P150
0
935
0.99
2.47
1.10
1.11
113
90
842


S72
P151
0
935
0.99
2.47
1.10
1.11
113
90
842


S73
P152
0
935
0.99
2.47
1.10
1.11
113
90
842


S74
P153
0
935
0.99
2.47
1.10
1.11
113
90
842


S75
P154
0
935
0.99
2.48
1.10
1.11
113
90
842


S76
P155
0
935
1.00
2.50
1.10
1.10
113
90
842


S77
P156
0
935
1.74
4.34
1.91
1.10
113
90
839


S78
P157
0
935
0.99
2.48
1.10
1.11
113
90
842


S79
P158
0
935
1.01
2.51
1.10
1.09
113
90
842


S80
P159
0
935
2.16
5.39
2.35
1.09
113
90
838


S81
P160
0
935
0.99
2.47
1.10
1.11
113
90
842


S82
P161
0
935
0.99
2.47
1.10
1.11
113
90
842


S83
P162
0
935
0.99
2.47
1.10
1.11
113
90
842


S84
P163
0
935
0.99
2.48
1.10
1.11
113
90
842


S85
P164
0
935
0.99
2.47
1.10
1.11
113
90
842


S86
P165
0
935
0.99
2.47
1.10
1.11
113
90
842


S87
P166
0
935
0.99
2.47
1.10
1.11
113
90
842


S88
P167
0
935
0.99
2.47
1.10
1.11
113
90
842


S89
P168
0
935
0.99
2.47
1.10
1.11
113
90
842


S90
P169
0
935
0.99
2.47
1.10
1.11
113
90
842


S91
P170
0
935
0.99
2.47
1.10
1.11
113
90
842


S92
P171
0
935
0.99
2.47
1.10
1.11
113
90
842


S93
P172
0
935
0.99
2.47
1.10
1.11
113
90
842



















TABLE 11









ROLLING IN RANGE OF
ROLLING IN RANGE OF T1 + 30° C. to T1 + 200° C.











1000° C. To 1200° C.

MAXIMUM OF




















FREQUENCY




FREQUENCY



TEMPERATURE




OF
EACH
GRAIN


OF



RISE




REDUCTION
REDUCTION
SIZE OF

FREQUENCY
REDUCTION



BETWEEN


STEEL
PRODUCTION
OF 40%
OF 40%
AUSTENITE/
CUMULATIVE
OF
OF 30%
EACH

Tf/
PASSES/


No.
No.
OR MORE/—
OR MORE/%
μm
REDUCTION/%
REDUCTION/—
OR MORE/—
REDUCTION/%
P1/%
° C.
° C.





S94
P173
1
45
180
55
4
1
13/13/15/30
30
935
20


S95
P174
1
45
180
55
4
1
13/13/15/30
30
935
20


S96
P175
1
45
180
55
4
1
13/13/15/30
30
935
20


S97
P176
1
45
180
55
4
1
13/13/15/30
30
935
20


S98
P177
1
45
180
55
4
1
13/13/15/30
30
935
20


S99
P178
1
45
180
55
4
1
13/13/15/30
30
935
20


S100
P179
1
45
180
55
4
1
13/13/15/30
30
935
20


S101
P180
1
45
180
55
4
1
13/13/15/30
30
935
20


S102
P181
1
45
180
55
4
1
13/13/15/30
30
935
20


S103
P182
1
45
180
55
4
1
13/13/15/30
30
935
20


S104
P183
1
45
180
55
4
1
13/13/15/30
30
935
20


S105
P184
1
45
180
55
4
1
13/13/15/30
30
935
20


S106
P185
1
45
180
55
4
1
13/13/15/30
30
935
20


S107
P186
1
45
180
55
4
1
13/13/15/30
30
935
20


S108
P187
1
45
180
55
4
1
13/13/15/30
30
935
20


S109
P188
1
45
180
55
4
1
13/13/15/30
30
935
20


S110
P189
1
45
180
55
4
1
13/13/15/30
30
935
20


S111
P190
1
45
180
55
4
1
13/13/15/30
30
935
20


S112
P191
1
45
180
55
4
1
13/13/15/30
30
935
20


S113
P192
1
45
180
55
4
1
13/13/15/30
30
935
20


S114
P193
1
45
180
55
4
1
13/13/15/30
30
935
20


S115
P194
1
45
180
55
4
1
13/13/15/30
30
935
20


S116
P195
1
45
180
55
4
1
13/13/15/30
30
935
20


S117
P196
1
45
180
55
4
1
13/13/15/30
30
935
20


S118
P197
1
45
180
55
4
1
13/13/15/30
30
935
20


S119
P198
1
45
180
55
4
1
13/13/15/30
30
935
20


S120
P199
1
45
180
55
4
1
13/13/15/30
30
935
20


S121
P200
1
45
180
55
4
1
13/13/15/30
30
935
20


S122
P201
1
45
180
55
4
1
13/13/15/30
30
935
20


S123
P202
1
45
180
55
4
1
13/13/15/30
30
935
20


S124
P203
1
45
180
55
4
1
13/13/15/30
30
935
20


S125
P204
1
45
180
55
4
1
13/13/15/30
30
935
20


S126
P205
1
45
180
55
4
1
13/13/15/30
30
935
20


S127
P206
1
45
180
55
4
1
13/13/15/30
30
935
20


S128
P207
1
45
180
55
4
1
13/13/15/30
30
935
20


S129
P208
1
45
180
55
4
1
13/13/15/30
30
935
20


S130
P209
1
45
180
55
4
1
13/13/15/30
30
935
20


S131
P210
1
45
180
55
4
1
13/13/15/30
30
935
20


S132
P211
1
45
180
55
4
1
13/13/15/30
30
935
20


S133
P212
1
45
180
55
4
1
13/13/15/30
30
935
20


S134
P213
1
45
180
55
4
1
13/13/15/30
30
935
20


S135
P214
1
45
180
55
4
1
13/13/15/30
30
935
20













ROLLING IN RANGE OF Ar3




TO LOWER THAN T1 + 30° C.
FIRST-COOLING






















ROLLING




AVERAGE
COOLING
TEMPERATURE






FINISH




COOLING
TEMPERATURE
AT COOLING



STEEL
PRODUCTION
CUMULATIVE
TEMPERATURE/




RATE/
CHANGE/
FINISH/



No.
No.
REDUCTION/%
° C.
t1/s
2.5 × t1/s
t/s
t/t1/—
° C./second
° C.
° C.







S94
P173
0
935
0.99
2.47
1.10
1.11
113
90
842



S95
P174
0
935
0.99
2.48
1.10
1.11
113
90
842



S96
P175
0
935
1.10
2.74
1.10
1.00
113
90
842



S97
P176
0
935
0.99
2.47
1.10
1.11
113
90
842



S98
P177
0
935
0.99
2.47
1.10
1.11
113
90
842



S99
P178
0
935
1.08
2.69
1.10
1.02
113
90
842



S100
P179
0
935
0.99
2.47
1.10
1.11
113
90
842



S101
P180
0
935
0.99
2.47
1.10
1.11
113
90
842



S102
P181
0
935
0.99
2.47
1.10
1.11
113
90
842



S103
P182
0
935
0.99
2.47
1.10
1.11
113
90
842



S104
P183
0
935
0.99
2.47
1.10
1.11
113
90
842



S105
P184
0
935
0.99
2.47
1.10
1.11
113
90
842



S106
P185
0
935
0.99
2.47
1.10
1.11
113
90
842



S107
P186
0
935
0.99
2.47
1.10
1.11
113
90
842



S108
P187
0
935
0.99
2.47
1.10
1.11
113
90
842



S109
P188
0
935
0.99
2.47
1.10
1.11
113
90
842



S110
P189
0
935
0.99
2.47
1.10
1.11
113
90
842



S111
P190
0
935
0.99
2.47
1.10
1.11
113
90
842



S112
P191
0
935
1.00
2.49
1.10
1.10
113
90
842



S113
P192
0
935
2.09
5.23
2.30
1.10
113
90
838



S114
P193
0
935
2.97
7.42
3.30
1.11
113
90
835



S115
P194
0
935
0.99
2.47
1.10
1.11
113
90
842



S116
P195
0
935
0.99
2.47
1.10
1.11
113
90
842



S117
P196
0
935
0.99
2.47
1.10
1.11
113
90
842



S118
P197
0
935
0.99
2.47
1.10
1.11
113
90
842



S119
P198
0
935
0.99
2.47
1.10
1.11
113
90
842



S120
P199
0
935
0.99
2.47
1.10
1.11
113
90
842



S121
P200
0
935
0.99
2.47
1.10
1.11
113
90
842



S122
P201
0
935
0.99
2.47
1.10
1.11
113
90
842



S123
P202
0
935
0.99
2.47
1.10
1.11
113
90
842



S124
P203
0
935
0.99
2.47
1.10
1.11
113
90
842



S125
P204
0
935
0.99
2.47
1.10
1.11
113
90
842



S126
P205
0
935
0.99
2.47
1.10
1.11
113
90
842



S127
P206
0
935
0.99
2.47
1.10
1.11
113
90
842



S128
P207
0
935
0.99
2.47
1.10
1.11
113
90
842



S129
P208
0
935
0.99
2.47
1.10
1.11
113
90
842



S130
P209
0
935
0.99
2.47
1.10
1.11
113
90
842



S131
P210
0
935
0.99
2.47
1.10
1.11
113
90
842



S132
P211
0
935
0.99
2.47
1.10
1.11
113
90
842



S133
P212
0
935
0.99
2.47
1.10
1.11
113
90
842



S134
P213
0
935
0.99
2.47
1.10
1.11
113
90
842



S135
P214
0
935
0.99
2.47
1.10
1.11
113
90
842






















TABLE 12









SECOND-COOLING

HEATING AND













TIME

HOLDING
THIRD-COOLING
















PRO-
UNTIL
AVERAGE
TEMPERATURE
COILING
COLD-
HEATING

AVERAGE
TEMPERATURE


DUC-
SECOND
COOLING
AT COOLING
TEMPER-
ROLLING
TEMPER-

COOLING
AT COOLING


TION
COOLING
RATE/
FINISH/
ATURE/
CUMULATIVE
ATURE/
HOLDING
RATE/
FINISH/


No.
START/s
° C./second
° C.
° C.
REDUCTION/%
° C.
TIME/s
° C./second
° C.





P1
3.5
70
330
330
50
850
10.0
5
650


P2
3.5
70
330
330
50
850
10.0
5
650


P3
2.8
70
330
330
50
850
10.0
5
650


P4
3.5
70
330
330
50
850
10.0
5
650


P5
2.8
70
330
330
50
850
10.0
5
650


P6
2.8
70
330
330
50
850
10.0
5
650


P7
2.8
70
330
330
50
850
10.0
5
650


P8
2.8
70
330
330
50
850
10.0
5
650


P9
2.8
70
330
330
50
850
10.0
5
650


P10
2.8
70
330
330
50
850
10.0
5
650


P11
2.8
70
330
330
50
850
10.0
5
650


P12
2.8
70
330
330
50
850
10.0
5
650


P13
2.8
70
330
330
50
850
10.0
2
610


P14
2.8
70
330
330
50
850
10.0
10
690


P15
2.8
70
330
330
50
850
10.0
8
680


P16
2.8
70
330
330
50
850
10.0
5
650


P17
3.5
70
330
330
50
850
10.0
5
650


P18
3.5
70
330
330
50
850
10.0
5
650


P19
2.8
70
330
330
50
850
10.0
5
650


P20
2.8
70
330
330
50
850
10.0
5
650


P21
2.8
70
330
330
50
850
10.0
5
650


P22
2.8
70
330
330
50
850
10.0
5
650


P23
2.8
70
330
330
50
850
10.0
5
650


P24
2.8
70
330
330
50
850
10.0
5
650


P25
2.8
70
330
330
50
850
10.0
5
650


P26
2.8
70
330
330
50
850
10.0
5
650


P27
2.8
70
330
330
50
850
10.0
2
610


P28
2.8
70
330
330
50
850
10.0
10
690


P29
2.8
70
330
330
50
850
10.0
8
680


P30
2.8
70
330
330
50
850
10.0
5
650


P31
3.5
70
330
330
50
850
10.0
5
650


P32
3.5
70
330
330
50
850
10.0
5
650


P33
3.5
70
330
330
50
850
10.0
5
650


P34
3.5
70
330
330
50
850
10.0
5
650


P35
3.5
70
330
330
50
850
10.0
5
650


P36
3.5
70
330
330
50
850
10.0
5
650


P37
3.5
70
330
330
50
850
10.0
5
650


P38
3.5
70
330
330
50
850
10.0
5
650


P39
3.5
70
330
330
50
850
10.0
5
650


P40
3.5
70

620


620

50
850
10.0
5
650


P41
3.5
70
330
330

27

850
10.0
5
650


P42
3.5
70
330
330

73

850
10.0
5
650


P43
3.5
70
330
330
50

730

10.0
5
650














FOURTH-COOLING
OVERAGEING TREATMENT
COATING













AVERAGE
TEMPERATURE
AGEING

TREATMENT















COOLING
AT COOLING
TEMPERATURE
CALCULATED
AGEING

ALLOYING


PRODUCTION
RATE/
FINISH/
T2/
UPPER VALUE
TIME

TREATMENT/


No.
° C./second
° C.
° C.
OF t2/s
t2/s
GALVANIZING
° C.





