A method for precision forging forming of a GH4065A alloy rotor blade

Abstract

The present application relates to the technical field of aero-engine blade precision forging, and discloses a GH4065A alloy rotor blade precision forging forming method, which comprises the following steps: first, a GH4065A alloy raw material is cut into a rod, the surface of the rod is coated with glass, and then the rod is extruded and upset to prepare a tenon structure upset preform; after the preform is cleaned and the glass is coated, the preform is heated to carry out a first pre-forging, vacuum annealing is carried out for the first time, the preform is heated again to carry out a second pre-forging and perform hot cutting, vacuum annealing is carried out for the second time, and a preform with a tenon positioning boss and a preliminary blade body surface is obtained; the preform is cleaned, coated with glass, and heated, and then final forging is completed through a final forging die to obtain a complete structure final forging piece; the final forging piece is sequentially subjected to solid solution, aging heat treatment and chemical milling to remove the surface excess amount, and finally, the surface, size and mechanical property of the final forging piece are detected to screen qualified blades. Through step-by-step pre-forging and multi-stage vacuum annealing, the glass protection and lubrication process is matched, the forging plasticity of the GH4065A alloy can be improved, and the size precision and comprehensive mechanical properties of the blade can be improved.

Description

Technical Field

[0001] This invention relates to the field of precision forging technology for aero-engine blades, specifically a method for precision forging GH4065A alloy rotor blades. Background Technology

[0002] The hot-end transmission components of aero-engines are core and critical components of aero-engine power equipment. Their service performance, service life, and reliability directly determine the overall performance level of the aero-engine, placing extremely high demands on the high-temperature strength, thermal stability, comprehensive mechanical properties, and service environment resistance of the materials used. As advanced aero-engines iterate towards higher thrust-to-weight ratios, higher service temperatures, and higher reliability, traditional high-temperature alloy materials are no longer sufficient to meet the stringent service requirements of high-end equipment. Developing and applying high-performance new high-temperature alloys has become the core key to breaking through the performance bottleneck of aero-engines.

[0003] GH4065A, as a new generation of nickel-based wrought superalloy, possesses extremely excellent comprehensive high-temperature service performance. Its γ′ strengthening phase volume fraction reaches 43.0%, an indicator that has reached the performance level of powder metallurgy superalloys, demonstrating outstanding material strengthening effect. Simultaneously, this alloy has an effective service temperature of up to 750℃, exhibiting excellent high-temperature mechanical properties, microstructural stability, and fatigue resistance. It is well-suited for the harsh high-temperature, high-pressure, and high-load service conditions of advanced aero-engine hot-end transmission components, effectively addressing the shortcomings of traditional superalloys such as insufficient service temperature and rapid performance degradation. It provides a high-quality and reliable new material solution for the domestic production of hot-end transmission components for advanced aero-engines in my country, possessing extremely high engineering application value and promising prospects for widespread application.

[0004] Despite the significant performance advantages of GH4065A alloy, its research and engineering application in precision forging technology for blades remains unexplored, lacking a mature and suitable precision forging process system to support its industrialization. Furthermore, GH4065A alloy inherently possesses low forging thermoplasticity, making it highly susceptible to various technical problems during conventional forging processes, such as forging cracking, poor metal filling capacity, and insufficient forming accuracy. These forging process defects severely impact the forming quality, dimensional accuracy, and yield rate of GH4065A alloy forgings, significantly hindering the mass engineering application and industrial promotion of this high-performance alloy. This prevents the full utilization of its excellent high-temperature service performance and limits its large-scale application in core components of advanced aero-engines.

[0005] In summary, given the lack of precision forging technology for GH4065A alloy and the technical challenges such as cracking and poor filling capacity during the forging process, developing a precision forging technology that is adapted to the characteristics of this alloy, has stable forming quality, and high reliability has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] In order to overcome the defects of the prior art, the present invention aims to provide a method for precision forging of GH4065A alloy rotor blades, so as to solve the technical problem of how to improve the precision forging quality and reliability of alloy rotor blades.

