Forging forming method for GH4738 alloy annular forge piece

Abstract

The invention belongs to the technical field of alloy hot working, and particularly relates to a forging forming method for a GH4738 alloy annular forge piece. The GH4738 alloy blank is subjected to cake upsetting, punching, horse expanding, end face flattening, pre-expanding and chambering forming treatment in sequence, and the grain size grade is graded; when the parameters of cake upsetting, horse expansion, pre-expansion and chambering forming are inconsistent, deformation is set for cake upsetting, horse expansion, pre-expansion and chambering forming steps according to a result corresponding to grain size rating; and when the parameters of the upset cake and the punched hole are inconsistent, according to the grain size rating result, heating temperatures are set for the upset cake, the punched hole, the horse expanding, the end face flattening, the pre-expanding and the hole expanding. According to the method, before forging, the internal microstructure grade of the GH4738 alloy blank is evaluated, the grain size grade is determined, the forging technical parameters are set according to the evaluation result and the weight of the forged piece, the mechanical property and the internal structure of the forged piece are inspected, the product meets the final required zero requirement, and the product yield is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of alloy hot working technology, and specifically relates to a forging method for GH4738 alloy ring forgings. Background Technology

[0002] GH4738 alloy is an deposition-hardening nickel-based wrought superalloy that exhibits excellent tensile strength, creep strength, and good oxidation resistance in the temperature range of 650℃ to 900℃. This alloy is particularly suitable for manufacturing components requiring high strength below 870℃ and oxidation resistance below 980℃. Due to its superior performance in high-temperature environments, GH4738 alloy is widely used in key components of aero-engines, such as support disks, turbine disks, and other structural components operating under high temperature and pressure conditions. The rotating components of aero-engines operate under extremely harsh conditions, requiring materials to maintain sufficient mechanical strength and creep resistance while withstanding high temperatures. To meet these practical application requirements, high demands are placed on the microstructure and properties of GH4738 forgings.

[0003] The conventional forging of GH4738 alloy typically follows this basic process: billet preparation → heating → forging deformation → cooling → heat treatment. During conventional forging, based on the technical requirements of the forging, the forging is subjected to physical and chemical testing after heat treatment. Usually, problems such as uneven grain size or coarse grains in the internal structure of the forging are found, leading to its eventual scrapping. Summary of the Invention

[0004] To improve the microstructure of GH4738 forgings and meet the grain size requirements, this invention provides a forging method for GH4738 alloy ring forgings. By controlling the microstructure of the GH4738 raw material, the GH4738 alloy billet is re-inspected before production to determine its internal high-magnification microstructure level. Grain size is graded according to different high-magnification levels. Forging technical parameters are set based on the evaluation results and the forging's own characteristics (weight). This allows for post-forging inspection of its mechanical properties and internal microstructure, ensuring the product meets final requirements and effectively improving the product yield.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] The purpose of this invention is to provide a forging method for GH4738 alloy ring forgings, including sequentially performing upsetting, punching, reaming, end-face flattening, pre-expansion, and forming reaming on the GH4738 alloy billet, and rating the internal grain size level of the GH4738 alloy billet: when the grain size level is 0-1, 2, 3, 4 and ≥5, its grain size rating corresponds to J1, J2, J3, J4 and J5.

[0007] When the parameters of upsetting, reaming, pre-reaming, and forming reaming are inconsistent, according to the results corresponding to the grain size rating, the forging deformation of upsetting, reaming, or pre-reaming is reduced by at least 5% in sequence, and the forging deformation of forming reaming is reduced by at least 0% to 5% in sequence.

[0008] When the parameters of the upsetting and punching are inconsistent, the forging temperature of both the upsetting and punching is reduced by 5℃ to 10℃ according to the grain size rating results; when the parameters of the pre-expansion and the flat end face are inconsistent, the forging temperature of both the pre-expansion and the flat end face is reduced by -10℃ to 10℃ according to the grain size rating results; when the parameters of the pre-expansion and the forming of the hole are inconsistent, the forging temperature of both the pre-expansion and the forming of the hole is reduced by 0℃ to 10℃ according to the grain size rating results.

