A method for manufacturing a powder metallurgy and isothermal forged in738 disc collar and applications

Abstract

The application belongs to the technical field of nickel-based alloy material processing and forming, and particularly relates to a preparation method and application of a powder metallurgy and isothermal forging In738 disc shaft ring piece. The application adopts a hot isostatic pressing technology to pre-form a blank, eliminates internal voids and cracks of the material, homogenizes the structure, improves element segregation, improves fatigue life, and provides a plastic blank for subsequent isothermal forging. Further, the application reduces the temperature difference between the blank and the mold through preheating treatment, avoids sudden deformation resistance caused by local quenching, and inhibits the initiation of micro-cracks. In addition, the application promotes dynamic recrystallization by using isothermal forging, obtains fine equiaxed crystal structure, and improves high-temperature strength; the application is subjected to solid solution treatment to inhibit grain coarsening and retain supersaturated solid solution, thereby providing driving force for aging precipitation. Then, the application forms a dual-mode gamma prime phase strengthening system through a two-stage aging process, and optimizes the stress rupture life. Therefore, the application improves the high-temperature comprehensive mechanical properties of the In738 nickel-based alloy, and meets the use requirements of the In738 nickel-based alloy at high temperatures.

Description

Technical Field

[0001] This invention belongs to the field of nickel-based alloy material processing and forming technology, specifically relating to a method for preparing In738 disc ring parts by powder metallurgy and isothermal forging and its application. Background Technology

[0002] Aero-engine disc and shaft collar components typically require long-term service in high-temperature, high-stress, and corrosive environments ranging from 650℃ to 900℃. Therefore, materials must possess high precision, high strength and toughness, creep resistance, oxidation resistance, and resistance to hot corrosion. In738 nickel-based superalloys have become a core material in this field due to their excellent high-temperature strength, oxidation resistance, and creep resistance.

[0003] However, In738 alloy has high deformation resistance, and ordinary forging easily leads to cracks and uneven deformation, with machining allowances as high as 50%-70%, making it difficult to meet the near-net-shape requirements of disc and shaft ring components. Traditional investment casting is prone to defects such as shrinkage cavities, porosity, and coarse grains, resulting in insufficient fatigue life of disc and shaft ring components. For emerging laser powder bed melting technology, near-net-shape forming of complex structures can be achieved, reducing machining workload. However, after remelting and solidification, the strength difference along the construction direction is as high as 15%-20%, which cannot meet the homogenization requirements of disc and shaft ring components for aero-engines.

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

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing In738 disc ring parts by powder metallurgy and isothermal forging, and its application.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] On one hand, the present invention provides a method for preparing In738 disc and shaft ring parts by powder metallurgy and isothermal forging, comprising the following steps:

[0008] Step 1: Prepare In738 high-temperature alloy powder with a particle size of 53μm-250μm; the prepared In738 high-temperature alloy powder has an O content of <100ppm and a N content of <100ppm; the In738 high-temperature alloy powder is a nickel-based high-temperature alloy powder.

[0009] Step 2: A near-net-shape sleeve is obtained by designing a three-dimensional model of the disc shaft ring, with a 15%-30% shrinkage allowance. The sleeve is made of 20 steel or 45 steel with a thickness of 2mm-10mm. The In738 high-temperature alloy powder is loaded into the sleeve. After the powder is filled, it is subjected to vibration compaction, degassing, and sealing welding. Then, hot isostatic pressing is performed. After cooling, the sleeve is removed to obtain the blank.

[0010] The parameters for vibration compaction are: vibration frequency of 30Hz-50Hz and amplitude of 1mm-5mm; the parameters for degassing are: heating temperature of 400℃-600℃, holding time of 4h-16h, and vacuum degree ≤5×10⁻⁶. -3 Pa; The parameters of the hot isostatic pressing are: temperature 1150℃-1250℃, pressure 100MPa-200MPa, and holding time 2h-4h.