P1
90
550
550
20184
120
unconducted
unconducted


P2
90
550
550
20184
120
unconducted
unconducted


P3
90
550
550
20184
120
unconducted
unconducted


P4
90
550
550
20184
120
unconducted
unconducted


P5
90
550
550
20184
120
unconducted
unconducted


P6
90
550
550
20184
120
unconducted
unconducted


P7
90
550
550
20184
120
unconducted
unconducted


P8
90
550
550
20184
120
unconducted
unconducted


P9
90
550
550
20184
120
unconducted
unconducted


P10
90
550
550
20184
120
unconducted
unconducted


P11
90
550
550
20184
120
unconducted
unconducted


P12
90
550
550
20184
120
unconducted
unconducted


P13
90
230
230
609536897
120
unconducted
unconducted


P14
10
580
580
966051
120
unconducted
unconducted


P15
250
220
220
3845917820
120
unconducted
unconducted


P16
90
550
550
20184
120
unconducted
unconducted


P17
90
550
550
20184
120
unconducted
unconducted


P18
90
550
550
20184
120
unconducted
unconducted


P19
90
550
550
20184
120
unconducted
unconducted


P20
90
550
550
20184
120
unconducted
unconducted


P21
90
550
550
20184
120
unconducted
unconducted


P22
90
550
550
20184
120
unconducted
unconducted


P23
90
550
550
20184
120
unconducted
unconducted


P24
90
550
550
20184
120
unconducted
unconducted


P25
90
550
550
20184
120
unconducted
unconducted


P26
90
550
550
20184
120
unconducted
unconducted


P27
90
230
230
609536897
120
unconducted
unconducted


P28
10
580
580
966051
120
unconducted
unconducted


P29
250
220
220
3845917820
120
unconducted
unconducted


P30
90
550
550
20184
120
unconducted
unconducted


P31
90
550
550
20184
120
unconducted
unconducted


P32
90
550
550
20184
120
unconducted
unconducted


P33
90
550
550
20184
120
unconducted
unconducted


P34
90
550
550
20184
120
unconducted
unconducted


P35
90
550
550
20184
120
unconducted
unconducted


P36
90
550
550
20184
120
unconducted
unconducted


P37
90
550
550
20184
120
unconducted
unconducted


P38
90
550
550
20184
120
unconducted
unconducted


P39
90
550
550
20184
120
unconducted
unconducted


P40
90
550
550
20184
120
unconducted
unconducted


P41
90
550
550
20184
120
unconducted
unconducted


P42
90
550
550
20184
120
unconducted
unconducted


P43
90
550
550
20184
120
unconducted
unconducted





















TABLE 13









SECOND-COOLING

HEATING AND













TIME

HOLDING
THIRD-COOLING
















PRO-
UNTIL
AVERAGE
TEMPERATURE
COILING
COLD-
HEATING

AVERAGE
TEMPERATURE


DUC-
SECOND
COOLING
AT COOLING
TEMPER-
ROLLING
TEMPER-

COOLING
AT COOLING


TION
COOLING
RATE/
FINISH/
ATURE/
CUMULATIVE
ATURE/
HOLDING
RATE/
FINISH/


No.
START/s
° C./second
° C.
° C.
REDUCTION/%
° C.
TIME/s
° C./second
° C.





P44
3.5
70
330
330
50
920
10.0
5
650


P45
3.5
70
330
330
50
850
0.5
5
650


P46
3.5
70
330
330
50
850

1005.0

5
650


P47
3.5
70
330
330
50
850
10.0
  0.5
650


P48
3.5
70
330
330
50
850
10.0

13

650


P49
3.5
70
330
330
50
850
10.0
5

560



P50
3.5
70
330
330
50
850
10.0
5

740



P51
3.5
70
330
330
50
850
10.0
5
650


P52
3.5
70
330
330
50
850
10.0
5
650


P53
3.5
70
330
330
50
850
10.0
5
650


P54
3.5
70
330
330
50
850
10.0
5
650


P55
3.5
70
330
330
50
850
10.0
5
650


P56
3.5
70
330
330
50
850
10.0
5
650


P57
3.5
70
330
330
50
850
10.0
5
650


P58
3.5
70
330
330
50
850
10.0
5
650


P59
3.5
70
330
330
50
850
10.0
5
650


P60
3.5
70
330
330
50
850
10.0
5
650


P61
3.5
70
330
330
50
850
10.0
5
650


P62
3.5
70
330
330
50
850
10.0
5
650


P63
3.5
70
330
330
50
850
10.0
5
650


P64
3.5
70
330
330
50
850
10.0
5
650


P65
3.5
70

620


620

50
850
10.0
5
650


P66
3.5
70
330
330

27

850
10.0
5
650


P67
3.5
70
330
330

73

850
10.0
5
650


P68
3.5
70
330
330
50

730

10.0
5
650


P69
3.5
70
330
330
50

920

10.0
5
650


P70
3.5
70
330
330
50
850
0.5
5
650


P71
3.5
70
330
330
50
850

1005.0

5
650


P72
3.5
70
330
330
50
850
10.0
  0.5
650


P73
3.5
70
330
330
50
850
10.0

13

650


P74
3.5
70
330
330
50
850
10.0
5

560



P75
3.5
70
330
330
50
850
10.0
5

740



P76
3.5
70
330
330
50
850
10.0
5
650


P77
3.5
70
330
330
50
850
10.0
5
650


P78
3.5
70
330
330
50
850
10.0
5
650


P79
3.5
70
330
330
50
850
10.0
5
650


P80
3.5
70
330
330
50
850
10.0
5
650


P81
3.5
70
330
330
50
850
10.0
5
650


P82
3.5
70
330
330
50
850
10.0
5
650


P83
3.5
70
330
330
50
850
10.0
5
650


P84
3.5
70
330
330
50
850
10.0
5
650


P85
3.5
70
330
330
50
850
10.0
5
650


P86
3.5
70
330
330
50
850
10.0
5
650














FOURTH-COOLING
OVERAGEING TREATMENT
COATING













AVERAGE
TEMPERATURE
AGEING

TREATMENT















COOLING
AT COOLING
TEMPERATURE
CALCULATED
AGEING

ALLOYING


PRODUCTION
RATE/
FINISH/
T2/
UPPER VALUE
TIME

TREATMENT/


No.
° C./second
° C.
° C.
OF t2/s
t2/s
GALVANIZING
° C.





P44
90
550
550
20184
120
unconducted
unconducted


P45
90
550
550
20184
120
unconducted
unconducted


P46
90
550
550
20184
120
unconducted
unconducted


P47
90
550
550
20184
120
unconducted
unconducted


P48
250 
220
220
3845917820
120
unconducted
unconducted


P49
90
550
550
20184
120
unconducted
unconducted


P50
250 
220
220
3845917820
120
unconducted
unconducted


P51
2
550
550
20184
120
unconducted
unconducted


P52

320

220
220
3845917820
120
unconducted
unconducted


P53
90

180


180

15310874616820
120
unconducted
unconducted


P54
90

620


620

609536897
120
unconducted
unconducted


P55
90
450
450
20

120

unconducted
unconducted


P56
90
550
550
20184
120
unconducted
unconducted


P57
90
550
550
20184
120
unconducted
unconducted


P58
90
550
550
20184
120
unconducted
unconducted


P59
90
550
550
20184
120
unconducted
unconducted


P60
90
550
550
20184
120
unconducted
unconducted


P61
90
550
550
20184
120
unconducted
unconducted


P62
90
550
550
20184
120
unconducted
unconducted


P63
90
550
550
20184
120
unconducted
unconducted


P64
90
550
550
20184
120
unconducted
unconducted


P65
90
550
550
20184
120
unconducted
unconducted


P66
90
550
550
20184
120
unconducted
unconducted


P67
90
550
550
20184
120
unconducted
unconducted


P68
90
550
550
20184
120
unconducted
unconducted


P69
90
550
550
20184
120
unconducted
unconducted


P70
90
550
550
20184
120
unconducted
unconducted


P71
90
550
550
20184
120
unconducted
unconducted


P72
90
550
550
20184
120
unconducted
unconducted


P73
250
220
220
3845917820
120
unconducted
unconducted


P74
90
550
550
20184
120
unconducted
unconducted


P75
250 
220
220
3845917820
120
unconducted
unconducted


P76
2
550
550
20184
120
unconducted
unconducted


P77

320

220
220
3845917820
120
unconducted
unconducted


P78
90

180


180

15310874616820
120
unconducted
unconducted


P79
90

620


620

609536897
120
unconducted
unconducted


P80
90
450
450
20

120

unconducted
unconducted


P81
90
550
550
20184
120
unconducted
unconducted


P82
90
550
550
20184
120
unconducted
unconducted


P83
90
550
550
20184
120
unconducted
unconducted


P84
90
550
550
20184
120
unconducted
unconducted


P85
90
550
550
20184
120
unconducted
unconducted


P86
90
550
550
20184
120
unconducted
unconducted






















TABLE 14









SECOND-COOLING


HEATING AND















TIME

TEMPERA-


HOLDING
THIRD-COOLING

















UNTIL
AVERAGE
TURE AT
COILING
COLD-
HEATING

AVERAGE
TEMPERATURE


PRODUC-
SECOND
COOLING
COOLING
TEMPERA-
ROLLING
TEMPERA-

COOLING
AT COOLING


TION
COOLING
RATE/
FINISH/
TURE/
CUMULATIVE
TURE/
HOLDING
RATE/
FINISH/


No.
START/s
° C./second
° C.
° C.
REDUCTION/%
° C.
TIME/s
° C./second
° C.





P87
3.5
70
330
330
50
850
10.0
5
650


P88
3.5
70
330
330
50
850
10.0
5
650








P89
Cracks occur during Hot rolling
















P90
3.5
70
330
330
50
850
10.0
5
650


P91
3.5
70
330
330
50
850
10.0
5
650


P92
3.5
70
330
330
50
850
10.0
5
650


P93
3.5
70
330
330
50
850
10.0
5
650


P94
3.5
70
330
330
50
850
10.0
5
650


P95
3.5
70
330
330
50
850
10.0
5
650


P96
3.5
70
330
330
50
850
10.0
5
650


P97
3.5
70
330
330
50
850
10.0
5
650


P98
3.5
70
330
330
50
850
10.0
5
650


P99
3.5
70
330
330
50
850
10.0
5
650


P100
3.5
70
330
330
50
850
10.0
5
650


P101
3.5
70
330
330
50
850
10.0
5
650


P102
3.5
70
330
330
50
850
10.0
5
650


P103
3.5
70
330
330
50
850
10.0
5
650


P104
3.5
70
330
330
50
850
10.0
5
650


P105
3.5
70
330
330
50
850
10.0
5
650


P106
3.5
70
330
330
50
850
10.0
5
650


P107
3.5
70
330
330
50
850
10.0
5
650








P108
Cracks occur during Hot rolling


P109
Cracks occur during Hot rolling
















P110
3.5
70
330
330
50
850
10.0
5
650


P111
3.5
70
330
330
50
850
10.0
5
650


P112
3.5
70
330
330
50
850
10.0
5
650


P113
3.5
70
330
330
50
850
10.0
5
650


P114
3.5
70
330
330
50
850
10.0
5
650


P115
3.5
70
330
330
50
850
10.0
5
650


P116
3.5
70
330
330
50
850
10.0
5
650


P117
3.5
70
330
330
50
850
10.0
5
650


P118
3.5
70
330
330
50
850
10.0
5
650


P119
3.5
70
330
330
50
850
10.0
5
650


P120
3.5
70
330
330
50
850
10.0
5
650


P121
3.5
70
330
330
50
850
10.0
5
650


P122
3.5
70
330
330
50
850
10.0
5
650


P123
3.5
70
330
330
50
850
10.0
5
650


P124
3.5
70
330
330
50
850
10.0
5
650


P125
3.5
70
330
330
50
850
10.0
5
650


P126
3.5
70
330
330
50
850
10.0
5
650


P127
3.5
70
330
330
50
850
10.0
5
650


P128
3.5
70
330
330
50
850
10.0
5
650


P129
3.5
70
330
330
50
850
10.0
5
650
















COATING



FOURTH-COOLING
OVERAGEING TREATMENT
TREATMENT















AVERAGE
TEMPERATURE
AGEING



ALLOYING



COOLING
AT COOLING
TEMPERATURE
CALCULATED
AGEING

TREAT-


PRODUCTION
RATE/
FINISH/
T2/
UPPER VALUE
TIME

MENT/


No.
° C./second
° C.
° C.
OF t2/s
t2/s
GALVANIZING
° C.