[0009] The parameters are the grain size rating result and the forging weight.

[0010] Furthermore, when the parameters of upsetting, reaming, pre-reaming, and forming reaming are inconsistent, according to the grain size ratings J1, J2, J3, J4, and J5, the forging deformation of upsetting corresponds to ≥35%, ≥30%, ≥25%, ≥20%, and ≥15%, the forging deformation of reaming corresponds to ≥30%, ≥25%, ≥20%, ≥15%, and ≥10%, the forging deformation of pre-reaming corresponds to ≥25%, ≥20%, ≥15%, ≥10%, and ≥10%, and the forging deformation of forming reaming corresponds to ≥25%, ≥20%, ≥15%, ≥10%, and ≥10%.

[0011] Furthermore, when the parameters of the upsetting and punching are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures of the upsetting and punching are 1115℃~1120℃, 1110℃~1115℃, 1100℃~1110℃, 1090℃~1100℃ and 1090℃ respectively.

[0012] Furthermore, when the parameters of the ferrule and the flat end face are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures of the ferrule and the flat end face are 1100℃~1110℃, 1100℃~1110℃, 1090℃~1100℃, 1080℃~1090℃ and 1080℃~1070℃ respectively.

[0013] Furthermore, when the parameters of pre-expansion and forming expansion are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures of pre-expansion and forming expansion are 1100℃~1110℃, 1090℃~1100℃, 1080℃~1090℃, 1080℃~1070℃ and 1060℃~1070℃ respectively. Furthermore, the forging time for upsetting, punching, reaming, flattening, pre-reaming, and forming reaming is ≤120min.

[0014] Furthermore, the parameters for the punching and the flat end face are consistent.

[0015] Furthermore, after the forming and pore-expanding process, final forging is carried out at a temperature ≥980℃, and the cooling method is air cooling.

[0016] Furthermore, after forming and expanding the hole or final forging, heat treatment is carried out. The heat treatment is to first hold at 815℃~835℃ for 120min, then raise the temperature to 1020℃~1040℃ and hold for 220min~260min, and then oil cool for ≥20min.

[0017] Compared with the prior art, the present invention has the following advantages: This invention provides a forging method for GH4738 alloy ring forgings. It utilizes GH4738 alloy billets of different specifications, heat numbers, and from different raw material manufacturers. By controlling the microstructure of the GH4738 raw materials, the method involves re-inspecting the billets before forging to determine the internal high-magnification microstructure level. Based on the high-magnification level of different raw materials, grain size is graded. Forging technical parameters are set according to the evaluation results and the characteristics (weight) of the forgings to produce different GH4738 forgings that meet the final physical and chemical requirements. This invention controls the number of forging passes by measuring the grain size of the raw materials and adjusting the forging temperature range and deformation amount. In particular, the control of process parameters at each stage, including temperature, time, and deformation amount, ensures that the deformation amount of each pass strictly matches the required grain size, thus meeting the final product requirements and effectively improving the product yield. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0020] This invention utilizes a re-inspection and testing technology for GH4738 raw material bars. Before production, bars of different specifications, heat numbers, and from different raw material manufacturers undergo corresponding low-magnification and high-magnification microstructure evaluations. Based on the evaluation results and the inherent characteristics (weight) of the forgings, forging technical parameters and heat treatment regimes are set. This method of controlling the forging process allows for the production of GH4738 forgings that meet the final physical and chemical requirements. Specifically:

[0021] A forging method for GH4738 alloy ring forging includes sequentially performing upsetting, punching, reaming, end-face flattening, pre-reaming, and reaming forming processes on the GH4738 alloy billet; conducting high-magnification physicochemical analysis on the internal microstructure of the GH4738 alloy billet to rate the internal grain size level of the GH4738 alloy billet: when the grain size level is 0-1, 2, 3, 4, and ≥5, its corresponding grain size rating is J1, J2, J3, J4, and J5.

