Patent Grant
12031190
This application is a 35 U.S.C. § 371 national stage application of PCT Application No. PCT/JP2020/043991, filed on Nov. 26, 2020, which claims priority from Japanese Patent Application No. 2019-215265, filed on Nov. 28, 2019, the contents of which are incorporated herein by reference in their entireties. The above-referenced PCT International Application was published in the Japanese language as International Publication No. WO 2021/106998 A1 on Jun. 3, 2021.
The present invention relates to a method for producing a nickel-based alloy product or a titanium-based alloy product.
When a solution treatment is carried out on a disk-shaped metal material that has been formed into a predetermined shape by hot forging or the like and made of a nickel-based alloy or titanium-based alloy, such as an aircraft engine member, the cooling rate of the entire disk-shaped metal material in the cooling process thereafter is controlled by spraying a gas such as air from a plurality of high-pressure nozzles close to the site where the disk-shaped metal material is to be locally cooled, because of the complex shape of the member, and a freely chosen site of a material held in a heated state is thus rapidly cooled to achieve the desired cooling rate. In addition to air, a liquid refrigerant such as water may be sprayed together with the gas.
When a gas or a liquid is sprayed from a fixed nozzle toward a disk-shaped metal material in an open space, a flow of the sprayed gas or liquid is generated in the direction moving away from the surface of the disk-shaped metal material, so it is difficult for the gas or liquid to hit the surface of the disk-shaped metal material as the target to be sprayed, and there may be an area where a desired cooling rate is not obtained. For example, if a uniform gas or liquid flow is applied to the entire surface of the disk-shaped metal material, the flow of the gas or liquid to be discharged is inhibited in the radial center part of the disk-shaped metal material, and in essence, a mass of the gas or liquid (an area with a low flow rate) is created, resulting in ineffective cooling.
In addition, since such gases and liquids are mainly sprayed into an open space with a fixed volume between the disk-shaped metal material and pipes or the like, the gases and liquids that reach the disk-shaped metal material surface after spraying have decreasing flow rate at the time of spraying, turning into a flow having a lower flow rate to be discharged, and so may not contribute much to the improvement of the local cooling rate.
An object of the present invention is to provide a method for producing a nickel-based alloy product or a titanium-based alloy product, the method being capable of locally increasing the cooling rate and efficiently utilizing an introduced fluid to perform effective cooling.
The present invention has been made in view of the problems described above.
One aspect of the present invention is a method for producing a nickel-based alloy product or a titanium-based alloy product, including: a material preparation step of preliminarily machining a hot working material of a nickel-based alloy or a titanium-based alloy after hot forging or hot ring rolling into a predetermined shape to prepare a material to be subjected to solution treatment; a heating and holding step of heating and holding the material to be subjected to solution treatment at a solution treatment temperature to obtain a material held in a heated state; and a cooling step of cooling the material held in a heated state to obtain a solution-treated material, in which the cooling step includes: placing a flow path-forming member having a space for forming a flow path for a fluid on a surface of the material held in a heated state to form a fluid flow path defined by the surface of the material held in a heated state and an inner surface of the space of the flow path-forming member; and allowing a fluid to flow in the fluid flow path formed between the flow path-forming member and the material held in a heated state so that the fluid in the flow path locally cools a part of the surface of the material held in a heated state.
The flow path-forming member may be configured such that a constricted part in which a cross section of the flow path narrows is formed on the surface of the material held in a heated state to increase a flow rate of the fluid introduced therein.
The flow path-forming member may include a plurality of fluid outlets connecting the flow path inside the flow path-forming member to an outside thereof in positions to be arranged on the material held in a heated state, and the fluid outlet may be configured to have a constricted shape with respect to a cross section of the flow path so as to increase a flow rate of the fluid so that the fluid ejected from the fluid outlets further locally cools at a fluid-ejected part of the surface of the material held in a heated state.
The flow path-forming member may be placed in contact with the surface of the material held in a heated state to form the fluid flow path.
Another aspect of the present invention is a method for producing a nickel-based alloy product or a titanium-based alloy product, including: a material preparation step of preliminarily machining a hot working material of a nickel-based alloy or a titanium-based alloy after hot forging or hot ring rolling into a predetermined shape to prepare a material to be subjected to solution treatment; a heating and holding step of heating and holding the material to be subjected to solution treatment at a solution treatment temperature to obtain a material held in a heated state; and a cooling step of cooling the material held in a heated state to obtain a solution-treated material, in which the cooling step includes: placing a flow path-forming member having a space for forming a flow path for a fluid in contact with a surface of the material held in a heated state to form a fluid flow path defined by the surface of the material held in a heated state and an inner surface of the space of the flow path-forming member, the flow path-forming member being configured such that a constricted part in which a cross section of the flow path narrows is formed on the surface of the material held in a heated state to increase a flow rate of the fluid introduced therein; and allowing a fluid to flow in the fluid flow path formed between the flow path-forming member and the material held in a heated state so that the fluid in the flow path locally cools a part of the surface of the material held in a heated state.