[0011] Step 3: Preheat the billet and the nickel-based high-temperature alloy mold; the parameters of the preheating treatment are: heating temperature of 1050℃-1150℃, holding time of 1h-2h; wherein, the protective atmosphere during the preheating treatment is argon, and the temperature difference between the billet and the nickel-based high-temperature alloy mold is ≤50℃ to prevent surface cooling from causing microcracks.

[0012] Step 4: The preheated billet is isothermally forged using a nickel-based high-temperature alloy die to obtain a forged billet; the isothermal forging is performed in three passes, with a single deformation of 15%-30% and a strain rate of 0.01s. -1 -0.05s -1 The forging temperature is 1050℃-1150℃, and the protective atmosphere is argon.

[0013] Step 5: After sequentially performing solution treatment and two-stage aging treatment on the forging billet, shot peening is performed. The shot peening pressure is 0.3MPa-0.5MPa, and the coverage is ≥200%, finally obtaining the required In738 disc ring part. The protective atmosphere during the solution treatment and two-stage aging treatment is argon. The solution treatment is performed by holding at 1150℃-1230℃ for 1-2 hours and then air cooling to suppress grain coarsening and retain supersaturated solid solution. The two-stage aging treatment consists of a first-stage aging treatment and a second-stage aging treatment. The first-stage aging treatment is performed by holding at 850℃-920℃ for 8-12 hours and then air cooling to precipitate a uniformly distributed main γ' phase. The second-stage aging treatment is performed by holding at 750℃-800℃ for 24-48 hours, furnace cooling to 500℃, and then air cooling to precipitate a fine γ' phase and improve creep strength.

[0014] On the other hand, this invention provides an application of the In738 disc bearing member prepared by a powder metallurgy and isothermal forging method. The In738 disc bearing member is used in aero-engines. The In738 disc bearing member exhibits a high-temperature tensile strength of 900MPa-1250MPa at 760℃, a creep rupture life of 150h-300h at 760℃ and 550MPa, and a fatigue life of 1.0×10⁻¹⁰ at 760℃, 500MPa, and R=-1. 6 -2.0×106 .

[0015] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0016] This invention utilizes high-purity In738 high-temperature alloy powder with a specific particle size distribution as raw material. The raw material is packaged and then subjected to hot isostatic pressing (HIP). Simultaneously, process parameters are controlled to eliminate internal voids and cracks in the material, increasing billet density, homogenizing the microstructure, improving elemental segregation, and enhancing fatigue life, thus providing a ductile billet for subsequent isothermal forging. Furthermore, the HIP technology pre-forms the billet, reducing subsequent processing and increasing material utilization by over 40% compared to traditional casting or forging, achieving near-net-shape forming of In738 disc ring parts. Further, preheating reduces the temperature difference between the billet and the die, avoiding sudden changes in deformation resistance caused by localized chilling and inhibiting microcrack initiation. In addition, isothermal forging promotes dynamic recrystallization, obtaining a fine equiaxed grain structure and improving high-temperature strength. Solution treatment inhibits grain coarsening and retains supersaturated solid solutions, providing a driving force for aging precipitation. Finally, a two-stage aging process forms a dual-modal γ' phase strengthening system, optimizing fatigue life. This improves the high-temperature comprehensive mechanical properties of In738 nickel-based alloys, meets their high-temperature application requirements, and overcomes the shortcomings of traditional technology, such as complex forming process, easy cracking of parts, uneven structure, and low raw material utilization. Attached Figure Description

[0017] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0021] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] Please see Figure 1 This invention provides a method for preparing In738 disc ring parts by powder metallurgy and isothermal forging, comprising the following steps:

[0023] Step 1: Prepare In738 high-temperature alloy powder with a particle size of 53μm-250μm; the prepared In738 high-temperature alloy powder has an O content of <100ppm and a N content of <100ppm;

[0024] Step 2: A near-net-shape sleeve is obtained by designing a three-dimensional model of the disc shaft ring, with a 15%-30% shrinkage allowance. The sleeve is made of 20 steel or 45 steel with a thickness of 2mm-10mm. The In738 high-temperature alloy powder is loaded into the sleeve. After the powder is filled, it is subjected to vibration compaction, degassing, and sealing welding. Then, hot isostatic pressing is performed. After cooling, the sleeve is removed to obtain the blank.