[0022] The internal grain size level of GH4738 alloy billets is rated according to standard 0000-005T18. Before forging, the GH4738 alloy billets are re-inspected to determine the internal high-magnification microstructure level. Grain size is rated based on different high-magnification levels. Forging technical parameters and heat treatment regimes are set based on the evaluation results and the characteristics (weight) of the forgings to produce different GH4738 forgings that meet the final physical and chemical requirements. This invention controls the number of forging passes by measuring the grain size of the raw materials and adjusting the forging temperature range and deformation amount. In particular, the control of process parameters at each stage, including temperature, time, and deformation amount, ensures that the deformation amount of each pass strictly matches the grain size requirements, enabling the product to meet the final requirements and effectively improving the product yield.

[0023] When the parameters of upsetting, mortising, pre-expansion, and expanding hole type are inconsistent, according to the results corresponding to the grain size rating, the forging deformation of upsetting, mortising, or pre-expansion is reduced by at least 5% in sequence, and the forging deformation of expanding hole type is reduced by at least 0% to 5% in sequence.

[0024] When the parameters of upsetting, reaming, pre-reaming, and hole-forming are inconsistent, according to the grain size ratings J1, J2, J3, J4, and J5, the forging deformation of upsetting corresponds to ≥40%, ≥35%, ≥30%, ≥25%, and ≥20%; the forging deformation of reaming corresponds to ≥35%, ≥30%, ≥25%, ≥20%, and ≥15%; the forging deformation of pre-reaming corresponds to ≥30%, ≥25%, ≥20%, ≥15%, and ≥10%; and the forging deformation of hole-forming corresponds to ≥25%, ≥20%, ≥15%, ≥10%, and ≥10%.

[0025] When the parameters of the upsetting and punching are inconsistent, the forging temperature of the upsetting and punching is reduced by 5℃ to 10℃ respectively, based on the grain size rating results.

[0026] When the parameters of the upsetting and punching are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures of the upsetting and punching are 1115℃~1120℃, 1110℃~1115℃, 1100℃~1110℃, 1090℃~1100℃ and 1090℃ respectively.

[0027] When the parameters of the roughing and flat-end faces are inconsistent, according to the grain size rating results, the forging temperature of both the roughing and flat-end faces decreases by -10℃ to 10℃ sequentially. When the parameters for pre-expansion and hole enlargement are inconsistent, according to grain size ratings J1, J2, J3, J4, and J5, the forging temperatures for both pre-expansion and hole enlargement are 1100℃~1110℃, 1100℃~1110℃, 1090℃~1100℃, 1080℃~1090℃, and 1080℃~1070℃, respectively. When the parameters for pre-expansion and hole enlargement are inconsistent, according to the grain size rating results, the forging temperatures for both pre-expansion and hole enlargement decrease by 0℃~10℃ sequentially.

[0028] When the parameters for pre-expansion and hole expansion are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures for pre-expansion and hole expansion are 1100℃~1110℃, 1090℃~1100℃, 1080℃~1090℃, 1080℃~1070℃ and 1060℃~1070℃ respectively.

[0029] In this invention, for GH4738 alloy billet, only the internal grain size level of GH4738 alloy billet is rated. Other parameters of GH4738 alloy billet are the same. By measuring the grain size of raw materials, the forging temperature range and deformation amount are adjusted to control the number of forging production. As the temperature decreases, the final deformation amount decreases. Using low temperature and small deformation amount is conducive to the final grain size refinement to meet the requirements.

[0030] The parameters are the grain size rating result and the forging weight.

[0031] In some embodiments, the forging time for upsetting, punching, reaming, flattening, pre-reaming, and reaming is ≤120min.

[0032] In some embodiments, after the hole-expanding forming process, final forging is performed at a temperature ≥980°C and the cooling method is air cooling.

[0033] In some embodiments, after the hole expansion forming process or final forging, heat treatment is performed. The heat treatment is first held at 815℃~835℃ for 120min, then heated to 1020℃~1040℃ and held for 220min~260min, and then oil cooled for ≥20min.

[0034] In some embodiments, the parameters of the punch and the flat end face are the same.

