Forging process for optimizing anti-fatigue performance of output shaft of wind power equipment

Abstract

The invention relates to the technical field of wind power equipment output shaft forging, and discloses a wind power equipment output shaft anti-fatigue performance optimization forging process which comprises the following steps that a blank is heated to a preset temperature to improve the forgeability of the blank, and a base is provided for subsequent forging; hot forging is conducted, specifically, a staged forging technology is adopted, grains are refined step by step, and forging defects are removed; cold forging is conducted, specifically, the blank is cooled to the room temperature to be subjected to cold forging treatment for optimizing the surface hardness and toughness of the forge piece, and the anti-fatigue performance is further enhanced; after finish forging and cold forging, residual compressive stress on the surface of the forge piece is treated; the temperature field is heated and detected, in the heating process, the temperature of the blank is detected in real time through temperature detection equipment, the temperature field is calculated, and it is ensured that the temperature is evenly distributed. The blank is subjected to hot forging in stages, grains can be gradually refined, forging defects are eliminated, then cold forging treatment is conducted, the surface hardness and toughness of the forge piece can be further optimized, the anti-fatigue performance is enhanced, and the quality and reliability of the forge piece are improved.

Description

Technical Field

[0001] The invention relates to the technical field of forging an output shaft of a wind power device, and in particular to a forging process for optimizing the fatigue resistance of an output shaft of a wind power device. Background Art

[0002] The output shaft of wind power equipment is one of the key components of wind turbines, which is mainly responsible for converting wind energy into mechanical energy and transmitting it to the generator. As an important transmission component of wind turbines, the output shaft bears the huge mechanical load from the wind wheel and converts it into stable rotational power to drive the generator to output electricity. The output shaft of wind power equipment usually needs to have high strength, high toughness, good wear resistance and fatigue resistance to ensure that it works stably and efficiently during long-term operation and avoid frequent failures and shutdowns.

[0003] During operation, the output shaft of wind power equipment is constantly subjected to periodic loads from the wind rotor and environmental factors, especially wind speed fluctuations and load changes, which cause alternating stress and fatigue damage to the output shaft. With long-term operation, cracks and fatigue fractures may appear on the surface of the output shaft, which may cause premature failure of the equipment in severe cases and affect the stability and safety of the wind turbine. In order to ensure the long-term stable operation of wind power equipment and avoid frequent shutdowns and maintenance of equipment, it is particularly important to improve the fatigue resistance of the output shaft. Improving the fatigue resistance of the output shaft can not only extend its service life and reduce maintenance costs, but also improve the power generation efficiency and reliability of wind turbines.

[0004] At present, the manufacturing technology of wind power equipment output shaft mostly adopts traditional forging process. Although these processes can improve the mechanical properties of output shaft to a certain extent, there are still some obvious disadvantages. First, the traditional forging process has limited improvement on the surface quality and internal structure of forgings. Especially in high stress and high fatigue environment, local stress concentration and crack propagation are prone to occur, resulting in shortened fatigue life. Secondly, the existing processes are mostly single hot forging or cold forging, lacking effective staged forging and post-processing measures, making it difficult to fully optimize the mechanical properties and fatigue resistance of forgings. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a forging process for optimizing the fatigue resistance of the output shaft of a wind power equipment, which solves the problems in the prior art that the traditional forging process is prone to local stress concentration and crack propagation, and the single hot forging or cold forging lacks effective staged forging and post-processing measures, making it difficult to comprehensively optimize the mechanical properties and fatigue resistance of the forgings.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A forging process for optimizing the fatigue resistance of an output shaft of a wind power equipment comprises the following steps:

[0007] Heating the blank to a preset temperature improves the forgeability of the blank and provides a base for subsequent forging;

[0008] Hot forging uses a staged forging process to gradually refine the grains and remove forging defects;

[0009] Cold forging, cooling the blank to room temperature for cold forging, is used to optimize the surface hardness and toughness of the forging and further enhance the fatigue resistance;

[0010] After final forging and cold forging, the residual compressive stress on the forging surface is treated;

[0011] Heating and detecting the temperature field: During the heating process, the temperature of the blank is detected in real time by the temperature detection equipment, and the temperature field is calculated to ensure uniform temperature distribution.

[0012] Preferably, when the blank is heated, the heating temperature is 1050° C. to 1100° C., and the heating time is 60 to 70 minutes.

[0013] Preferably, the temperature detection device includes a high-precision temperature sensor for detecting the surface and internal temperature of the blank in real time;

[0014] The temperature field calculation module calculates the temperature distribution based on real-time data.

[0015] Preferably, the temperature distribution is calculated using the following formula:

[0016]

[0017] Where: T is the temperature field, which indicates the change of the temperature inside and on the surface of the blank with time and space; α is the thermal diffusivity, in m 2 / s, is the Laplace operator of temperature, which describes the change of temperature in space.

[0018] Preferably, the hot forging is divided into three stages:

[0019] Rough forging stage: Rough forging is performed through a large deformation to ensure that the blank obtains a preliminary shape and avoid internal stress concentration;

[0020] Fine forging stage: fine processing of the blank to eliminate rough forging defects and further refine the grains;

[0021] Detail forging stage: The forgings are finally processed through a small deformation to ensure the surface quality and dimensional accuracy of the forgings.

