A gear steel for wind turbine

Abstract

The present invention provides a gear steel for a wind turbine. The gear steel comprises a gear steel body and groove steps symmetrically arranged at both ends, and the bottom and upper edges of the groove steps have transition fillets with a radius of 1 / 8 of the width of the groove steps. This design significantly reduces stress concentration at sharp corners, reduces the risk of cracks and fractures, and improves the fatigue strength and durability of the gear steel. The forging process includes preheating, preliminary forging, remelting and heat preservation, mold forming, cooling, post-processing and surface treatment. By multiple step-by-step forging and controlling the deformation amount each time, local stress can be effectively dispersed and released, and the material fluidity and mechanical properties can be optimized, thereby significantly improving the overall quality, stability and service life of the gear steel.

Description

Technical Field

[0001] The invention relates to the field of processing, and in particular to a gear steel for a wind turbine generator. Background Art

[0002] As the global demand for renewable energy continues to increase, wind power generation has become an important form of green energy. In a wind turbine, the gear transmission system is one of the core components, and its performance directly affects the efficiency and life of the entire generator set. The gear steel used in wind turbines is usually required to have high strength, good toughness and wear resistance, and be able to withstand long-term cyclic loads.

[0003] At present, the traditional forging process of gear steel mainly includes the following steps: material preparation, heating, forging, heat treatment and subsequent processing. However, these traditional processes have some problems and challenges in practical applications: The patent with publication number CN104907473A discloses a hot processing method for large die flat steel forgings, but it still has certain limitations in practical applications, including: 1. Fiber damage: During the forging process, the fibers inside the steel are easily damaged, affecting the mechanical properties of the gear steel. Due to improper fiber damage and forging process control, the wear resistance and toughness of the gear steel are poor, affecting the service life and reliability of the gear. 2. Stress concentration: The bottom and edges of the groove steps are areas of stress concentration. During the forging process, the material is subjected to local stress concentration in these areas, which can easily lead to the formation and expansion of cracks, and may eventually cause the forgings to crack and break. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a gear steel for a wind turbine generator, which solves the problems existing in the prior art. The present invention adopts a specific groove die design so that the fibers of the steel can be continuously distributed during the forging process. This design not only improves the material utilization rate, but also maintains the integrity of the fibers, greatly improving the strength and toughness of the gear steel. Due to the retention of the continuous fiber structure, the wear resistance and toughness of the gear steel are significantly improved, thereby improving the service life and reliability of the gear.

[0006] By completing the forging of complex shapes in multiple steps and controlling the deformation of each forging, local stress can be effectively dispersed and released to avoid stress concentration. At the same time, by setting transition fillets when designing grooves and steps, stress concentration can be significantly reduced to avoid material fracture in stress concentrated areas. Combined with controlling forging process parameters and multiple stress release treatments, the quality and performance of forgings are ensured.

[0007] (II) Technical solution

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A gear steel for a wind turbine generator comprises a gear steel body and groove steps symmetrically arranged at both ends of the gear steel body, and a mounting hole is arranged through the middle of the gear steel body. The bottom and upper edges of the groove steps are provided with transition fillets, and the radius of the transition fillets is 1 / 8 of the width of the groove steps. The gear steel body is the main load-bearing structure of the entire assembly, and it has high strength and good toughness to support the torque and bending stress generated during the operation of the wind turbine generator. The groove steps symmetrically arranged at both ends can improve the stress distribution of the gear steel during rotation and reduce the stress concentration caused by centrifugal force. These groove steps help absorb vibration and reduce noise, which is an advantage for the operating environment of the wind turbine generator. And the steps can serve as an additional supporting structure to enhance the overall rigidity and stability of the gear steel. The mounting hole is located in the middle of the gear steel for installing the shaft. The transition fillet refers to a smooth transition portion arranged at the bottom and upper edges of the groove step, and its radius is 1 / 8 of the width of the groove step. This setting has the following benefits by changing sharp corners into smooth transition angles:

[0010] 1. Reduce stress concentration: Sharp corners are the most obvious areas of stress concentration, and materials are prone to cracks and fractures in these areas. By setting a rounded transition, the stress can be evenly distributed over a larger area to avoid excessive local stress. The rounded corner design at the bottom and upper edge of the groove step can effectively alleviate stress concentration and reduce the risk of cracks and fractures caused by excessive stress, thereby improving the overall strength and reliability of the forging. The use of a rounded transition design can effectively improve the fatigue strength of gear steel under repeated loads, making it more durable and reliable during long-term operation.