The flow path-forming member may include a plurality of fluid outlets connecting the flow path inside the flow path-forming member to an outside thereof in positions to be contact with the material held in a heated state, and the fluid outlet may be configured to have a constricted shape with respect to a cross section of the flow path so as to increase a flow rate of the fluid so that the fluid ejected from the fluid outlets further locally cools at a fluid-ejected part of the surface of the material held in a heated state.
According to the present invention, the cooling rate can be locally increased to carry out effective cooling even for a material to be treated that has a complex shape, such as a disk-shaped metal material.
Material Preparation Step
First, in the present invention, a material to be subjected to solution treatment is obtained by machining a hot working material of a nickel-based alloy or a titanium-based alloy after hot forging or hot ring rolling into a predetermined shape in advance.
Typical examples of hot forging include die forging. As used herein, “die forging” is forging that enables forming into a shape close to the final product by upper and lower dies. “Hot forging” includes isothermal forging, in which the forging temperature and the temperature of the metal die are almost the same temperature, and hot die forging, in which the die temperature is set lower than in isothermal forging. In hot ring rolling, the height of a ring-shaped rolling material is pressed while expanding the diameter of the rolling material using a ring rolling mill having at least a main roll, a mandrel roll, and a pair of axial rolls to hot roll a ring-shaped rolling material. The hot working material as the object in the present invention is a material in which thickness changes as viewed on a cross section of the hot working material.
The hot working material formed into a predetermined shape by the hot working is machined into a predetermined shape in advance. The purpose of this machining is, for example, to remove a relatively thick oxidized scale formed during the hot working or modify the contour of the surface of the hot working material by machining such as grinding, cutting, or a blasting treatment, so that when the flow path-forming member and the material held in a heated state, which are described later, are in contact with each other, the contact surfaces are in close contact to suppress unnecessary fluid leakage from the flow path.
In a case of carrying out the solution treatment in an oxidizing atmosphere such as in air, if the roughness of the machined surface is too great, the surface area increases, which may increase the amount of oxidized scale formed during heating and holding at the time of the solution treatment. Therefore, it is desirable that the surface be a surface having a rough finish or finer level in terms of roughness (for example, a surface roughness Ra of 5 to 25 μm), and preferably is a smooth surface having a standard finish or finer level (for example, a surface roughness Ra of 5 to 10 μm).
As used herein, “nickel-based alloy” is an alloy for use in a high temperature region of 600° C. or higher, which is also referred to as a superalloy or heat-resistant superalloy, and is an alloy strengthened by a precipitation phase such as γ′. Typical alloys include 718 alloys and Waspaloy alloys. In addition, 64Ti is an example of a typical titanium-based alloy.
Heating and Holding Step
The material to be subjected to solution treatment, which is obtained by machining the hot working material, is heated and held at a predetermined temperature to obtain a material held in a heated state. The heating temperature and holding time depend on the kind and size of the material, but for example, a temperature range of about 900 to 1200° C. and a time of about 5 to 6 hours are acceptable for a nickel-based alloy. For a titanium-based alloy, a temperature range of about 700 to 1000° C., and a time of about 0.5 to 6 hours are acceptable.
Cooling Step
The material held in a heated state, which is heated and held at the above-described solution treatment temperature, is cooled to obtain a solution-treated material. Since the cooling step is the most characteristic step of the present invention, the cooling step will be described with reference to the drawings. Examples of the fluid used as a refrigerant for cooling the material held in a heated state include gases, liquids, and mixtures of mists and gases. Among these, gases exhibit little volume change even when in contact with a high temperature material held in a heated state, and are refrigerants that are easiest to control the cooling rate. In the following description, a gas is used as the fluid.
As shown in
Furthermore, in the present invention, the flow path-forming member 1A is configured such that a constricted part 5 in which the cross section of the flow path narrows is formed on the surface of the material held in a heated state 10 in order to increase the flow rate of a gas to be introduced due to the so-called Venturi effect. The narrowed part 5 corresponds to a part 11 to be preferentially cooled (surrounded by the dash-dot-dash line in
The gas may be a single gas or a mixed gas. For example, He gas or a mixed gas thereof may be used for parts where cooling is particularly required, or air may be used for parts where a cooling rate with air is acceptable thereto.