[0035] In summary, this invention provides a method for evaluating the low-magnification and high-magnification microstructure of forgings from bars of different specifications, heat numbers, and raw material manufacturers before production. Based on the evaluation results and the forging's inherent characteristics (weight), forging technical parameters and heat treatment regimes are set. This method controls the forging process to meet the final physical and chemical requirements of different GH4738 forgings. By measuring the grain size of the raw materials and controlling the forging temperature range and deformation, the number of forging passes is controlled. In particular, the control of process parameters at each stage, including temperature, time, and deformation, ensures that the deformation of each pass strictly matches the grain size requirements, ensuring the product meets the final requirements and effectively improving the product yield.

[0036] The following specific examples will provide further explanation.

[0037] Example 1 A method for forging GH4738 alloy ring forgings, wherein the GH4738 alloy billet dimensions are: Φ ×Φ ×Φ Target dimensions: Φ230mm×430mm, weight: 150.42Kg; Category: II, the ring forging is a heat-insulating gasket ring, ingot section number: 1-1-1-7. Includes the following steps:

[0038] Step 1: Based on the required forging size, the raw material of GH4738 alloy billet, which is a Φ230mm bar, is re-inspected. The internal structure of the raw material is subjected to high-magnification physical and chemical testing and rated as follows: grain size level is 2.

[0039] Step 2: Based on the high-magnification physical and chemical testing results of the internal structure of the GH4738 alloy billet, which is rated as level 2, the forging deformation amount δ1 of the upsetting is set to ≥35%, the forging deformation amount δ2 of the expansion is set to ≥30%, the forging deformation amount δ3 of the pre-expansion is set to ≥25%, and the forging deformation amount δ4 of the hole expansion is set to ≥20%.

[0040] Step 3: Based on the high-magnification physical and chemical testing of the internal structure of the GH4738 alloy billet, the rating result is 2. The forging temperature for upsetting and punching is set to 1110℃~1115℃, the forging temperature for reaming and flattening is set to 1100℃~1110℃, and the forging temperature for pre-expansion and reaming is set to 1090℃~1100℃.

[0041] Step 4, Detailed Process Flow: S1, Forging blank, center punch: Electric furnace, heating temperature: ≤800℃. The furnace temperature is increased by (850℃±50℃)×140min and then increased by (1118℃±10℃)×100min; the maximum forging time is ≤120min.

[0042] Forging: Forging equipment: 3500 hydraulic press.

[0043] Forging: First heat: Upsetting plate: ~Φ350mm×(185mm±3mm); Second heat: Upsetting plate, center punching to: ~Φ430mm×(Φ160mm±3mm)×(130mm±3mm).

[0044] S2, Ma-bo, flat end face: electric furnace, heating temperature: ≤800℃. The furnace is heated by raising the temperature (850℃±50℃) for 120 minutes, and then by raising the temperature (1105℃±+10℃) for 105 minutes. The maximum construction time is ≤120 minutes.

[0045] Forging: Forging equipment: 1600 high-speed forging machine.

[0046] Forging: First heat: widening and flattening the end face to: ~Φ470mm×(Φ260mm±3mm)×(130mm±3mm); Second heat: widening and flattening the end face to: ~Φ560mm×(Φ400mm±3mm)×(130mm±3mm).

[0047] S3, Pre-expansion, Final expansion: Electric furnace, heating temperature: ≤800℃. When entering the furnace, the temperature is increased by 850℃±50℃×120min, and then increased by 1095℃±10℃×105min; the maximum forging time is ≤120min.

[0048] Forging: Forging equipment: 1600mm reamer; Forging: First heat: Pre-expansion to: ~Φ690mm × (Φ560mm±3mm) × (130mm±3mm); Second heat: Final expansion to: Φ mm×Φ mm×Φ mm.

[0049] The required forging process technical parameters can be controlled according to S1 to S3 above.

[0050] The remaining forgings are completed step by step according to the conventional process of material cutting and heating, and the heating and production fires are completed according to the forging forming design process steps.

[0051] Step 5: After fabrication, sandblasting and grinding are performed to check if the dimensions meet the requirements of the forging.

[0052] Step 6, heat treatment: ≤800℃ into the furnace, 825℃±10℃×120min, heat up to 1030±10℃×240±20min, oil cooling (≥20min).

[0053] Step 7: Physicochemical testing.

[0054] Step 8: Final inspection and warehousing.