[0011] 2. Improve material fluidity: During the forging process, material fluidity is crucial to the quality of the forming. The rounded corner design can make the material flow more smoothly in the die, reduce material accumulation and uneven deformation. The rounded corner transition design can promote uniform distribution of materials during the forging process, improve the forming quality, reduce defects, and improve the appearance and performance of the final product.

[0012] 3. Optimize stress distribution: Fillet transition can optimize stress distribution, making stress evenly distributed in the entire groove step area, avoiding stress concentration in a single part. By optimizing stress distribution, the overall mechanical properties of gear steel are improved, so that it can better withstand various complex loads during use, and improve service life and reliability.

[0013] Furthermore, the radius of the transition fillet is 1 / 8 of the width of the groove step. Based on their own creative work, the inventors found that forging within this range can effectively reduce the concentration of stress at the bottom and edge of the groove step, optimize stress distribution, increase fatigue life, improve material fluidity, improve processing performance, and achieve design standardization while ensuring strength and life. These benefits work together to significantly improve the overall performance and reliability of gear steel for wind turbines.

[0014] The forging process of the gear steel for the wind turbine generator comprises the following steps:

[0015] S1 Preheating the billet: Preheat the billet in the furnace, raise the temperature to 1050℃~1200℃, and keep it for 30 minutes. Preheating the billet to a high temperature can significantly increase the plasticity of the steel. When steel is heated to a certain temperature, its internal structure becomes more deformable, which helps the subsequent forging process. Increased plasticity means that the billet can change shape more easily under the applied pressure without breaking. Preheating the billet to a high temperature can significantly increase the plasticity of the steel. When steel is heated to a certain temperature, its internal structure becomes more deformable, which helps the subsequent forging process. Increased plasticity means that the billet can change shape more easily under the applied pressure without breaking.

[0016] S2 Preliminary forging: The billet is roughened and stretched for 2 to 3 cycles, and the deformation of the billet is controlled to be 40% to 50% each time; then the billet is rounded, leveled, and angled to form a preliminary forging. Among them, roughening is the process of forging the original billet along the axial direction to reduce its height and increase its cross-section, and drawing is the process of forging the original billet along the axial direction to reduce its height and increase its cross-section. The rounding step is to roll the end of the billet into a round shape, which helps the subsequent forming process and can provide better mechanical properties. The leveling and angle clearing steps are to level the surface and edges of the billet, remove any sharp edges or irregular parts, and ensure the smoothness and precision of the product.

[0017] S3 Reheating: After forging, the forging is reheated to 1200℃~1250℃ and kept at this temperature for 1 to 3 hours. Through reheating, the microstructure of the material (such as grain size, phase composition, etc.) will be improved, thereby improving the mechanical properties of the material, including strength, toughness and hardness.

[0018] S4 die forming: The forging is transferred to the groove die, and pressure is applied to the groove die multiple times by a 10t hammer, so that the forging undergoes plastic deformation in the die and is finally formed.

[0019] The molds such as Figure 1As shown, the die includes a die sleeve, a lower punch and an upper punch. The pre-forged billet is placed between the lower punch and the upper punch. The die sleeve is the main structure that accommodates other components in the entire forging process and has an inner cavity whose shape is designed to accommodate and guide the shape change of the material during the forging process. The die sleeve not only provides physical positioning of the punch, but also helps to ensure that the deformation of the material during the forging process meets the design requirements. The lower punch is located at the bottom of the die sleeve and is used to support the pre-forged billet. During the forging process, the lower punch can move upward to apply pressure to the pre-forged billet, causing it to deform to fill the cavity of the die sleeve. The upward movement of the lower punch is controlled to ensure that the material is evenly stressed and deformed during the forging process. The upper punch is located at the top of the die sleeve, opposite to the lower punch. During the forging process, the upper punch moves downward and presses on the pre-forged billet, cooperating with the lower punch to act on the material together to cause it to plastically deform. The design of the upper punch matches its corresponding lower punch and die sleeve to ensure that a uniform and controlled force can be applied to the material.

[0020] S5 Forging cooling: After forging is completed, the forging is taken out from the die and gradually cooled to 350℃~400℃ by air cooling to avoid internal stress caused by temperature difference.

