Powder metallurgy preparation method of GH2907 casing

Abstract

The invention relates to the technical field of powder metallurgy, in particular to a powder metallurgy preparation method of a GH2907 casing. The preparation method comprises the following steps: (a) filling GH2907 alloy powder into a casing sheath, and carrying out hot isostatic pressing treatment to obtain a hot isostatic pressing state blank; (b) carrying out heat treatment on the blank in the hot isostatic pressing state; the temperature of the hot isostatic pressing treatment is 1150-1180 DEG C, and the pressure of the hot isostatic pressing treatment is 130-160 MPa. The process route of hot isostatic pressing and heat treatment is adopted, the cogging process in a traditional GH2907 manufacturing process is omitted, the defects caused by a cogging forging process are avoided, the casing forming process is simplified, the production period is shortened, and meanwhile the material utilization rate is greatly increased. The GH2907 casing prepared by the method has a uniform fine grain structure, and compared with a GH2907 casing prepared by a traditional process, the GH2907 casing prepared by the method has the advantages that the structure stability and the mechanical property are obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to a powder metallurgy preparation method for a GH2907 casing. Background Art

[0002] GH2907 alloy is a low expansion precipitation (aging) strengthened iron-based high temperature alloy based on iron-cobalt-nickel and strengthened by γ' phase. It is comprehensively strengthened with a small amount of Nb, Ti, Si and a trace amount of B element. It has high strength, low elastic modulus and expansion coefficient, as well as good thermal fatigue performance and hot working plasticity below 650℃. The Curie point is about 400-450℃. It is ferromagnetic below the Curie point and paramagnetic above the Curie point. GH2907 alloy is suitable for manufacturing various types of aero-engine rings and casings with a use temperature below 650℃.

[0003] The current GH2907 manufacturing process (casting + forging) has the disadvantages of uneven structure, which leads to excessive flaw detection, large casing processing allowance, low material utilization, difficult to control residual stress, and long processing cycle.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] One object of the present invention is to provide a powder metallurgy preparation method for a GH2907 casing, wherein the casing has uniform structure, small machining allowance and controllable residual stress.

[0006] Another object of the present invention is to provide a GH2907 casing manufactured by a powder metallurgy preparation method.

[0007] In order to achieve the above-mentioned object of the present invention, the present invention provides a powder metallurgy preparation method of a GH2907 casing, comprising the following steps:

[0008] (a) GH2907 alloy powder is loaded into a casing and subjected to hot isostatic pressing to obtain a hot isostatically pressed blank;

[0009] (b) heat treating the hot isostatically pressed blank;

[0010] The temperature of the hot isostatic pressing treatment is 1150-1180° C., and the pressure is 130-160 MPa.

[0011] In a specific embodiment of the present invention, the hot isostatic pressing time is 2 to 6 hours.

[0012] In a specific embodiment of the present invention, the heat treatment includes solution treatment and aging treatment; in the solution treatment, the insulation temperature is 980-1040° C. and the insulation time is 0.5-2 h.

[0013] In a specific embodiment of the present invention, the aging treatment comprises: after heat preservation treatment at 770-780° C., furnace cooling to 615-625° C. for heat preservation treatment, and then air cooling.

[0014] In a specific embodiment of the present invention, in the aging treatment, the time of heat preservation treatment at 770-780°C is ≤1h. Furthermore, the time of heat preservation treatment at 770-780°C is 0.5-1h.

[0015] In a specific embodiment of the present invention, in the aging treatment, the time of heat preservation treatment at 615-625°C is ≤12h. Furthermore, the time of heat preservation treatment at 615-625°C is 8-12h.

[0016] In a specific embodiment of the present invention, the particle size of the GH2907 alloy powder is 75-150 μm. Further, the GH2907 alloy powder is prepared by plasma rotating electrode atomization.

[0017] Another aspect of the present invention provides a GH2907 casing, which is prepared by any one of the preparation methods described above.

[0018] In a specific embodiment of the present invention, the grain size of the GH2907 casing is 6.5-7.

[0019] In a specific embodiment of the present invention, the room temperature tensile strength of the GH2907 casing is ≥1125 MPa, the room temperature yield strength is ≥845 MPa, the room temperature elongation after fracture is ≥5%, and the room temperature section shrinkage is ≥9%.