[0025] The parameters for vibration compaction are: vibration frequency of 30Hz-50Hz and amplitude of 1mm-5mm; the parameters for degassing are: heating temperature of 400℃-600℃, holding time of 4h-16h, and vacuum degree ≤5×10⁻⁶. -3 Pa; The parameters of the hot isostatic pressing are: temperature 1150℃-1250℃, pressure 100MPa-200MPa, and holding time 2h-4h.

[0026] Step 3: Preheat the billet and the nickel-based high-temperature alloy mold; the parameters of the preheating treatment are: heating temperature of 1050℃-1150℃, holding time of 1h-2h; wherein, the protective atmosphere during the preheating treatment is argon, and the temperature difference between the billet and the nickel-based high-temperature alloy mold is ≤50℃ to prevent surface cooling from causing microcracks.

[0027] Step 4: The preheated billet is isothermally forged using a nickel-based high-temperature alloy die to obtain a forged billet; the isothermal forging is performed in three passes, with a single deformation of 15%-30% and a strain rate of 0.01s. -1 -0.05s -1 The forging temperature is 1050℃-1150℃, and the protective atmosphere is argon.

[0028] Step 5: After performing solution treatment and two-stage aging treatment on the forging billet, shot peening is performed. The shot peening pressure is 0.3MPa-0.5MPa, and the coverage is ≥200%, finally obtaining the required In738 disc ring part. The protective atmosphere during the solution treatment and two-stage aging treatment is argon. The solution treatment is performed by holding at 1150℃-1230℃ for 1-2 hours and then air cooling to suppress grain coarsening and retain supersaturated solid solution. The two-stage aging treatment is performed by first-stage aging treatment and second-stage aging treatment. The first-stage aging treatment is performed by holding at 850℃-920℃ for 8-12 hours and then air cooling to precipitate a uniformly distributed main γ' phase. The second-stage aging treatment is performed by holding at 750℃-800℃ for 24-48 hours, furnace cooling to 500℃, and then air cooling to precipitate a fine γ' phase, thereby improving high-temperature creep resistance and endurance strength.

[0029] To demonstrate the effectiveness of the present invention, the following embodiments are provided for verification.

[0030] Example 1

[0031] This embodiment provides a method for preparing In738 discs using powder metallurgy and isothermal forging, specifically including the following steps:

[0032] Step 1: Prepare In738 high-temperature alloy powder with a particle size of 53μm-150μm; the prepared In738 high-temperature alloy powder has an O content of <100ppm and a N content of <100ppm;

[0033] Step 2: Based on the 3D model of the disc, a near-net-shape sleeve is designed, with a 25% shrinkage allowance. The sleeve material is 20 steel with a thickness of 6mm. The In738 high-temperature alloy powder is loaded into the sleeve. After the powder is full, it is compacted by vibration at a frequency of 30Hz and an amplitude of 1mm. The sleeve is then heated to 400℃ and held for 16 hours, with a vacuum degree ≤5×10⁻⁶. -3 The gas is degassed by Pa, then sealed by welding, and then hot isostatic pressing is performed at a temperature of 1240℃ and a pressure of 120MPa for 2 hours. After cooling in the furnace, the cladding is removed by machining to obtain the billet.

[0034] Step 3: Preheat the billet and the nickel-based high-temperature alloy mold at 1100℃ for 1 hour in an argon atmosphere; wherein the temperature difference between the nickel-based high-temperature alloy mold and the billet is ≤50℃ to prevent microcracks caused by surface cooling.