[0007] This invention is achieved through the following technical solution: This invention provides a method for precision forging GH4065A alloy rotor blades, comprising: S1, The GH4065A alloy raw material is processed according to the preset blanking size to obtain bar stock; S2, according to the deformation requirements of each forging process, matching extrusion mold and upsetting mold, the bar material with glass surface coated is extruded and upsetting in sequence to prepare upsetting preform with tenon structure; S3. After cleaning the surface of the upset head preform and coating it with glass, it is heated and pre-forged in one step, and then subjected to a first vacuum annealing treatment. The workpiece is then heated and pre-forged in two steps. After trimming with residual heat, it is subjected to a second vacuum annealing treatment to obtain a preform with a tenon positioning boss and a preliminary blade profile structure. S4. After cleaning, coating the surface with glass and heating the preform, the final forging is performed using a final forging die to obtain a final forging with a complete tenon, blade profile and blade tip positioning boss structure. S5, the final forging is subjected to solution heat treatment, aging heat treatment and chemical milling treatment in sequence to remove the workpiece surface excess and optimize the surface quality. S6. The surface quality, blade shape and mechanical properties of the finished blades are tested to select qualified precision forged blades for aero-engine rotors.

[0008] Preferably, in S2, the bar stock undergoes extrusion and upsetting processes in sequence. The extrusion and upsetting processes are based on the deformation amount of the forging process to calculate the corresponding workpiece forming size and match the mold. Furthermore, the bar stock is coated with a glass protective layer throughout the entire process before forming.

[0009] Preferably, in S3, the process parameters for both the primary pre-forging and the secondary pre-forging satisfy the following: The screw press is used, with an impact speed of 1.2 to 3.6 m / s, a strain rate of 2 to 10 m / s, an equivalent variable of 40% to 45%, and a workpiece heating temperature of 1060℃ ± 10℃.

[0010] Preferably, in S3, the production cycle control method for primary pre-forging and secondary pre-forging is as follows: After the mold surface is coated with graphite, it is left to stand for 10 to 20 seconds before production begins. The operation time from the time the workpiece is taken out of the furnace to the time it is forged and removed from the mold should not exceed 4 to 6 seconds.

[0011] Preferably, in S3, the process parameters for both the first and second vacuum annealing processes satisfy the following: First, heat the part to 800℃ in a vacuum at a rate of 2-10℃ / min and hold it until the part reaches the specified temperature. Then, heat the part to 1050℃±10℃ in a vacuum at a rate of 2-5℃ / min with a partial pressure of 0.2mbar and hold it for 60±6min. After holding, cool the part to below 60℃ using a fan.

[0012] Preferably, in S3, the parameters for the residual heat trimming process are: the trimming operation is completed within 20 seconds after the second pre-forging is completed, and the workpiece heat preservation temperature is controlled at 890℃±20℃.

[0013] Preferably, in S4, the process parameters for final forging include: screw press impact speed of 1.2 to 3.6 m / s, strain rate of 2 to 10 m / s, equivalent variable of 40% to 45%, workpiece heating temperature of 1060℃±10℃, and matching the same production cycle control standards for mold spraying and forging operation time.

[0014] Preferably, in S5, the process parameters for sequentially performing solution heat treatment on the final forging are: holding temperature 1060℃±10℃, holding time 60±6min, and after the holding is completed, the part is cooled by a fan to below 60℃.

[0015] Preferably, in S5, the surface quality, blade shape and mechanical properties of the finished blade are tested, and the qualified standards for the precision forged blades of the aero-engine rotor are as follows: the blade profile is not greater than 0.08mm, the bending value tolerance of each section is ±0.04mm, the torsional value tolerance of each section is ±0°8′, the thickness tolerance is -0.04mm to +0.10mm, and the blade grain size reaches level 9.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides a precision forging method for GH4065A alloy rotor blades. Through a complete precision forging process flow, including defined blanking, extrusion upsetting, staged pre-forging with double vacuum annealing, final forging, composite heat treatment, and finished product inspection, it effectively fills the technological gap in precision forging of this alloy for aero-engine rotor blades. This method employs a staged forging mode with two pre-forging stages and a final forging stage, which can rationally distribute the deformation amount throughout the alloy forging process, avoiding defects such as stress concentration and forging cracking caused by single large deformation forging. This ensures stable grain size and overall mechanical properties of the blade after forming, meeting the stringent technical requirements for aero-engine blades. Simultaneously, this method includes a vacuum annealing process after the two pre-forging stages, which effectively promotes static recrystallization during alloy forging, significantly improving the inherent low thermoplasticity of the alloy and greatly enhancing the material's high-temperature plasticity forming ability and forging adaptability.