[0020] In a specific embodiment of the present invention, the GH2907 casing has a tensile strength of ≥865 MPa at 540°C, a yield strength of ≥630 MPa at 540°C, an elongation at break of ≥10% at 540°C, and a cross-sectional shrinkage of ≥13% at 540°C.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention prepares the GH2907 casing through a process of hot isostatic pressing and heat treatment, which not only saves the blanking process in the traditional GH2907 manufacturing process but also avoids the defects introduced by the blanking forging process, simplifies the casing forming process, shortens the production cycle, and can also solve problems such as segregation, ensure uniform and refined casing structure, and greatly improve material utilization;

[0023] (2) The GH2907 casing produced by the method of the present invention has a uniform fine-grained structure, and its structural stability and mechanical properties are significantly improved compared with the GH2907 casing produced by the traditional process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The microstructure diagram of the hot isostatically pressed GH2907 blank provided in Example 1 of the present invention;

[0026] Figure 2 The microstructure diagram of the hot isostatically pressed GH2907 blank provided in Comparative Example 1 of the present invention;

[0027] Figure 3 The metallographic structure of the GH2907 casing after aging treatment provided in Example 1 of the present invention;

[0028] Figure 4 The metallographic structure of the GH2907 casing after aging treatment provided in Example 6 of the present invention;

[0029] Figure 5 The metallographic structure of the GH2907 casing after aging treatment provided in Example 7 of the present invention;

[0030] Figure 6 The microstructure of the GH2907 casing after aging treatment provided in Example 1 of the present invention;

[0031] Figure 7 The microstructure of the GH2907 casing after aging treatment provided in Example 6 of the present invention;

[0032] Figure 8 The microstructure of the GH2907 casing after aging treatment provided in Example 7 of the present invention. DETAILED DESCRIPTION

[0033] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0034] At present, the GH2907 casing is prepared by forging process. With the increase of the types of elements added to the alloy, the traditional casting / deformation process faces the problems of increasing difficulty in hot processing, serious component segregation of disc forgings, poor uniformity of organization and performance, etc. The alloy powder particles are obtained by powder metallurgy process, which helps to eliminate the macro segregation existing in traditional casting. Hot isostatic pressing is a material forming method based on traditional powder metallurgy and mold manufacturing technology. It can complete the manufacturing process of metal powder densification and forming in one operation step, and only a small amount of machining is needed to obtain the target product. However, due to the particularity of the process, after hot isostatic pressing of powder high-temperature alloy, the organization has defects mainly in the prior particle boundary (PPB), and the main components of PPB are carbon oxides and coarse γ' phase. The γ' phase is the main strengthening phase of high-temperature alloys. The main strengthening method of high-temperature alloys is to precipitate fine γ' with similar size and uniform distribution after solid solution strengthening at a temperature higher than γ'. The production of PPB will weaken the metallurgical bonding between powder particles, becoming a weak link in the material, easily leading to crack initiation and accelerating crack propagation, significantly reducing the alloy's endurance strength and fatigue life.

[0035] Based on the characteristics of GH2907 alloy and the formation mechanism of PPB defects, the present invention controls, utilizes and eliminates PPB defects in coordination with the regulation of hot isostatic pressing and heat treatment to obtain a GH2907 casing with optimal matching of microstructure and mechanical properties.

[0036] Based on this, the present invention provides a powder metallurgy preparation method for a GH2907 casing, comprising the following steps:

[0037] (a) GH2907 alloy powder is loaded into a casing and subjected to hot isostatic pressing to obtain a hot isostatically pressed blank;

[0038] (b) heat treating the hot isostatically pressed blank;

[0039] The temperature of hot isostatic pressing is 1150-1180°C and the pressure is 130-160 MPa.

[0040] The present invention prepares the GH2907 casing through a process route of hot isostatic pressing and heat treatment, which not only saves the blanking process in the traditional GH2907 manufacturing process but also avoids the defects introduced by the blanking forging process, simplifies the casing forming process, shortens the production cycle, and can also solve problems such as segregation, ensure that the casing structure is uniform and refined, and greatly improve material utilization.

