Class of warm forming advanced high strength steel

Information

  • Patent Grant
  • 9493855
  • Patent Number
    9,493,855
  • Date Filed
    Monday, February 24, 2014
    10 years ago
  • Date Issued
    Tuesday, November 15, 2016
    8 years ago
Abstract
Metallic alloys are disclosed containing Fe at 48.0 to 81.0 atomic percent, B at 2.0 to 8.0 atomic percent, Si at 4.0 to 14.0 atomic percent, and at least one or more of Cu, Mn or Ni, wherein the Cu is present at 0.1 to 6.0 atomic percent, Mn is present at 0.1 to 21.0 atomic percent and Ni is present at 0.1 to 16.0 atomic percent. The alloys may be heated at temperatures of 200° C. to 850° C. for a time period of up to 1 hour and upon cooling there is no eutectoid transformation. The alloys may then be formed into a selected shape.
Description
FIELD OF THE INVENTION

This present disclosure is directed at a new type of warm formable advanced high strength steel (AHSS). This steel can be warm formed due to its unique structure which allows it to develop relatively high strength without the need for austenitizing and quenching.


BACKGROUND

Existing hot forming steels are variations of martensitic grades produced by various trade names including USIBOR™, DUXTIBOR™, etc. This class of materials can develop high strength commonly in the 1200 to 1600 MPa range with limited ductility of 5 to 8%. In the as-produced condition, these grades of steel are in their annealed soft conditions and consist of mainly ferrite plus cementite and thus exhibit low tensile strength. To produce high strength parts, the steel must then be heated up to its austenitizing temperature (i.e. A3), which depending on the chemistry is typically in the range of 850 to 1000° C. After an appropriate hold time to form a single phase solid solution of austenite, the steel is then deformed to produce a part which can be a wide variety of structural and non-structural components. After deformation, the part is held to ensure the shape is maintained and then quenched in oil or water depending on the thickness of the part formed and the specific hardenability of the steel alloy. Often small additions of boron typically up to 0.05 wt % are used to increase the hardenability of the steel which means that it opens up the process window for martensite formation. Upon proper quenching, the steel part then forms a martensitic structure which is strong and brittle. Subsequent heat treating is commonly done to produce tempered martensite which results in an improvement of ductility through sacrificing some of the strength levels.


SUMMARY

The present disclosure is directed at steel alloys which may be wormed formed (treated at temperatures of 200° C. to 850° C. for time period of 1.0 second to 1 hour either by direct heating or induction heating). The elemental composition ranges (atomic percent) include: Fe present at 48.0 to 81.0, B at 2.0-8.0, Si at 4.0 to 14.0 and at least one austenite stabilizer (element that stabilizes austenite formation) comprising one or more of Cu, Mn and Ni, where the Cu is present at 0.1-6.0 atomic percent, Mn is present at 0.1-21.0 atomic percent and Ni is present at 0.1-16.0 atomic percent. Optionally, one may include Cr at a level of up to 32.0 atomic percent. Other optional elements such as C, Al, Ti, V, Nb, Mo, Zr, W and Pd may be present at up to 10.0 atomic percent. Impurities known/expected to be present include Nb, Ti, S, O, N, P, W, Co, Sn, which may present at levels up to 10.0 atomic percent. The alloys herein that are suitable for warm forming include the Class 1, Class 2 and Class 3 Steels described herein. Steel alloys of the present disclosure with application to centrifugal casting provide unique property combinations in wide ranges of strength and ductility depending on the aforementioned class of steel due to new enabling structure types facilitated by new enabling mechanisms.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 Binary phase diagram for the iron rich region of the iron carbon binary system.



FIG. 2 Binary Fe—C phase diagram illustrating the differences between new grades of warm forming steel (top call-out) and conventional steels (bottom call-out).



FIG. 3 Model phase diagram indicating the expected phase equilibria of the new warm forming steel grades.



FIG. 4 illustrates structures and mechanisms regarding the formation of Class 1 Steel herein.



FIG. 5 illustrates a representative stress-strain curve of a material with Modal Structure.



FIG. 6 illustrates structures and mechanism regarding the formation of Class 2 steel alloys herein.



FIG. 7 illustrates a stress-strain curve for the indicated structures and associated mechanisms in Class 2 alloys.



FIG. 8 illustrates structures and mechanism regarding the formation of Class 3 steel alloys herein.



FIG. 9 illustrates a stress-strain curve for the indicated structures and associated mechanisms in Class 3 alloys.



FIG. 10 Picture of the plate in as-cast state.



FIG. 11 NanoSteel sized R&D specimen geometry that was modified to increase the grip sections to 9.5 mm in order to accommodate ⅛″ grip pinholes.



FIG. 12 Temperature dependence of yield stress and tensile elongation in Alloy 213.



FIG. 13 View of the Class 3 Alloy 36 specimen after HIP cycle and heat treatment before and after deformation to 57.5%.



FIG. 14 Tensile strength, yield stress and tensile elongation as a function of testing temperature in commercial sheet from Alloy 82.





DETAILED DESCRIPTION
New Class of Warm Forming Steel

The new class of warm forming steel does not need to be austenitized due to a much different metallurgy and enabling metallurgical transformations (i.e. not austenite to martensite). In FIG. 1, the iron rich binary portion of the binary Fe—C phase diagram is shown. This diagram is used to describe the basic phase equilibria in ˜30,000 known worldwide equivalent iron and steel alloys. In FIG. 2, the Fe—C binary phase diagram is utilized to show the differences between the new class of warm forming steels and conventional steels. Almost all conventional steels with the exception of austenitic stainless and TWIP (Twinning Induced Plasticity) steels are developed with main focus of heat treatment and structural development based on the eutectoid transformation. While the heat treatment temperatures, times, and strategies can vary widely, generally the first step is to heat the steel up to the single phase austenite region. Heating rate to the targeted temperature and time at temperature is important as the hardenability of the steel is sensitive to the average grain size of the material. Depending on how the steel is cooled or quenched from the austenitizing temperature will result in a wide range of characteristic structures produced including pearlite, upper and lower bainite, spherodite, and martensite. Additionally, complex or dual phase microstructures can be produced with different fractions of all of these characteristic microstructures along with ferrite, retained austenite, and cementite phases.


As shown in FIG. 2, the new class of warm forming steels is intrinsically different as the focus on phase and structural development is on the peritectic region and not the eutectoid region. Note that the peritectic invariant reaction involves liquid with the specific transformation liquid+delta ferrite producing austenite. This is much different than the solid state eutectoid transformation which involves austenite producing ferrite plus cementite.


To further explain these differences, a model phase diagram for the warm forming alloys is provided in FIG. 3. The x-axis (labeled as Atomic Percent Alloying) is reference to an alloy that, as noted above, comprises Fe, B and Si, and at least one of Cu, Mn or Ni. The temperature on the y-axis will then vary depending upon the alloy selected. As can be seen, the eutectoid transformation that is so crucial to existing steels is missing in the complex multicomponent phase diagram for the steels herein. Transitions include the initial solidification through the peritectic transformation and the high temperature portion of the austenite to ferrite transformation associated with the gamma/austenite stability loop.


The new type of steel produced herein may include any of the Class 1, Class 2 or Class 3 Steel Alloys noted herein that are warm formed, but preferably include warm forming of the Class 2 or Class 3 Steel Alloys. These Class 1, Class 2 and Class 3 Steel structure is stable to high temperatures and could be hot formed at conventional temperatures known for hot forming processes with typical hot forming ductility from 30 to 120%. However, the Class 1, Class 2 and Class 3 Steels herein exhibit relatively high strength and ductility at room temperature and maintains its high ductility at warm temperatures (i.e. 200 to 850°). Thus, it is applicable for cold deformation through a variety of methods including cold rolling, stamping, roll forming, hydroforming etc. Furthermore, the Class 1, Class 2 and Class 3 steel can now be treated by a warm forming process. In warm forming, the aforementioned steels are now heated up to a temperature range which is less than hot forming, typically 200 to 850° C., and for a time period of 1.0 seconds to 1 hour via direct heating (e.g. furnace heating) and/or induction heating. This temperature range is enabling for manufacturing for a number of key factors which will be described subsequently. In short, warm forming may now reduce cost while producing new functionality through minimizing or avoiding springback issues found in cold forming steels.


Enabling Advantages/New Functionality of Warm Forming Steels
Zinc Coatings

Steels are protected from corrosion through a process generally called galvanization which provides an anodic sacrificial coating to protect the surface of the steel from corrosion. There are various methods of applying the zinc or zinc alloy to the surface including conventional galvanization, hot dip galvanization, galvannealing etc. All of these processes share the same feature with zinc being bonded to different extents to the surface of steel. For hot forming this is a problem, since zinc exhibits a low melting point of 419° C. Thus, during hot forming of conventional martensitic/press formable steels, the zinc coating melts and vaporizes off, thus leaving the resulting steel part vulnerable to corrosive attack. While efforts are being done to produce thicker initial layers of zinc and/or to shorten the cycle time of hot forming to limit high temperature exposure, the results have been ineffective, resulting in costly post part forming coating steps to restore the anodic surface. Through warm forming at temperatures below the melting point of zinc (i.e. ˜200 to ˜419° C.), the problem of zinc loss can be minimized or entirely avoided. Thus the new NanoModal steels processed through warm forming creates new functionality through the ability to pre-coat with conventional galvanization processes and then maintaining this protective coating in the finished warm deformed part.


Cycle Time

Conventional hot forming lines utilize conveyor type continuous ovens which allow the hot formed parts to be feed in a continuous manner reaching their targeted austenitizing temperature prior to hot deformation. The length of these continuous gas fired ovens can be upwards of 50 meters and if any issue occurs during the hot forming operation, all of the parts moving through the long furnace are generally scrapped since during subsequent re-heating their metallurgical structure will be deleteriously non-recoverably affected. By heating up to lower temperature for warm forming, the length of this continuous oven used will be needed to be much less thus, requiring less infrastructure, lower amounts of scrapped parts, and especially lower energy cost. This ultimately results in lower cost parts thus, enabling the technology for a wider range of applications.


Oxidation/Post Processing

A cost factor limiting hot forming is the scale/oxide removal which forms during the elevated temperature exposure and then needs to be removed through existing shot/grit blasting processes. The oxidation occurs due to the elevated temperature exposure necessary to austenitize existing materials. Furthermore, the process does not lend itself to inert gas atmospheres because after hot forming, the parts must be quenched in a liquid medium to form martensite, thus creating additional oxidation. With the new class of Warm Forming steels, the temperature of deformation will be much lower which limits/prevents the oxidation typical for high temperature exposure. Additionally, since the Warm Forming steels do not need to be quenched and they exhibit an insensitive response to cooling rates in the solid state, the warm formed parts may be able to be processed while remaining in an inert atmosphere to prevent or minimize oxidation. This then is expected to result in a part which does not need to go through the expensive grit/shot blasting processes since scale formation is avoided.