[0055] The performance of the GH4738 alloy ring forging prepared in Example 1 was tested, and the results are shown in Tables 1 to 3.

[0056] Table 1 High-Temperature Tensile Properties of GH4738 Alloy Ring Forgings Table 2 Room temperature mechanical properties of GH4738 alloy ring forgings Table 3 Combined creep properties of GH4738 alloy ring forgings As shown in Tables 1 to 3, half of the GH4738 alloy ring forging prepared in Example 1 was subjected to the above-mentioned physical and chemical tests according to the corresponding standards, and all of them met the corresponding standard requirements.

[0057] Example 2 A method for forging GH4738 alloy ring forgings, wherein the GH4738 alloy billet dimensions are: Φ ×Φ ×Φ Target dimensions: Φ230mm×130mm, weight: 45.5Kg; category: II, ring forging is a connecting ring, ingot section number: 1-1-1-5. Includes the following steps:

[0058] Step 1: Based on the required forging dimensions, the raw material of the GH4738 alloy billet, which is a Φ230mm bar, is re-inspected. The internal structure of the raw material is subjected to high-magnification physical and chemical testing and rated as follows: grain size level is 4.

[0059] Step 2: Based on the high-magnification physical and chemical analysis of the internal structure of the GH4738 alloy billet, the rating result is level 4. The forging deformation amount δ1 for the upsetting is set to ≥25%, the forging deformation amount δ2 for the expansion is set to ≥20%, the forging deformation amount δ3 for the pre-expansion is set to ≥15%, and the forging deformation amount δ4 for the hole expansion is set to ≥10%.

[0060] Step 3: Based on the high-magnification physical and chemical testing of the internal structure of the GH4738 alloy billet, the rating result is 4. The forging temperature for upsetting and punching is set to 1090℃~1100℃, the forging temperature for reaming and flattening is set to 1080℃~1090℃, and the forging temperature for pre-expansion and reaming is set to 1070℃~1080℃.

[0061] Step 4, Detailed Process Flow: S1, Forging blank, center punch: Electric furnace, heating temperature: ≤800℃, furnace heating (850℃±50℃)×155min, furnace heating (1095℃±10℃)×155min; maximum forging time ≤120min.

[0062] Forging: Forging equipment: 3500 hydraulic press.

[0063] Forging: First heat: Upsetting plate: ~Φ350mm×(185mm±3mm); Second heat: Upsetting plate, center punching to: ~Φ350mm×(Φ110mm±3mm)×(55mm±3mm).

[0064] S2, Ma-bo, flat end face: electric furnace, heating temperature: ≤800℃. The furnace is heated to 850℃±50℃×60min, and then heated to (1085℃±+10℃)×105min. The maximum construction time is ≤120min.

[0065] Forging: Forging equipment: 1600 high-speed forging machine.

[0066] Forging: First heat: widening and flattening the end face to: ~Φ370mm×(Φ220mm±10mm)×(55mm±3mm); Second heat: widening and flattening the end face to: ~Φ435mm×(Φ320mm±3mm)×(55mm±3mm).

[0067] S3, Pre-expansion and Final Expansion: Electric furnace, heating temperature: ≤800℃. The furnace temperature is increased by 850℃±50℃ for 120 minutes, and then increased by 1095℃±10℃ for 105 minutes. The maximum forging time is ≤120 minutes.

[0068] Forging: Forging equipment: 1600mm reamer; Forging: First heat: Pre-expansion to: ~Φ500mm × (Φ400mm±3mm) × (130mm±3mm); Second heat: Final expansion to: Φ mm×Φ mm×Φ mm.

[0069] S4, Final Forging: ≥980℃; Cooling Method: Air Cooling.

[0070] The required forging process technical parameters can be controlled according to S1 to S4 above.

[0071] The remaining forgings are completed step by step according to the conventional process of material cutting and heating, and the heating and production fires are completed according to the forging forming design process steps.

[0072] Step 5: After fabrication, sandblasting and grinding are performed to check if the dimensions meet the requirements of the forging.

[0073] Step 6, heat treatment; put into the furnace at ≤800℃, heat at 825℃±10℃×120min, raise the temperature to 1030±10℃×240±20min, and cool in oil (≥20min).