[0041] The present invention adopts a suitable hot isostatic pressing temperature to effectively alleviate the PPB phenomenon and avoid coarsening of the grain structure, and then cooperates with the subsequent heat treatment process to obtain excellent alloy properties. If the hot isostatic pressing temperature is too high, the grain size will be coarse, resulting in low casing strength; if the hot isostatic pressing temperature is too low, the PPB will be serious, and the high-temperature plasticity and fatigue properties will deteriorate. The present invention regulates the temperature of the hot isostatic pressing treatment within the range of 1150 to 1180°C to obtain a microstructure containing less PPB structure and moderate grain size, and cooperates with the subsequent heat treatment process to take into account PPB, grain size and mechanical properties. For example, in different embodiments, the temperature of the hot isostatic pressing treatment of the present invention can be 1150°C, 1155°C, 1160°C, 1165°C, 1170°C, 1175°C, 1180°C or a range consisting of any two of them.

[0042] For example, in different embodiments, the pressure of the hot isostatic pressing process is 130 MPa, 140 MPa, 150 MPa, 160 MPa, or a range consisting of any two thereof.

[0043] In a specific embodiment of the present invention, the hot isostatic pressing time is 2 to 6 hours.

[0044] If the hot isostatic pressing time is too long, the grains will be coarse and energy will be wasted; if the hot isostatic pressing time is too short, the PPB elimination will be poor and the structural uniformity will be relatively poor. The present invention regulates the hot isostatic pressing time within the above range, taking into account the grain fineness and structural uniformity of the hot isostatic pressed blank. For example, in different embodiments, the hot isostatic pressing time can be 2h, 3h, 4h, 5h, 6h or a range consisting of any two of them.

[0045] In a specific embodiment of the present invention, the heat treatment includes solution treatment and aging treatment; in the solution treatment, the insulation temperature is 980-1040° C. and the insulation time is 0.5-2 h.

[0046] In accordance with the structure of the hot isostatically pressed blank, the temperature of the above-mentioned solid solution treatment is adopted, and the presence of a small amount of PPB in the hot isostatically pressed blank can appropriately hinder the migration of grain boundaries, and in the solid solution treatment stage, the growth of grains can be suppressed while making the structure uniform, and the coarsening of grains can be avoided. Based on this, in the solid solution treatment of the present invention, a higher temperature such as 1020-1040°C is preferred, which is conducive to the formation of a uniform solid solution, the reduction of impurities and defects, etc., and the excessive coarsening of grains can be avoided. For example, in different embodiments, in the solid solution treatment, the insulation temperature can be 980°C, 990°C, 1000°C, 1010°C, 1020°C, 1030°C, 1040°C or a range consisting of any two thereof, and the insulation time can be 0.5-2h or a range consisting of any two thereof.

[0047] In a specific embodiment of the present invention, the aging treatment comprises: after heat preservation treatment at 770-780° C., furnace cooling to 615-625° C. for heat preservation treatment, and then air cooling.

[0048] By using the precipitation of the corresponding ε phase and γ' strengthening phase at 770-780°C and 615-625°C, the billet after aging treatment has suitable ε phase and γ' strengthening phase, taking into account the strength and plasticity of the alloy. For example, in different embodiments, the aging treatment may include: heat preservation treatment at 770°C, 772°C, 775°C, 778°C, 780°C or any two thereof, furnace cooling to 615°C, 618°C, 620°C, 622°C, 625°C or any two thereof, and then air cooling.

[0049] In a specific embodiment of the present invention, in the aging treatment, the time of heat preservation treatment at 770-780° C. is ≤1 hour. Furthermore, the time of heat preservation treatment at 770-780° C. is 0.5-1 hour.

[0050] The present invention has found through research that, for the case where the hot isostatically pressed blank of the present invention is subjected to solution treatment and then aging treatment, when the insulation treatment time at 770-780°C exceeds 1h, a large amount of ε phase will precipitate, the alloy strength can be improved but the alloy plasticity is seriously reduced; and when the insulation treatment time at 770-780°C exceeds 2h, over-aging phenomenon will occur, the ability of the ε phase to improve strength and reduce plasticity decreases, the alloy plasticity increases, but the strength decreases. Therefore, for the case where the hot isostatically pressed blank of the present invention is subjected to solution treatment and then aging treatment, the insulation treatment at 770-780°C for ≤1h, such as 0.5-1h, can give full play to the improvement of the alloy strength by the ε phase, while avoiding excessive reduction of the alloy plasticity.