[0017] Furthermore, the forming process of this invention is matched with forging processing and production cycle control logic suitable for alloy properties, standardizing the core process flow of alloy forging. By precisely controlling the mold pretreatment settling time and forging operation duration, the working state of the mold and the blade forming environment are optimized, effectively improving the service life of the mold and ensuring the integrity of the blade surface and the consistency of the blade shape dimensions. Combined with subsequent solution treatment, aging, chemical milling composite post-treatment and full-dimensional inspection of finished products, the surface quality, dimensional accuracy and comprehensive mechanical properties of the blade are stably optimized, realizing high-quality, high-reliability precision forming of high-performance alloy rotor blades. This provides mature and reliable process support for the engineering and large-scale application of such high-temperature alloy aerospace hot-end core components. Attached Figure Description

[0018] Figure 1 This is a flowchart of the alloy rotor blade precision forging method in an embodiment of the present invention; Figure 2 This is a schematic diagram of a pre-forged part in an embodiment of the present invention; Figure 3 This is a schematic diagram of a secondary pre-forging part in an embodiment of the present invention; Figure 4 This is a schematic diagram of the final forging in an embodiment of the present invention; Figure 5 This is a schematic diagram of grain size in an embodiment of the present invention; In the diagram: 1. Tenon positioning boss; 2. Tenon; 3. Blade profile; 4. Blade tip positioning boss. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a precision forging method for GH4065A alloy rotor blades, so as to solve the technical problem of how to improve the precision forging quality and reliability of alloy rotor blades.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings: This invention discloses a precision forging method for GH4065A alloy rotor blades, particularly suitable for the precision forging of GH4065A nickel-based wrought high-temperature alloy aero-engine rotor blades with high γ′ strengthening phase volume fraction. The overall process flow of the precision forging method is as follows: blanking → extrusion → upsetting → pre-forming → final forming → heat treatment → inspection. By using graded controllable forging, a matched and suitable vacuum annealing regime, precise production cycle control, and post-precision heat treatment and chemical milling correction, this method solves the technical problems of low thermoplasticity, easy forging cracking, poor filling capacity, poor dimensional consistency, and unstable surface quality and mechanical properties of existing GH4065A alloys, filling the technological gap in the precision forging of GH4065A alloy aero-engine rotor blades.

[0022] The overall process steps of this invention are as follows: S1, Blanking: The GH4065A alloy raw material is processed according to the preset blanking size to obtain a standard bar with precise specifications, which provides a qualified blank base for subsequent forming processes.

[0023] S2, Extrusion and Upsetting Pre-forming: The forming dimensions of the extruded and upsetting workpieces are precisely calculated based on the deformation requirements of each forging process, and specialized extrusion dies and upsetting dies are designed and manufactured accordingly. Before billet forming, a glass protective layer is applied to the entire surface of the bar stock. The bar stock with the glass protective layer is then sequentially placed into the extrusion die and upsetting die to complete the extrusion and upsetting process, producing an upsetting pre-formed part with a tenon structure. The glass protective layer effectively isolates air during high-temperature forging, preventing oxidation and ablation of the billet surface, while also acting as a lubricant and friction reducer, improving the fluidity of the alloy forming process.

[0024] S3, Graded Pre-forging and Double Vacuum Annealing: The prepared upsetting preforms undergo surface cleaning to remove oxide scale, impurities, and oil stains, followed by a glass protective layer coating. They are then heated and pre-forged in one stage. The one-stage pre-forging uses a screw press with the following process parameters: impact speed 1.2–3.6 m / s, strain rate 2–10 m / s, equivalent variable 40%–45%, and workpiece heating temperature 1060℃±10℃. Strict control of the pre-forging production cycle is maintained: after spraying graphite onto the die surface, the die is allowed to stand for 10–20 seconds before production begins to ensure uniform graphite lubrication and stable forming conditions. The overall operation time from furnace exit to die demolding does not exceed 4–6 seconds to avoid excessive temperature drop in the high-temperature billet, which could lead to decreased thermoplasticity and forming defects. Figure 2 As shown.