Cooling/Water Quenching

Existing hot forming steels need to be quenched from their high temperature austenitizing temperatures in order to form the martensitic structure that provides high strength. During quenching into oil, water, salt water brines, etc. part distortion and/or cracking can occur which can create higher rates of scraps. Additionally, since the formation of the martensitic structure is highly cooling rate dependent, some areas of insufficient cooling may occur for example when a vapor barrier is created from the liquid medium. This results in lower strength levels in certain areas creating a limiting strength debit which while accounted for in the part design often results in higher gauge thicknesses and higher weight parts than necessary in order to overcome local strength variations. The new class of NanoModal Warm Forming Steels does not need to be water quenched and do not need to be heated up to the high temperatures found in conventional austenitizing. Thus, strict dimensional control is possible due to the lack of quench distortion. This results in a lower scrap rate and reduced cost enabling the technology.


Pre-Shaping/Final Finishing

Due to the fact that existing martensitic steels need to be austenitized at high temperatures, hot deformed, and then quenched in a liquid medium, the resulting part is distorted from the original blank dimensions. Due to the presence of distortion, especially during quenching, the final details (i.e. final trimming, hole incorporation, etc.) in the part cannot be pre-shaped in the starting blanks. Thus, expensive laser trimming or mechanical re-striking in a post stamping operation is needed which requires expensive dies that need regular maintenance to handle the extremely strong material resulting from the hot forming needed as a final post finishing process to put in the final holes and trim to the final part dimensions. Through warm forming, there is a lot less temperature range resulting in a lot less thermal expansion and this along with the lack of the need to quench, means that the Warm Forming Steels offer previously unknown design and process capability. Thus, the starting blanks can be fully or partially preformed with holes and trimmed appropriately prior to warm forming, thus creating new functionality and eliminating the final costly laser trimming processing inherent to existing hot forming processes.


New Classes of Steel Alloys

The non-stainless steel alloys herein are such that they are capable of formation of what is described herein as Class 1 Steel, Class 2 Steel or Class 3 Steel which are preferably crystalline (non-glassy) with identifiable crystalline grain size morphology. The ability of the alloys to form Class 1, Class 2 or Class 3 Steels herein is described in detail herein. However, it is useful to first consider a description of the general features of Class 1, Class 2 and Class 3 Steels, which is now provided below.


Class 1 Steel


The formation of Class 1 Steel herein is illustrated in FIG. 4. As shown therein, a Modal structure is initially formed which modal structure is the result of starting with a liquid melt of the alloy and solidifying by cooling, which provides nucleation and growth of particular phases having particular grain sizes. Reference herein to modal may therefore be understood as a structure having at least two grain size distributions. Grain size herein may be understood as the size of a single crystal of a specific particular phase preferably identifiable by methods such as scanning electron microscopy or transmission electron microscopy. Accordingly, Structure #1 of the Class 1 Steel may be preferably achieved by processing through either laboratory scale procedures and/or through industrial scale methods such as powder atomization or alloy casting.


The Modal Structure of Class 1 Steel will therefore initially indicate, when cooled from the melt, the following grain sizes: (1) matrix grain size of 500 nm to 20,000 nm containing austenite and/or ferrite; (2) boride grain size of 25 nm to 500 nm (i.e. non-metallic grains such as M2B where M is the metal and is covalently bonded to B). The boride grains may also preferably be “pinning” type phases which is reference to the feature that the matrix grains will effectively be stabilized by the pinning phases which resist coarsening at elevated temperature. Note that the metal boride grains have been identified as exhibiting the M2B stoichiometry but other stoichiometries are possible and may provide pinning including M3B, MB (M1B1), M23B6, and M7B3.


The Modal Structure of Class 1 Steel may be subjected to thermomechanical deformation and/or heat treatment, resulting in some variation in properties, but the Modal Structure may be maintained.


When the Class 1 Steel noted above is exposed to a mechanical stress, the observed stress versus strain diagram is illustrated in FIG. 5. It is therefore observed that the Modal Structure undergoes what is identified as Dynamic Nanophase Precipitation leading to a second type structure for the Class 1 Steel which is Modal Nanophase Structure. Such Dynamic Nanophase Precipitation is therefore triggered when the alloy experiences a yield under stress, and it has been found that the yield strength of Class 1 Steels which undergo Dynamic Nanophase Precipitation may preferably occur at 400 MPa to 1300 MPa. Accordingly, it may be appreciated that Dynamic Nanophase Precipitation occurs due to the application of mechanical stress that exceeds such indicated yield strength. Dynamic Nanophase Precipitation itself may be understood as the formation of a further identifiable phase in the Class 1 Steel which is termed a precipitation phase with an associated grain size. That is, the result of such Dynamic Nanophase Precipitation is to form an alloy which still indicates identifiable matrix grain size of 500 nm to 20,000 nm, boride pinning grain size of 25 nm to 500 nm, along with the formation of precipitation grains which contain hexagonal phases and grains of 1.0 nm to 200 nm. As noted above, the grain sizes therefore do not coarsen when the alloy is stressed, but does lead to the development of the precipitation grains as noted.


Reference to the hexagonal phases may be understood as a dihexagonal pyramidal class hexagonal phase with a P63mc space group (#186) and/or a ditrigonal dipyramidal class with a hexagonal P6bar2C space group (#190). In addition, the mechanical properties of such second type structure of the Class 1 Steel are such that the tensile strength is observed to fall in the range of 700 MPa to 1400 MPa, with an elongation of 10-50%. Furthermore, the second type structure of the Class 1 Steel is such that it exhibits a strain hardening coefficient from 0.1 to 0.4 that is nearly flat after undergoing the indicated yield. The strain hardening coefficient is reference to the n-value in the formula σ=Kεn, where σ represents the applied stress on the material, ε is the strain and K is the strength coefficient. The value of the strain hardening exponent n lies between 0 and 1. A value of 0 means that the alloy is a perfectly plastic solid (i.e. the material undergoes non-reversible changes to applied force), while a value of 1 represents a 100% elastic solid (i.e. the material undergoes reversible changes to an applied force).


Table 1A below provides a comparison and performance summary for Class 1 Steel herein.









TABLE 1A







Comparison of Structure and Performance for Class 1 Steel









Class 1 Steel









Property/
Structure Type #1
Structure Type #2


Mechanism
Modal Structure
Modal Nanophase Structure





Structure
Starting with a liquid melt,
Dynamic Nanophase Precipitation


Formation
solidifying this liquid melt and
occurring through the application of



forming directly
mechanical stress


Transformations
Liquid solidification followed by
Stress induced transformation involving



nucleation and growth
phase formation and precipitation


Enabling Phases
Austenite and/or ferrite with
Austenite, optionally ferrite, boride



boride pinning
pinning phases, and hexagonal phase(s)




precipitation


Matrix Grain
500 to 20,000 nm
500 to 20,000 nm


Size
Austenite and/or ferrite
Austenite optionally ferrite


Boride Grain Size
25 to 500 nm
25 to 500 nm



Non metallic (e.g. metal boride)
Non-metallic (e.g. metal boride)


Precipitation

1 nm to 200 nm


Grain Sizes

Hexagonal phase(s)


Tensile Response
Intermediate structure;
Actual with properties achieved based



transforms into Structure #2
on structure type #2



when undergoing yield



Yield Strength
300 to 600 MPa
400 to 1300 MPa


Tensile Strength

700 to 1400 MPa


Total Elongation

10 to 50%


Strain Hardening

Exhibits a strain hardening coefficient


Response

between 0.1 to 0.4 and a strain hardening




coefficient as a function of strain which




is nearly flat or experiencing a slow




increase until failure










Class 2 Steel


The formation of Class 2 Steel herein is illustrated in FIG. 6. Class 2 steel may also be formed herein from the identified alloys, which involves two new structure types after starting with Structure type #1, Modal Structure, followed by two new mechanisms identified herein as Static Nanophase Refinement and Dynamic Nanophase Strengthening. The new structure types for Class 2 Steel are described herein as Nanomodal Structure and High Strength Nanomodal Structure. Accordingly, Class 2 Steel herein may be characterized as follows: Structure #1-Modal Structure (Step #1), Mechanism #1—Static Nanophase Refinement (Step #2), Structure #2-Nanomodal Structure (Step #3), Mechanism #2—Dynamic Nanophase Strengthening (Step #4), and Structure #3—High Strength Nanomodal Structure (Step #5).


As shown therein, Structure #1 is initially formed in which Modal Structure is the result of starting with a liquid melt of the alloy and solidifying by cooling, which provides nucleation and growth of particular phases having particular grain sizes. Grain size herein may again be understood as the size of a single crystal of a specific particular phase preferably identifiable by methods such as scanning electron microscopy or transmission electron microscopy. Accordingly, Structure #1 of the Class 2 Steel may be preferably achieved by processing through either laboratory scale procedures and/or through industrial scale methods such as powder atomization or alloy casting.


The Modal Structure of Class 2 Steel will therefore initially indicate, when cooled from the melt, the following grain sizes: (1) matrix grain size of 500 nm to 20,000 nm containing austenite and/or ferrite; (2) boride grain size of 25 nm to 500 nm (i.e. non-metallic grains such as M2B where M is the metal and is covalently bonded to B). The boride grains may also preferably be “pinning” type phases which are referenced to the feature that the matrix grains will effectively be stabilized by the pinning phases which resist coarsening at elevated temperature. Note that the metal boride grains have been identified as exhibiting the M2B stoichiometry but other stoichiometries are possible and may provide pinning including M3B, MB (M1B1), M23B6, and M7B3 and which are unaffected by Mechanisms #1 or #2 noted above). Reference to grain size is again to be understood as the size of a single crystal of a specific particular phase preferably identifiable by methods such as scanning electron microscopy or transmission electron microscopy. Furthermore, Structure #1 of Class 2 steel herein includes austenite and/or ferrite along with such boride phases.


In FIG. 7, a stress strain curve is shown that represents the non-stainless steel alloys herein which undergo a deformation behavior of Class 2 steel. The Modal Structure is preferably first created (Structure #1) and then after the creation, the Modal Structure may now be uniquely refined through Mechanism #1, which is a Static Nanophase Refinement mechanism, leading to Structure #2. Static Nanophase Refinement is reference to the feature that the matrix grain sizes of Structure 1 which initially fall in the range of 500 nm to 20,000 nm are reduced in size to provide Structure 2 which has matrix grain sizes that typically fall in the range of 100 nm to 2000 nm. Note that the boride pinning phase can change size significantly in some alloys, while it is designed to resist matrix grain coarsening during the heat treatments. Due to the presence of these boride pinning sites, the motion of a grain boundaries leading to coarsening would be expected to be retarded by a process called Zener pinning or Zener drag. Thus, while grain growth of the matrix may be energetically favorable due to the reduction of total interfacial area, the presence of the boride pinning phase will counteract this driving force of coarsening due to the high interfacial energies of these phases.


Characteristic of the Static Nanophase Refinement Mechanism #1 in Class 2 steel, the micron scale austenite phase (gamma-Fe) which was noted as falling in the range of 500 nm to 20,000 nm is partially or completely transformed into new phases (e.g. ferrite or alpha-Fe). The volume fraction of ferrite (alpha-iron) initially present in the Modal Structure (Structure 1) of Class 2 steel is 0 to 45%. The volume fraction of ferrite (alpha-iron) in Structure #2 as a result of Static Nanophase Refinement Mechanism #2 is typically from 20 to 80%. The static transformation preferably occurs during elevated temperature heat treatment and thus involves a unique refinement mechanism since grain coarsening rather than grain refinement is the conventional material response at elevated temperature.