[0051] In a specific embodiment of the present invention, in the aging treatment, the time of heat preservation treatment at 615-625° C. is ≤12 hours. Furthermore, the time of heat preservation treatment at 615-625° C. is 8-12 hours.

[0052] After the hot isostatically pressed billet of the present invention is solution treated, it is then heat treated at 770-780°C for ≤1h, and then heat treated at 615-625°C to precipitate the γ' strengthening phase, which can not only improve the strength of the alloy but also improve the plasticity of the alloy. The present invention further discovered that when the heat treatment time at 615-625°C is too long, too much γ' strengthening phase precipitates, resulting in too few strengthening phase elements in the γ matrix, reducing the strength and plasticity of the matrix, thereby affecting the overall performance of the alloy. By adjusting the heat treatment time at 615-625°C to be within the range of 8-12h, an appropriate γ' strengthening phase is precipitated in the alloy, ensuring both the strength and plasticity of the alloy.

[0053] In a specific embodiment of the present invention, the particle size of the GH2907 alloy powder is 75-150 μm. Further, the GH2907 alloy powder is prepared by plasma rotating electrode atomization.

[0054] In actual operation, GH2907 alloy powder is prepared by plasma rotating electrode atomization, screened under argon protection, and electrostatic separation is used to remove non-metallic inclusions. The powder is then packed into a package and sealed under vacuum conditions, and then hot isostatic pressing is performed.

[0055] Another aspect of the present invention provides a GH2907 casing, which is prepared by any one of the above preparation methods.

[0056] In a specific embodiment of the present invention, the grain size of the GH2907 casing is 6.5-7.

[0057] In a specific embodiment of the present invention, in the GH2907 casing, the volume fraction of the γ phase is 70% to 78%, the volume fraction of the γ' phase is 11% to 13.2%, and the volume fraction of the ε phase is 1.1% to 2.2%.

[0058] In a specific embodiment of the present invention, the room temperature tensile strength of the GH2907 casing is ≥1125MPa, preferably ≥1127MPa, ≥1132MPa, ≥1165MPa, ≥1173MPa, ≥1186MPa, etc., the room temperature yield strength is ≥845MPa, preferably ≥847MPa, ≥855MPa, ≥865MPa, ≥875MPa, ≥885MPa, etc., the room temperature elongation after break is ≥5%, preferably ≥7.5%, ≥12%, ≥25%, ≥26.5%, etc., the room temperature section shrinkage is ≥9%, preferably ≥15%, ≥20%, ≥30%, ≥40%, etc.

[0059] In a specific embodiment of the present invention, the 540°C tensile strength of the GH2907 casing is ≥865MPa, preferably ≥867MPa, ≥880MPa, ≥891MPa, ≥966MPa, ≥976MPa, etc., the 540°C yield strength is ≥630MPa, preferably ≥643MPa, ≥648MPa, ≥657MPa, etc., the elongation at break at 540°C is ≥10%, preferably ≥12%, ≥15%, ≥22%, ≥26%, ≥31.5%, etc., the cross-sectional shrinkage at 540°C is ≥13%, preferably ≥15%, ≥30%, ≥46%, ≥50%, etc.

[0060] Example 1

[0061] This embodiment provides a powder metallurgy preparation method for a GH2907 casing, comprising the following steps:

[0062] (1) GH2907 master alloy was prepared by conventional vacuum induction melting, and GH2907 alloy powder was prepared by plasma rotating electrode atomization. Screening was performed under argon protection to collect powder with a particle size of 75 to 150 μm. After electrostatic separation to remove non-metallic inclusions, the powder was packed into a package under vacuum conditions and sealed with welding.

[0063] (2) placing the package after sealing and welding in step (1) in a hot isostatic pressing device, and performing hot isostatic pressing by simultaneously increasing the temperature and pressure. After the hot isostatic pressing is completed, heating is stopped, cooling to room temperature, and machining to remove the package to obtain a hot isostatically pressed blank; wherein the holding temperature of the hot isostatic pressing is 1165° C., the pressure is 150 MPa, and the holding time is 4 hours.

[0064] (3) subjecting the hot isostatically pressed billet obtained in step (2) to solution treatment and aging treatment; the solution treatment comprises: heat preservation treatment at 1040° C. for 2 h, and air cooling to room temperature; the aging treatment comprises: heat preservation treatment at 775° C. for 1 h, furnace cooling to 620° C. for 8 h, and air cooling to obtain a GH2907 alloy part.