P87
90
550
550
20184
120
unconducted
unconducted


P88
90
550
550
20184
120
unconducted
unconducted








P89
Cracks occur during Hot rolling














P90
90
550
550
20184
120
unconducted
unconducted


P91
90
550
550
20184
120
unconducted
unconducted


P92
90
550
550
20184
120
unconducted
unconducted


P93
90
550
550
20184
120
unconducted
unconducted


P94
90
550
550
20184
120
unconducted
unconducted


P95
90
550
550
20184
120
unconducted
unconducted


P96
90
550
550
20184
120
unconducted
unconducted


P97
90
550
550
20184
120
unconducted
unconducted


P98
90
550
550
20184
120
unconducted
unconducted


P99
90
550
550
20184
120
unconducted
unconducted


P100
90
550
550
20184
120
unconducted
unconducted


P101
90
550
550
20184
120
unconducted
unconducted


P102
90
550
550
20184
120
unconducted
unconducted


P103
90
550
550
20184
120
unconducted
unconducted


P104
90
550
550
20184
120
unconducted
unconducted


P105
90
550
550
20184
120
unconducted
unconducted


P106
90
550
550
20184
120
unconducted
unconducted


P107
90
550
550
20184
120
unconducted
unconducted








P108
Cracks occur during Hot rolling


P109
Cracks occur during Hot rolling














P110
90
550
550
20184
120
unconducted
unconducted


P111
90
550
550
20184
120
unconducted
unconducted


P112
90
550
550
20184
120
unconducted
unconducted


P113
90
550
550
20184
120
unconducted
unconducted


P114
90
550
550
20184
120
unconducted
unconducted


P115
90
550
550
20184
120
unconducted
unconducted


P116
90
550
550
20184
120
unconducted
unconducted


P117
90
550
550
20184
120
unconducted
unconducted


P118
90
550
550
20184
120
unconducted
unconducted


P119
90
550
550
20184
120
unconducted
unconducted


P120
90
550
550
20184
120
unconducted
unconducted


P121
90
550
550
20184
120
unconducted
unconducted


P122
90
550
550
20184
120
unconducted
unconducted


P123
90
550
550
20184
120
unconducted
unconducted


P124
90
550
550
20184
120
unconducted
unconducted


P125
90
550
550
20184
120
unconducted
unconducted


P126
90
550
550
20184
120
unconducted
unconducted


P127
90
550
550
20184
120
unconducted
unconducted


P128
90
550
550
20184
120
unconducted
unconducted


P129
90
550
550
20184
120
unconducted
unconducted






















TABLE 15









SECOND-COOLING


HEATING AND















TIME

TEMPERA-


HOLDING
THIRD-COOLING

















UNTIL
AVERAGE
TURE AT
COILING
COLD-
HEATING

AVERAGE
TEMPERATURE


PRODUC-
SECOND
COOLING
COOLING
TEMPERA-
ROLLING
TEMPERA-

COOLING
AT COOLING


TION
COOLING
RATE/
FINISH/
TURE/
CUMULATIVE
TURE/
HOLDING
RATE/
FINISH/


No.
START/s
° C./second
° C.
° C.
REDUCTION/%
° C.
TIME/s
° C./second
° C.





P130
3.5
70
330
330
50
850
10.0
5
650


P131
3.5
70
330
330
50
850
10.0
5
650


P132
3.5
70
330
330
50
850
10.0
5
650


P133
3.5
70
330
330
50
850
10.0
5
650


P134
3.5
70
330
330
50
850
10.0
5
650


P135
3.5
70
330
330
50
850
10.0
5
650


P136
3.5
70
330
330
50
850
10.0
5
650


P137
3.5
70
330
330
50
850
10.0
5
650


P138
3.5
70
330
330
50
850
10.0
5
650


P139
3.5
70
330
330
50
850
10.0
5
650


P140
3.5
70
330
330
50
850
10.0
5
650


P141
3.5
70
330
330
50
850
10.0
5
650


P142
3.5
70
330
330
50
850
10.0
5
650


P143
3.5
70
330
330
50
850
10.0
5
650


P144
3.5
70
330
330
50
850
10.0
5
650


P145
3.5
70
330
330
50
850
10.0
5
650


P146
3.5
70
330
330
50
850
10.0
5
650


P147
3.5
70
330
330
50
850
10.0
5
650


P148
3.5
70
330
330
50
850
10.0
5
650


P149
3.5
70
330
330
50
850
10.0
5
650


P150
3.5
70
330
330
50
850
10.0
5
650


P151
3.5
70
330
330
50
850
10.0
5
650


P152
3.5
70
330
330
50
850
10.0
5
650


P153
3.5
70
330
330
50
850
10.0
5
650


P154
3.5
70
330
330
50
850
10.0
5
650


P155
3.5
70
330
330
50
850
10.0
5
650


P156
3.5
70
330
330
50
850
10.0
5
650


P157
3.5
70
330
330
50
850
10.0
5
650


P158
3.5
70
330
330
50
850
10.0
5
650


P159
3.5
70
330
330
50
850
10.0
5
650


P160
3.5
70
330
330
50
850
10.0
5
650


P161
3.5
70
330
330
50
850
10.0
5
650


P162
3.5
70
330
330
50
850
10.0
5
650


P163
3.5
70
330
330
50
850
10.0
5
650


P164
3.5
70
330
330
50
850
10.0
5
650


P165
3.5
70
330
330
50
850
10.0
5
650


P166
3.5
70
330
330
50
850
10.0
5
650


P167
3.5
70
330
330
50
850
10.0
5
650


P168
3.5
70
330
330
50
850
10.0
5
650


P169
3.5
70
330
330
50
850
10.0
5
650


P170
3.5
70
330
330
50
850
10.0
5
650


P171
3.5
70
330
330
50
850
10.0
5
650


P172
3.5
70
330
330
50
850
10.0
5
650
















COATING



FOURTH-COOLING
OVERAGEING TREATMENT
TREATMENT















AVERAGE
TEMPERATURE
AGEING



ALLOYING



COOLING
AT COOLING
TEMPERATURE
CALCULATED
AGEING

TREAT-


PRODUCTION
RATE/
FINISH/
T2/
UPPER VALUE
TIME

MENT/


No.
° C./second
° C.
° C.
OF t2/s
t2/s
GALVANIZING
° C.





P130
90
550
550
20184
120
unconducted
unconducted


P131
90
550
550
20184
120
unconducted
unconducted


P132
90
550
550
20184
120
unconducted
unconducted


P133
90
550
550
20184
120
unconducted
unconducted


P134
90
550
550
20184
120
unconducted
unconducted


P135
90
550
550
20184
120
unconducted
unconducted


P136
90
550
550
20184
120
unconducted
unconducted


P137
90
550
550
20184
120
unconducted
unconducted


P138
90
550
550
20184
120
unconducted
unconducted


P139
90
550
550
20184
120
unconducted
unconducted


P140
90
550
550
20184
120
unconducted
unconducted


P141
90
550
550
20184
120
unconducted
unconducted


P142
90
550
550
20184
120
unconducted
unconducted


P143
90
550
550
20184
120
unconducted
unconducted


P144
90
550
550
20184
120
unconducted
unconducted


P145
90
550
550
20184
120
unconducted
unconducted


P146
90
550
550
20184
120
unconducted
unconducted


P147
90
550
550
20184
120
unconducted
unconducted


P148
90
550
550
20184
120
unconducted
unconducted


P149
90
550
550
20184
120
unconducted
unconducted


P150
90
550
550
20184
120
unconducted
unconducted


P151
90
550
550
20184
120
unconducted
unconducted


P152
90
550
550
20184
120
unconducted
unconducted


P153
90
550
550
20184
120
unconducted
unconducted


P154
90
550
550
20184
120
unconducted
unconducted


P155
90
550
550
20184
120
unconducted
unconducted


P156
90
550
550
20184
120
unconducted
unconducted


P157
90
550
550
20184
120
unconducted
unconducted


P158
90
550
550
20184
120
unconducted
unconducted


P159
90
550
550
20184
120
unconducted
unconducted


P160
90
550
550
20184
120
unconducted
unconducted


P161
90
550
550
20184
120
unconducted
unconducted


P162
90
550
550
20184
120
unconducted
unconducted


P163
90
550
550
20184
120
unconducted
unconducted


P164
90
550
550
20184
120
unconducted
unconducted


P165
90
550
550
20184
120
unconducted
unconducted


P166
90
550
550
20184
120
unconducted
unconducted


P167
90
550
550
20184
120
unconducted
unconducted


P168
90
550
550
20184
120
unconducted
unconducted


P169
90
550
550
20184
120
unconducted
unconducted


P170
90
550
550
20184
120
unconducted
unconducted


P171
90
550
550
20184
120
unconducted
unconducted


P172
90
550
550
20184
120
unconducted
unconducted





















TABLE 16









SECOND-COOLING

HEATING AND
THIRD-COOLING
















TIME

TEMPE-


HOLDING

TEMPE-

















UNTIL
AVERAGE
RATURE
COILING
COLD-
HEATING

AVERAGE
RATURE


PRODUC-
SECOND
COOLING
AT COOLING
TEMPER-
ROLLING
TEMPE-

COOLING
AT COOLING


TION
COOLING
RATE/
FINISH/
ATURE/
CUMULATIVE
RATURE/
HOLDING
RATE/
FINISH/


No.
START/s
° C./second
° C.
° C.
REDUCTION/%
° C.
TIME/s
° C./second
° C.





P173
3.5
70
330
330
50
850
10.0
5
650


P174
3.5
70
330
330
50
850
10.0
5
650


P175
3.5
70
330
330
50
850
10.0
5
650


P176
3.5
70
330
330
50
850
10.0
5
650


P177
3.5
70
330
330
50
850
10.0
5
650


P178
3.5
70
330
330
50
850
10.0
5
650


P179
3.5
70
330
330
50
850
10.0
5
650


P180
3.5
70
330
330
50
850
10.0
5
650


P181
3.5
70
330
330
50
850
10.0
5
650


P182
3.5
70
330
330
50
850
10.0
5
650


P183
3.5
70
330
330
50
850
10.0
5
650


P184
3.5
70
330
330
50
850
10.0
5
650


P185
3.5
70
330
330
50
850
10.0
5
650


P186
3.5
70
330
330
50
850
10.0
5
650


P187
3.5
70
330
330
50
850
10.0
5
650


P188
3.5
70
330
330
50
850
10.0
5
650


P189
3.5
70
330
330
50
850
10.0
5
650


P190
3.5
70
330
330
50
850
10.0
5
650


P191
3.5
70
330
330
50
850
10.0
5
650


P192
3.5
70
330
330
50
850
10.0
5
650


P193
3.5
70
330
330
50
850
10.0
5
650


P194
3.5
70
330
330
50
850
10.0
5
650


P195
3.5
70
330
330
50
850
10.0
5
650


P196
3.5
70
330
330
50
850
10.0
5
650


P197
3.5
70
330
330
50
850
10.0
5
650


P198
3.5
70
330
330
50
850
10.0
5
650


P199
3.5
70
330
330
50
850
10.0
5
650


P200
3.5
70
330
330
50
850
10.0
5
650


P201
3.5
70
330
330
50
850
10.0
5
650


P202
3.5
70
330
330
50
850
10.0
5
650


P203
3.5
70
330
330
50
850
10.0
5
650


P204
3.5
70
330
330
50
850
10.0
5
650


P205
3.5
70
330
330
50
850
10.0
5
650


P206
3.5
70
330
330
50
850
10.0
5
650


P207
3.5
70
330
330
50
850
10.0
5
650


P208
3.5
70
330
330
50
850
10.0
5
650


P209
3.5
70
330
330
50
850
10.0
5
650


P210
3.5
70
330
330
50
850
10.0
5
650


P211
3.5
70
330
330
50
850
10.0
5
650


P212
3.5
70
330
330
50
850
10.0
5
650


P213
3.5
70
330
330
50
850
10.0
5
650


P214
3.5
70
330
330
50
850
10.0
5
650














FOURTH-COOLING
OVERAGEING TREATMENT
COATING













AVERAGE
TEMPERATURE
AGEING

TREATMENT















COOLING
AT COOLING
TEMPERATURE
CALCULATED
AGEING

ALLOYING


PRODUCTION
RATE/
FINISH/
T2/
UPPER VALUE
TIME
GALVA-
TREATMENT/


No.
° C./second
° C.
° C.
OFt2/s
t2/s
NIZING
° C.