Accordingly, grain coarsening does not occur with the alloys of Class 2 Steel herein during the Static Nanophase Refinement mechanism. Structure #2 is uniquely able to transform to Structure #3 during Dynamic Nanophase Strengthening and as a result Structure #3 is formed and indicates tensile strength values in the range from 800 to 1800 MPa with 5 to 40% total elongation.


Depending on alloy chemistries, nano-scale precipitates can form during Static Nanophase Refinement and the subsequent thermal process in some of the non-stainless high-strength steels. The nano-precipitates are in the range of 1 nm to 200 nm, with the majority (>50%) of these phases 10˜20 nm in size, which are much smaller than the boride pinning phase formed in Structure #1 for retarding matrix grain coarsening. Also, during Static Nanophase Refinement, the boride grain sizes grow larger to a range from 200 to 2500 nm in size.


Expanding upon the above, in the case of the alloys herein that provide Class 2 Steel, when such alloys exceed their yield point, plastic deformation at constant stress occurs followed by a dynamic phase transformation leading toward the creation of Structure #3. More specifically, after enough strain is induced, an inflection point occurs where the slope of the stress versus strain curve changes and increases (FIG. 7) and the strength increases with strain indicating an activation of Mechanism #2 (Dynamic Nanophase Strengthening).


With further straining during Dynamic Nanophase Strengthening, the strength continues to increase but with a gradual decrease in strain hardening coefficient value up to nearly failure. Some strain softening occurs but only near the breaking point which may be due to reductions in localized cross sectional area at necking. Note that the strengthening transformation that occurs at the material straining under the stress generally defines Mechanism #2 as a dynamic process, leading to Structure #3. By dynamic, it is meant that the process may occur through the application of a stress which exceeds the yield point of the material. The tensile properties that can be achieved for alloys that achieve Structure 3 include tensile strength values in the range from 800 to 1800 MPa and 5 to 40% total elongation. The level of tensile properties achieved is also dependent on the amount of transformation occurring as the strain increases corresponding to the characteristic stress strain curve for a Class 2 steel.


Thus, depending on the level of transformation, tunable yield strength may also now be developed in Class 2 Steel herein depending on the level of deformation and in Structure #3 the yield strength can ultimately vary from 400 MPa to 1700 MPa. That is, conventional steels outside the scope of the alloys here exhibit only relatively low levels of strain hardening, thus their yield strengths can be varied only over small ranges (e.g., 100 to 200 MPa) depending on the prior deformation history. In Class 2 steels herein, the yield strength can be varied over a wide range (e.g. 400 to 1700 MPa) as applied to Structure #2 transformation into Structure #3, allowing tunable variations to enable both the designer and end users in a variety of applications, and utilize Structure #3 in various applications such as crash management in automobile body structures.


With regards to this dynamic mechanism, new and/or additional precipitation phase or phases are observed that indicates identifiable grain sizes of 1 nm to 200 nm. In addition, there is the further identification in said precipitation phase a dihexagonal pyramidal class hexagonal phase with a P63mc space group (#186), a ditrigonal dipyramidal class with a hexagonal P6bar2C space group (#190), and/or a M3Si cubic phase with a Fm3m space group (#225). Accordingly, the dynamic transformation can occur partially or completely and results in the formation of a microstructure with novel nanoscale/near nanoscale phases providing relatively high strength in the material. That is, Structure #3 may be understood as a microstructure having matrix grains sized generally from 100 nm to 2000 nm which are pinned by boride phases which are in the range of 200 to 2500 nm and with precipitate phases which are in the range of 1 nm to 200 nm. The initial formation of the above referenced precipitation phase with grain sizes of 1 nm to 200 nm starts at Static Nanophase Refinement and continues during Dynamic Nanophase Strengthening leading to Structure 3 formation. The volume fraction of the precipitation phase with grain size from 1 nm to 200 nm in Structure 2 increases in Structure 3 and assists with the identified strengthening mechanism. It should also be noted that in Structure 3, the level of gamma-iron is optional and may be eliminated depending on the specific alloy chemistry and austenite stability.


Note that dynamic recrystallization is a known process but differs from Mechanism #2 (FIG. 6) since it involves the formation of large grains from small grains so that it is not a refinement mechanism but a coarsening mechanism. Additionally, as new undeformed grains are replaced by deformed grains no phase changes occur in contrast to the mechanisms presented here and this also results in a corresponding reduction in strength in contrast to the strengthening mechanism here. Note also that metastable austenite in steels is known to transform to martensite under mechanical stress but, preferably, no evidence for martensite or body centered tetragonal iron phases are found in the new steel alloys described in this application.


Table 1B below provides a comparison of the structure and performance features of Class 2 Steel herein.









TABLE 1B







Comparison Of Structure and Performance of Class 2 Steel









Class 2 Steel













Structure Type #3


Property/
Structure Type #1
Structure Type #2
High Strength


Mechanism
Modal Structure
Nanomodal Structure
Nanomodal Structure





Structure
Starting with a liquid
Static Nanophase
Dynamic Nanophase


Formation
melt, solidifying this
Refinement mechanism
Strengthening mechanism



liquid melt and forming
occurring during heat
occurring through application of



directly
treatment
mechanical stress


Transformations
Liquid solidification
Solid state phase
Stress induced transformation



followed by nucleation
transformation of
involving phase formation and



and growth
supersaturated gamma iron
precipitation


Enabling Phases
Austenite and/or
Ferrite, austenite, boride
Ferrite, optionally austenite,



ferrite with boride
pinning phases, and
boride pinning phases,



pinning phases
hexagonal phase
hexagonal and additional phases




precipitation
precipitation


Matrix Grain
500 to 20000 nm
Grain Refinement
Grain size remains refined at


Size
Austenite
(100 nm to 2000 nm)
100 nm to 2000 nm/Additional




Austenite to ferrite and
precipitation formation




precipitation phase





transformation



Boride Grain
25 to 500 nm
200 to 2500 nm
200 to 2500 nm


Size
borides (e.g. metal
borides (e.g. metal boride)
borides (e.g. metal boride)



boride)




Precipitation

1 nm to 200 nm
1 nm to 200 nm


Grain Sizes





Tensile
Actual with properties
Intermediate structure;
Actual with properties achieved


Response
achieved based on
transforms into Structure #3
based on formation of structure



structure type #1
when undergoing yield
type #3 and fraction of





transformation.


Yield Strength
300 to 600 MPa
300 to 800 MPa
400 to 1700 MPa


Tensile Strength


800 to 1800 MPa


Total Elongation


5 to 40%


Strain

After yield point, exhibit a
Strain hardening coefficient may


Hardening

strain softening at initial
vary from 0.2 to 1.0 depending


Response

straining as a result of phase
on amount of deformation and




transformation, followed by
transformation




a significant strain





hardening effect leading to a





distinct maxima










Class 3 Steel


Class 3 steel is associated with formation of a High Strength Lamellae Nanomodal Structure through a multi-step process as now described herein.


In order to achieve a tensile response involving high strength with adequate ductility in non-stainless carbon-free steel alloys, a preferred seven-step process is now disclosed and shown in FIG. 8. Structure development starts from the Structure #1—Modal Structure (Step #1). However, Mechanism #1 in Class 3 steel is now related to Lath Phase Creation (Step #2) that leads to Structure #2—Modal Lath Phase Structure (Step #3), which through Mechanism #2—Lamellae Nanophase Creation (Step #4) transforms into Structure #3—Lamellae Nanomodal Structure (Step #5). Deformation of Structure #3 results in activation of Mechanism #3-Dynamic Nanophase Strengthening (Step #6) which leads to formation of Structure #4—High Strength Lamellae Nanomodal Structure (Step #7). Reference is also made to Table 1C below.


Structure #1 involving the formation of the Modal Structures (i.e. bi, tri, and higher order) may be achieved in the alloys with the referenced chemistries in this application by processing through the laboratory scale as shown and/or through industrial scale methods involving chill surface processing such as twin roll casting or thin slab casting. The Modal Structure of Class 3 Steel will therefore initially indicate, when cooled from the melt, the following grain sizes: (1) matrix grain size of 500 nm to 20,000 nm containing ferrite or alpha-Fe (required) and optionally austenite or gamma-Fe; and (2) boride grain size of 100 nm to 2500 nm (i.e. non-metallic grains such as M2B where M is the metal and is covalently bonded to B); (3) yield strengths of 350 to 1000 MPa; (4) tensile strengths of 400 to 1200 MPa; and total elongation of 0-3.0%. It will also indicate dendritic growth morphology of the matrix grains. The boride grains may also preferably be “pinning” type phases which is reference to the feature that the matrix grains will effectively be stabilized by the pinning phases which resist coarsening at elevated temperature. Note that the metal boride grains have been identified as exhibiting the M2B stoichiometry but other stoichiometries are possible and may provide pinning including M3B, MB (M1B1), M23B6, and M7B3 and which are unaffected by Mechanism #1, #2 or #3 noted above). Reference to grain size is again to be understood as the size of a single crystal of a specific particular phase preferably identifiable by methods such as scanning electron microscopy or transmission electron microscopy. Accordingly, Structure #1 of Class 3 steel herein includes ferrite along with such boride phases.


Structure #2 involves the formation of the Modal Lath Phase Structure with uniformly distributed precipitates from Modal Structure (Structure 1) with dendritic morphology though Mechanism #1. Lath phase structure may be generally understood as a structure composed from plate-shaped crystal grains. Reference to “dendritic morphology” may be understood as tree-like and reference to “plate shaped” may be understood as sheet like. Lath structure formation preferably occurs at elevated temperature (e.g. at temperatures of 700° C. to 1200° C.) through plate-like crystal grain formation with: (1) lath structural grain sizes typically from 100 to 10,000 nm; (2) boride grain size of 100 nm to 2,500 nm; (3) yield strengths of 350 MPa to 1400 MPa; (4) tensile strengths of 350 MPa to 1600 MPa; (5) elongation of 0-12%. Structure #2 also contains alpha-Fe and gamma-Fe remains optional.


A second phase of boride precipitates with a size typically from 100 to 1000 nm may be found distributed in the lath matrix as isolated particles. The second phase of boride precipitates may be understood as non-metallic grains of different stoichiometry (M2B, M3B, MB (M1B1), M23B6, and M7B3) where M is the metal and is covalently bonded to Boron. These boride precipitates are distinguished from the boride grains in Structure #1 with little or no change in size.


Structure #3 (Lamellae Nanomodal Structure) involves the formation of the lamellae morphology as a result of static transformation of ferrite into one or several phases through Mechanism #2 identified as Lamellae Nanophase Creation. Static transformation is a decomposition of the parent phase into new phase or several new phases due to alloying elements distribution by diffusion during elevated temperature heat treatment, which may preferably occur in the temperature range from 700° C. to 1200° C. Lamellae (or layered) structure is composed of alternating layers of two phases whereby individual lamellae exist within a colony connected in three dimensions. In Class 3 alloys, Lamellae Nanomodal Structure contains: (1) lamellas of 100 nm to 1000 nm wide with a thickness in the range of 100 nm to 10,000 nm and with a length of 0.1 to 5 microns; (2) boride grains of 100 nm to 2500 nm of different stoichiometry (M2B, M3B, MB (M1B1), M23B6, and M7B3) where M is the metal and is covalently bonded to Boron, (3) precipitation grains of 1 nm to 100 nm; (4) yield strength of 350 MPa to 1400 MPa. The Lamellae Nanomodal Structure continues to contain alpha-Fe and gamma-Fe remains optional.