[0065] Example 2

[0066] This embodiment refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, with the only difference being that in step (2), the holding temperature of the hot isostatic pressing is different.

[0067] In this embodiment, the holding temperature of the hot isostatic pressing is 1150°C.

[0068] Example 3

[0069] This embodiment refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, with the only difference being that in step (2), the holding temperature of the hot isostatic pressing is different.

[0070] In this embodiment, the holding temperature of hot isostatic pressing is 1180°C.

[0071] Example 4

[0072] This embodiment refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, with the only difference being that in step (3), the temperature of the solution treatment is different.

[0073] In this embodiment, the temperature of the solution treatment is 1020°C.

[0074] Example 5

[0075] This embodiment refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, with the only difference being that in step (3), the temperature of the solution treatment is different.

[0076] In this embodiment, the temperature of the solution treatment is 980°C.

[0077] Example 6

[0078] This embodiment refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, with the only difference being that in step (3), the aging treatment is different.

[0079] In this embodiment, the aging treatment includes: heat preservation treatment at 775° C. for 2 hours, furnace cooling to 620° C. for heat preservation treatment for 8 hours, and air cooling.

[0080] Example 7

[0081] This embodiment refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, with the only difference being that in step (3), the aging treatment is different.

[0082] In this embodiment, the aging treatment includes: heat preservation treatment at 775° C. for 4 hours, furnace cooling to 620° C. for heat preservation treatment for 8 hours, and air cooling.

[0083] Comparative Example 1

[0084] Comparative Example 1 refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, except that: in step (2), the holding temperature of the hot isostatic pressing is different.

[0085] In Comparative Example 1, the holding temperature of the hot isostatic pressing was 1130°C.

[0086] Comparative Example 2

[0087] Comparative Example 2 refers to the powder metallurgy preparation method of the GH2907 casing provided in Example 1, except that: in step (2), the holding temperature of the hot isostatic pressing is different.

[0088] In Comparative Example 2, the holding temperature of the hot isostatic pressing was 1190°C.

[0089] Comparative Example 3

[0090] Comparative Example 3 provides a method for preparing a GH2907 casing, comprising the following steps:

[0091] (1) Prepare GH2907 master alloy by vacuum induction melting according to Example 1.

[0092] (2) Pre-forging: The mother alloy is placed in a pre-forging die using an isothermal forging method and forged into a long plate intermediate billet.

[0093] (3) Forming forging: Continue to use the isothermal forging method to place the long plate intermediate billet into the forming forging die to forge the finished casing forging.

[0094] (4) Heat treatment: The finished casing forgings are subjected to standard heat treatment.

[0095] Experimental Example 1

[0096] Figure 1 and Figure 2 The microstructure diagram of the hot isostatically pressed GH2907 billet provided in Example 1 of the present invention and Comparative Example 1. As can be seen from the figure, the hot isostatic pressing temperature of Comparative Example 1 is too low, so that there are more original grain boundaries in the hot isostatically pressed GH2907 alloy obtained, which will lead to a decrease in the plasticity of the alloy. Example 1 adopts a relatively high hot isostatic pressing temperature, which can effectively alleviate PPB, thereby improving the tensile properties of the alloy.

[0097] Figure 3 to Figure 5 and Figure 6 to Figure 8 The metallographic organization diagram and microstructure diagram after aging treatment of Example 1, Example 6 and Example 7 of the present invention are shown respectively. It can be seen from the figure that in Example 6, the 775℃ holding time is 2h. If it exceeds 1h, a large amount of ε phase will precipitate, which will cause the alloy plasticity to be seriously reduced; in Example 7, the 775℃ holding time is further extended to 4h, and over-aging phenomenon occurs. The ability of ε to increase relative strength and reduce plasticity is weakened, which will cause the alloy strength to decrease. In Example 1, the 775℃ holding time is 1h, which can obtain a suitable microstructure and improve the strength and plasticity of the alloy.

[0098] The microstructure and grain size of the GH2907 alloy parts prepared in different embodiments and comparative examples were further characterized, and the results are shown in Table 1. The tensile properties and endurance properties of the GH2907 alloy parts prepared in different embodiments and comparative examples are shown in Tables 2 and 3.