[0025] After the first pre-forging, the pre-forged workpiece undergoes a first vacuum annealing treatment. The vacuum annealing process is characterized by controlled temperature, pressure, and speed. Specifically, the temperature is first increased to 800℃ at a rate of 2–10℃ / min under vacuum, and held at this temperature until the overall part reaches the target temperature. Then, the temperature is increased to 1050℃±10℃ under vacuum partial pressure at a rate of 2–5℃ / min, with the vacuum partial pressure set at 0.2 mbar, and the holding time controlled at 60±6 min. After the holding process, forced cooling with a fan is used to cool the part to below 60℃, completing the first vacuum annealing. This process effectively promotes the static recrystallization of the GH4065A alloy, eliminates work hardening and residual stress generated during the first pre-forging, significantly improves the alloy's thermoplasticity, and provides a good microstructure foundation for the second pre-forging.

[0026] After the first vacuum annealing and workpiece cleaning, the workpiece is reheated and subjected to secondary pre-forging. The equipment, process parameters, and production cycle of the secondary pre-forging are consistent with those of the first pre-forging, namely, using a screw press with a striking speed of 1.2–3.6 m / s, a strain rate of 2–10 m / s, an equivalent variable of 40%–45%, and a workpiece heating temperature of 1060℃±10℃. After the die is coated with graphite, it is left to stand for 10–20 seconds before production, and the time from furnace exit to die exit does not exceed 4–6 seconds. Secondary pre-forging can further rationally distribute the forging deformation, gradually form the blade base profile, and avoid stress concentration and cracking defects caused by single large deformation forging.

[0027] After the secondary pre-forging, a residual heat trimming process is used. This trimming operation must be completed within 20 seconds of the secondary pre-forging. The workpiece temperature is controlled at 890℃±20℃. The residual heat of the workpiece is used to remove the flash, eliminating the need for secondary heating. This avoids fluctuations in microstructure and properties caused by temperature drops, improves processing efficiency, and ensures the regularity of the trimmed surface. Figure 3 As shown.

[0028] After the residual heat trimming is completed, the workpiece undergoes a second vacuum annealing process. The process parameters for the second vacuum annealing are exactly the same as those for the first vacuum annealing: the part is heated to 800℃ at a rate of 2–10℃ / min and held until the part reaches the specified temperature. Then, the part is heated to 1050℃±10℃ at a rate of 2–5℃ / min and a partial pressure of 0.2mbar, held for 60±6 minutes, and then cooled to below 60℃ by a fan. Through double vacuum annealing, the residual stress from multiple pre-forging passes is fully released, the recrystallization structure of the alloy is improved, and the shortcoming of poor thermoplasticity of GH4065A alloy forging is thoroughly overcome, resulting in a preform with a tenon positioning boss 1 and a blade profile 3.

[0029] S4, Final Forging: After secondary pre-forging, the preformed part is surface-cleaned to remove impurities and oxide scale, and then uniformly coated with a glass protective layer. The workpiece is heated to a preset temperature and then final-forged using a dedicated final forging die. The final forging process parameters and production cycle are consistent with the pre-forging process: screw press impact speed 1.2–3.6 m / s, strain rate 2–10 m / s, equivalent variable 40%–45%, workpiece heating temperature 1060℃±10℃; after the die is coated with graphite, it is allowed to stand for 10–20 seconds before starting production; the time from workpiece exiting the furnace to forging and demolding does not exceed 4–6 seconds. Through precise shaping in the final forging process, a final forged part with a complete tenon 2, blade profile 3, and blade tip positioning boss 4 structure is obtained, ensuring the overall structural integrity and profile accuracy of the blade. Figure 4 As shown.

[0030] S5, Composite Heat Treatment and Precision Milling: The final forging is subjected to solution heat treatment, aging heat treatment, and precision milling in sequence. The solution heat treatment process parameters are: holding temperature 1060℃±10℃, holding time 60±6min, and after holding, forced cooling by a fan to the part temperature below 60℃ is used to achieve homogenization of the alloy structure and lay the microstructure foundation for subsequent aging precipitation of strengthening phases.

[0031] After solution treatment, aging heat treatment is performed. The aging process parameters are: holding temperature 760℃±10℃, holding time 480±30min, and after holding, the part is cooled by fan to below 60℃. The γ′ strengthening phase is accurately precipitated through aging treatment to ensure the high-temperature mechanical properties and service stability of the alloy.