Lamellae Nanomodal Structure (Structure #3) transforms into Structure #4 through Dynamic Nanophase Strengthening (Mechanism #3, exposure to mechanical stress) during plastic deformation (i.e. exceeding the yield stress for the material) displaying relatively high tensile strengths in the range of 1000 MPa to 2000 MPa. In FIG. 9, a stress-strain curve is shown that represents the alloys with Structure #3 herein which undergo a deformation behavior of Class 3 steel as compared to that of Class 2. As illustrated in FIG. 9, Structure #3, upon application of stress, provides the indicated curve, resulting in Structure #4 of Class 3 steel.


The strengthening during deformation is related to phase transformation that occurs as the material strains under stress and defines Mechanism #3 as a dynamic process. For the alloy to display high strength at the level described in this application, lamellae structure is preferably formed prior to deformation. Specific to this mechanism, the micron scale austenite phase is transformed into new phases with reductions in microstructural feature scales generally down to the nanoscale regime. Some fraction of austenite may initially form in some Class 3 alloys during casting and then may remain present in Structure #1 and Structure #2. During straining when stress is applied, new or additional phases are formed with nanograins typically in a range from 1 to 100 nm.


In the post-deformed Structure #4 (High Strength Lamellae Nanomodal Structure), the ferrite grains contain alternating layers with nanostructure composed from new phases formed during deformation. Depending on the specific chemistry and the stability of the austenite, some austenite may be additionally present. In contrast with layers in Structure #3 where each layer represents a single or just few grains, in Structure #4, a large number of nanograins of different phases are present as a result of Dynamic Nanophase Strengthening. Since nanoscale phase formation occurs during alloy deformation, it represents a stress induced transformation and defined as a dynamic process. Nanoscale phase precipitations during deformation are responsible for extensive strain hardening of the alloys. The dynamic transformation can occur partially or completely and results in the formation of a microstructure with novel nanoscale/near nanoscale phases specified as High Strength Lamellae Nanomodal Structure (Structure #4) that provides high strength in the material. Thus the Structure #4 can be formed with various levels of strengthening depending on specific chemistry and the amount of strengthening achieved by Mechanism #3.


Table 1C below provides a comparison of the structure and performance features of Class 3 Steel herein.









TABLE 1C







Comparison of Structure and Performance of New Structure Types









Class 3 Steel















Structure Type #4





Structure Type #3
High Strength




Structure Type #2
Lamellae
Lamellae


Property/
Structure Type #1
Modal Lath
Nanomodal
Nanomodal


Mechanism
Modal Structure
Phase Structure
Structure
Structure





Structure
Starting with a liquid
As-cast structural
Lath phase dissolution
Nanoprecipitate


Formation
melt, solidifying on a
homogenization and
and Lamellae
phase formation and



chill surface
lath phase formation
Nanomodal Structure
high strength




during high
creation during heat
structure formation




temperature heat
treatment
through application




treatment optionally

of stress




with pressure




Transformations
Liquid solidification
Morphology change
Solid state phase
Stress induced



followed by nucleation
(dendrites to laths)
transformation of
transformation



and growth

supersaturated alpha
involving phase





iron
formation and






precipitation


Enabling Phases
Ferrite, optionally
Ferrite, optionally
Ferrite, optionally
Ferrite, optionally



austenite with boride
austenite with boride
austenite, boride, and
austenite, boride,



pinning phases
pinning phases
additional phase
and additional phase





precipitations
precipitations


Matrix Grain Size
500 to 20,000 nm
100 to 10,000 nm
100 to 10,000 nm thick
100 to 5000 nm,





lamellae, 0.1- 5.0
non-uniform grains





microns in length and






100 nm-1000 nm in






width



Boride Grain Size
100 to 2,500 nm
100 to 2,500 nm
100 to 2,500 nm
100 to 2,500 nm


Precipitate
N/A
N/A
1 to 100 nm
1 to 100 nm


Grains






Tensile Response
Actual with properties
Actual with
Intermediate structure;
Actual with



achieved based on
properties achieved
transforms into Structure
properties achieved



structure type #1
based on structure
#4 during tensile testing
based on formation




type #2

of structure type #3






and fraction of






transformation


Yield Strength
350 to 1000 MPa
300 to 1400 MPa
350 to 1400 MPa
500 to 1800 MPa


Tensile Strength
200 to 1200 MPa
350 to 1600 MPa

1000 to 2000 MPa


Total Elongation
0 to 3%
0 to 12%

0.5 to 15%


Strain hardening
Exhibits limited
Strain hardening
After yield point, exhibit
Strain Hardening


Response
hardening resulted in
coefficient may vary
a high strain hardening
coefficient may vary



low ductility
from 0.09 to 0.73
coefficient at initial
from 0.1 to 0.9




depending on alloy
straining and a strain
depending on




chemistry and level
hardening coefficient as
amount of




of structural
a function of strain
deformation and




formation
which is experiencing a
transformation





decrease until failure









Alloy Properties

In the new alloys, melting occurs in one or multiple stages with initial melting from ˜1000° C. depending on alloy chemistry and final melting temperature might be up to ˜1500° C. Variations in melting behavior reflect a complex phase formation at chill surface processing of the alloys depending on their chemistry. The density of the alloys varies from 7.2 g/cm3 to 8.2 g/cm3. The mechanical characteristic values in the alloys from each Class will depend on alloy chemistry and processing/treatment condition. For Class 1 Steels, the ultimate tensile strength values may vary from 700 to 1500 MPa with tensile elongation from 5 to 40%. The yield stress is in a range from 400 to 1300 MPa. For Class 2 Steels, the ultimate tensile strength values may vary from 800 to 1800 MPa with tensile elongation from 5 to 40%. The yield stress is in a range from 400 to 1700 MPa. For Class 3 Steels, the ultimate tensile strength values may vary from 1000 to 2000 MPa with tensile elongation from 0.5 to 15%. The yield stress is in a range from 500 to 1800 MPa. Additional classes of steel are anticipated with possible yield strengths, tensile strengths, and elongation values outside of the limits listed above.


EXAMPLES
Preferred Alloy Chemistries and Sample Preparation

The chemical composition of the alloys studied is shown in Table 2 which provides the preferred atomic ratios utilized. These chemistries have been studied by using material processing through sheet casting in a Pressure Vacuum Caster (PVC). Using high purity elements or ferroadditives and other readily commercially available constituents, 35 g alloy feedstocks of the targeted alloys were weighed out according to the atomic ratios provided in Table 2. The feedstock material was then placed into the copper hearth of an arc-melting system. The feedstock was arc-melted into an ingot using high purity argon as a shielding gas. The ingots were flipped several times and re-melted to ensure homogeneity. After mixing, the ingots were then cast in the form of a finger approximately 12 mm wide by 30 mm long and 8 mm thick. The resulting fingers were then placed in a PVC chamber, melted using RF induction and then ejected onto a copper die designed for casting 3 by 4 inches sheets with thickness of 1.8 mm. An example of the cast plate is shown in FIG. 10. Utilized die casting of the alloys relates to the melt solidification at relatively high cooling rate that can be correlated with metal solidification at different sheet production methods including but not limited to sheet solidification on chill surface at twin roll, thin strip, and thin slab casting.









TABLE 2







Chemical Composition of the Alloys (atomic %)






