P173
90
550
550
20184
120
unconducted
unconducted


P174
90
550
550
20184
120
unconducted
unconducted


P175
90
550
550
20184
120
unconducted
unconducted


P176
90
550
550
20184
120
unconducted
unconducted


P177
90
550
550
20184
120
unconducted
unconducted


P178
90
550
550
20184
120
unconducted
unconducted


P179
90
550
550
20184
120
unconducted
unconducted


P180
90
550
550
20184
120
unconducted
unconducted


P181
90
550
550
20184
120
unconducted
unconducted


P182
90
550
550
20184
120
unconducted
unconducted


P183
90
550
550
20184
120
unconducted
unconducted


P184
90
550
550
20184
120
unconducted
unconducted


P185
90
550
550
20184
120
unconducted
unconducted


P186
90
550
550
20184
120
unconducted
unconducted


P187
90
550
550
20184
120
unconducted
unconducted


P188
90
550
550
20184
120
unconducted
unconducted


P189
90
550
550
20184
120
unconducted
unconducted


P190
90
550
550
20184
120
unconducted
unconducted


P191
90
550
550
20184
120
unconducted
unconducted


P192
90
550
550
20184
120
unconducted
unconducted


P193
90
550
550
20184
120
unconducted
unconducted


P194
90
550
550
20184
120
unconducted
unconducted


P195
90
550
550
20184
120
unconducted
unconducted


P196
90
550
550
20184
120
unconducted
unconducted


P197
90
550
550
20184
120
unconducted
unconducted


P198
90
550
550
20184
120
unconducted
unconducted


P199
90
550
550
20184
120
unconducted
unconducted


P200
90
550
550
20184
120
unconducted
unconducted


P201
90
550
550
20184
120
conducted
570


P202
90
550
550
20184
120
conducted
570


P203
90
550
550
20184
120
conducted
540


P204
90
550
550
20184
120
conducted
530


P205
90
550
550
20184
120
conducted
570


P206
90
550
550
20184
120
conducted
570


P207
90
550
550
20184
120
conducted
540


P208
90
550
550
20184
120
conducted
540


P209
90
550
550
20184
120
conducted
570


P210
90
550
550
20184
120
conducted
540


P211
90
550
550
20184
120
conducted
570


P212
90
550
550
20184
120
conducted
570


P213
90
550
550
20184
120
conducted
540


P214
90
550
550
20184
120
conducted
570


















TABLE 17









AREA FRACTION OF METALLOGRAPHIC STRUCTURE














PHASE WITH
AREA





EXCEPTION
FRACTION


PRODUCTION
TEXTURE

OF F, B,
OF COARSE

















No.
D1/—
D2/—
F/%
B/%
F + B/%
fM/%
P/%
γ/%
AND M/%
GRAINS/%





P1
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P2
4.5
3.5
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.5


P3
4.4
3.4
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.0


P4
4.9
3.8
75.0
22.0
97.0
3.0
0.0
0.0
0.0
7.5


P5
4.2
3.2
75.0
22.0
97.0
3.0
0.0
0.0
0.0
8.0


P6
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
7.5


P7
3.8
2.8
75.0
22.0
97.0
3.0
0.0
0.0
0.0
7.3


P8
4.4
3.4
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.0


P9
3.7
2.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
7.2


P10
4.2
3.2
75.0
22.0
97.0
3.0
0.0
0.0
0.0
8.0


P11
3.9
2.9
75.0
22.0
97.0
3.0
0.0
0.0
0.0
7.4


P12
4.6
3.6
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.0


P13
3.7
2.7
95.0
3.0
98.0
2.0
0.0
0.0
0.0
12.0


P14
3.7
2.7
22.0
75.0
97.0
2.0
1.0
0.0
1.0
7.2


P15
3.7
2.7
35.0
2.0
37.0
60.0 
0.0
3.0
3.0
7.2


P16
3.8
2.8
75.0
22.0
97.0
3.0
0.0
0.0
0.0
5.0


P17
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P18
3.8
2.8
75.0
22.0
97.0
3.0
0.0
0.0
0.0
15.0


P19
3.5
2.5
75.0
22.0
97.0
3.0
0.0
0.0
0.0
10.0


P20
3.3
2.3
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.5


P21
3.1
2.1
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.3


P22
3.7
2.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
11.0


P23
3.0
2.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.2


P24
3.5
2.5
75.0
22.0
97.0
3.0
0.0
0.0
0.0
10.0


P25
3.2
2.2
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.4


P26
3.9
2.9
75.0
22.0
97.0
3.0
0.0
0.0
0.0
11.0


P27
3.0
2.0
95.0
3.0
98.0
2.0
0.0
0.0
0.0
9.2


P28
3.0
2.0
22.0
75.0
97.0
2.0
1.0
0.0
1.0
9.2


P29
3.0
2.0
35.0
2.0
37.0
60.0 
0.0
3.0
3.0
9.2


P30
2.9
1.9
75.0
22.0
97.0
3.0
0.0
0.0
0.0
9.7


P31

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P32

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P33

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P34

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P35

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P36
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P37
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P38

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P39
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P40

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P41

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P42

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P43
4.7
3.7
77.0
23.0

100.0


0.0

0.0
0.0
0.0
12.0













SIZE OF METALLOGRAPHIC




STRUCTURE














VOLUME


AREA FRACTION




AVERAGE


WHERE La/Lb



PRODUCTION
DIAMETER/
dia/
dis/
≦5.0 IS



No.
μm
μm
μm
SATISFIED/%







P1
29.5
7.5
27.0
51.0



P2
28.5
7.0
26.5
53.0



P3
27.5
6.5
26.0
54.0



P4
22.0
5.5
25.5
55.0



P5
25.0
6.0
25.8
55.0



P6
22.0
5.5
25.5
56.0



P7
20.0
5.3
25.0
57.0



P8
27.5
6.5
26.0
54.0



P9
19.0
5.2
25.0
57.5



P10
25.0
6.0
25.8
55.0



P11
21.0
5.4
25.3
56.0



P12
27.5
6.5
26.0
54.0



P13
29.5
5.0
24.5
58.0



P14
19.0
5.2
25.0
57.5



P15
19.0
1.0
25.0
57.5



P16
15.0
4.2
24.3
59.5



P17
31.0
8.0
27.5
51.0



P18
35.0
8.5
28.0
50.6



P19
26.5
6.5
26.3
55.0



P20
23.5
6.0
26.0
56.0



P21
21.5
5.8
25.5
57.0



P22
29.0
7.0
26.5
54.0



P23
20.5
5.7
25.5
57.5



P24
26.5
6.5
26.3
55.0



P25
22.5
5.9
25.8
56.0



P26
29.0
7.0
26.5
54.0



P27
20.5
5.5
25.0
58.0



P28
20.5
5.7
25.5
57.5



P29
20.5
1.0
25.0
57.5



P30
22.5
6.0
26.2
57.3



P31
40.0
15.0
35.0
50.0



P32
40.0
15.0
35.0
50.0



P33
40.0
15.0
35.0
50.0



P34
42.0
15.0
35.0
45.0



P35
29.5
10.0
30.0
45.0



P36
40.0
15.0
35.0
50.0



P37
40.0
15.0
35.0
50.0



P38
29.5
10.0
30.0
50.0



P39
40.0
15.0
35.0
50.0



P40
29.5
10.0
30.0
45.0



P41
40.0
15.0
35.0
50.0



P42
29.5
10.0
30.0
45.0



P43
29.5






















TABLE 18









AREA FRACTION OF METALLOGRAPHIC STRUCTURE














PHASE WITH
AREA





EXCEPTION
FRACTION


PRODUCTION
TEXTURE

OF F, B,
OF COARSE

















No.
D1/—
D2/—
F/%
B/%
F + B/%
fM/%
P/%
γ/%
AND M/%
GRAINS/%





P44
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P45
4.7
3.7
77.0
23.0

100.0


0.0

0.0
0.0
0.0
12.0


P46
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
20.0


P47

5.1


4.1

78.0
1.5
79.5

0.5

20.0
0.0
20.0
12.0


P48
4.7
3.7
21.5
2.0

23.5


71.0

0.0
5.5
5.5
12.0


P49

5.1


4.1

78.0
1.5
79.5

0.5

20.0
0.0
20.0
12.0


P50
4.7
3.7
21.5
2.0

23.5


71.0

0.0
5.5
5.5
12.0


P51
5.1
4.1
78.0
1.5
79.5

0.5

20.0
0.0
20.0
12.0


P52
4.7
3.7
21.5
2.0

23.5


71.0

0.0
5.5
5.5
12.0


P53
4.7
3.7
21.5
2.0

23.5


71.0

0.0
5.5
5.5
12.0


P54

5.1


4.1

78.0
1.5
79.5

0.5

20.0
0.0
20.0
12.0


P55
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P56

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P57

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P58

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P59

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
16.0


P60

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
18.0


P61
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P62
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P63

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
16.0


P64
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P65

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
16.0


P66

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P67

5.1


4.1

75.0
22.0
97.0
3.0
0.0
0.0
0.0
16.0


P68
4.0
3.0
77.0
23.0

100.0


0.0

0.0
0.0
0.0
14.0


P69
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P70
4.0
3.0
77.0
23.0

100.0


0.0

0.0
0.0
0.0
14.0


P71
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
22.0


P72

5.1


4.1

78.0
1.5
79.5

0.5

20.0
0.0
20.0
14.0


P73
4.0
3.0
21.5
2.0

23.5


71.0

0.0
5.5
5.5
14.0


P74

5.1


4.1

78.0
1.5
79.5
0.5
20.0
0.0
20.0
14.0


P75
4.0
3.0
21.5
2.0

23.5


71.0

0.0
5.5
5.5
14.0


P76

5.1


4.1

78.0
1.5
79.5

0.5

20.0
0.0
20.0
14.0


P77
4.0
3.0
21.5
2.0

23.5


71.0

0.0
5.5
5.5
14.0


P78
4.0
3.0
21.5
2.0

23.5


71.0

0.0
5.5
5.5
14.0


P79

5.1


4.1

78.0
1.5
79.5

0.5

20.0
0.0
20.0
14.0


P80
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P81
4.7
3.7
76.5
23.3

99.8


0.2

0.0
0.0
0.0
12.0


P82
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P83
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P84
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P85
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P86
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0













SIZE OF METALLOGRAPHIC




STRUCTURE














VOLUME


AREA FRACTION




AVERAGE


WHERE La/Lb



PRODUCTION
DIAMETER/
dia/
dis/
≦5.0 IS



No.
μm
μm
μm
SATISFIED/%







P44
40.0
15.0
35.0
50.0



P45
29.5






P46
40.0
15.0
35.0
50.0



P47
29.5
7.5
27.0
51.0



P48
29.5
15.0
27.0
51.0



P49
29.5
7.5
27.0
51.0



P50
29.5
15.0
27.0
51.0



P51
29.5
7.5
27.0
51.0



P52
29.5
15.0
27.0
51.0



P53
29.5
15.0
27.0
51.0



P54
29.5
7.5
27.0
51.0



P55
29.5
7.5
27.0
51.0



P56
41.5
15.5
35.5
50.0



P57
41.5
15.5
35.5
50.0



P58
43.5
15.5
35.5
45.0



P59
31.0
10.5
30.5
45.0



P60
34.0
10.5
30.5
51.0



P61
41.5
15.5
35.5
50.0



P62
41.5
15.5
35.5
50.0



P63
31.0
10.5
30.5
50.0



P64
41.5
15.5
35.5
50.0



P65
31.0
10.5
30.5
45.0



P66
41.5
15.5
35.5
50.0



P67
31.0
10.5
30.5
45.0



P68
31.0






P69
41.5
15.5
35.5
50.0



P70
31.0






P71
41.5
15.5
35.5
50.0



P72
31.0
8.0
27.5
51.0



P73
31.0
15.5
27.5
51.0



P74
31.0
8.0
27.5
51.0



P75
31.0
15.5
27.5
51.0



P76
31.0
8.0
27.5
51.0



P77
31.0
15.5
27.5
51.0



P78
31.0
15.5
27.5
51.0



P79
31.0
8.0
27.5
51.0



P80
31.0
8.0
27.5
51.0



P81
29.5
7.5
27.0
51.0



P82
29.5
7.5
27.0
51.0



P83
29.5
7.5
27.0
51.0



P84
29.5
7.5
27.0
51.0



P85
29.5
7.5
27.0
51.0



P86
29.5
7.5
27.0
51.0



















TABLE 19









AREA FRACTION OF METALLOGRAPHIC STRUCTURE
























PHASE WITH
AREA










EXCEPTION
FRACTION


PRODUCTION
TEXTURE






OF F, B,
OF COARSE

















No.
D1/—
D2/—
F/%
B/%
F + B/%
fM/%
P/%
γ/%
AND M/%
GRAINS/%





P87
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P88
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0








P89
Cracks occur during Hot rolling

















P90
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P91
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P92
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P93
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P94
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P95
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P96
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P97

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P98

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P99

5.8


4.8

75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P100
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P101
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P102
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P103
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P104
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P105
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P106
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P107
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0








P108
Cracks occur during Hot rolling


P109
Cracks occur during Hot rolling

















P110
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P111
4.7
3.7
75.0
22.0
97.0
3.0
0.0
0.0
0.0
12.0


P112
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P113
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P114
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P115
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P116
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P117
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P118
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P119
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P120
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P121
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P122
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P123
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P124
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P125
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P126
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P127
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P128
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P129
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0