[0032] After aging treatment, the workpiece is subjected to chemical milling for finishing. The amount removed by each chemical milling is strictly controlled, and the amount removed by each chemical milling is no more than 0.15mm. The workpiece surface allowance is gradually removed by repeated micro-milling to correct the blade profile dimensional deviation and optimize the surface quality until the forging size meets the design requirements. This avoids surface deviation and local over-etching defects caused by a single large allowance chemical milling.

[0033] S6, Finished Product Inspection and Screening: A comprehensive quality inspection is conducted on the finished blades that have undergone heat treatment and chemical milling. Inspection items include surface quality, airfoil dimensional accuracy, and mechanical properties. Qualified blades must meet the following standards: blade profile deviation not exceeding 0.08mm; bending tolerance range for each section within ±0.04mm; torsional tolerance range for each section within ±0°8′; thickness tolerance range within -0.04mm to +0.10mm; blade grain size reaching level 9; and high-temperature creep resistance, room-temperature tensile properties, and high-temperature tensile properties all meeting the requirements of the aerospace blade technical documents. Qualified precision-forged aero-engine rotor blades are then selected. Figure 5 As shown.

[0034] Example 1 This embodiment describes a method for extrusion precision forging of nine-stage rotor blades for a certain machine. The specific process steps are as follows: Step 1, Blanking: Precision process the GH4065A alloy raw material according to the preset blanking size to obtain standard specification bars.

[0035] Step 2, Extrusion: Calculate the forming dimensions of the extruded part according to the deformation requirements of the forging process, make a special extrusion die, coat the surface of the bar stock with a glass protective layer evenly, and then place it into the extrusion die to complete the extrusion forming and obtain a qualified extruded part.

[0036] Step 3, Upsetting: Calculate the forming dimensions of the upsetting part according to the deformation requirements of the forging process, make a special upsetting mold, put the bar material with glass protective layer on the surface into the upsetting mold to complete the upsetting, and obtain the upsetting preform with tenon 2 structure.

[0037] Step 4, Pre-forming process: Clean the surface of the extruded part and coat it with a glass protective layer. After heating to 1060℃, perform a pre-forging process. Use a screw press with a striking speed of 1.2m / s, a strain rate of 2m / s, and an equivalent variable of 40%. Production cycle control: After the mold is sprayed with graphite, let it stand for 10 seconds before production. The time from the workpiece exiting the furnace to the forging mold exit is controlled to be 4 seconds to obtain a pre-forged part.

[0038] The first vacuum annealing was then performed: the temperature was increased to 800°C at a rate of 2°C / min and held until the part temperature met the standard; then the temperature was increased to 1050°C at a rate of 2°C / min and a partial pressure of 0.2mbar and held for 61 minutes. After the holding period, the part was cooled by a fan to below 60°C.

[0039] The surface of the pre-forged part is cleaned and coated with a glass protective layer. After heating to 1060℃, it is subjected to secondary pre-forging. The equipment, parameters and production cycle are the same as those of the primary pre-forging: impact speed 1.2m / s, strain rate 2m / s, equivalent variable 40%, graphite spraying on the mold and standing for 10s, and time from furnace to mold exit 4s to obtain the secondary pre-forged part.

[0040] After the second pre-forging is completed, the residual heat is trimmed within 20 seconds, and the workpiece is kept at 890℃. After trimming, a second vacuum annealing is performed. The annealing process is the same as the first vacuum annealing: heating to 800℃ at 2℃ / min, heating to 1050℃ at 2℃ / min partial pressure, partial pressure value of 0.2mbar, holding for 61min, and cooling the fan to below 60℃ to obtain a preform with a tenon positioning boss 1 and blade profile 3 as the preliminary structure.

[0041] Step 5, Final forming process: Clean the surface of the preform and coat it with a glass protective layer. Heat it to 1060℃ and place it into a special final forging mold for forming. Use a screw press with a striking speed of 1.2m / s, a strain rate of 2m / s, and an equivalent variable of 40%. Spray graphite on the mold and let it stand for 10s. The time from taking it out of the furnace to taking it out of the mold is 4s. The final forging part with a complete tenon 2, blade profile 3, and blade tip positioning boss 4 structure is obtained.