[0021] S6 post-treatment: After cooling, the forgings will undergo a series of heat treatment processes to optimize their microstructure and mechanical properties. Including normalizing and tempering. The temperature of normalizing is controlled at 850°C~950°C, and the holding time is 2h. Normalizing is to make the structure of the steel uniform by heating it above the critical temperature and keeping it warm for a period of time, and then slowly cooling it. Eliminate the stress and structural inhomogeneity generated during the forging process and refine the grains. The temperature of tempering is controlled at 780°C~850°C, and the holding time is 3h. The purpose of tempering is to reduce hardness and brittleness and increase the toughness and ductility of the material. Reduce the risk of deformation or cracking that may occur during subsequent processing or use.

[0022] S7 Surface Treatment: Treatment of the forged gear steel surface and groove steps, including grinding and polishing; the purpose of this step is to remove any surface defects that may have occurred during the forging process, such as cracks, dents or burn marks.

[0023] S8 Inspection and Quality Control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing.

[0024] Furthermore, the gear steel is made of alloy structural steel or carburizing steel.

[0025] Furthermore, the number of forgings is controlled to 10 times, the forging deformation of 1-3 times is controlled at 15%-20%, the forging deformation of 4-6 times is controlled at 10%-12%, and the forging deformation of 7-10 times is controlled at 5%-8%. By gradually completing the forging of complex shapes in multiple times and controlling the deformation of each forging, local stress can be effectively dispersed and released, stress concentration can be reduced, and cracks and fractures in detail parts such as grooves and steps of forgings can be avoided. And controlling the deformation each time can make the material flow evenly in the mold, avoiding uneven deformation and material accumulation. And improving the molding quality, optimizing the material fluidity can reduce defects such as pores, inclusions, etc., and improve the quality of the final forging.

[0026] Based on their own creative work, the inventors found that forging within this range can effectively improve the metal fiber distribution of the overall forging, reduce the breakage and dislocation of the metal fibers, and thus improve the overall mechanical properties and fatigue life of the forging. This forging process not only optimizes the internal structure of the material, but also enhances the stability and reliability of the forging in practical applications, thereby improving the overall quality and performance of the gear steel for wind turbines.

[0027] (III) Beneficial effects

[0028] The present invention aims to provide a gear steel for a wind turbine generator. The present invention provides a transition fillet with a radius of 1 / 8 of the groove step width at the bottom and upper edge of the groove step. This design effectively reduces the stress concentration caused by sharp corners, thereby significantly reducing the risk of cracks and fractures. By changing the sharp corners into smooth transition angles, the stress distribution is improved, the fatigue strength of the gear steel under repeated loads is improved, and its durability and reliability in long-term operation are ensured.

[0029] Gradual forging process: This invention divides the forging process of complex shapes into multiple steps and controls the deformation in each forging, thereby effectively dispersing and releasing local stress. Controlling the deformation in each forging helps optimize the fluidity of the material, reduce uneven deformation and material accumulation, avoid stress concentration, and further improve the forming quality and final performance of the forging. This process improvement not only maintains strength and extends service life, but also significantly improves the stability and safety of the forging.

[0030] Optimize material fluidity: The rounded corner design and the multi-stage forging process work together to promote uniform material flow in the die and reduce defects such as pores and inclusions during the forging process. This not only improves the appearance and performance of the final product, but also ensures the consistency and reliability of the material throughout the entire processing process.

[0031] Comprehensive quality control: The present invention combines the process steps of preheating, furnace insulation, mold forming, cooling, post-processing, surface treatment, inspection and quality control. Through the comprehensive application of these steps, the high performance and high reliability of gear steel are achieved. Each step of the process is optimized for the different characteristics of the material, ensuring the excellent quality of the final product.

[0032] Through these innovations, the present invention effectively solves the stress concentration and material fluidity problems of traditional gear steel in complex shape forging, and improves the overall performance, service life and reliability of gear steel for wind turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0034] Figure 1 It is a schematic diagram of the initial state of the mold in the processing technology of this application.

[0035] Figure 2 This is a schematic diagram of the finished gear steel for wind turbines in this application.

[0036] Figure 3 This is a cross-sectional schematic diagram in Example 1 of the present application.

[0037] Figure 4 This is a cross-sectional schematic diagram of comparative example 1 of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the attached examples of the present invention Figure 1 to Figure 4 A clear and complete description is given to the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] Embodiment 1: The molding size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R30.