SIZE OF METALLOGRAPHIC




STRUCTURE














VOLUME


AREA FRACTION




AVERAGE


WHERE La/Lb



PRODUCTION
DIAMETER/
dia/
dis/
≦5.0 IS



No.
μm
μm
μm
SATISFIED/%







P87
29.5
7.5
27.0
51.0



P88
29.5
7.5
27.0
51.0










P89
Cracks occur during Hot rolling













P90
29.5
7.5
27.0
51.0



P91
29.5
7.5
27.0
51.0



P92
29.5
7.5
27.0
51.0



P93
29.5
7.5
27.0
51.0



P94
29.5
7.5
27.0
51.0



P95
29.5
7.5
27.0
51.0



P96
29.5
7.5
27.0
51.0



P97
29.5
7.5
27.0
51.0



P98
29.5
7.5
27.0
51.0



P99
29.5
7.5
27.0
51.0



P100
29.5
7.5
27.0
51.0



P101
29.5
7.5
27.0
51.0



P102
29.5
7.5
27.0
51.0



P103
29.5
7.5
27.0
51.0



P104
29.5
7.5
27.0
51.0



P105
29.5
7.5
27.0
51.0



P106
29.5
7.5
27.0
51.0



P107
29.5
7.5
27.0
51.0










P108
Cracks occur during Hot rolling



P109
Cracks occur during Hot rolling













P110
29.5
7.5
27.0
51.0



P111
29.5
7.5
27.0
51.0



P112
31.0
8.0
27.5
51.0



P113
31.0
8.0
27.5
51.0



P114
31.0
8.0
27.5
51.0



P115
31.0
8.0
27.5
51.0



P116
31.0
8.0
27.5
51.0



P117
31.0
8.0
27.5
51.0



P118
31.0
8.0
27.5
51.0



P119
31.0
8.0
27.5
51.0



P120
31.0
8.0
27.5
51.0



P121
31.0
8.0
27.5
51.0



P122
31.0
8.0
27.5
51.0



P123
31.0
8.0
27.5
51.0



P124
31.0
8.0
27.5
51.0



P125
31.0
8.0
27.5
51.0



P126
31.0
8.0
27.5
51.0



P127
31.0
8.0
27.5
51.0



P128
31.0
8.0
27.5
51.0



P129
31.0
8.0
27.5
51.0



















TABLE 20









AREA FRACTION OF METALLOGRAPHIC STRUCTURE
























PHASE WITH
AREA










EXCEPTION
FRACTION


PRODUCTION
TEXTURE






OF F, B,
OF COARSE

















No.
D1/—
D2/—
F/%
B/%
F + B/%
fM/%
P/%
γ/%
AND M/%
GRAINS/%





P130
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P131
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P132
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P133
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P134
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P135
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P136
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P137
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P138
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P139
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P140
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P141
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P142
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P143
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P144
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P145
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P146
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P147
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P148
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P149
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P150
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P151
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P152
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P153
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P154
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P155
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P156
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P157
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P158
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P159
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P160
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P161
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P162
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P163
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P164
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P165
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P166
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P167
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P168
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P169
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P170
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P171
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P172
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0













SIZE OF METALLOGRAPHIC




STRUCTURE














VOLUME


AREA FRACTION




AVERAGE


WHERE La/Lb



PRODUCTION
DIAMETER/
dia/
dis/
≦5.0 IS



No.
μm
μm
μm
SATISFIED/%







P130
31.0
8.0
27.5
51.0



P131
31.0
8.0
27.5
51.0



P132
31.0
8.0
27.5
51.0



P133
31.0
8.0
27.5
51.0



P134
31.0
8.0
27.5
51.0



P135
31.0
8.0
27.5
51.0



P136
31.0
8.0
27.5
51.0



P137
31.0
8.0
27.5
51.0



P138
31.0
8.0
27.5
51.0



P139
31.0
8.0
27.5
51.0



P140
31.0
8.0
27.5
51.0



P141
31.0
8.0
27.5
51.0



P142
31.0
8.0
27.5
51.0



P143
31.0
8.0
27.5
51.0



P144
31.0
8.0
27.5
51.0



P145
31.0
8.0
27.5
51.0



P146
31.0
8.0
27.5
51.0



P147
31.0
8.0
27.5
51.0



P148
31.0
8.0
27.5
51.0



P149
31.0
8.0
27.5
51.0



P150
31.0
8.0
27.5
51.0



P151
31.0
8.0
27.5
51.0



P152
31.0
8.0
27.5
51.0



P153
31.0
8.0
27.5
51.0



P154
31.0
8.0
27.5
51.0



P155
31.0
8.0
27.5
51.0



P156
31.0
8.0
27.5
51.0



P157
31.0
8.0
27.5
51.0



P158
31.0
8.0
27.5
51.0



P159
31.0
8.0
27.5
51.0



P160
31.0
8.0
27.5
51.0



P161
31.0
8.0
27.5
51.0



P162
31.0
8.0
27.5
51.0



P163
31.0
8.0
27.5
51.0



P164
31.0
8.0
27.5
51.0



P165
31.0
8.0
27.5
51.0



P166
31.0
8.0
27.5
51.0



P167
31.0
8.0
27.5
51.0



P168
31.0
8.0
27.5
51.0



P169
31.0
8.0
27.5
51.0



P170
31.0
8.0
27.5
51.0



P171
31.0
8.0
27.5
51.0



P172
31.0
8.0
27.5
51.0



















TABLE 21









AREA FRACTION OF METALLOGRAPHIC STRUCTURE
























PHASE WITH
AREA










EXCEPTION
FRACTION


PRODUCTION
TEXTURE






OF F, B,
OF COARSE

















No.
D1/—
D2/—
F/%
B/%
F + B/%
fM/%
P/%
γ/%
AND M/%
GRAINS/%





P173
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P174
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P175
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P176
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P177
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P178
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P179
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P180
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P181
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P182
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P183
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P184
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P185
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P186
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P187
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P188
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P189
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P190
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P191
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P192
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P193
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P194
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P195
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P196
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P197
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P198
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P199
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P200
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P201
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P202
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P203
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P204
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P205
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P206
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P207
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P208
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P209
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P210
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P211
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P212
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P213
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0


P214
4.0
3.0
75.0
22.0
97.0
3.0
0.0
0.0
0.0
14.0













SIZE OF METALLOGRAPHIC




STRUCTURE














VOLUME


AREA FRACTION




AVERAGE


WHERE La/Lb



PRODUCTION
DIAMETER/
dia/
dis/
≦5.0 IS



No.
μm
μm
μm
SATISFIED/%







P173
31.0
8.0
27.5
51.0



P174
31.0
8.0
27.5
51.0



P175
31.0
8.0
27.5
51.0



P176
31.0
8.0
27.5
51.0



P177
31.0
8.0
27.5
51.0



P178
31.0
8.0
27.5
51.0



P179
31.0
8.0
27.5
51.0



P180
31.0
8.0
27.5
51.0



P181
31.0
8.0
27.5
51.0



P182
31.0
8.0
27.5
51.0



P183
31.0
8.0
27.5
51.0



P184
31.0
8.0
27.5
51.0



P185
31.0
8.0
27.5
51.0



P186
31.0
8.0
27.5
51.0



P187
31.0
8.0
27.5
51.0



P188
31.0
8.0
27.5
51.0



P189
31.0
8.0
27.5
51.0



P190
31.0
8.0
27.5
51.0



P191
31.0
8.0
27.5
51.0



P192
31.0
8.0
27.5
51.0



P193
31.0
8.0
27.5
51.0



P194
31.0
8.0
27.5
51.0



P195
31.0
8.0
27.5
51.0



P196
31.0
8.0
27.5
51.0



P197
31.0
8.0
27.5
51.0



P198
31.0
8.0
27.5
51.0



P199
31.0
8.0
27.5
51.0



P200
31.0
8.0
27.5
51.0



P201
31.0
8.0
27.5
51.0



P202
31.0
8.0
27.5
51.0



P203
31.0
8.0
27.5
51.0



P204
31.0
8.0
27.5
51.0



P205
31.0
8.0
27.5
51.0



P206
31.0
8.0
27.5
51.0



P207
31.0
8.0
27.5
51.0



P208
31.0
8.0
27.5
51.0



P209
31.0
8.0
27.5
51.0



P210
31.0
8.0
27.5
51.0



P211
31.0
8.0
27.5
51.0



P212
31.0
8.0
27.5
51.0



P213
31.0
8.0
27.5
51.0



P214
31.0
8.0
27.5
51.0





















TABLE 22









PRODUCTION
LANKFORD-VLAUE















No.
rL/—
rC/—
r30/—
r60/—
REMARKS







P1
0.74
0.76
1.44
1.45
EXAMPLE



P2
0.76
0.78
1.42
1.43
EXAMPLE



P3
0.78
0.80
1.40
1.42
EXAMPLE



P4
0.72
0.74
1.46
1.48
EXAMPLE



P5
0.84
0.85
1.35
1.36
EXAMPLE



P6
0.86
0.87
1.33
1.34
EXAMPLE



P7
0.89
0.91
1.29
1.31
EXAMPLE



P8
0.78
0.80
1.40
1.42
EXAMPLE



P9
0.92
0.92
1.28
1.28
EXAMPLE



P10
0.84
0.85
1.35
1.36
EXAMPLE



P11
0.86
0.87
1.33
1.34
EXAMPLE



P12
0.76
0.77
1.43
1.44
EXAMPLE



P13
0.92
0.92
1.28
1.28
EXAMPLE



P14
0.92
0.92
1.28
1.28
EXAMPLE



P15
0.92
0.92
1.28
1.28
EXAMPLE



P16
0.90
0.92
1.28
1.29
EXAMPLE



P17
0.89
0.91
1.29
1.31
EXAMPLE



P18
0.95
0.96
1.24
1.25
EXAMPLE



P19
0.98
1.00
1.20
1.22
EXAMPLE



P20
1.00
1.01
1.19
1.20
EXAMPLE



P21
1.04
1.04
1.16
1.16
EXAMPLE



P22
0.92
0.94
1.26
1.28
EXAMPLE



P23
1.06
1.07
1.13
1.14
EXAMPLE



P24
0.98
1.00
1.20
1.22
EXAMPLE



P25
1.00
1.01
1.19
1.20
EXAMPLE



P26
0.90
0.92
1.28
1.29
EXAMPLE



P27
1.06
1.07
1.13
1.14
EXAMPLE



P28
1.06
1.07
1.13
1.14
EXAMPLE



P29
1.06
1.07
1.13
1.14
EXAMPLE



P30
1.08
1.09
1.11
1.12
EXAMPLE



P31
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P32
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P33
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P34
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P35
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P36
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P37
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P38
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P39
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P40
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P41
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P42
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P43
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE














MECHANICAL PROPERTIES


















STANDARD











DEVIATION


PRODUCTION
RATIO OF
TS/



TS × u-EL/
TS × EL/
TS × λ/


No.
HARDNESS/—
MPa
u-EL/%
EL/%
λ/%
MPa %
MPa %
MPa %
REMARKS





P1
0.23
600
15
29
71.0
9000
17400
42600
EXAMPLE


P2
0.23
610
16
31
73.0
9760
18910
44530
EXAMPLE


P3
0.23
620
17
33
74.0
10540
20460
45880
EXAMPLE


P4
0.23
630
18
34
67.0
11340
21420
42210
EXAMPLE


P5
0.23
625
18
34
79.0
11250
21250
49375
EXAMPLE


P6
0.22
630
19
36
80.0
11970
22680
50400
EXAMPLE


P7
0.21
640
20
37
82.0
12800
23680
52480
EXAMPLE


P8
0.21
620
17
33
74.0
10540
20460
45880
EXAMPLE


P9
0.18
645
21
39
83.0
13545
25155
53535
EXAMPLE


P10
0.21
620
18
34
79.0
11160
21080
48980
EXAMPLE


P11
0.21
640
20
37
81.0
12800
23680
51840
EXAMPLE


P12
0.21
620
17
33
72.0
10540
20460
44640
EXAMPLE


P13
0.18
580
25
45
85.0
14500
26100
49300
EXAMPLE


P14
0.18
900
13
16
75.0
11700
14400
67500
EXAMPLE


P15
0.18
1220
8
12
35.0
9760
14640
42700
EXAMPLE


P16
0.18
655
23
42
81.0
15065
27510
53055
EXAMPLE


P17
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P18
0.23
560
13
25
81.0
7280
14000
45360
EXAMPLE