[0042] Step 6, Heat treatment and chemical milling: Solution treatment: Hold at 1060℃ for 61 min, then cool with a fan to below 60℃; Aging treatment: Hold at 760℃ for 480 min, then cool with a fan to below 60℃; Chemical milling: Control the amount of chemical milling in a single step to 0.15 mm, and repeat the chemical milling multiple times until the blade size meets the standard.

[0043] Step 7, Finished Product Inspection: After molding, the blade profile is ≤0.08mm, the bending value of each section is ±0.04mm, the torsion value of each section is ±0°8′, the thickness tolerance meets -0.04mm~+0.10mm, the grain size reaches level 9, and the high temperature creep, room temperature and high temperature tensile properties all meet the requirements of the technical documents.

[0044] Example 2 This embodiment describes a method for extrusion precision forging of ten-stage rotor blades for a certain machine. The specific process steps are as follows: Step 1, Blanking: Precision process the GH4065A alloy raw material into standard bars according to the preset blanking dimensions.

[0045] Step 2, Extrusion: Calculate the size of the extruded part based on the forging deformation and make a special mold. After coating the surface of the bar with a glass protective layer, the extrusion molding is completed to obtain a qualified extruded part.

[0046] Step 3, Upsetting: Calculate the size of the upsetting part based on the forging deformation and make a special mold. The bar material with glass coating is formed by the upsetting mold to obtain the upsetting preform with tenon 2 structure.

[0047] Step 4, Preforming process: After cleaning and coating the extruded part with glass, it is heated to 1060℃ for a first pre-forging; the screw press impact speed is 3.6m / s, the strain rate is 10m / s, and the equivalent strain is 45%; after the mold is sprayed with graphite, it is left to stand for 20s for production, and the time from furnace exit to mold exit is ≤6s, to obtain a first pre-forged part.

[0048] First vacuum annealing: Heat to 800℃ at a rate of 10℃ / min and hold until the part temperature stabilizes, then heat to 1050℃ at a rate of 5℃ / min and a partial pressure of 0.2mbar, hold for 61 minutes, and then cool with a fan to below 60℃.

[0049] After the workpiece is cleaned and coated with glass, it undergoes secondary pre-forging. The process parameters are the same as those for the primary pre-forging: impact speed 3.6 m / s, strain rate 10 m / s, equivalent variable 45%, heating temperature 1060℃, graphite settling time 20 s, and forging operation time ≤ 6 s.

[0050] After the second pre-forging, the residual heat at 890℃ is cut within 20 seconds, followed by a second vacuum annealing. The process parameters are: heating to 800℃ at 10℃ / min, heating to 1050℃ at 5℃ / min with partial pressure of 0.2mbar, holding for 66min, and cooling to below 60℃ by the fan to obtain a preform with a tenon positioning boss 1 and blade profile 3 as the preliminary structure.

[0051] Step 5, Final forming process: The preformed part is cleaned and coated with glass, heated to 1060℃ and then forged. A screw press is used with an impact speed of 3.6m / s, a strain rate of 10m / s, and an equivalent variable of 45%. The mold is sprayed with graphite and left to stand for 20s. The time from furnace exit to mold exit is ≤6s, resulting in a final forging part containing a complete tenon 2, blade profile 3, and blade tip positioning boss 4.

[0052] Step 6, Heat treatment and chemical milling: Solution treatment: Hold at 1060℃ for 66 minutes, then cool with a fan to below 60℃; Aging treatment: Hold at 760℃ for 510 minutes, then cool with a fan to below 60℃; The amount of chemical milling in a single process shall not exceed 0.15mm, and multiple processes shall be performed until the blade dimensions are qualified.

[0053] Step 7, Finished Product Inspection: The finished blade profile, cross-sectional curvature, cross-sectional torsion, and thickness tolerance all meet the design standards, the grain size reaches level 9, and the high-temperature creep, room temperature tensile, and high-temperature tensile mechanical properties all meet the requirements of the aviation technical documents.