[0040] S1 Preheating the steel billet: Place the steel billet in the furnace for preheating, raise the temperature to 1200℃, and maintain it for 30 minutes.

[0041] S2 preliminary forging: The steel billet is roughened and stretched twice, and the deformation of the steel billet is controlled to be 40% during each roughening and stretching; then the steel billet is rounded, flattened, and corner-cleared to form a preliminary forging.

[0042] S3 reheating: After forging is completed, the forging is heated to 1200℃ and kept at this temperature for 1 hour.

[0043] S4 die forming: the forging is transferred to the groove die, and pressure is applied to the groove die by a 10t hammer for multiple times, so that the forging is plastically deformed in the die and finally formed; the number of forging times is controlled to be 10 times, and the controlled forging deformation is: 19.78%, 17.2%, 16.13%, 11.85%, 11.1%, 10.4%, 7.95%, 7.41%, 6.83%, 5.55% in sequence.

[0044] Mould Figure 1 As shown, the die includes a die sleeve, a lower punch and an upper punch. The pre-forged blank is placed between the lower punch and the upper punch.

[0045] S5 Forging cooling: After forging is completed, the forging is taken out from the die and gradually cooled to 350℃ by air cooling.

[0046] S6 Post-treatment: After cooling, the forgings will go through a series of heat treatment processes. The temperature of normalizing treatment is controlled at 850°C and the holding time is 2h. The temperature of tempering treatment is controlled at 780°C and the holding time is 3h.

[0047] S7 surface treatment: treatment of forged gear steel surface and groove steps, including grinding and polishing.

[0048] S8 Inspection and Quality Control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing.

[0049] Embodiment 2: The molding size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R30.

[0050] S1 Preheating the billet: Place the billet in the furnace for preheating, raise the temperature to 1150℃, and maintain it for 30 minutes.

[0051] S2 preliminary forging: The steel billet is roughened and stretched twice, and the deformation of the steel billet is controlled to be 40% during each roughening and stretching; then the steel billet is rounded, flattened, and corner-cleared to form a preliminary forging.

[0052] S3 reheating and heat preservation: After forging is completed, the forging is heated to 1200℃ and kept at this temperature for 1 hour.

[0053] S4 die forming: the forging is transferred to the groove die, and pressure is applied to the groove die by a 10t hammer for multiple times, so that the forging undergoes plastic deformation in the die and is finally formed; the number of forging times is controlled to be 6 times, and the forging deformation amounts are: 25.52%, 23.12%, 19.33%, 18.66%, 16.5%, and 14.31% respectively.

[0054] S5 Forging cooling: After forging is completed, the forging is taken out from the die and gradually cooled to 350℃ by air cooling.

[0055] S6 Post-treatment: After cooling, the forgings will go through a series of heat treatment processes. The temperature of normalizing treatment is controlled at 850°C and the holding time is 2h. The temperature of tempering treatment is controlled at 780°C and the holding time is 3h.

[0056] S7 surface treatment: treatment of forged gear steel surface and groove steps, including grinding and polishing.

[0057] S8 Inspection and Quality Control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing.

[0058] Embodiment 3: The molding size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R30.

[0059] S1 Preheating the steel billet: Place the steel billet in the furnace for preheating, raise the temperature to 1150℃, and keep it for 30 minutes.

[0060] S2 preliminary forging: The steel billet is roughened and stretched twice, and the deformation of the steel billet is controlled to be 40% during each roughening and stretching; then the steel billet is rounded, flattened, and corner-cleared to form a preliminary forging.

[0061] S3 reheating and heat preservation: After forging is completed, the forging is heated to 1200℃ and kept at this temperature for 1 hour.

[0062] S4 die forming: the forging is transferred to the groove die, and pressure is applied to the groove die by a 10t hammer for multiple times, so that the forging is plastically deformed in the die and finally formed; the number of forging times is controlled to 8 times, and the forging deformation amounts are: 22.41%, 21.73%, 20.64%, 18.81%, 16.72%, 15.36%, 12.13%, and 8.81% respectively.

[0063] S5 Forging cooling: After forging is completed, the forging is taken out from the die and gradually cooled to 350℃ by air cooling.

[0064] S6 Post-treatment: After cooling, the forgings will go through a series of heat treatment processes. The temperature of normalizing treatment is controlled at 850°C and the holding time is 2h. The temperature of tempering treatment is controlled at 780°C and the holding time is 3h.