P19
0.23
600
14
28
88.0
8400
16800
52800
EXAMPLE


P20
0.22
610
15
29
89.0
9150
17690
54290
EXAMPLE


P21
0.21
620
16
31
91.0
9920
19220
56420
EXAMPLE


P22
0.21
600
13
27
85.0
7800
16200
51000
EXAMPLE


P23
0.18
625
17
33
94.0
10625
20625
58750
EXAMPLE


P24
0.21
600
14
28
88.0
8400
16800
52800
EXAMPLE


P25
0.21
620
16
31
90.0
9920
19220
55800
EXAMPLE


P26
0.21
600
13
27
81.0
7800
16200
48600
EXAMPLE


P27
0.18
560
21
39
94.0
11760
21840
52640
EXAMPLE


P28
0.18
880
14
16
104.0
12320
14080
91520
EXAMPLE


P29
0.18
1200
8
12
35.0
9600
14400
42000
EXAMPLE


P30
0.18
615
16
31
94.5
9840
19065
58118
EXAMPLE


P31
0.23
460
9
24
55.0
4140
11040
25300
COMPARATIVE EXAMPLE


P32
0.24
460
9
24
55.0
4140
11040
25300
COMPARATIVE EXAMPLE


P33
0.23
460
9
24
55.0
4140
11040
25300
COMPARATIVE EXAMPLE


P34
0.23
470
9
24
55.0
4230
11280
25850
COMPARATIVE EXAMPLE


P35
0.23
470
9
24
55.0
4230
11280
25850
COMPARATIVE EXAMPLE


P36
0.23
460
9
24
65.0
4140
11040
29900
COMPARATIVE EXAMPLE


P37
0.23
460
9
24
65.0
4140
11040
29900
COMPARATIVE EXAMPLE


P38
0.23
490
9
24
55.0
4410
11760
26950
COMPARATIVE EXAMPLE


P39
0.23
460
9
24
65.0
4140
11040
29900
COMPARATIVE EXAMPLE


P40
0.23
470
9
24
55.0
4230
11280
25850
COMPARATIVE EXAMPLE


P41
0.23
460
9
24
55.0
4140
11040
25300
COMPARATIVE EXAMPLE


P42
0.23
470
9
24
55.0
4230
11280
25850
COMPARATIVE EXAMPLE


P43
0.23
430
7
21
66.0
3010
9030
28380
COMPARATIVE EXAMPLE













OTHERS














PRODUCTION

Rm45/
TS/fM ×




No.
d/RmC/—
RmC/—
dis/dia/—
REMARKS







P1
1.0
1.9
720
EXAMPLE



P2
1.2
1.8
770
EXAMPLE



P3
1.1
1.8
827
EXAMPLE



P4
1.0
2.0
974
EXAMPLE



P5
1.2
1.7
896
EXAMPLE



P6
1.2
1.7
974
EXAMPLE



P7
1.3
1.6
1006
EXAMPLE



P8
1.1
1.8
827
EXAMPLE



P9
1.3
1.6
1034
EXAMPLE



P10
1.2
1.7
889
EXAMPLE



P11
1.2
1.7
1000
EXAMPLE



P12
1.1
1.9
827
EXAMPLE



P13
1.4
1.5
1421
EXAMPLE



P14
1.6
1.3
2163
EXAMPLE



P15
1.1
1.6
508
EXAMPLE



P16
1.3
1.6
1263
EXAMPLE



P17
1.2
1.7
676
EXAMPLE



P18
1.3
1.6
615
EXAMPLE



P19
1.4
1.5
809
EXAMPLE



P20
1.4
1.4
881
EXAMPLE



P21
1.5
1.4
909
EXAMPLE



P22
1.3
1.6
757
EXAMPLE



P23
1.5
1.3
932
EXAMPLE



P24
1.4
1.5
809
EXAMPLE



P25
1.4
1.4
904
EXAMPLE



P26
1.3
1.6
757
EXAMPLE



P27
1.6
1.3
1273
EXAMPLE



P28
1.8
1.0
1968
EXAMPLE



P29
1.3
1.5
500
EXAMPLE



P30
1.5
1.3
895
EXAMPLE



P31
0.7
2.4
358
COMPARATIVE EXAMPLE



P32
0.7
2.4
358
COMPARATIVE EXAMPLE



P33
0.7
2.4
358
COMPARATIVE EXAMPLE



P34
0.7
2.4
366
COMPARATIVE EXAMPLE



P35
0.7
2.4
470
COMPARATIVE EXAMPLE



P36
1.0
2.4
358
COMPARATIVE EXAMPLE



P37
1.0
2.4
358
COMPARATIVE EXAMPLE



P38
0.7
2.4
490
COMPARATIVE EXAMPLE



P39
1.0
2.4
358
COMPARATIVE EXAMPLE



P40
0.7
2.4
470
COMPARATIVE EXAMPLE



P41
0.7
2.4
358
COMPARATIVE EXAMPLE



P42
0.7
2.4
470
COMPARATIVE EXAMPLE



P43
1.0
2.0

COMPARATIVE EXAMPLE





















TABLE 23









PRODUCTION
LANKFORD-VLAUE















No.
rL/—
rC/—
r30/—
r60/—
REMARKS







P44
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P45
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P46
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P47
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P48
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P49
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P50
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P51
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P52
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P53
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P54
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P55
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P56
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P57
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P58
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P59
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P60
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P61
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P62
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P63
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P64
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P65
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P66
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P67
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P68
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P69
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P70
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P71
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P72
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P73
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P74
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P75
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P76
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P77
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P78
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P79
0.68

0.66


1.52

1.54
COMPARATIVE EXAMPLE



P80
0.89
0.91
1.29
1.31
COMPARATIVE EXAMPLE



P81
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P82
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P83
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P84
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P85
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P86
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE














MECHANICAL PROPERTIES


















STANDARD











DEVIATION


PRODUCTION
RATIO OF
TS/



TS × u-EL/
TS × EL/
TS × λ/



No.
HARDNESS/—
MPa
u-EL/%
EL/%
λ/%
MPa %
MPa %
MPa %
REMARKS





P44
0.23
460
9
24
65.0
4140
11040
29900
COMPARATIVE EXAMPLE


P45
0.23
430
7
21
66.0
3010
9030
28380
COMPARATIVE EXAMPLE


P46
0.23
460
9
24
65.0
4140
11040
29900
COMPARATIVE EXAMPLE


P47
0.23
500
8
22
55.0
4000
11000
27500
COMPARATIVE EXAMPLE


P48
0.23
1290
1
10
65.0
1290
12900
83850
COMPARATIVE EXAMPLE


P49
0.23
500
8
22
55.0
4000
11000
27500
COMPARATIVE EXAMPLE


P50
0.23
1290
1
10
65.0
1290
12900
83850
COMPARATIVE EXAMPLE


P51
0.23
500
8
22
55.0
4000
11000
27500
COMPARATIVE EXAMPLE


P52
0.23
1290
1
10
65.0
1290
12900
83850
COMPARATIVE EXAMPLE


P53
0.23
1290
1
10
65.0
1290
12900
83850
COMPARATIVE EXAMPLE


P54
0.23
500
8
22
55.0
4000
11000
27500
COMPARATIVE EXAMPLE


P55
0.23
430
8
22
65.0
3440
9460
27950
COMPARATIVE EXAMPLE


P56
0.23
440
5
19
64.0
2200
8360
28160
COMPARATIVE EXAMPLE


P57
0.24
440
5
19
64.0
2200
8360
28160
COMPARATIVE EXAMPLE


P58
0.23
450
7
21
64.0
3150
9450
28800
COMPARATIVE EXAMPLE


P59
0.23
450
7
21
64.0
3150
9450
28800
COMPARATIVE EXAMPLE


P60
0.23
430
8
22
64.0
3440
9460
27520
COMPARATIVE EXAMPLE


P61
0.23
440
7
21
75.0
3080
9240
33000
COMPARATIVE EXAMPLE


P62
0.23
440
7
21
75.0
3080
9240
33000
COMPARATIVE EXAMPLE


P63
0.23
470
5
19
64.0
2350
8930
30080
COMPARATIVE EXAMPLE


P64
0.23
440
7
21
75.0
3080
9240
33000
COMPARATIVE EXAMPLE


P65
0.23
450
7
21
64.0
3150
9450
28800
COMPARATIVE EXAMPLE


P66
0.23
440
5
19
64.0
2200
8360
28160
COMPARATIVE EXAMPLE


P67
0.23
450
7
21
64.0
3150
9450
28800
COMPARATIVE EXAMPLE


P68
0.23
410
3
17
75.0
1230
6970
30750
COMPARATIVE EXAMPLE


P69
0.23
440
7
21
75.0
3080
9240
33000
COMPARATIVE EXAMPLE


P70
0.23
410
3
17
75.0
1230
6970
30750
COMPARATIVE EXAMPLE


P71
0.23
440
7
21
75.0
3080
9240
33000
COMPARATIVE EXAMPLE


P72
0.23
480
4
18
55.0
1920
8640
26400
COMPARATIVE EXAMPLE


P73
0.23
1270
1
10
65.0
1270
12700
82550
COMPARATIVE EXAMPLE


P74
0.23
480
4
18
55.0
1920
8640
26400
COMPARATIVE EXAMPLE


P75
0.23
1270
1
10
65.0
1270
12700
82550
COMPARATIVE EXAMPLE


P76
0.23
480
4
18
55.0
1920
8640
26400
COMPARATIVE EXAMPLE


P77
0.23
1270
1
10
65.0
1270
12700
82550
COMPARATIVE EXAMPLE


P78
0.23
1270
1
10
65.0
1270
12700
82550
COMPARATIVE EXAMPLE


P79
0.23
480
4
18
55.0
1920
8640
26400
COMPARATIVE EXAMPLE


P80
0.23
410
4
18
65.0
1640
7380
26650
COMPARATIVE EXAMPLE


P81
0.23
410
7
21
66.0
2870
8610
27060
COMPARATIVE EXAMPLE


P82
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P83
0.23
430
15
29
71.0
6450
12470
30530
COMPARATIVE EXAMPLE


P84
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P85
0.23
430
15
29
71.0
6450
12470
30530
COMPARATIVE EXAMPLE


P86
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE













OTHERS














PRODUCTION

Rm45/
TS/fM ×




No.
d/RmC/—
RmC/—
dis/dia/—
REMARKS







P44
1.0
2.4
358
COMPARATIVE EXAMPLE



P45
1.0
2.0

COMPARATIVE EXAMPLE



P46
1.0
2.4
358
COMPARATIVE EXAMPLE



P47
0.7
2.4
3600
COMPARATIVE EXAMPLE



P48
1.0
2.4
33
COMPARATIVE EXAMPLE



P49
0.7
2.4
3600
COMPARATIVE EXAMPLE



P50
1.0
2.4
33
COMPARATIVE EXAMPLE



P51
0.7
2.4
3600
COMPARATIVE EXAMPLE



P52
1.0
2.4
33
COMPARATIVE EXAMPLE



P53
1.0
2.4
33
COMPARATIVE EXAMPLE



P54
0.7
2.4
3600
COMPARATIVE EXAMPLE



P55
1.0
2.4
516
COMPARATIVE EXAMPLE



P56
0.9
2.2
336
COMPARATIVE EXAMPLE



P57
0.9
2.2
336
COMPARATIVE EXAMPLE



P58
0.9
2.2
344
COMPARATIVE EXAMPLE



P59
0.9
2.2
436
COMPARATIVE EXAMPLE



P60
0.9
2.2
416
COMPARATIVE EXAMPLE



P61
1.1
1.8
336
COMPARATIVE EXAMPLE



P62
1.1
1.8
336
COMPARATIVE EXAMPLE



P63
0.9
2.2
455
COMPARATIVE EXAMPLE



P64
1.1
1.8
336
COMPARATIVE EXAMPLE



P65
0.9
2.2
436
COMPARATIVE EXAMPLE



P66
0.9
2.2
336
COMPARATIVE EXAMPLE



P67
0.9
2.2
436
COMPARATIVE EXAMPLE



P68
1.2
1.8

COMPARATIVE EXAMPLE



P69
1.1
1.8
336
COMPARATIVE EXAMPLE



P70
1.2
1.8

COMPARATIVE EXAMPLE



P71
1.1
1.8
336
COMPARATIVE EXAMPLE



P72
0.9
2.2
3300
COMPARATIVE EXAMPLE



P73
1.2
1.7
32
COMPARATIVE EXAMPLE



P74
0.9
2.2
3300
COMPARATIVE EXAMPLE



P75
1.2
1.7
32
COMPARATIVE EXAMPLE



P76
0.9
2.2
3300
COMPARATIVE EXAMPLE



P77
1.2
1.7
32
COMPARATIVE EXAMPLE



P78
1.1
1.7
32
COMPARATIVE EXAMPLE



P79
0.9
2.2
3300
COMPARATIVE EXAMPLE



P80
1.2
1.7
470
COMPARATIVE EXAMPLE



P81
1.0
2.0
7380
COMPARATIVE EXAMPLE



P82
1.0
2.3
1020
COMPARATIVE EXAMPLE



P83
1.0
1.9
516
COMPARATIVE EXAMPLE



P84
1.0
2.3
1020
COMPARATIVE EXAMPLE



P85
1.0
1.9
516
COMPARATIVE EXAMPLE



P86
1.0
2.3
1020
COMPARATIVE EXAMPLE





















TABLE 24









PRODUCTION
LANKFORD-VLAUE















No.
rL/—
rC/—
r30/—
r60/—
REMARKS







P87
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P88
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE












P89
Cracks occur during Hot rolling

COMPARATIVE EXAMPLE














P90
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P91
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P92
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P93
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P94
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P95
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P96
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P97
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P98
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P99
0.52

0.56


1.66

1.69
COMPARATIVE EXAMPLE



P100
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P101
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P102
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P103
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P104
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P105
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P106
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P107
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE












P108
Cracks occur during Hot rolling

COMPARATIVE EXAMPLE



P109
Cracks occur during Hot rolling

COMPARATIVE EXAMPLE














P110
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P111
0.74
0.76
1.44
1.45
COMPARATIVE EXAMPLE



P112
0.89
0.91
1.29
1.31
EXAMPLE



P113
0.89
0.91
1.29
1.31
EXAMPLE



P114
0.89
0.91
1.29
1.31
EXAMPLE



P115
0.89
0.91
1.29
1.31
EXAMPLE



P116
0.89
0.91
1.29
1.31
EXAMPLE



P117
0.89
0.91
1.29
1.31
EXAMPLE



P118
0.89
0.91
1.29
1.31
EXAMPLE



P119
0.89
0.91
1.29
1.31
EXAMPLE



P120
0.89
0.91
1.29
1.31
EXAMPLE



P121
0.89
0.91
1.29
1.31
EXAMPLE



P122
0.89
0.91
1.29
1.31
EXAMPLE



P123
0.89
0.91
1.29
1.31
EXAMPLE



P124
0.89
0.91
1.29
1.31
EXAMPLE



P125
0.89
0.91
1.29
1.31
EXAMPLE



P126
0.89
0.91
1.29
1.31
EXAMPLE



P127
0.89
0.91
1.29
1.31
EXAMPLE



P128
0.89
0.91
1.29
1.31
EXAMPLE



P129
0.89
0.91
1.29
1.31
EXAMPLE














MECHANICAL PROPERTIES


















STANDARD











DEVIATION


PRODUCTION
RATIO OF
TS/



TS × u-EL/
TS × EL/
TS × λ/


No.
HARDNESS/—
MPa
u-EL/%
EL/%
λ/%
MPa %
MPa %
MPa %
REMARKS





P87
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P88
0.23
590
11
29
62.0
6490
17110
36580
COMPARATIVE EXAMPLE