[0035] Step 4: The preheated billet is isothermally forged using a nickel-based high-temperature alloy die. The forging is performed in three passes, with the first pass having a deformation of 30% and a strain rate of 0.05 s. -1 The blanking process is carried out; the deformation amount in the second pass is 25%, and the strain rate is 0.03s.-1 To refine the grain size; the third pass deformation was 15%, and the strain rate was 0.01 s⁻¹. -1 The blank is then shaped to ensure dimensional accuracy, resulting in a forging billet; the isothermal forging temperature is 1100℃, and the protective atmosphere is argon.

[0036] Step 5: First, the forging billet undergoes solution treatment at 1160℃ for 2 hours, followed by air cooling to suppress grain coarsening and retain supersaturated solid solution. Then, a first-stage aging treatment is performed at 900℃ for 8 hours, followed by air cooling to precipitate a uniformly distributed main γ' phase. Next, a second-stage aging treatment is performed at 750℃ for 46 hours, followed by furnace cooling to 500℃ and air cooling to precipitate fine γ' phase and improve creep strength. Finally, shot peening is performed under shot peening pressure of 0.5MPa and coverage ≥200% to obtain the desired In738 disc A.

[0037] Example 2

[0038] This embodiment provides a method for preparing In738 shaft parts by powder metallurgy and isothermal forging, specifically including the following steps:

[0039] Step 1: Prepare In738 high-temperature alloy powder with a particle size of 53μm-250μm; the prepared In738 high-temperature alloy powder has an O content of <100ppm and a N content of <100ppm;

[0040] Step 2: Based on the 3D model of the shaft, a near-net-shape sleeve is designed, with a 30% shrinkage allowance. The sleeve material is 45 steel with a thickness of 8mm. The In738 high-temperature alloy powder is loaded into the sleeve. After the powder is full, it is compacted by vibration at a frequency of 50Hz and an amplitude of 5mm. The sleeve is then heated to 450℃ and held for 10 hours, with a vacuum degree ≤5×10⁻⁶. -3 The gas is degassed by Pa, then sealed by welding, and then hot isostatic pressing is performed at a temperature of 1180℃ and a pressure of 160MPa for 3 hours. After cooling in the furnace, the cladding is removed by machining to obtain the billet.

[0041] Step 3: Preheat the billet and the nickel-based high-temperature alloy mold at 1130℃ for 2 hours in an argon atmosphere; wherein the temperature difference between the nickel-based high-temperature alloy mold and the billet is ≤50℃ to prevent microcracks caused by surface cooling.

[0042] Step 4: The preheated billet is isothermally forged using a nickel-based high-temperature alloy die. The forging is performed in three passes, with the first pass having a deformation of 30% and a strain rate of 0.05 s. -1 The blanking process is carried out; the deformation amount in the second pass is 25%, and the strain rate is 0.03s. -1To refine the grain size; the third pass deformation was 15%, and the strain rate was 0.01 s⁻¹. -1 The blank is then shaped to ensure dimensional accuracy, resulting in a forging billet. The isothermal forging temperature is 1130℃, and the protective atmosphere is argon.

[0043] Step 5: First, the forging billet undergoes solution treatment at 1220℃ for 1 hour, followed by air cooling to suppress grain coarsening and retain supersaturated solid solution. Then, a first-stage aging treatment is performed at 880℃ for 10 hours, followed by air cooling to precipitate a uniformly distributed main γ' phase. Next, a second-stage aging treatment is performed at 780℃ for 26 hours, followed by furnace cooling to 500℃ and then air cooling to precipitate a fine γ' phase and improve creep strength. Finally, shot peening is performed under shot peening pressure of 0.3MPa and coverage ≥200% to obtain the desired In738 shaft part B.