Alloy
Fe
Cr
Ni
B
Si
W
Mo
Nb
Ti
Al
Cu
V
Zr
Mn
C

























Alloy 1
59.35
17.43
14.05
4.77
4.40












Alloy 2
58.35
17.43
14.05
4.77
4.40






1.00





Alloy 3
54.52
17.43
14.05
7.00
7.00












Alloy 4
53.52
17.43
14.05
7.00
5.00






3.00





Alloy 5
55.52
17.43
14.05
7.00
5.00







1.00




Alloy 6
60.22
17.43
11.05
5.00
6.30












Alloy 7
77.05

11.05
5.30
6.60


Alloy 8
58.92
17.43
11.05
5.60
7.00












Alloy 9
58.27
17.43
11.05
5.90
7.35












Alloy 10
59.25
17.43
11.05
5.45
6.82












Alloy 11
59.25
17.43
8.29
5.45
6.82








2.76



Alloy 12
61.25
15.43
5.53
5.45
6.82








5.52



Alloy 13
63.62
17.43
7.05
5.30
6.60












Alloy 14
63.22
17.43
7.05
5.00
6.30
1.00











Alloy 15
66.35
17.43
7.05
4.77
4.40












Alloy 16
62.22
19.43
7.05
5.00
6.30












Alloy 17
59.90
22.03
6.17
5.30
6.60












Alloy 18
61.67
19.21
7.22
5.30
6.60












Alloy 19
66.95
10.75
10.40
5.30
6.60












Alloy 20
60.97
18.99
7.14
6.05
6.85












Alloy 21
61.67
18.21
7.22
5.30
6.60
1.00











Alloy 22
61.67
18.21
7.22
5.30
6.60

1.00










Alloy 23
61.67
18.21
7.22
5.30
6.60


1.00









Alloy 24
61.67
18.21
7.22
5.30
6.60






1.00





Alloy 25
61.67
19.21
6.22
5.30
6.60




1.00







Alloy 26
61.67
18.21
7.22
5.30
6.60



1.00








Alloy 27
61.67
19.21
6.22
5.30
6.60





1.00






Alloy 28
63.08
15.95
4.54
5.30
6.60








4.53



Alloy 29
61.10
19.21
5.85
5.30
6.60








1.94



Alloy 30
62.11
20.31
4.26
5.30
6.60








1.42



Alloy 31
68.70
15.00
5.00
5.00
6.30












Alloy 32
77.05

11.05
5.30
6.60












Alloy 33
68.72
7.93
11.45
5.30
6.60












Alloy 34
61.67
19.21
7.22
5.30
6.60


Alloy 35
76.45

11.05
4.70
7.80












Alloy 36
75.05

11.05
5.30
6.60





2.00






Alloy 37
72.45

15.05
4.70
7.80












Alloy 38
72.45

13.05
4.70
7.80





2.00






Alloy 39
73.05

7.53
5.30
6.60








7.52



Alloy 40
72.45

7.53
4.70
7.80








7.52


Alloy 41
76.45

8.29
4.70
7.80








2.76



Alloy 42
64.42
15.99
6.24
5.30
6.60








1.45



Alloy 43
63.53
17.06
6.09
5.30
6.60








1.42



Alloy 44
62.64
18.14
5.94
5.30
6.60






1.00

1.38



Alloy 45
61.74
19.21
5.80
5.30
6.60








1.35



Alloy 46
62.91
16.89
6.90
5.30
6.60








1.40



Alloy 47
62.02
17.96
6.75
5.30
6.60






1.00

1.37



Alloy 48
61.14
19.03
6.60
5.30
6.60






3.00

1.33



Alloy 49
61.44
19.27
6.69
4.97
6.28






1.00

1.35



Alloy 50
60.95
18.89
6.55
5.44
6.85







1.00
1.32



Alloy 51
64.08
15.81
6.17
5.20
7.30








1.44


Alloy 52
76.53

6.18
5.25
6.71








5.33



Alloy 53
72.98
3.66
6.16
5.24
6.71








5.25



Alloy 54
77.23
3.66
3.52
5.23
6.73








3.63


Alloy 55
76.89
1.83
4.84
5.24
6.72








4.48



Alloy 56
80.85

2.64
5.24
6.73








4.54



Alloy 57
79.42
1.47
2.64
5.23
6.73








4.51



Alloy 58
77.93
2.34
2.63
5.21
7.42








4.47



Alloy 59
77.06
2.34
3.51
5.21
7.42








4.46



Alloy 60
77.13
2.18
3.50
5.80
6.95








4.44



Alloy 61
76.88
1.09
4.82
5.81
6.95








4.45



Alloy 62
76.64

6.14
5.82
6.94








4.46



Alloy 63
74.93

6.14
5.81
6.94








6.18



Alloy 64
73.54
5.08
2.53
5.78
6.96








6.11



Alloy 65
60.74
19.43
6.60
5.30
6.60








1.33



Alloy 66
61.44
18.73
6.60
5.30
6.60








1.33



Alloy 67
60.79
19.03
6.95
5.30
6.60








1.33



Alloy 68
61.49
19.03
6.25
5.30
6.60








1.33



Alloy 69
61.44
19.03
6.60
5.30
6.60








1.03



Alloy 70
60.74
19.03
6.60
5.30
6.60








1.73



Alloy 71
61.64
19.03
6.60
4.80
6.60








1.33



Alloy 72
60.49
19.03
6.60
5.95
6.60








1.33



Alloy 73
61.64
19.03
6.60
5.30
6.10








1.33



Alloy 74
60.74
19.03
6.60
5.30
7.00








1.33



Alloy 75
72.45

8.29
4.70
7.80








6.76



Alloy 76
72.45

9.79
4.70
7.80








5.26



Alloy 77
76.45

8.29
4.70
7.80








2.76



Alloy 78
77.05

8.29
5.30
6.60








2.76



Alloy 79
77.65

8.29
3.50
7.80








2.76



Alloy 80
74.87
2.18
8.29
5.30
6.60








2.76



Alloy 81
74.27
2.18
8.29
4.70
7.80








2.76


Alloy 82
61.30
18.90
6.80
5.50
6.60








0.90



Alloy 83
60.69
18.71
6.73
5.45
6.53








0.89
1.00


Alloy 84
60.08
18.52
6.66
5.39
6.47








0.88
2.00


Alloy 85
61.85
18.90
6.80
5.40
6.60








0.45



Alloy 86
62.30
18.90
6.80
5.40
6.60












Alloy 87
61.00
18.90
6.80
5.80
6.60








0.90



Alloy 88
74.45

8.29
4.70
7.80








4.76



Alloy 89
75.05

8.29
4.10
7.80








4.76



Alloy 90
75.65

8.29
3.50
7.80








4.76



Alloy 91
73.05

8.29
4.10
7.80








6.76



Alloy 92
73.65

8.29
3.50
7.80








6.76



Alloy 93
74.85

8.29
3.50
6.60








6.76



Alloy 94
72.15

8.59
4.70
7.80








6.76



Alloy 95
72.75

8.59
4.10
7.80








6.76



Alloy 96
73.35

8.59
3.50
7.80








6.76



Alloy 97
72.75

7.99
4.70
7.80








6.76



Alloy 98
73.35

7.99
4.10
7.80








6.76



Alloy 99
73.95

7.99
3.50
7.80








6.76



Alloy 100
73.25

8.29
4.70
7.00








6.76



Alloy 101
71.65

8.29
4.70
8.60








6.76



Alloy 102
72.45

8.29
4.70
7.80








6.76



Alloy 103
72.45

9.79
4.70
7.80








5.26



Alloy 104
76.45

8.29
4.70
7.80








2.76



Alloy 105
77.05

8.29
5.30
6.60








2.76



Alloy 106
77.65

8.29
3.50
7.80








2.76



Alloy 107
74.87
2.18
8.29
5.30
6.60








2.76



Alloy 108
74.27
2.18
8.29
4.70
7.80








2.76



Alloy 109
71.75

8.59
4.70
7.80








7.16



Alloy 110
71.35

8.59
4.70
7.80








7.56



Alloy 111
70.95

8.59
4.70
7.80








7.96



Alloy 112
72.15

8.19
4.70
7.80








7.16



Alloy 113
72.15

7.79
4.70
7.80








7.56



Alloy 114
72.15

7.39
4.70
7.80








7.96



Alloy 115
72.55

8.59
4.70
7.40








6.76



Alloy 116
71.75

8.59
5.10
7.80








6.76



Alloy 117
72.15

8.59
5.10
7.40








6.76



Alloy 118
73.15

8.59
4.10
7.40








6.76



Alloy 119
69.52
1.79
5.28
4.78
7.35








11.28



Alloy 120
67.59
1.78
3.51
4.77
7.34








15.01



Alloy 121
65.64
1.78
1.75
4.76
7.33








18.74



Alloy 122
69.85
3.37
5.27
4.77
7.35








9.39



Alloy 123
67.88
3.37
3.51
4.77
7.34








13.13



Alloy 124
65.95
3.36
1.75
4.76
7.33








16.85



Alloy 125
70.15
4.96
5.27
4.77
7.34








7.51



Alloy 126
68.21
4.95
3.51
4.76
7.33








11.24



Alloy 127
66.27
4.94
1.75
4.75
7.32








14.97



Alloy 128
70.46
6.54
5.27
4.76
7.34








5.63



Alloy 129
68.51
6.53
3.51
4.76
7.33








9.36



Alloy 130
66.58
6.52
1.75
4.75
7.31








13.09



Alloy 131
70.78
8.12
5.26
4.76
7.33








3.75



Alloy 132
68.85
8.10
3.50
4.75
7.32








7.48



Alloy 133
66.89
8.09
1.75
4.75
7.31








11.21



Alloy 134
65.86
6.93
4.82
4.76
7.33








10.30



Alloy 135
64.41
6.92
3.50
4.75
7.32








13.10



Alloy 136
62.96
6.91
2.19
4.75
7.31








15.88



Alloy 137
68.70
5.94
4.83
4.76
7.33








8.44



Alloy 138
67.22
5.94
3.51
4.76
7.33








11.24



Alloy 139
65.78
5.93
2.19
4.75
7.32








14.03



Alloy 140
66.77
7.91
4.82
4.76
7.32








8.42



Alloy 141
65.31
7.90
3.50
4.75
7.32








11.22



Alloy 142
63.85
7.89
2.19
4.75
7.31








14.01



Alloy 143
71.53
4.96
4.83
4.77
7.34








6.57



Alloy 144
70.08
4.95
3.51
4.76
7.33








9.37



Alloy 145
68.61
4.95
2.19
4.76
7.32








12.17



Alloy 146
69.60
6.93
4.82
4.76
7.33








6.56



Alloy 147
68.14
6.92
3.50
4.76
7.32








9.36



Alloy 148
66.69
6.91
2.19
4.75
7.31








12.15



Alloy 149
67.65
8.90
4.82
4.76
7.32








6.55



Alloy 150
66.20
8.89
3.50
4.75
7.31








9.35



Alloy 151
64.76
8.88
2.18
4.74
7.30








12.14



Alloy 152
72.42
5.95
4.83
4.77
7.34








4.69



Alloy 153
70.97
5.94
3.51
4.76
7.33








7.49



Alloy 154
69.51
5.93
2.19
4.76
7.32








10.29



Alloy 155
73.33
6.93
4.83
4.76
7.34








2.81



Alloy 156
71.85
6.93
3.51
4.76
7.33








5.62



Alloy 157
70.40
6.92
2.19
4.75
7.32








8.42



Alloy 158
59.35
18.87
5.06
5.51
6.60








4.61



Alloy 159
57.45
18.84
3.32
5.50
6.59








8.30



Alloy 160
55.56
18.81
1.58
5.49
6.58








11.98



Alloy 161
60.70
12.70
4.94
5.39
11.77








4.50



Alloy 162
58.84
12.68
3.24
5.38
11.75








8.11



Alloy 163
56.98
12.66
1.55
5.37
11.73








11.71



Alloy 164
65.10
13.05
5.08
5.53
6.62








4.62



Alloy 165
63.18
13.03
3.33
5.52
6.61








8.33



Alloy 166
61.24
13.01
1.59
5.52
6.61








12.03



Alloy 167
67.21
4.95
3.51
5.76
7.33








11.24



Alloy 168
69.21
4.95
3.51
3.76
7.33








11.24



Alloy 169
69.21
4.95
3.51
4.76
6.33








11.24



Alloy 170
70.21
4.95
3.51
3.76
6.33








11.24



Alloy 171
69.66
3.50
3.51
4.76
7.33








11.24



Alloy 172
66.21
4.95
3.51
4.76
7.33





2.00


11.24



Alloy 173
66.71
4.95
3.51
4.76
7.33








11.24
1.50


Alloy 174
66.65
8.90
4.82
5.76
7.32








6.55



Alloy 175
68.65
8.90
4.82
3.76