[0074] Step 7: Physicochemical testing.

[0075] Step 8: Final inspection and warehousing.

[0076] The performance of the GH4738 alloy ring forging prepared in Example 2 was tested, and the results are shown in Tables 4 to 6.

[0077] Table 4 High-Temperature Tensile Properties of GH4738 Alloy Ring Forgings Table 5. Room temperature mechanical properties of GH4738 alloy ring forgings Table 6 Combined creep properties of GH4738 alloy ring forgings As shown in Tables 4 to 6, the GH4738 alloy ring forgings prepared in Example 2, when half of each piece was subjected to the above-mentioned physical and chemical tests according to the corresponding standards, all met the corresponding standard requirements.

[0078] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0079] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A forging method for a GH4738 alloy ring forging, comprising sequentially performing upsetting, punching, reaming, end-face flattening, pre-reaming, and reaming forming processes on a GH4738 alloy billet, characterized in that, The internal grain size of GH4738 alloy billet is rated as follows: when the grain size is 0-1, 2, 3, 4 and ≥5, the corresponding grain size ratings are J1, J2, J3, J4 and J5. When the parameters of upsetting, mortising, pre-expansion, and expanding hole type are inconsistent, according to the results corresponding to the grain size rating, the forging deformation of upsetting, mortising, or pre-expansion should be reduced by at least 5% in sequence, and the forging deformation of expanding hole type should be reduced by at least 0% to 5% in sequence. When the parameters of upsetting and punching are inconsistent, the forging temperature of upsetting and punching is reduced by 5℃ to 10℃ according to the grain size rating results; when the parameters of pre-expansion and reaming are inconsistent, the forging temperature of pre-expansion and reaming is reduced by -10℃ to 10℃ according to the grain size rating results; when the parameters of pre-expansion and reaming are inconsistent, the forging temperature of pre-expansion and reaming is reduced by 0℃ to 10℃ according to the grain size rating results. The parameters are the grain size rating result and the forging weight.

2. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, When the parameters of upsetting, reaming, pre-reaming, and forming reaming are inconsistent, according to the grain size ratings J1, J2, J3, J4, and J5, the forging deformation of upsetting corresponds to ≥35%, ≥30%, ≥25%, ≥20%, and ≥15%; the forging deformation of reaming corresponds to ≥30%, ≥25%, ≥20%, ≥15%, and ≥10%; the forging deformation of pre-reaming corresponds to ≥25%, ≥20%, ≥15%, ≥10%, and ≥10%; and the forging deformation of forming reaming corresponds to ≥25%, ≥20%, ≥15%, ≥10%, and ≥10%.

3. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, When the parameters of the upsetting and punching are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures of the upsetting and punching are 1115℃~1120℃, 1110℃~1115℃, 1100℃~1110℃, 1090℃~1100℃ and 1090℃ respectively.

4. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, When the parameters of the ferrule and the flat end face are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures of the ferrule and the flat end face are 1100℃~1110℃, 1100℃~1110℃, 1090℃~1100℃, 1080℃~1090℃ and 1080℃~1070℃ respectively.

5. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, When the parameters for pre-expansion and forming expansion are inconsistent, according to the grain size ratings J1, J2, J3, J4 and J5, the forging temperatures for pre-expansion and forming expansion are 1100℃~1110℃, 1090℃~1100℃, 1080℃~1090℃, 1080℃~1070℃ and 1060℃~1070℃ respectively.

6. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, The forging time for upsetting, punching, reaming, flattening, pre-reaming, and forming reaming is ≤120min.

7. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, The parameters for punching and flat end faces are the same.

8. The forging method for GH4738 alloy ring forgings according to claim 1, characterized in that, After the hole expansion and forming process, the final forging is carried out at a temperature ≥980℃ and the cooling method is air cooling.

9. The forging method for GH4738 alloy ring forgings according to claim 8, characterized in that, After the hole expansion forming process or final forging, heat treatment is carried out. The heat treatment is first held at 815℃~835℃ for 120min, then heated to 1020℃~1040℃ and held for 220min~260min, and then oil cooled for ≥20min.

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