[0099] Table 1 Microstructure of different GH2907 alloy parts

[0100] serial number γ phase volume fraction / % γ' phase volume fraction / % ε phase volume fraction / % Grain size Example 1 73.5 11.3 1.5 6.5-7 Example 2 75.8 12.2 1.3 6.5-7 Example 3 77.2 11.6 1.5 6.5-7 Example 4 73.5 11.9 1.1 6.5-7 Example 5 71.6 13.2 2.2 6.5-7 Example 6 78.5 15.3 4.5 6.5-7 Example 7 68.9 16.2 6.8 6.5-7 Comparative Example 1 77.5 14.3 1.2 6.5-7 Comparative Example 2 73.4 13.5 0.9 6-6.5 Comparative Example 3 74.3 10.5 1.3 5-6

[0101] Table 2 Tensile properties of different GH2907 alloy parts

[0102]

[0103] Table 3 Durability properties of different GH2907 alloy parts

[0104] serial number Test conditions Durable life / h Example 1 540℃ / 825MPa ＞100h Example 2 540℃ / 825MPa ＞100h Example 3 540℃ / 825MPa ＞100h Example 4 540℃ / 825MPa ＞100h Example 5 540℃ / 825MPa ＞100h Example 6 540℃ / 825MPa ＞100h Example 7 540℃ / 825MPa ＞100h Comparative Example 1 540℃ / 825MPa ＞100h Comparative Example 2 540℃ / 825MPa ＞100h Comparative Example 3 540℃ / 825MPa ＞100h

[0105] From the above test results, it can be seen that the GH2907 casing prepared by the preparation method of the present invention greatly improves the tensile, endurance and low-cycle fatigue strength of the alloy, shortens the production cycle, improves material utilization, and effectively controls residual stress, compared with the GH2907 casing prepared by the traditional process, without significantly increasing the cost.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The powder metallurgy preparation method of GH2907 casing is characterized in that: The steps include: (a) GH2907 alloy powder is loaded into a casing and subjected to hot isostatic pressing to obtain a hot isostatically pressed blank; (b) heat treating the hot isostatically pressed blank; The temperature of the hot isostatic pressing treatment is 1150-1180° C., and the pressure is 130-160 MPa.

2. The powder metallurgy preparation method of GH2907 casing according to claim 1, characterized in that: The hot isostatic pressing time is 2 to 6 hours.

3. The powder metallurgy preparation method of GH2907 casing according to claim 1, characterized in that: The heat treatment includes solution treatment and aging treatment; During the solution treatment, the holding temperature is 980-1040°C; Preferably, in the solution treatment, the holding time is 0.5 to 2 hours.

4. The powder metallurgy preparation method of GH2907 casing according to claim 3, characterized in that: The aging treatment comprises: after heat preservation treatment at 770-780° C., furnace cooling to 615-625° C. for heat preservation treatment, and then air cooling.

5. The powder metallurgy preparation method of GH2907 casing according to claim 4, characterized in that: In the aging treatment, the time of heat preservation treatment at 770-780°C is ≤1h; Preferably, the heat preservation treatment time at 770-780° C. is 0.5-1 h.

6. The powder metallurgy preparation method of GH2907 casing according to claim 4, characterized in that: In the aging treatment, the time of heat preservation treatment at 615-625°C is ≤12h; Preferably, the heat preservation treatment time at 615-625° C. is 8-12 hours.

7. The powder metallurgy preparation method of GH2907 casing according to claim 1, characterized in that: The particle size of the GH2907 alloy powder is 75 to 150 μm; Preferably, the GH2907 alloy powder is prepared by plasma rotating electrode atomization.

8. A GH2907 casing, characterized in that: The method is prepared by the method according to any one of claims 1 to 7.

9. The GH2907 casing according to claim 8, characterized in that: The grain size of the GH2907 casing is 6.5 to 7 levels.

10. The GH2907 casing according to claim 8, characterized in that: The room temperature tensile strength of the GH2907 casing is ≥1125MPa, the room temperature yield strength is ≥845MPa, the room temperature elongation is ≥5%, and the room temperature section shrinkage is ≥9%; The GH2907 casing has a tensile strength of ≥865 MPa at 540°C, a yield strength of ≥630 MPa at 540°C, an elongation at break of ≥10% at 540°C, and a cross-sectional shrinkage of ≥13% at 540°C.

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