[0065] S7 surface treatment: treatment of forged gear steel surface and groove steps, including grinding and polishing.

[0066] S8 Inspection and Quality Control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing.

[0067] Embodiment 4: The molding size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R30.

[0068] S1 Preheating the steel billet: Place the steel billet in the furnace for preheating, raise the temperature to 1150℃, and keep it for 30 minutes.

[0069] S2 preliminary forging: The steel billet is roughened and stretched twice, and the deformation of the steel billet is controlled to be 40% during each roughening and stretching; then the steel billet is rounded, flattened, and corner-cleared to form a preliminary forging.

[0070] S3 reheating and heat preservation: After forging is completed, the forging is heated to 1200℃ and kept at this temperature for 1 hour.

[0071] S4 die forming: the forging is transferred to the groove die, and pressure is applied to the groove die by a 10t hammer for multiple times, so that the forging is plastically deformed in the die and finally formed; the number of forging times is controlled to be 12 times, and the forging deformation is: 18.31%, 17.58%, 16.13%, 14.22%, 10.58%, 10.16%, 7.33%, 6.51%, 6.17%, 5.55%, 5.01%, and 3.52% respectively.

[0072] S5 Forging cooling: After forging is completed, the forging is taken out from the die and gradually cooled to 350℃ by air cooling.

[0073] S6 Post-treatment: After cooling, the forgings will go through a series of heat treatment processes. The temperature of normalizing treatment is controlled at 850°C and the holding time is 2h. The temperature of tempering treatment is controlled at 780°C and the holding time is 3h.

[0074] S7 surface treatment: treatment of forged gear steel surface and groove steps, including grinding and polishing.

[0075] S8 Inspection and Quality Control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing.

[0076] Comparative Example 1: It is a traditional free forging process, the forming size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R30.

[0077] The processing technology includes the following steps:

[0078] S1 Preheating the billet: Place the billet in the furnace for preheating, raise the temperature to 1150℃, and maintain it for 30 minutes.

[0079] S2 free forging: The steel billet is roughened and stretched twice, and the deformation of the steel billet is controlled to be 40% during each roughening and stretching; the steel billet is rounded, flattened, and angled to form a preliminary forging.

[0080] S3 reheating and heat preservation: After forging is completed, the forging is heated to 1200℃ and kept at this temperature for 1 hour.

[0081] S4 forging: The forging is repeatedly pressurized by a 10t hammer, and the number of forgings is controlled to 10 times.

[0082] S5 Forging Cooling: After forging, the forging is gradually cooled to 350℃ by air cooling.

[0083] S6 Post-treatment: After cooling, the forgings undergo a heat treatment process, in which the temperature of the normalizing treatment is controlled at 850°C and the holding time is 2h. The temperature of the tempering treatment is controlled at 780°C and the holding time is 3h.

[0084] S7 groove processing: After complete cooling, the forging is processed by milling to complete the processing of the groove step.

[0085] S8 surface treatment: Processing of forged gear steel surface and groove steps, including grinding and polishing.

[0086] S9 Inspection and Quality Control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing.

[0087] Comparative Example 2: The molding size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R15.

[0088] Comparative Example 3: The molding size is φ1230*175mm, the groove step width is 240mm, and the radius of the transition fillet is R60.

[0089] The forgings in the above embodiments and comparative examples were tested, and the test results are shown in Table 1 below:

[0090] Table 1

[0091]

[0092] Among them, RM is the abbreviation of tensile strength, which means the pressure that the material can withstand when subjected to the maximum force, that is, the destructive strength of the material. Rp0.2 stands for yield strength, which refers to the ability of the material to resist deformation before permanent deformation occurs. A% stands for elongation after fracture, which is the ratio of the increased length of the material after it breaks in a tensile test to the original length, expressed as a percentage, showing the extent to which the material can stretch before breaking. Z% section shrinkage refers to the ratio of the difference between the minimum cross-sectional area of ​​the fracture and the original cross-sectional area after the material breaks in a tensile test to the original cross-sectional area, usually expressed as a percentage. The section shrinkage reflects how much plastic deformation the material can withstand in the process of being subjected to tensile force until it breaks. This is an indicator to measure the ductility and toughness of the material. K It is used to indicate the absorbed energy of a material under an impact load. It is tested through a V-notch impact test. By measuring the absorbed energy of a material under an impact load, its toughness and brittleness can be effectively evaluated. The value of is a test for determining the notch sensitivity (toughness) of metal materials.