The constricted part 5 shown in
Similarly, a constricted part 8 shown in
A ratio between a cross-sectional area CA1 of the flow path in the gas introduction part 2, 6 of the flow path-forming member 1 and a cross-sectional area CA2 of the constricted part 5, 8 in the gas flow path formed between the surface of the material held in a heated state 10 and the inner surface of the flow path-forming member 1, i.e., CA2/CA1 (hereinafter, referred to as the “area ratio”), is preferably less than 1.0, more preferably 0.8 or less, and further preferably 0.4 or less. The cross section of the flow path having an area ratio of less than 1 in this way is narrow as described above, and the flow rate of the introduced gas increases due to the so-called Venturi effect, to remarkably exhibiting a local cooling effect. The lower limit of the area ratio is not particularly limited, but for example, the area ratio is preferably 0.05 or more, more preferably 0.10 or more, and further preferably 0.15 or more. Although the widths (also referred to as the “gap distance”) A2 and B2 of the cross sections of the flow path in the constricted parts 5 and 8 depend on the shape of the material held in a heated state 10, these widths are each preferably 0.5 mm or more, and more preferably 1.0 mm or more, for example. The upper limit of the gap distances A2 and B2 of the constricted parts 5, 8 is not particularly limited, but the gap distance is preferably 30 mm or less, and more preferably 20 mm or less, for example.
The local cooling in the flow path-forming member 1 may be effective until the temperature of the locally cooled part becomes equal to or less than a certain temperature. This temperature depends on the purpose for controlling the cooling rate of the material held in a heated state by the local cooling. For example, in the case of improving heterogeneity due to the precipitation behavior of the nickel-based alloy and the cooling temperature distribution of the material held in a heated state, the control of the cooling rate by local cooling functions sufficiently if the local cooling is effective until about 700° C. On the other hand, in the case of improving the heterogeneity of a strain distribution due to heat shrinkage during cooling of the material held in a heated state, the local cooling needs to be effective as far as a temperature range below 700° C.
Next,
In
The shielding portion 22 and the introduction portion 21 shown in
The structure shown in
Moreover, the flow path-forming member 1 shown in
In the cooling using the flow path-forming member having the structure shown in
Furthermore, according to the present invention, since leaking gas can be minimized, the cooling efficiency can be increased even at the same flow rate, compared to blowing in an open space. In addition, from the combination of the heat capacity of the flow path-forming member itself with the of continuous cooling effect of the gas on the forming member itself, it can be expected that the flow path-forming member exhibits a cooling effect by physically contacting to the material to be treated to transfer heat, depending on the thickness and shape of the flow path-forming member.
Furthermore, it is not necessary to bring the high-pressure nozzles close to the material held in a heated state, the gas can be supplied to the flow path-forming member by a large introduction pipe, and energy loss due to pressure loss can thus be reduced. In addition, there is no need for a large number of introduction pipes and nozzles as in the prior art, and the structure can be simplified.
In addition, it is also possible to form a structure that enhances the contact cooling effect by providing fins for expanding the heat transfer area in the flow path-forming member.
Furthermore,
Hereinafter, examples and comparative examples of the present invention will be described.
First, as the hot working material, a disk-shaped material to be subjected to solution treatment having a diameter of 220 mm and a thickness of 40 mm was obtained from a forged round bar of a nickel-based heat-resistant superalloy (718 alloy) having a diameter of 260 mm by machining involving saw cutting and turning. The surface was finished to a standard finish level with a surface roughness Ra of 6.3 μm. Next, this material to be subjected to solution treatment was heated to a solution treatment temperature of 1120° C. and held at uniform heat for 70 to 100 minutes to obtain a material held in a heated state. Then, a cooling test for obtaining a solution-treated material was carried out by cooling this material held in a heated state using a flow path-forming member 40 shown in
The flow path-forming member 40 included a cylindrical member 41 and a disk member 42 provided at one end of the cylindrical member 41. The cylindrical member 41 was made of carbon steel (S45C) for mechanical structural use, and had a pipe inner diameter D of 20 mm and a length of 100 mm. The disk member 42 was made of carbon steel (SS400) for general structural use, and had a diameter of 150 mm and a thickness of 8 mm. The flow path-forming member 40 was placed on a material held in a heated state 50 so as to form a fluid flow path by the lower surface of the disk member 42 of the flow path-forming member 40 and the surface 51 of the material held in a heated state 50. The lower surface of the disk member 42 of the flow path-forming member 40 and the surface 51 of the material held in a heated state 50 had a structure in which a width H of the flow path, which is the distance between them, was variable using an adjustment screw 43. The material held in a heated state 50 was placed on an insulation material 60.