[0044] Example 3

[0045] This embodiment provides a method for preparing In738 rings using powder metallurgy and isothermal forging, specifically including the following steps:

[0046] Step 1: Prepare In738 high-temperature alloy powder with a particle size of 53μm-106μm; the prepared In738 high-temperature alloy powder has an O content of <100ppm and a N content of <100ppm;

[0047] Step 2: Based on the 3D model of the ring, a near-net-shape sleeve is designed, with a 15% shrinkage allowance. The sleeve material is 20 steel with a thickness of 10mm. The In738 high-temperature alloy powder is loaded into the sleeve. After the powder is full, it is compacted by vibration at a frequency of 40Hz and an amplitude of 3mm. The sleeve is then heated to 480℃ and held for 4 hours, and a vacuum degree ≤5×10 -3 The gas is degassed by Pa, then sealed by welding, and then hot isostatic pressing is performed at a temperature of 1160℃ and a pressure of 180MPa for 4 hours. After cooling in the furnace, the cladding is removed by machining to obtain the billet.

[0048] Step 3: Preheat the billet and the nickel-based high-temperature alloy mold at 1060℃ for 2 hours in an argon atmosphere; wherein the temperature difference between the nickel-based high-temperature alloy mold and the billet is ≤50℃ to prevent microcracks caused by surface cooling.

[0049] Step 4: The preheated billet is isothermally forged using a nickel-based high-temperature alloy die. The forging is performed in three passes, with the first pass having a deformation of 30% and a strain rate of 0.05 s. -1 The blanking process is carried out; the deformation amount in the second pass is 25%, and the strain rate is 0.03s. -1To refine the grain size; the third pass deformation was 15%, and the strain rate was 0.01 s⁻¹. -1 The blank is then shaped to ensure dimensional accuracy, resulting in a forging billet; the isothermal forging temperature is 1060℃, and the protective atmosphere is argon.

[0050] Step 5: First, the forging billet undergoes solution treatment at 1200℃ for 1 hour, followed by air cooling to suppress grain coarsening and retain supersaturated solid solution. Then, a first-stage aging treatment is performed at 850℃ for 12 hours, followed by air cooling to precipitate a uniformly distributed main γ' phase. Next, a second-stage aging treatment is performed at 800℃ for 24 hours, followed by furnace cooling to 500℃ and then air cooling to precipitate fine γ' phase and improve creep strength. Finally, shot peening is performed under shot peening pressure of 0.4MPa and coverage ≥200% to obtain the desired In738 ring C.

[0051] To further verify the effectiveness of the technical solution provided by the present invention, the following tests were performed on the In738 disc A, In738 shaft B, and In738 ring C respectively:

[0052] (1) High-temperature tensile strength test was conducted at 760℃;

[0053] (2) Conduct a long-term life test at 760℃ and 550MPa.

[0054] (3) Fatigue life test was conducted at 760℃, 500MPa and R=-1.

[0055] The test results are shown in Table 1:

[0056] Table 1

[0057]

[0058] In summary, as shown in Table 1, the In738 discs, In738 shafts, and In738 rings prepared by the method of this invention exhibit high-temperature tensile strengths between 900 MPa and 1250 MPa at 760℃, creep rupture lives between 150 h and 300 h at 760℃ and 550 MPa, and fatigue lives of 1.0 × 10⁻¹⁰ at 760℃, 500 MPa, and R = -1. 6 -2.0×10 6 The above demonstrates that the In738 disc, In738 shaft, and In738 ring components prepared by the method of the present invention all meet the design requirements and are suitable for application in aero engines.

[0059] This invention employs hot isostatic pressing (HIP) to preform the billet, eliminating internal voids and cracks, homogenizing the microstructure, improving elemental segregation, and enhancing fatigue life, thus providing a ductile billet for subsequent isothermal forging. Furthermore, preheating reduces the temperature difference between the billet and the die, preventing sudden changes in deformation resistance caused by localized chilling and inhibiting microcrack initiation. In addition, isothermal forging promotes dynamic recrystallization, resulting in a fine equiaxed grain structure and improved high-temperature strength. Solution treatment suppresses grain coarsening and retains supersaturated solid solutions, providing a driving force for aging precipitation. A two-stage aging process then forms a dual-modal γ' phase strengthening system, optimizing fatigue life. This improves the overall high-temperature mechanical properties of In738 nickel-based alloys, meeting their high-temperature performance requirements and overcoming the drawbacks of traditional techniques, such as complex forming processes, susceptibility to cracking, uneven microstructure, and low raw material utilization.