[0093] It can be seen from the data in Table 1 that the gear steel processed and manufactured by the present invention has obvious advantages in yield strength, tensile strength and elongation compared with the gear steel in the prior art, especially the advantages of the gear steel manufactured in Examples 1 and 4 are more obvious. After comprehensive production cost considerations, the processing technology in Example 1 is a more preferred solution.

[0094] Figure 3 This is a schematic diagram of the cross-sectional fiber of the gear steel made by this process. The metal fibers of the groove step formed by die forging are continuously distributed along the step profile, which significantly improves the tensile strength and compressive strength of the step. In practical applications, gears produced by forging technology show better mechanical properties under high load and impact environments, and their service life is significantly extended.

[0095] Figure 4 This is a schematic diagram of the cross-section fiber of gear steel made by traditional technology, and its metal fiber is broken at the step. This kind of fiber breakage leads to a significant reduction in the strength and toughness of the material at the step, which is prone to failure under high load and impact environment, and has a relatively short service life.

[0096] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gear steel for a wind turbine generator, comprising: A gear steel body and groove steps symmetrically arranged at both ends of the gear steel body, wherein a mounting hole is penetrated through the middle of the gear steel body, and characterized in that transition fillets are arranged at the bottom and upper edge of the groove step, and the radius of the transition fillet is 1 / 8 of the width of the groove step; The groove die forging process of the gear steel for a wind turbine generator comprises the following steps: S1 Preheating the steel billet: Put the steel billet into the furnace for preheating to reduce the resistance of the steel billet during forging and improve the plasticity; S2 Preliminary forging: The steel billet is roughened and stretched, and the number of stretching is controlled to 2 to 3 times. After the stretching is completed, the steel billet is rounded, flattened, and corners are cleared to form a preliminary forging; S3 Return to furnace and keep warm: return the forgings to furnace and keep warm, the temperature is controlled at 1200℃~1250℃, and the keeping warm time is controlled at 1~3h; S4 die forming: the forging is transferred to the groove die, and pressure is applied to the groove die by a 10t hammer for multiple times, so that the forging undergoes plastic deformation in the die and is finally formed; S5 Forging cooling: After forging is completed, the forging is taken out from the die and air-cooled to avoid internal stress caused by temperature difference; S6 post-treatment: After the forging is cooled, it is heat treated, including normalizing and tempering, to optimize the microstructure and mechanical properties of the material; S7 surface treatment: treatment of forged gear steel surface and groove steps, including grinding and polishing; S8 Inspection and quality control: Conduct comprehensive quality inspection, including dimensional measurement, surface inspection, and material performance testing; In the S4 die forming step, the number of forgings is controlled to be 10 times, the forging deformation of the 1st to 3rd times is controlled to be 15%-20%, the forging deformation of the 4th to 6th times is controlled to be 10%-12%, and the forging deformation of the 7th to 10th times is controlled to be 5%-8%; In the step of preheating the steel billet in step S1, the target temperature is set to 1050°C to 1200°C, and the holding time is 30 minutes; The S2 preliminary forging step includes: roughening and stretching the steel billet for 2 to 3 cycles, and controlling the deformation of the steel billet to be 40% to 50% during each roughening and stretching; and rounding, flattening, and corner cleaning the steel billet after roughening and stretching to form a preliminary forging. In the S4 die forming step, the groove die includes a die sleeve, a lower punch and an upper punch, the die sleeve has an inner cavity, the shape of the inner cavity is designed to accommodate and guide the shape change of the material during the forging process, the lower punch can move upward to apply pressure to the pre-forged billet, and the upper punch can move downward and press on the pre-forged billet to cooperate with the lower punch; In the S5 forging cooling step, the cooling temperature is controlled at 350°C to 400°C.

2. The gear steel for wind turbine generator according to claim 1, characterized in that: In the S6 post-treatment step, the normalizing treatment temperature is controlled at 850° C. to 950° C., and the holding time is 2 hours.

3. The gear steel for wind turbine generator according to claim 1, characterized in that: In the S6 post-treatment step, the tempering treatment temperature is controlled at 780° C. to 850° C., and the insulation time is 3 hours.

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