As for the cooling conditions, the velocity of the gas (compressed air) introduced into the cylindrical member 41 of the flow path-forming member 40 was about 17 m/s (approximate value), and cooling was performed until the temperature of the measurement site was 500° C. or lower. Furthermore, the time taken to convey the material held in a heated state from the completion of the solution treatment to the start of cooling was 24 to 40 seconds. As for the temperature measuring method, thermocouples (K type thermocouples) 61, 62, and 63 were attached to and contacted with the rear surface of the material held in a heated state 50 (also in contact with the insulation material 60). The measurement positions were the center position of the disk-shaped material held in a heated state 50, a position 45 mm from the center, and a position 90 mm from the center. The cooling experiment was performed under three conditions: a width H of the flow path of 2 mm, 4 mm, or 8 mm. The results are shown in Table 1 and
Results in comparative examples are also shown, for a case in which the cooling test was carried out in the same manner as in the examples, except that compressed air was injected from a position 8 mm away onto the surface 51 of the material held in a heated state 50 using a nozzle having an inner diameter of 20 mm instead of the flow path-forming member (Comparative Example 1), and a case in which the cooling test was carried out in the same manner as in the examples, except that the material held in a heated state was left to cool without placing the flow path-forming member or injecting a gas (Comparative Example 2).
The “area ratio” in Table 1 is the ratio CA2/CA1, and specifically, the ratio between the cross-sectional area CA1 of a flow path F1 of the cylindrical member 41 of the flow path-forming member 40 and the cross-sectional area CA2 of a flow path F2 defined by the lower surface of the disk member 42 of the flow path-forming member 40 and the surface 51 of the material held in a heated state 50. The cross-sectional area CA2 is the cross-sectional area at a position P at which the flow path switches from the flow path F1 to the flow path F2 (specifically, a position 10 mm (=D/2) from the center of the flow path-forming member 40). Therefore, the area ratio CA2/CA1 can be calculated by the following formula. When the area ratio CA2/CA1 is less than 1, the flow path is constricted at the position P.
CA2/CA1=(2π×D/2×H)/π(D/2)2
D: Pipe inner diameter of cylindrical member of flow path-forming member
H: Width between the lower surface of the disk of the flow path-forming member and the surface of the material held in a heated state
As shown in
As shown in
As shown in
As shown in
When an effect of providing the constricted part in the flow path is examined, it can be seen that in Examples 1 and 2, in which the area ratio was less than 1, and specifically was 0.4 and 0.8, respectively, the average cooling rate from 1000 to 700° C. at the center position of the material held in a heated state (adjacent to position P, which was the constricted part) was higher than in Example 3, in which the area ratio was 1.6, as shown in Table 1 and
The cooling using the flow path-forming member according to the present invention can be expected to be applied not only to nickel-based alloys and titanium-based alloys, but to other alloys as well. In addition, mixture of a liquid or a mist with a gas can also be applied as the fluid to be used.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-215265 | Nov 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/043991 | 11/26/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/106998 | 6/3/2021 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4842652 | Smith et al. | Jun 1989 | A |
| 5419792 | King et al. | May 1995 | A |
| 20030098106 | Rabinovich et al. | May 2003 | A1 |
| 20050012250 | Rabinovich | Jan 2005 | A1 |
| 20050056354 | Groh et al. | Mar 2005 | A1 |
| 20070113937 | Rabinovich | May 2007 | A1 |
| 20130333190 | Mizumura et al. | Dec 2013 | A1 |
| 20170081748 | Adam et al. | Mar 2017 | A1 |
| Number | Date | Country |
|---|---|---|
| 0284876 | Oct 1988 | EP |
| 3290536 | Mar 2018 | EP |
| H10331659 | Dec 1998 | JP |
| 2000080458 | Mar 2000 | JP |
| 2003221617 | Aug 2003 | JP |
| 2005036318 | Feb 2005 | JP |
| 2017515689 | Jun 2017 | JP |
| 2012118223 | Sep 2012 | WO |
| 2015136299 | Sep 2015 | WO |
| Entry |
|---|
| “English language translation of International Search Report”, International Application No. PCT/JP2020/043991, Feb. 9, 2021, 2 pp. |
| “English language translation of International Search Report”, International Application No. PCT/JP2020/043993, Feb. 9, 2021, 2 pp. |
| “Communication with Supplementary European Search Report”, EP Application No. 20892781.4, Dec. 12, 2022, 9 pp. |
| “Communication with Supplementary European Search Report”, EP Application No. 20892472.0, Nov. 17, 2022, 10 pp. |
| Number | Date | Country | |
|---|---|---|---|
| 20220389535 A1 | Dec 2022 | US |