7.32








6.55



Alloy 176
68.65
8.90
4.82
4.76
6.32








6.55



Alloy 177
69.65
8.90
4.82
3.76
6.32








6.55



Alloy 178
71.60
4.95
4.82
4.76
7.32








6.55



Alloy 179
73.05
3.50
4.82
4.76
7.32








6.55



Alloy 180
65.65
8.90
4.82
4.76
7.32





2.00


6.55



Alloy 181
66.15
8.90
4.82
4.76
7.32








6.55
1.50


Alloy 182
67.73
4.95
3.51
4.76
7.33





2.00


9.72



Alloy 183
65.21
4.95
3.51
4.76
7.33





3.00


11.24



Alloy 184
67.49
4.95
3.51
4.76
7.33





3.00


8.96



Alloy 185
70.32
4.95
4.10
4.76
7.32





2.00


6.55



Alloy 186
68.60
4.95
4.82
4.76
7.32





3.00


6.55



Alloy 187
69.68
4.95
3.74
4.76
7.32





3.00


6.55



Alloy 188
68.73
4.95
3.51
3.76
7.33





2.00


9.72



Alloy 189
66.21
4.95
3.51
3.76
7.33





3.00


11.24



Alloy 190
68.49
4.95
3.51
3.76
7.33





3.00


8.96



Alloy 191
71.32
4.95
4.10
3.76
7.32





2.00


6.55



Alloy 192
69.60
4.95
4.82
3.76
7.32





3.00


6.55



Alloy 193
70.68
4.95
3.74
3.76
7.32





3.00


6.55



Alloy 194
67.21
4.95
3.51
3.76
7.33





2.00


11.24



Alloy 195
71.32
4.95
4.10
3.76
7.32





2.00


6.55



Alloy 196
69.60
4.95
4.82
3.76
7.32





3.00


6.55



Alloy 197
70.68
4.95
3.74
3.76
7.32





3.00


6.55



Alloy 198
71.82
4.95
4.10
3.26
7.32





2.00


6.55



Alloy 199
70.10
4.95
4.82
3.26
7.32





3.00


6.55



Alloy 200
71.18
4.95
3.74
3.26
7.32





3.00


6.55



Alloy 201
72.32
4.95
4.10
2.76
7.32





2.00


6.55



Alloy 202
70.60
4.95
4.82
2.76
7.32





3.00


6.55



Alloy 203
71.68
4.95
3.74
2.76
7.32





3.00


6.55



Alloy 204
72.82
3.45
4.10
3.76
7.32





2.00


6.55



Alloy 205
71.10
3.45
4.82
3.76
7.32





3.00


6.55



Alloy 206
72.18
3.45
3.74
3.76
7.32





3.00


6.55



Alloy 207
70.32
4.95
4.10
3.76
7.32





3.00


6.55



Alloy 208
71.82
4.95
4.10
3.76
7.32





1.50


6.55



Alloy 209
71.10
4.95
4.82
3.76
7.32





1.50


6.55



Alloy 210
72.18
4.95
3.74
3.76
7.32





1.50


6.55



Alloy 211
71.82
4.95
4.10
3.76
7.32





2.00


6.05



Alloy 212
72.32
4.95
4.10
3.76
7.32





2.00


5.55



Alloy 213
71.62
4.95
4.10
3.76
7.02





2.00


6.55



Alloy 214
71.92
4.95
4.10
3.76
6.72





2.00


6.55



Alloy 215
72.12
4.95
4.10
3.76
7.02





2.00


6.05



Alloy 216
60.47
19.43
6.60
5.29
6.60





0.28


1.33



Alloy 217
69.62
4.95
2.10
3.76
7.02





2.00


10.55



Alloy 218
70.62
4.95
2.10
3.76
7.02





2.00


9.55



Alloy 219
71.62
4.95
2.10
3.76
7.02





2.00


8.55



Alloy 220
72.62
4.95
2.10
3.76
7.02





2.00


7.55



Alloy 221
69.62
4.95
2.10
3.76
7.02





6.00


6.55



Alloy 222
70.62
4.95
2.10
3.76
7.02





5.00


6.55



Alloy 223
71.62
4.95
2.10
3.76
7.02





4.00


6.55



Alloy 224
72.62
4.95
2.10
3.76
7.02





3.00


6.55



Alloy 225
69.62
6.95
2.10
3.76
7.02





2.00


8.55



Alloy 226
73.62
2.95
2.10
3.76
7.02





2.00


8.55



Alloy 227
71.12
4.95
2.60
3.76
7.02





2.00


8.55



Alloy 228
72.12
4.95
1.60
3.76
7.02





2.00


8.55



Alloy 229
71.12
4.95
2.10
4.26
7.02





2.00


8.55



Alloy 230
72.12
4.95
2.10
3.26
7.02





2.00


8.55



Alloy 231
70.92
4.95
2.10
3.76
7.72





2.00


8.55



Alloy 232
72.32
4.95
2.10
3.76
6.32





2.00


8.55



Alloy 233
71.12
4.95
2.10
3.76
7.02





2.50


8.55



Alloy 234
72.12
4.95
2.10
3.76
7.02





1.50


8.55



Alloy 235
70.12
4.95
1.60
3.76
7.02





2.00


10.55



Alloy 236
70.62
4.95
1.10
3.76
7.02





2.00


10.55



Alloy 237
66.62
7.95
2.10
3.76
7.02





2.00


10.55



Alloy 238
68.12
6.45
2.10
3.76
7.02





2.00


10.55



Alloy 239
68.22
4.95
2.10
3.76
8.42





2.00


10.55



Alloy 240
68.92
4.95
2.10
3.76
7.72





2.00


10.55



Alloy 241
68.62
4.95
2.10
3.76
7.02





3.00


10.55



Alloy 242
70.62
4.95
2.10
3.76
7.02





1.00


10.55



Alloy 243
69.12
4.95
1.60
3.76
7.02





3.00


10.55



Alloy 244
69.62
4.95
1.10
3.76
7.02





3.00


10.55



Alloy 245
59.97
7.36

5.43
6.80








20.44



Alloy 246
60.80
3.63

5.35
10.07








20.15



Alloy 247
61.60


5.28
13.25








19.87



Alloy 248
61.87
5.41

5.44
6.81








20.47



Alloy 249
62.48
2.67

5.38
9.22








20.25



Alloy 250
63.02


5.32
11.62








20.04



Alloy 251
63.79
3.45

5.44
6.82








20.50



Alloy 252
64.19
1.71

5.41
8.33








20.36



Alloy 253
64.49


5.37
9.92








20.22



Alloy 254
63.67
7.37

5.43
6.80








16.73



Alloy 255
64.44
3.63

5.36
10.07








16.50



Alloy 256
65.20


5.28
13.26








16.26



Alloy 257
65.58
5.41

5.44
6.81








16.76



Alloy 258
66.13
2.68

5.38
9.23








16.58



Alloy 259
66.64


5.33
11.62








16.41



Alloy 260
67.50
3.45

5.45
6.82








16.78



Alloy 261
67.88
1.71

5.41
8.33








16.67



Alloy 262
68.15


5.37
9.93








16.55



Alloy 263
67.36
7.37

5.44
6.81








13.02



Alloy 264
68.09
3.63

5.36
10.08








12.84



Alloy 265
68.80


5.28
13.26








12.66



Alloy 266
69.30
5.41

5.44
6.81








13.04



Alloy 267
69.80
2.68

5.39
9.23








12.90



Alloy 268
70.27


5.33
11.63








12.77



Alloy 269
71.22
3.45

5.45
6.82








13.06



Alloy 270
71.56
1.71

5.42
8.34








12.97



Alloy 271
71.81


5.38
9.93








12.88



Alloy 272
59.70
18.00
6.80
5.50
6.60

2.50






0.90



Alloy 273
57.20
21.00
6.80
5.50
6.60

2.00






0.90



Alloy 274
55.20
23.50
6.80
5.50
6.60

1.50






0.90



Alloy 275
53.20
26.00
6.80
5.50
6.60

1.00






0.90



Alloy 276
50.70
29.00
6.80
5.50
6.60

0.50






0.90



Alloy 277
48.20
32.00
6.80
5.50
6.60








0.90



Alloy 278
65.62
7.95
2.10
4.76
7.02





2.00


10.55



Alloy 279
66.62
6.95
2.10
4.76
7.02





2.00


10.55



Alloy 280
67.62
5.95
2.10
4.76
7.02





2.00


10.55



Alloy 281
65.42
7.95
2.10
4.26
7.72





2.00


10.55



Alloy 282
66.42
6.95
2.10
4.26
7.72





2.00


10.55



Alloy 283
67.42
5.95
2.10
4.26
7.72





2.00


10.55



Alloy 284
68.97
7.95
1.25
4.76
5.52





1.00


10.55



Alloy 285
69.47
6.95
1.25
4.76
6.02





1.00


10.55



Alloy 286
69.97
5.95
1.25
4.76
6.52





1.00


10.55



Alloy 287
71.67
3.55
1.25
4.26
7.72





1.00


10.55



Alloy 288
72.17
3.05
1.25
4.26
7.72





1.00


10.55


Alloy 289
72.37
3.55
1.25
4.26
7.02





1.00


10.55


Alloy 290
69.22
4.95
1.75
3.76
7.77





2.00


10.55


Alloy 291
69.27
4.95
2.10
3.76
7.77





1.60


10.55


Alloy 292
68.02
4.95
2.10
4.61
7.77





2.00


10.55



Alloy 293
68.29
5.53
2.10
3.76
7.77





2.00


10.55



Alloy 294
68.43
4.95
2.10
3.76
7.77





2.00


10.99



Alloy 295
69.31
4.95
2.10
3.76
7.77





2.00


10.11



Alloy 296
68.52
4.95
2.45
3.76
7.77





2.00


10.55



Alloy 297
68.17
4.95
2.80
3.76
7.77





2.00


10.55



Alloy 298
68.37
4.95
2.10
3.76
7.77





2.50


10.55



Alloy 299
72.20
4.37
2.10
3.76
7.02





2.00


8.55



Alloy 300
71.27
4.95
2.45
3.76
7.02





2.00


8.55



Alloy 301
72.06
4.95
2.10
3.76
7.02





2.00


8.11



Alloy 302
70.77
4.95
2.10
4.61
7.02





2.00


8.55



Alloy 303
70.97
4.95
2.10
3.76
7.67





2.00


8.55



Alloy 304
70.62
4.95
2.10
3.76
7.02





3.00


8.55



Alloy 305
70.69
4.66
2.28
4.19
7.35





2.50


8.33



Alloy 306
70.19
5.53
2.10
4.61
7.02





2.00


8.55



Alloy 307
71.12
4.95
1.75
4.61
7.02





2.00


8.55



Alloy 308
70.42
4.95
2.45
4.61
7.02





2.00


8.55



Alloy 309
71.65
4.95
2.10
4.61
7.02





2.00


7.67



Alloy 310
69.92
4.95
2.10
5.46
7.02





2.00


8.55



Alloy 311
70.12
4.95
2.10
4.61
7.67





2.00


8.55



Alloy 312
70.27
4.95
2.10
4.61
7.02





2.50


8.55



Alloy 313
69.91
5.24
2.10
5.04
7.35





2.25


8.11



Alloy 314
68.40
4.95
2.10
6.98
7.02





2.00


8.55



Alloy 315
69.29
4.95
2.10
6.09
7.02





2.00


8.55



Alloy 316
70.20
4.95
2.10
5.18
7.02





2.00


8.55



Alloy 317
70.79
4.95
2.10
6.09
5.52





2.00


8.55



Alloy 318
72.29
4.95
2.10
6.09
4.02





2.00


8.55



Alloy 319
73.79
4.95
2.10
6.09
2.52





2.00


8.55



Alloy 320
68.29
5.95
2.10
6.09
7.02





2.00


8.55



Alloy 321
70.29
3.95
2.10
6.09
7.02





2.00


8.55



Alloy 322
70.30
4.95
2.10
5.50
6.60





2.00


8.55



Alloy 323
71.29
4.95
2.10
6.09
7.02





2.00


6.55



Alloy 324
67.29
4.95
2.10
6.09
7.02





2.00


10.55



Alloy 325
70.29
4.95
2.10
6.09
7.02





1.00


8.55



Alloy 326
71.29
4.95
2.10
6.09
7.02








8.55



Alloy 327
68.54
4.95
2.10
6.09
7.02



0.75

2.00


8.55



Alloy 328
68.29
4.95
2.10
6.09
7.02



1.00

2.00


8.55



Alloy 329
68.79
4.95
2.10
6.09
7.02



0.75

1.00


9.30



Alloy 330
72.79
4.95
2.10
6.09
4.02





1.50


8.55



Alloy 331
71.79
5.95
2.10
6.09
4.02





1.50


8.55



Alloy 332
72.42
4.95
2.10
6.09
4.02





1.50


8.92



Alloy 333
71.42
5.95
2.10
6.09
4.02





1.50


8.92



Alloy 334
70.42
6.95
2.10
6.09
4.02





1.50


8.92



Alloy 335
70.80
4.95
2.10
5.50
6.60





1.50


8.55



Alloy 336
69.80
5.95
2.10
5.50
6.60





1.50


8.55



Alloy 337
70.43
4.95
2.10
5.50
6.60





1.50


8.92