[0054] This invention effectively solves the industry pain points of forging cracks, poor filling, unstable microstructure and properties, and poor dimensional accuracy of this type of high γ′ phase high-temperature alloy by limiting multi-pass graded forging, double precision vacuum annealing, exclusive forging temperature and kinetic parameters, standardized production cycle, and precision heat treatment and micro-milling correction system. It fills the gap in precision forging process of GH4065A alloy aerospace rotor blades, and can stably produce qualified blades with high dimensional accuracy, high surface quality and high mechanical properties. The process has good repeatability and high reliability, and has good value for engineering promotion and application.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for precision forging GH4065A alloy rotor blades, characterized in that, include: S1, The GH4065A alloy raw material is processed according to the preset blanking size to obtain bar stock; S2, according to the deformation requirements of each forging process, matching extrusion mold and upsetting mold, the bar material with glass surface coated is extruded and upsetting in sequence to prepare upsetting preform with tenon structure; S3. After cleaning the surface of the upset head preform and coating it with glass, it is heated and pre-forged in one step, and then subjected to a first vacuum annealing treatment. The workpiece is then heated and pre-forged in two steps. After trimming with residual heat, it is subjected to a second vacuum annealing treatment to obtain a preform with a tenon positioning boss and a preliminary blade profile structure. S4. After cleaning, coating the surface with glass and heating the preform, the final forging is performed using a final forging die to obtain a final forging with a complete tenon, blade profile and blade tip positioning boss structure. S5, the final forging is subjected to solution heat treatment, aging heat treatment and chemical milling treatment in sequence to remove the workpiece surface excess and optimize the surface quality. S6. The surface quality, blade shape and mechanical properties of the finished blades are tested to select qualified precision forged blades for aero-engine rotors.

2. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S2, the bar stock undergoes extrusion and upsetting processes in sequence. The extrusion and upsetting processes are based on the deformation amount of the forging process to calculate the corresponding workpiece forming size and match the mold. The bar stock is coated with a glass protective layer throughout the entire process before forming.

3. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S3, the process parameters for both primary and secondary pre-forging are satisfied: The screw press is used, with an impact speed of 1.2 to 3.6 m / s, a strain rate of 2 to 10 m / s, an equivalent variable of 40% to 45%, and a workpiece heating temperature of 1060℃ ± 10℃.

4. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S3, the production cycle control method for primary pre-forging and secondary pre-forging is as follows: After the mold surface is coated with graphite, it is left to stand for 10 to 20 seconds before production begins. The operation time from the time the workpiece is taken out of the furnace to the time it is forged and removed from the mold should not exceed 4 to 6 seconds.

5. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S3, the process parameters for both the first and second vacuum annealing processes meet the following requirements: First, heat the part to 800℃ in a vacuum at a rate of 2-10℃ / min and hold it until the part reaches the specified temperature. Then, heat the part to 1050℃±10℃ in a vacuum at a rate of 2-5℃ / min with a partial pressure of 0.2mbar and hold it for 60±6min. After holding, cool the part to below 60℃ using a fan.

6. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S3, the parameters for the residual heat trimming process are as follows: the trimming operation is completed within 20 seconds after the second pre-forging, and the workpiece heat preservation temperature is controlled at 890℃±20℃.

7. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S4, the process parameters for final forging include: screw press impact speed of 1.2 to 3.6 m / s, strain rate of 2 to 10 m / s, equivalent variable of 40% to 45%, workpiece heating temperature of 1060℃±10℃, and matching the same production cycle control standards for mold spraying and forging operation time.

8. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S5, the process parameters for sequential solution heat treatment of the final forging are: holding temperature 1060℃±10℃, holding time 60±6min, and after the holding is completed, the part is cooled by fan to below 60℃.

9. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S5, the process parameters for sequentially performing aging heat treatment on the final forging are: holding temperature 760℃±10℃, holding time 480±30min, and after the holding is completed, the part is cooled by a fan to below 60℃; during chemical milling, the single chemical milling amount is no more than 0.15mm, and chemical milling is repeated multiple times until the workpiece size meets the standard.

10. The method for precision forging of GH4065A alloy rotor blades according to claim 1, characterized in that, In S5, the surface quality, airfoil dimensions and mechanical properties of the finished blades are tested. The qualified standards for precision-forged blades for aero-engine rotors are as follows: blade profile not greater than 0.08mm, bending value tolerance of each section within ±0.04mm, torsional value tolerance of each section within ±0°8′, thickness tolerance of -0.04mm to +0.10mm, and blade grain size reaching level 9.

Images