[0060] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0061] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing In738 disc bearing parts by powder metallurgy and isothermal forging, characterized in that, The steps include the following: Step 1: Prepare In738 high-temperature alloy powder with a specific particle size; the prepared In738 high-temperature alloy powder has an O content of <100ppm and a N content of <100ppm; the particle size of the In738 high-temperature alloy powder is 53μm-250μm; Step 2: First, the In738 high-temperature alloy powder is loaded into a sleeve and then subjected to vibration compaction, degassing, and sealing treatment in sequence. Then, hot isostatic pressing is performed. After cooling, the sleeve is removed to obtain the billet. The vibration compaction parameters are: vibration frequency of 30Hz-50Hz and amplitude of 1mm-5mm. The hot isostatic pressing parameters are: temperature of 1150℃-1250℃, pressure of 100MPa-200MPa, and time of 2h-4h. Step 3: Preheat the billet and the nickel-based superalloy mold; the parameters of the preheating treatment are: heating temperature of 1050℃-1150℃, holding time of 1h-2h; the temperature difference between the billet and the nickel-based superalloy mold is ≤50℃. Step 4: The preheated billet is isothermally forged using a nickel-based high-temperature alloy die to obtain a forged billet; the isothermal forging is performed in three passes, with a single deformation of 15%-30% and a strain rate of 0.01s. -1 -0.05s -1 The forging temperature is 1050°C-1150°C; Step 5: After performing solution treatment and two-stage aging treatment on the forging billet in sequence, a strengthening treatment is then performed to obtain the required In738 disc ring part; The solution treatment is as follows: solution is applied at a temperature of 1150°C-1230°C for 1-2 hours, followed by air cooling. The two-stage aging process consists of a first-stage aging process and a second-stage aging process. The first-stage aging process involves holding the furnace at 850℃-920℃ for 8-12 hours followed by air cooling. The second-stage aging process involves holding the furnace at 750℃-800℃ for 24-48 hours followed by furnace cooling to 500℃ followed by air cooling.

2. The preparation method according to claim 1, characterized in that, In step 2, a near-net-shape sleeve is obtained through three-dimensional model design, with a 15%-30% shrinkage allowance reserved. The sleeve is made of 20 steel or 45 steel with a thickness of 2mm-10mm.

3. The preparation method according to claim 1, characterized in that, In step 2, the degassing parameters are: heating temperature 400℃-600℃, holding time 4h-16h, and vacuum degree ≤5×10⁻⁶. -3 Pa.

4. The preparation method according to claim 1, characterized in that, In step 3, the protective atmosphere during the preheating treatment is argon.

5. The preparation method according to claim 1, characterized in that, In step 4, the protective atmosphere for the isothermal forging is argon.

6. The preparation method according to claim 1, characterized in that, In step 5, the protective atmosphere during the solution treatment and the two-stage aging treatment is argon.

7. The preparation method according to claim 1, characterized in that, In step 5, shot peening is used for strengthening. The parameters for strengthening are: shot peening pressure of 0.3MPa-0.5MPa and coverage of ≥200%.

8. The application of the In738 disc collar component prepared by any one of the preparation methods described in claims 1-7, characterized in that, The In738 disc bearing member is used in aero-engines. The In738 disc bearing member exhibits a high-temperature tensile strength of 900MPa-1250MPa at 760°C, a creep rupture life of 150h-300h at 760°C and 550MPa, and a fatigue life of 1.0×10⁻¹⁰ at 760°C, 500MPa, and R=-1. 6 -2.0×10 6 .

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