Alloy 338
69.43
5.95
2.10
5.50
6.60





1.50


8.92



Alloy 339
68.43
6.95
2.10
5.50
6.60





1.50


8.92



Alloy 340
71.79
4.95
2.10
6.09
7.02





1.50


6.55



Alloy 341
72.29
4.95
2.10
6.09
7.02





2.00


5.55



Alloy 342
73.29
4.95
2.10
6.09
7.02





2.00


4.55










The atomic percent of Fe present may therefore be 48.0, 48.1, 48.2, 48.3, 48.4, 48.5, 48.6, 48.7, 48.8, 48.9, 49.0, 49.1, 49.2, 49.3, 49.4, 49.5, 49.6, 49.7, 49.8, 49.9, 50.0, 50.1, 50.2, 50.3, 50.4, 50.5, 50.6, 50.7, 50.8, 50.9, 51.0, 51.1, 51.2, 51.3, 51.4, 51.5, 51.6, 51.7, 51.8, 51.9, 52.0, 52.1, 52.2, 52.3, 52.4, 52.5, 52.6, 52.7, 52.8, 52.9, 53.0, 53.1, 53.2, 53.3, 53.4, 53.5, 53.6, 53.7, 54.8, 53.9, 53.0 53.1, 53.2, 53.3, 53.4, 53.5, 53.6, 53.7, 53.8, 53.9, 54.0, 54.1, 54.2, 54.3, 54.4, 54.5, 54.6, 54.7, 54.8, 54.9, 55.0, 55.1, 55.2, 55.3, 55.4, 55.5, 55.6, 55.7, 55.8, 55.9, 56.0, 56.1, 56.2, 56.3, 56.4, 56.5, 56.6, 56.7, 56.8, 56.9 57.0, 57.1, 57.2, 57.3, 57.4, 57.5, 57.6, 57.7, 57.8, 57.9, 58.0, 58.1, 58.2, 58.3, 58.4, 58.5, 58.6, 58.7, 58.8, 58.9, 59.0, 59.1, 59.2, 59.3, 59.4, 59.5, 59.6, 59.7, 59.8, 59.9, 60.0, 60.1, 60.2, 60.3, 60.4, 60.5, 60.6, 60.7, 60.8, 60.9 61.0, 61.1, 61.2, 61.3, 61.4, 61.5, 61.6, 61.7, 61.8, 61.9, 62.0, 62.1, 62.2, 62.3, 62.4, 62.5, 62.6, 62.7, 62.8, 62.9, 63.0, 63.1, 63.2, 63.3, 63.4, 63.5, 63.6, 63.7, 63.8, 63.9, 64.0, 64.1, 64.2, 64.3, 64.4, 64.5, 64.6, 64.7, 64.8, 64.9, 65.0, 65.1, 65.2, 65.3, 65.4, 65.5, 65.6, 65.7, 65.8, 65.9, 66.0, 66.1, 66.2, 66.3, 66.4, 66.5, 66.6, 66.7, 66.8, 66.9, 67.0, 67.1, 67.2, 67.3, 67.4, 67.5, 67.6, 67.7, 67.8, 67.9, 68.0, 68.1, 68.2, 68.3, 68.4, 68.5, 68.6, 68.7, 68.8, 68.9, 69.0, 69.1, 69.2, 69.3, 69.4, 69.5, 69.6, 69.7, 69.8, 69.9, 70.0, 70.1, 70.2, 70.3, 70.4, 70.5, 70.6, 70.7, 70.8, 70.9, 71.0, 71.1, 71.2, 71.3, 71.4, 71.5, 71.6, 71.7, 71.8, 71.9, 72.0, 72.1, 72.2, 72.3, 72.4, 72.5, 72.6, 72.7, 72.8, 72.9, 73.0, 73.1, 73.2, 73.3, 73.4, 73.5, 73.6, 73.7, 73.8, 73.9, 74.0, 74.1, 74.2, 74.3, 74.4, 74.5, 74.6, 74.7, 74.8, 74.9, 75.0, 75.1, 75.2, 75.3, 75.4, 75.5, 75.6, 75.7, 75.8, 75.9, 76.0, 76.1, 76.2, 76.3, 76.4, 76.5, 76.6, 76.7, 76.8, 76.9, 77.0, 77.1, 77.2, 77.3, 77.4, 77.5, 77.6, 77.7, 77.8, 77.9, 78.0, 78.1, 78.2, 78.3, 78.4, 78.5, 78.6, 78.7, 78.8, 78.9, 79, 79.1, 79.2, 79.3, 79.4, 79.5, 79.6, 79.7, 79.8, 79.9, 80.0, 80.1, 80.2, 80.3, 80.4, 80.5, 80.6, 80.7, 80.8, 80.9, 81.0.


The atomic percent of B may therefore be 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 2.7, 2.8, 2.9 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0.


The atomic percent of Si may therefore be 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0.


The atomic percent of Cu may therefore be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 2.7, 2.8, 2.9 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0.


The atomic ratio of Mn may therefore be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, 14.8, 14.9, 15.0, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 15.7, 15.8, 15.9, 16.0, 16.1, 16.2, 16.3, 16.4, 16.5, 16.6, 16.7, 16.8, 16.9, 17.0, 17.1, 17.2, 17.3, 17.4, 17.5, 17.6, 17.7, 17.8, 17.9, 18.0, 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 19.0, 19.1, 19.2, 19.3, 19.4, 19.5, 19.6, 19.7, 19.8, 19.9, 20.0, 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 21.0.


The atomic ratio of Ni may therefore be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 2.7, 2.8, 2.9 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, 14.8, 14.9, 15.0, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 15.7, 15.8, 15.9, 16.0.


The atomic ratio of Cr as an optional element, if present, may therefore be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7., 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, 14.8, 14.9, 15.0, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 15.7, 15.8, 15.9, 16.0, 16.1, 16.2, 16.3, 16.4, 16.5, 16.6, 16.7, 16.8, 16.9, 17.0, 17.1, 17.2, 17.3, 17.4, 17.5, 17.6, 17.7, 17.8, 17.9, 18.0, 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 19.0, 19.1, 19.2, 19.3, 19.4, 19.5, 19.6, 19.7, 19.8, 19.9, 20.0, 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 21.0, 21.1, 21.2, 21.3, 21.4, 21.5, 21.6, 21.7, 21.8, 21.9, 22.0, 22.1, 22.2, 22.3, 22.4, 22.5, 22.6, 22.7, 22.8, 22.9, 23.0, 23.1, 23.2, 23.3, 23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3, 24.4, 24.5, 24.6, 24.7, 24.8, 24.9, 25.0, 25.1, 25.2, 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9, 26.0, 26.1, 26.2, 26.3, 26.4, 26.5, 26.6, 26.7, 26.8, 26.9, 27, 27.1, 27.2, 27.3, 27.4, 27.5, 27.6, 27.7, 27.8, 27.9, 28.0, 28.1, 28.2, 28.3, 28.4, 28.5, 28.6, 28.7, 28.8, 28.9, 29.0, 29.1, 29.2, 29.3, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 30.0, 30.1, 30.2, 30.3, 30.4, 30.5, 30.6, 30.7, 30.8, 30.9, 31.0, 31.1, 31.2, 31.3, 31.4, 31.5, 31.6, 31.7, 31.8, 31.9, 32.0.


Case Example #1
Warm Formability of Class 2 Stainless Alloy

The study was performed to evaluate warm formability of the alloys described in this application at elevated temperatures. In a case of plate production by Twin Roll Casting or Thin Slab Casting, utilized alloys should have good formability to be processed by hot rolling as a step at production process. Moreover, hot forming ability is a critical feature of the high strength alloys in terms of their usage for part production with different configuration by such methods as hot pressing, hot stamping, etc.


Using ferroadditives and other readily commercially available constituents, 35 g commercial purity (CP) feedstocks for Alloy 82 representing Class 2 steel were weighed out according to the atomic ratio provided in Table 2. The feedstock material was then placed into the copper hearth of an arc-melting system. The feedstock was arc-melted into an ingot using high purity argon as a shielding gas. The ingots were flipped several times and re-melted to ensure homogeneity. The resulting ingots were then placed in a PVC chamber, melted using RF induction and then ejected onto a copper die designed for casting a 3×4 inches plates with thickness of 1.8 mm.


Resultant plate from the Alloy 82 was subjected to a HIP cycle at 1150° C. using an American Isostatic Press Model 645 machine with a molybdenum furnace with furnace chamber size of 4 inch diameter by 5 inch height. The plates were heated at 10° C./min until the target temperature and were exposed to an isostatic pressure of 30 ksi for 1 hour. Heat treatment at 850° C. for 1 hour was applied after HIP cycle. Tensile specimens with a gage length of 12 mm and a width of 3 mm were cut from the treated plate.


The tensile measurements were done with testing parameters listed in Table 3 at temperatures specified in Table 4. The NanoSteel R&D specimen geometry (shown in FIG. 11) was modified by enlarging the grip section to accommodate for pinholes required for elevated temperature tensile testing. The modified grip section of the sample is 9.5 mm (⅜″). In Table 5, a summary of the tensile test results including total tensile elongation (strain), yield stress, and ultimate tensile strength are shown for the treated plate from Alloy 82. Room temperature tensile property ranges for the same alloy after the same treatments are listed for comparison. As can be seen, ductility in high strength alloy is twice higher at 700° C. and reaches up to 92% when tested at 800° C. demonstrating high warm forming ability of the alloy. Warm temperature ductility of the alloys strongly depends on alloy chemistry, thermal mechanical treatment parameters and testing temperature.









TABLE 3







Tensile Testing Parameters










Parameter
Value







Testing Standard
ASTM E21-09



Soak time
5 to 30 minutes



Test Speed
0.020 in/min

















TABLE 4







Testing Temperatures











Parameter
Testing
Homologous



Set
Temperature (° C.)
Temperature







1
700
0.65



2
800
0.71

















TABLE 5







Tensile Test Results for Alloy 82












Test






Temperature
Elongation at
Yield Strength
UTS



[° C.]
Fracture [%]
[GPa]
[MPa]
















25
27
455.9
1256



700
56
281.3
386.1




58
287.5
388.2



800
66
156.5
206.2




92
179.3
215.1










Case Example #2
Warm Formability of Class 2 Non-Stainless Alloy

Using ferroadditives and other readily commercially available constituents, 35 g commercial purity (CP) feedstocks for Alloy 213 representing Class 2 steel were weighed out according to the atomic ratio provided in Table 2. The feedstock material was then placed into the copper hearth of an arc-melting system. The feedstock was arc-melted into an ingot using high purity argon as a shielding gas. The ingots were flipped several times and re-melted to ensure homogeneity. The resulting ingots were then placed in a PVC chamber, melted using RF induction and then ejected onto a copper die designed for casting a 3×4 inches plates with thickness of 1.8 mm.