P89
Cracks occur during Hot rolling
COMPARATIVE EXAMPLE
















P90
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P91
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P92
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P93
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P94
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P95
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P96
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P97
0.23
790
8
22
55.0
6320
17380
43450
COMPARATIVE EXAMPLE


P98
0.23
830
8
22
55.0
6640
18260
45650
COMPARATIVE EXAMPLE


P99
0.23
790
8
22
55.0
6320
17380
43450
COMPARATIVE EXAMPLE


P100
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P101
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P102
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P103
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P104
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P105
0.23
590
8
22
62.0
4720
12980
36580
COMPARATIVE EXAMPLE


P106
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE


P107
0.23
850
8
22
62.0
6800
18700
52700
COMPARATIVE EXAMPLE









P108
Cracks occur during Hot rolling
COMPARATIVE EXAMPLE


P109
Cracks occur during Hot rolling
COMPARATIVE EXAMPLE
















P110
0.23
590
11
23
62.0
6490
13570
36580
COMPARATIVE EXAMPLE


P111
0.23
590
11
23
62.0
6490
13570
36580
COMPARATIVE EXAMPLE


P112
0.23
467
15
30
66.0
7005
14010
30822
EXAMPLE


P113
0.23
489
15
29
65.7
7335
14181
32127
EXAMPLE


P114
0.23
511
14
29
65.4
7154
14819
33419
EXAMPLE


P115
0.23
585
13
28
64.7
7605
16380
37850
EXAMPLE


P116
0.23
632
12
27
64.1
7584
17064
40511
EXAMPLE


P117
0.23
711
11
26
63.5
7821
18486
45149
EXAMPLE


P118
0.23
746
11
25
63.1
8206
18650
47073
EXAMPLE


P119
0.23
759
10
25
62.9
7590
18975
47741
EXAMPLE


P120
0.23
840
9
23
62.2
7560
19320
52248
EXAMPLE


P121
0.23
471
15
30
70.8
7065
14130
33347
EXAMPLE


P122
0.23
482
15
30
70.5
7230
14460
33981
EXAMPLE


P123
0.23
550
14
28
68.9
7700
15400
37895
EXAMPLE


P124
0.23
670
11
25
65.2
7370
16750
43684
EXAMPLE


P125
0.23
842
9
23
62.1
7578
19366
52288
EXAMPLE


P126
0.23
467
15
30
70.9
7005
14010
33110
EXAMPLE


P127
0.23
475
15
30
70.7
7125
14250
33583
EXAMPLE


P128
0.23
521
14
29
69.5
7294
15109
36210
EXAMPLE


P129
0.23
615
13
27
67.6
7995
16605
41574
EXAMPLE













OTHERS














PRODUCTION

Rm45/
TS/fM ×




No.
d/RmC/—
RmC/—
dis/dia/—
REMARKS







P87
1.0
2.3
708
COMPARATIVE EXAMPLE



P88
1.0
1.9
708
COMPARATIVE EXAMPLE











P89
Cracks occur during Hot rolling
COMPARATIVE EXAMPLE













P90
1.0
2.3
708
COMPARATIVE EXAMPLE



P91
1.0
2.3
708
COMPARATIVE EXAMPLE



P92
1.0
2.3
708
COMPARATIVE EXAMPLE



P93
1.0
2.3
1020
COMPARATIVE EXAMPLE



P94
1.0
2.3
1020
COMPARATIVE EXAMPLE



P95
1.0
2.3
1020
COMPARATIVE EXAMPLE



P96
1.0
2.3
1020
COMPARATIVE EXAMPLE



P97
0.7
2.4
948
COMPARATIVE EXAMPLE



P98
0.7
2.4
996
COMPARATIVE EXAMPLE



P99
0.7
2.4
948
COMPARATIVE EXAMPLE



P100
1.0
2.3
1020
COMPARATIVE EXAMPLE



P101
1.0
2.3
1020
COMPARATIVE EXAMPLE



P102
1.0
2.3
708
COMPARATIVE EXAMPLE



P103
1.0
2.3
708
COMPARATIVE EXAMPLE



P104
1.0
2.3
1020
COMPARATIVE EXAMPLE



P105
1.0
2.3
708
COMPARATIVE EXAMPLE



P106
1.0
2.3
1020
COMPARATIVE EXAMPLE



P107
1.0
2.3
1020
COMPARATIVE EXAMPLE











P108
Cracks occur during Hot rolling
COMPARATIVE EXAMPLE



P109
Cracks occur during Hot rolling
COMPARATIVE EXAMPLE













P110
1.0
2.3
708
COMPARATIVE EXAMPLE



P111
1.0
2.3
708
COMPARATIVE EXAMPLE



P112
1.4
1.4
535
EXAMPLE



P113
1.4
1.4
560
EXAMPLE



P114
1.3
1.6
586
EXAMPLE



P115
1.3
1.6
670
EXAMPLE



P116
1.2
1.7
724
EXAMPLE



P117
1.2
1.7
815
EXAMPLE



P118
1.1
1.8
855
EXAMPLE



P119
1.1
1.8
870
EXAMPLE



P120
1.0
2.0
963
EXAMPLE



P121
1.4
1.4
540
EXAMPLE



P122
1.4
1.4
552
EXAMPLE



P123
1.3
1.6
630
EXAMPLE



P124
1.2
1.7
768
EXAMPLE



P125
1.0
2.0
965
EXAMPLE



P126
1.4
1.4
535
EXAMPLE



P127
1.4
1.4
544
EXAMPLE



P128
1.3
1.6
597
EXAMPLE



P129
1.3
1.6
705
EXAMPLE





















TABLE 25









PRODUCTION
LANKFORD-VLAUE















No.
rL/—
rC/—
r30/—
r60/—
REMARKS







P130
0.89
0.91
1.29
1.31
EXAMPLE



P131
0.89
0.91
1.29
1.31
EXAMPLE



P132
0.89
0.91
1.29
1.31
EXAMPLE



P133
0.89
0.91
1.29
1.31
EXAMPLE



P134
0.89
0.91
1.29
1.31
EXAMPLE



P135
0.89
0.91
1.29
1.31
EXAMPLE



P136
0.89
0.91
1.29
1.31
EXAMPLE



P137
0.89
0.91
1.29
1.31
EXAMPLE



P138
0.89
0.91
1.29
1.31
EXAMPLE



P139
0.89
0.91
1.29
1.31
EXAMPLE



P140
0.89
0.91
1.29
1.31
EXAMPLE



P141
0.89
0.91
1.29
1.31
EXAMPLE



P142
0.89
0.91
1.29
1.31
EXAMPLE



P143
0.89
0.91
1.29
1.31
EXAMPLE



P144
0.89
0.91
1.29
1.31
EXAMPLE



P145
0.89
0.91
1.29
1.31
EXAMPLE



P146
0.89
0.91
1.29
1.31
EXAMPLE



P147
0.89
0.91
1.29
1.31
EXAMPLE



P148
0.89
0.91
1.29
1.31
EXAMPLE



P149
0.89
0.91
1.29
1.31
EXAMPLE



P150
0.89
0.91
1.29
1.31
EXAMPLE



P151
0.89
0.91
1.29
1.31
EXAMPLE



P152
0.89
0.91
1.29
1.31
EXAMPLE



P153
0.89
0.91
1.29
1.31
EXAMPLE



P154
0.89
0.91
1.29
1.31
EXAMPLE



P155
0.89
0.91
1.29
1.31
EXAMPLE



P156
0.89
0.91
1.29
1.31
EXAMPLE



P157
0.89
0.91
1.29
1.31
EXAMPLE



P158
0.89
0.91
1.29
1.31
EXAMPLE



P159
0.89
0.91
1.29
1.31
EXAMPLE



P160
0.89
0.91
1.29
1.31
EXAMPLE



P161
0.89
0.91
1.29
1.31
EXAMPLE



P162
0.89
0.91
1.29
1.31
EXAMPLE



P163
0.89
0.91
1.29
1.31
EXAMPLE



P164
0.89
0.91
1.29
1.31
EXAMPLE



P165
0.89
0.91
1.29
1.31
EXAMPLE



P166
0.89
0.91
1.29
1.31
EXAMPLE



P167
0.89
0.91
1.29
1.31
EXAMPLE



P168
0.89
0.91
1.29
1.31
EXAMPLE



P169
0.89
0.91
1.29
1.31
EXAMPLE



P170
0.89
0.91
1.29
1.31
EXAMPLE



P171
0.89
0.91
1.29
1.31
EXAMPLE



P172
0.89
0.91
1.29
1.31
EXAMPLE














MECHANICAL PROPERTIES


















STANDARD











DEVIATION


PRODUCTION
RATIO OF
TS/



TS × u-EL/
TS × EL/
TS × λ/


No.
HARDNESS/—
MPa
u-EL/%
EL/%
λ/%
MPa %
MPa %
MPa %
REMARKS





P130
0.23
698
11
25
64.8
7678
17450
45230
EXAMPLE


P131
0.23
740
11
25
63.9
8140
18500
47286
EXAMPLE


P132
0.23
777
10
24
63.3
7770
18648
49184
EXAMPLE


P133
0.23
801
10
24
62.8
8010
19224
50303
EXAMPLE


P134
0.23
845
9
23
61.9
7605
19435
52306
EXAMPLE


P135
0.23
590
12
24
60.0
7080
14160
35400
EXAMPLE


P136
0.23
590
13
24
70.0
7670
14160
41300
EXAMPLE


P137
0.23
590
13
24
80.0
7670
14160
47200
EXAMPLE


P138
0.23
590
13
24
80.0
7670
14160
47200
EXAMPLE


P139
0.23
590
12
24
60.0
7080
14160
35400
EXAMPLE


P140
0.23
570
14
29
80.0
7980
16530
45600
EXAMPLE


P141
0.23
570
13
28
80.0
7410
15960
45600
EXAMPLE


P142
0.23
570
13
28
80.0
7410
15960
45600
EXAMPLE


P143
0.23
590
12
27
75.0
7080
15930
44250
EXAMPLE


P144
0.23
590
12
27
75.0
7080
15930
44250
EXAMPLE


P145
0.23
590
13
25
80.0
7670
14750
47200
EXAMPLE


P146
0.23
590
13
24
65.0
7670
14160
38350
EXAMPLE


P147
0.23
590
12
24
65.0
7080
14160
38350
EXAMPLE


P148
0.23
590
13
25
80.0
7670
14750
47200
EXAMPLE


P149
0.23
590
13
24
65.0
7670
14160
38350
EXAMPLE


P150
0.23
590
12
24
65.0
7080
14160
38350
EXAMPLE


P151
0.23
590
13
25
80.0
7670
14750
47200
EXAMPLE


P152
0.23
590
13
24
65.0
7670
14160
38350
EXAMPLE


P153
0.23
590
12
24
65.0
7080
14160
38350
EXAMPLE


P154
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P155
0.23
650
12
26
74.0
7800
16900
48100
EXAMPLE


P156
0.23
780
11
23
68.0
8580
17940
53040
EXAMPLE


P157
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P158
0.23
680
12
26
74.0
8160
17680
50320
EXAMPLE


P159
0.23
720
11
23
68.0
7920
16560
48960
EXAMPLE


P160
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P161
0.23
640
12
26
75.0
7680
16640
48000
EXAMPLE


P162
0.23
780
11
23
70.0
8580
17940
54600
EXAMPLE


P163
0.23
780
10
20
58.0
7800
15600
45240
EXAMPLE


P164
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P165
0.23
570
13
28
85.0
7410
15960
48450
EXAMPLE


P166
0.23
570
13
30
90.0
7410
17100
51300
EXAMPLE


P167
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P168
0.23
570
13
27
85.0
7410
15390
48450
EXAMPLE


P169
0.23
570
13
30
90.0
7410
17100
51300
EXAMPLE


P170
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P171
0.23
570
13
27
85.0
7410
15390
48450
EXAMPLE