Resultant plate from the Alloy 213 was subjected to a HIP cycle at 1125° C. using an American Isostatic Press Model 645 machine with a molybdenum furnace with furnace chamber size of 4 inch diameter by 5 inch height. The plates were heated at 10° C./min until the target temperature and were exposed to an isostatic pressure of 30 ksi for 1 hour. Tensile specimens with NanoSteel R&D specimen geometry (FIG. 11) were cut from the treated plate.


The tensile measurements were done with testing parameters listed in Table 6 at temperatures specified in Table 7. In Table 8, a summary of the tensile test results including total tensile elongation (strain), yield stress, and ultimate tensile strength are shown for the treated plate from Alloy 213. Room temperature tensile property ranges for the same alloy after the same treatments are listed for comparison. As can be seen, this alloy shows high ductility up to 74% when tested at 700° C. demonstrating high warm forming ability. Temperature dependence of yield stress and tensile elongation is illustrated on FIG. 12. Warm temperature ductility of the alloys strongly depends on alloy chemistry, thermal mechanical treatment parameters and testing temperature.









TABLE 6







Tensile Testing Parameters










Parameter
Value







Test Standard
ASTM E21-09



Test atmosphere
Ambient



Soak time
20-30 minutes



Strain rate
0.424/minute



Displacement rate
0.020 in/min (0.508 mm/min)



(Control parameter)

















TABLE 7







Testing Temperatures










Testing
Homologous


Parameter
Temperature
Temperature


Set
(° C.)
(K/K)












1
300
0.4


2
500
0.54


3
600
0.61


4
700
0.68
















TABLE 8







Test Results for Alloy 213












Test

Yield




Temperature
Elongation
Strength




[° C.]
[%]
[MPa]
UTS [MPa]







 20
11.7
383
1321 



300
47.0
329
692




44.5
305
674




57.5
334
698



500
47.0
319
596




44.5
281
599




51.0
265
562



600
66.0
276
479




66.0
281
464




61.5
252
460



700
64.0
232
297




70.0
232
285




74.5
224
280










Case Example #3
Warm Formability of Class 3 Alloy

The study was performed to evaluate warm formability of the alloys described in this application at elevated temperatures. In a case of plate production by Twin Roll Casting or Thin Slab Casting, utilized alloys should have good formability to be processed by hot rolling as a step at production process. Moreover, hot forming ability is a critical feature of the high strength alloys in terms of their usage for part production with different configuration by such methods as hot pressing, hot stamping, etc.


Using high purity elements, 35 g alloy feedstocks of the Alloy 36 representing Class 3 steel were weighed out according to the atomic ratios provided in Table 2. The feedstock material was then placed into the copper hearth of an arc-melting system. The feedstock was arc-melted into an ingot using high purity argon as a shielding gas. The ingots were flipped several times and re-melted to ensure homogeneity. The resulting ingots were then placed in a PVC chamber, melted using RF induction and then ejected onto a copper die designed for casting a 3×4 inches plates with thickness of 1.8 mm.


Resultant plate from the Alloy 36 was subjected to a HIP cycle at 1100° C. using an American Isostatic Press Model 645 machine with a molybdenum furnace with furnace chamber size of 4 inch diameter by 5 inch height. The plates were heated at 10° C./min until the target temperature and were exposed to an isostatic pressure of 30 ksi for 1 hour. Heat treatment at 850° C. for 1 hour was applied after HIP cycle. Tensile specimens with NanoSteel R&D specimen geometry (FIG. 11) were cut from the treated plate.


The tensile measurements were done at strain rate of 0.001 s−1 at 700° C. In Table 9, a summary of the tensile test results including total tensile elongation (strain), yield stress, and ultimate tensile strength are shown for the treated plate from Alloy 36. Room temperature tensile property ranges for the same alloy after the same treatments are listed for comparison. As can be seen, high strength alloys with ultimate strength up to 1650 MPa at room temperature show high ductility up to 88.5% when tested at 700° C. demonstrating high warm forming ability. Warm temperature ductility of the alloys strongly depends on alloy chemistry, thermal mechanical treatment parameters and testing temperature. An example of tested specimen is shown in FIG. 13.









TABLE 9







Tensile Test Results for Alloy 36












Test
Elongation
Yield
Ultimate



Temperature
at Fracture
Stress
Strength


Alloy
[° C.]
[%]
[MPa]
[MPa]





Alloy 36
RT
3.4-7.4
850-1145
1525-1653



700
57.5
66.9
157.9




88.5
68.3
157.9









Case Example #4
Warm Formability of Commercial Sheet from Class 2 Alloy

Alloy 82 was utilized for commercial sheet production by Thin Strip casting with in-line hot rolling that was done at ˜1050° C. to ˜9% reduction. The condition of the sheet material is not optimized (partial transformation into NanoModal structure due to low temperature and reduction at in-line rolling). Tensile specimens with NanoSteel R&D specimen geometry (FIG. 11) were cut from the produced sheet. The tensile measurements were done with testing parameters listed in Table 10 at temperatures specified in Table 11. In Table 12, a summary of the tensile test results including total tensile elongation (strain), yield stress, and ultimate tensile strength are shown for the produced sheet from Alloy 82. Temperature dependence of strength characteristics and tensile elongation is shown in FIG. 14. As it can be seen, that despite only partial transformation into NanoModal structure at in-line hot rolling, the ductility of up to 30% can be achieved at 700° C. Even higher warm forming ability is expected in the sheet with full transformation.









TABLE 10







Tensile Testing Parameters








Parameter
Value





Testing Standard
ASTM E21-09


Soak time
5 to 30 minutes


Test Speed 1
0.020 in/min


Test Speed 2
0.005 in/in-min, 0.05 in/in-min
















TABLE 11







Testing Temperatures












Testing
Homologous



Parameter
Temperature
Temperature



Set
(° C.)
(K/K)







1
400
0.45



2
450
0.48



3
500
0.51



4
550
0.55



5
600
0.58



6
650
0.61



7
700
0.65

















TABLE 12







Test Results










Test





Temperature
Elongation at
Yield Strength
UTS


[° C.]
Fracture [%]
[GPa]
[MPa]













400
4.66
375.8
672.9



3.58
366.8
633.6


450
5.69
353.0
664.0



4.31
380.6
649.5


500
4.03
386.1
605.4



2.95
389.6
602.6


550
3.69
413.7
600.5



4.28
464.7
610.2


600
5.90
408.2
596.4



4.92
389.6
583.3


650
10.1
301.3
492.3



4.47
260.6
447.5


700
13.4
326.1
402.7



18.7
337.2
402.0


750
32.93
180.6
313.0



28.8
217.2
301.3


800
46.0
163.4
214.4



42.5
160.0
207.5








Claims
  • 1. A method comprising: supplying a metal alloy comprising Fe at 48.0 to 81.0 atomic percent, B at 2.0to 8.0atomic percent, Si at 4.0 to 14.0 atomic percent, Cu at 0.1 to 6.0 atomic percent and Mn at 10.5 to 21.0 atomic percent and optionally Ni present at 0.1 to 16.0 atomic percent;melting said alloy and solidifying, without quenching, to form a matrix grain size of 500 nm to 20,000 nm and a boride grain size of 25 nm to 500 nm;mechanical stressing, or heating and mechanical stressing said alloy form at least one of the following:(a) matrix grain size of 500 nm to 20,000 nm, boride grains of 25 nm to 500 nm, precipitation grain size of 1 nm to 200 nm wherein said alloy indicates a yield strength of 400 MPa to 1300 MPa, tensile strength of 700 MPa to 1400 MPa and a tensile elongation of 10% to 50%;(b) refined matrix grain size of 100 nm to 2000 nm, precipitation grain size of 1 nm to 200 nm, boride grain size of 200 nm to 2500 nm where the alloy has yield strength of 300 MPa to 800 MPa; andheating of the alloy (a) or alloy (b) at a temperature of 200° C. to 850° C. for a time period of up to 1 hour wherein upon cooling there is no eutectoid transformation.
  • 2. The method of claim 1 wherein said alloy is formed into a selected shape.
  • 3. The method of claim 1 wherein said alloy having said refined matrix grain size (b) is exposed to a stress that exceeds said yield strength of 300 MPa to 800 MPa wherein said refined matrix grain size remains at 100 nm to 2000 nm, said boride grain size remains at 200 nm to 2500 nm, said precipitation grain size remains at 1 nm to 200 nm wherein said alloy indicates a yield strength of 400 MPa to 1700 MPa, tensile strength of 800 MPa to 1800 MPa and an elongation of 5% to 40%.
  • 4. The method of claim 3 wherein said alloy is formed into a selected shape.
  • 5. The method of claim 1 including Cr at a level of up to 32 atomic percent.
  • 6. The method of claim 1 including C, Al, Ti, V, Nb, Mo, Zr, W or Pd at a level of up to 10 atomic percent.
  • 7. A method comprising: (a) supplying a metal alloy comprising Fe at 48.0 to 81.0 atomic percent, B at 2.0 to 8.0 atomic percent, Si at 4.0 to 14.0 atomic percent, Cu at 0.1 to 6.0 atomic percent and at least one or more of Mn at 10.5 to 21.0 atomic percent and optionally Ni at 0.1 to 16.0 atomic percent;(b) melting said alloy and solidifying, without quenching, to provide dendritic morphology and matrix grain size of 500 nm to 20,000 nm and boride grain size of 100 nm to 2500 nm;(c) heat treating said alloy and forming lath structure including grains of 100 nm to 10,000 nm, boride grains of 100 nm to 2500 nm wherein said alloy has a yield strength of 300 MPa to 1400 MPa, tensile strength of 350 MPa to 1600 MPa and elongation of 0-12%;(d) heat treating said alloy after step (c) and forming lamellae grains 100 nm to 10,000 nm thick, 0.1 microns to 5.0 microns in length and 100 nm to 1000 nm in width along with boride grains of 100 nm to 25000 nm and precipitation grains of 1.0 nm to 100 nm wherein said alloy indicates a yield strength of 350 MPa to 1400 MPa;(e) wherein said alloy is heated a temperature of 200° C. to 850° C. for a time period of up to 1 hour and upon cooling there is no eutectoid transformation.
  • 8. The method of claim 7 wherein the alloy formed in step (d) is stressed prior to step (e) and forms an alloy having grains of 100 nm to 5000 nm, boride grains of 100 nm to 2500 nm, precipitation grains of 1 nm to 100 nm and said alloy has a yield strength of 500 MPa to 1800 MPa, tensile strength of 1000 to 2000 MPa, and an elongation of 0.5% to 15%.
  • 9. The method of claim 7 wherein said alloy is formed into a selected shape.
  • 10. The method of claim 8 wherein said alloy is formed into a selected shape.
  • 11. The method of claim 7 including Cr at a level of up to 32 atomic percent.
  • 12. The method of claim 7 including C, Al, Ti, V, Nb, Mo, Zr, W or Pd at a level of up to 10 atomic percent.
CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/768,131 filed Feb. 22, 2013.

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Related Publications (1)
Number Date Country
20140238556 A1 Aug 2014 US
Provisional Applications (1)
Number Date Country
61768131 Feb 2013 US