P172
0.23
570
13
29
89.0
7410
16530
50730
EXAMPLE













OTHERS














PRODUCTION

Rm45/
TS/fM ×




No.
d/RmC/—
RmC/—
dis/dia/—
REMARKS







P130
1.2
1.7
800
EXAMPLE



P131
1.1
1.8
848
EXAMPLE



P132
1.1
1.8
890
EXAMPLE



P133
1.1
1.8
918
EXAMPLE



P134
1.0
2.0
968
EXAMPLE



P135
1.2
1.7
676
EXAMPLE



P136
1.3
1.6
676
EXAMPLE



P137
1.3
1.6
676
EXAMPLE



P138
1.3
1.6
676
EXAMPLE



P139
1.2
1.7
676
EXAMPLE



P140
1.4
1.4
653
EXAMPLE



P141
1.3
1.6
653
EXAMPLE



P142
1.3
1.6
653
EXAMPLE



P143
1.2
1.7
676
EXAMPLE



P144
1.2
1.7
676
EXAMPLE



P145
1.2
1.7
676
EXAMPLE



P146
1.1
1.8
676
EXAMPLE



P147
1.1
1.8
676
EXAMPLE



P148
1.2
1.7
676
EXAMPLE



P149
1.1
1.8
676
EXAMPLE



P150
1.1
1.8
676
EXAMPLE



P151
1.2
1.7
676
EXAMPLE



P152
1.1
1.8
676
EXAMPLE



P153
1.1
1.8
676
EXAMPLE



P154
1.2
1.7
676
EXAMPLE



P155
1.1
1.8
745
EXAMPLE



P156
1.0
2.0
894
EXAMPLE



P157
1.2
1.7
676
EXAMPLE



P158
1.1
1.8
779
EXAMPLE



P159
1.0
2.0
825
EXAMPLE



P160
1.2
1.7
676
EXAMPLE



P161
1.1
1.8
733
EXAMPLE



P162
1.1
1.8
894
EXAMPLE



P163
1.0
2.0
894
EXAMPLE



P164
1.2
1.7
676
EXAMPLE



P165
1.3
1.6
653
EXAMPLE



P166
1.4
1.4
653
EXAMPLE



P167
1.2
1.7
676
EXAMPLE



P168
1.3
1.6
653
EXAMPLE



P169
1.4
1.4
653
EXAMPLE



P170
1.2
1.7
676
EXAMPLE



P171
1.3
1.6
653
EXAMPLE



P172
1.3
1.6
653
EXAMPLE





















TABLE 26









PRODUCTION
LANKFORD-VLAUE















No.
rL/—
rC/—
r30/—
r60/—
REMARKS







P173
0.89
0.91
1.29
1.31
EXAMPLE



P174
0.89
0.91
1.29
1.31
EXAMPLE



P175
0.89
0.91
1.29
1.31
EXAMPLE



P176
0.89
0.91
1.29
1.31
EXAMPLE



P177
0.89
0.91
1.29
1.31
EXAMPLE



P178
0.89
0.91
1.29
1.31
EXAMPLE



P179
0.89
0.91
1.29
1.31
EXAMPLE



P180
0.89
0.91
1.29
1.31
EXAMPLE



P181
0.89
0.91
1.29
1.31
EXAMPLE



P182
0.89
0.91
1.29
1.31
EXAMPLE



P183
0.89
0.91
1.29
1.31
EXAMPLE



P184
0.89
0.91
1.29
1.31
EXAMPLE



P185
0.89
0.91
1.29
1.31
EXAMPLE



P186
0.89
0.91
1.29
1.31
EXAMPLE



P187
0.89
0.91
1.29
1.31
EXAMPLE



P188
0.89
0.91
1.29
1.31
EXAMPLE



P189
0.89
0.91
1.29
1.31
EXAMPLE



P190
0.89
0.91
1.29
1.31
EXAMPLE



P191
0.89
0.91
1.29
1.31
EXAMPLE



P192
0.89
0.91
1.29
1.31
EXAMPLE



P193
0.89
0.91
1.29
1.31
EXAMPLE



P194
0.89
0.91
1.29
1.31
EXAMPLE



P195
0.89
0.91
1.29
1.31
EXAMPLE



P196
0.89
0.91
1.29
1.31
EXAMPLE



P197
0.89
0.91
1.29
1.31
EXAMPLE



P198
0.89
0.91
1.29
1.31
EXAMPLE



P199
0.89
0.91
1.29
1.31
EXAMPLE



P200
0.89
0.91
1.29
1.31
EXAMPLE



P201
0.89
0.91
1.29
1.31
EXAMPLE



P202
0.89
0.91
1.29
1.31
EXAMPLE



P203
0.89
0.91
1.29
1.31
EXAMPLE



P204
0.89
0.91
1.29
1.31
EXAMPLE



P205
0.89
0.91
1.29
1.31
EXAMPLE



P206
0.89
0.91
1.29
1.31
EXAMPLE



P207
0.89
0.91
1.29
1.31
EXAMPLE



P208
0.89
0.91
1.29
1.31
EXAMPLE



P209
0.89
0.91
1.29
1.31
EXAMPLE



P210
0.89
0.91
1.29
1.31
EXAMPLE



P211
0.89
0.91
1.29
1.31
EXAMPLE



P212
0.89
0.91
1.29
1.31
EXAMPLE



P213
0.89
0.91
1.29
1.31
EXAMPLE



P214
0.89
0.91
1.29
1.31
EXAMPLE













MECHANICAL PROPERTIES

















STANDARD











DEVIATION


PRODUCTION
RATIO OF
TS/



TS × u-EL/
TS × EL/
TS × λ/


No.
HARDNESS/—
MPa
u-EL/%
EL/%
λ/%
MPa %
MPa %
MPa %
REMARKS





P173
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P174
0.23
640
12
26
80.0
7680
16640
51200
EXAMPLE


P175
0.23
720
10
20
75.0
7200
14400
54000
EXAMPLE


P176
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P177
0.23
645
12
26
80.0
7740
16770
51600
EXAMPLE


P178
0.23
720
10
20
75.0
7200
14400
54000
EXAMPLE


P179
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P180
0.23
650
12
26
80.0
7800
16900
52000
EXAMPLE


P181
0.23
720
10
20
75.0
7200
14400
54000
EXAMPLE


P182
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P183
0.23
640
12
26
80.0
7680
16640
51200
EXAMPLE


P184
0.23
710
10
20
75.0
7100
14200
53250
EXAMPLE


P185
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P186
0.23
640
12
26
80.0
7680
16640
51200
EXAMPLE


P187
0.23
780
10
20
75.0
7800
15600
58500
EXAMPLE


P188
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P189
0.23
640
12
26
80.0
7680
16640
51200
EXAMPLE


P190
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P191
0.23
670
12
26
80.0
8040
17420
53600
EXAMPLE


P192
0.23
750
11
23
80.0
8250
17250
60000
EXAMPLE


P193
0.23
780
11
23
75.0
8580
17940
58500
EXAMPLE


P194
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P195
0.23
680
12
26
80.0
8160
17680
54400
EXAMPLE


P196
0.23
780
11
23
80.0
8580
17940
62400
EXAMPLE


P197
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P198
0.23
640
12
26
80.0
7680
16640
51200
EXAMPLE


P199
0.23
700
11
23
75.0
7700
16100
52500
EXAMPLE


P200
0.23
760
10
20
75.0
7600
15200
57000
EXAMPLE


P201
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P202
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P203
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P204
0.23
640
11
24
65.0
7040
15360
41600
EXAMPLE


P205
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P206
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P207
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P208
0.23
640
11
24
65.0
7040
15360
41600
EXAMPLE


P209
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P210
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P211
0.23
640
11
23
65.0
7040
14720
41600
EXAMPLE


P212
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P213
0.23
590
12
26
80.0
7080
15340
47200
EXAMPLE


P214
0.23
640
11
23
65.0
7040
14720
41600
EXAMPLE













OTHERS














PRODUCTION

Rm45/
TS/fM ×




No.
d/RmC/—
RmC/—
dis/dia/—
REMARKS







P173
1.2
1.7
676
EXAMPLE



P174
1.1
1.8
733
EXAMPLE



P175
1.0
2.0
825
EXAMPLE



P176
1.2
1.7
676
EXAMPLE



P177
1.1
1.8
739
EXAMPLE



P178
1.0
2.0
825
EXAMPLE



P179
1.2
1.7
676
EXAMPLE



P180
1.1
1.8
745
EXAMPLE



P181
1.0
2.0
825
EXAMPLE



P182
1.2
1.7
676
EXAMPLE



P183
1.1
1.8
733
EXAMPLE



P184
1.0
2.0
814
EXAMPLE



P185
1.2
1.7
676
EXAMPLE



P186
1.1
1.8
733
EXAMPLE



P187
1.0
2.0
894
EXAMPLE



P188
1.2
1.7
676
EXAMPLE



P189
1.1
1.8
733
EXAMPLE



P190
1.2
1.7
676
EXAMPLE



P191
1.2
1.7
768
EXAMPLE



P192
1.2
1.7
859
EXAMPLE



P193
1.1
1.8
894
EXAMPLE



P194
1.2
1.7
676
EXAMPLE



P195
1.2
1.7
779
EXAMPLE



P196
1.1
1.8
894
EXAMPLE



P197
1.2
1.7
676
EXAMPLE



P198
1.2
1.7
733
EXAMPLE



P199
1.1
1.8
802
EXAMPLE



P200
1.0
2.0
871
EXAMPLE



P201
1.2
1.7
676
EXAMPLE



P202
1.2
1.7
676
EXAMPLE



P203
1.2
1.7
676
EXAMPLE



P204
1.1
1.8
733
EXAMPLE



P205
1.2
1.7
676
EXAMPLE



P206
1.2
1.7
676
EXAMPLE



P207
1.2
1.7
676
EXAMPLE



P208
1.1
1.8
733
EXAMPLE



P209
1.2
1.7
676
EXAMPLE



P210
1.2
1.7
676
EXAMPLE



P211
1.0
2.0
733
EXAMPLE



P212
1.2
1.7
676
EXAMPLE



P213
1.2
1.7
676
EXAMPLE



P214
1.0
2.0
733
EXAMPLE










INDUSTRIAL APPLICABILITY

According to the above aspects of the present invention, it is possible to obtain the cold-rolled steel sheet which simultaneously has the high-strength, the excellent uniform deformability, the excellent local deformability, and the excellent Lankford-value. Accordingly, the present invention has significant industrial applicability.

Claims
  • 1. A cold-rolled steel sheet treated via an annealing processing line, the cold-rolled steel sheet comprising, as a chemical composition, by mass %, C: 0.01% to 0.4%,Si: 0.001% to 2.5%,Mn: 0.001% to 4.0%,Al: 0.001% to 2.0%,P: limited to 0.15% or less,S: limited to 0.03% or less,N: limited to 0.01% or less,O: limited to 0.01% or less, anda balance consisting of Fe and unavoidable impurities,wherein: an average pole density of an orientation group of {100}<011> to {223}<110>, which is a pole density represented by an arithmetic average of pole densities of each crystal orientation {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110>, is 1.0 to 5.0 and a pole density of a crystal orientation {332}<113> is 1.0 to 4.0 in a thickness central portion which is a thickness range of ⅝ to ⅜ based on a surface of the steel sheet;a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50 and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50; andthe steel sheet includes, as a metallographic structure, plural grains, and includes, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.
  • 2. The cold-rolled steel sheet treated via an annealing processing line according to claim 1, further comprising, as the chemical composition, by mass %, at least one selected from the group consisting of Ti: 0.001% to 0.2%,Nb: 0.001% to 0.2%,B: 0.0001% to 0.005%,Mg: 0.0001% to 0.01%,Rare Earth Metal: 0.0001% to 0.1%,Ca: 0.0001% to 0.01%,Mo: 0.001% to 1.0%,Cr: 0.001% to 2.0%,V: 0.001% to 1.0%,Ni: 0.001% to 2.0%,Cu: 0.001% to 2.0%,Zr: 0.0001% to 0.2%,W: 0.001% to 1.0%,As: 0.0001% to 0.5%,Co: 0.0001% to 1.0%,Sn: 0.0001% to 0.2%,Pb: 0.0001% to 0.2%,Y: 0.001% to 0.2%, andHf: 0.001% to 0.2%.
  • 3. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein a volume average diameter of the grains is 5 μm to 30 μm.
  • 4. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein the average pole density of the orientation group of {100}<011> to {223}<110> is 1.0 to 4.0, and the pole density of the crystal orientation {332}<113> is 1.0 to 3.0.
  • 5. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein a Lankford-value rL in the rolling direction is 0.70 to 1.50, and a Lankford-value r60 in a direction making an angle of 60° with the rolling direction is 0.70 to 1.50.
  • 6. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein an area fraction of the martensite is defined as fM in unit of area %, an average grain size of the martensite is defined as dia in unit of μm, an average distance between the martensite grains is defined as dis in unit of μm, and a tensile strength of the steel sheet is defined as TS in unit of MPa, a following Expression 1 and a following Expression 2 are satisfied, dia≦13 μm  (Expression 1),TS/fM×dis/dia≧500  (Expression 2).
  • 7. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein an area fraction of the martensite is defined as fM in unit of area %, a major axis of the martensite grain is defined as La, and a minor axis of the martensite grain is defined as Lb, an area fraction of the martensite satisfying a following Expression 3 is 50% to 100% as compared with the area fraction fM of the martensite, La/Lb≦5.0  (Expression 3).
  • 8. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein the steel sheet includes, as the metallographic structure, by area %, the bainite of 5% to 80%.
  • 9. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein the steel sheet includes a tempered martensite in the martensite.
  • 10. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein an area fraction of coarse grain having grain size of more than 35 μm is 0% to 10% among the grains in the metallographic structure of the steel sheet.
  • 11. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein, when a hardness of the ferrite or the bainite which is a primary phase is measured at 100 points or more, a value dividing a standard deviation of the hardness by an average of the hardness is 0.2 or less.
  • 12. The cold-rolled steel sheet treated via an annealing processing line according to claim 1 or 2, wherein a galvanized layer or a galvannealed layer is arranged on the surface of the steel sheet.
Priority Claims (1)
Number Date Country Kind
2011-117432 May 2011 JP national
PCT Information
Filing Document Filing Date Country Kind 371c Date
PCT/JP2012/063261 5/24/2012 WO 00 11/20/2013
Publishing Document Publishing Date Country Kind
WO2012/161241 11/29/2012 WO A
US Referenced Citations (25)
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Related Publications (1)
Number Date Country
20140087208 A1 Mar 2014 US