[0022] Preferably, in the rough forging stage: the blank is heated to 1000° C. to 1100° C., and the deformation rate is 10 to 12 mm / s;

[0023] Precision forging stage: heat the blank to 950℃~1050℃, and the deformation rate is 7~5mm / s;

[0024] Detail forging stage: heat the billet to 900℃~1000℃, and the deformation rate is 4~6mm / s.

[0025] Preferably, after hot forging, the blank is cooled to room temperature and then cold forged, and the specific steps include:

[0026] Cool the blank to room temperature, and control the cooling rate at 10-30℃ / s;

[0027] When the temperature of the billet drops to 100-150°C, cold forging is carried out with a cold forging pressure of 50-100 MPa and a deformation rate of 1-1.5 mm / s, which is used to optimize the surface hardness and fatigue resistance of the forging.

[0028] Preferably, when the forging is subjected to surface residual compressive stress treatment, an ultrasonic generator is used to perform ultrasonic impact treatment on the forging, and the frequency range is 20 to 40 kHz, and the treatment efficiency is 0.5 to 0.8 m 2 / min.

[0029] Preferably, after the surface residual compressive stress treatment, the forging is subjected to low temperature tempering treatment, and the forging is heated to 200-300° C. and kept warm for 30-60 min to stabilize the internal metallographic structure and residual stress field.

[0030] Preferably, during the entire forging process, the forging parameters are dynamically adjusted based on the real-time temperature field distribution data provided by the temperature detection equipment to further improve the comprehensive mechanical properties and fatigue life of the forgings.

[0031] The present invention provides a forging process for optimizing the fatigue resistance of the output shaft of a wind power device. It has the following beneficial effects:

[0032] 1. The present invention performs hot forging on the blank in stages, thereby gradually refining the grains and eliminating forging defects, and then performs cold forging treatment, which can further optimize the surface hardness and toughness of the forging, enhance the fatigue resistance, and improve the quality and reliability of the forging.

[0033] 2. The ultrasonic impact treatment of the present invention forms a compressive stress layer on the surface of the forging through high-frequency vibration without affecting the overall structure and metallographic structure of the forging, which not only effectively reduces the generation of surface cracks, but also improves the hardness and toughness of the surface layer, reduces the propagation rate of fatigue cracks, and improves the overall fatigue resistance life and durability.

[0034] 3. The present invention can monitor the temperature change of the blank in real time and accurately calculate its temperature field distribution by introducing high-precision temperature detection equipment and temperature field calculation module, so as to effectively control the temperature uniformity during the heating process. It can not only avoid the internal stress concentration caused by uneven temperature, but also ensure that the blank reaches the ideal forging temperature range during the entire heating process, reducing the process problems caused by too high or too low temperature. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In order to better understand the present invention, the above contents are described in detail below in conjunction with specific embodiments.

[0037] Embodiment 1

[0038] The embodiment of the present invention provides a forging process for optimizing the fatigue resistance of an output shaft of a wind power device, comprising the following steps:

[0039] Heating the blank to a preset temperature improves the forgeability of the blank and provides a base for subsequent forging;

[0040] Hot forging uses a staged forging process to gradually refine the grains and remove forging defects;

[0041] Cold forging, cooling the blank to room temperature for cold forging, is used to optimize the surface hardness and toughness of the forging and further enhance the fatigue resistance;

[0042] After final forging and cold forging, the residual compressive stress on the forging surface is treated;

[0043] Heating and detecting the temperature field: During the heating process, the temperature of the blank is detected in real time by the temperature detection equipment, and the temperature field is calculated to ensure uniform temperature distribution.

[0044] In the present invention, the forging process for optimizing the fatigue resistance of the output shaft of the wind power equipment specifically comprises the following steps:

[0045] Billet heating: In this step, the billet is heated to a preset temperature to improve the forgeability of the billet and provide a good base for the subsequent forging process. By precisely controlling the heating temperature and heating time, the internal structure of the billet is ensured to be in the best state for the subsequent hot forging process;

[0046] Hot forging: The present invention adopts a staged forging process, which includes three stages: rough forging, fine forging and detail forging. In the rough forging stage, a large deformation is used to give the blank a preliminary shape and avoid internal stress concentration caused by uneven deformation; in the fine forging stage, the blank is finely processed to eliminate rough forging defects and further refine the grains; in the detail forging stage, a small deformation is used to perform final processing on the forging to ensure the surface quality and dimensional accuracy of the forging. This staged forging process not only helps to remove forging defects, but also gradually refines the grains, improving the mechanical properties and fatigue life of the forgings;

[0047] Cold forging: After hot forging, the blank is cooled to room temperature and cold forged at this temperature. Cold forging can effectively optimize the hardness and toughness of the forging surface and enhance the fatigue resistance of the forging. The cold forging process further improves the metallographic structure of the surface layer and improves the surface wear resistance and crack resistance by applying appropriate cold forging pressure and deformation rate to the blank;

[0048] Surface residual compressive stress treatment: After final forging and cold forging, the forging surface will be treated with residual compressive stress. This treatment can form a uniform residual compressive stress layer on the forging surface through ultrasonic impact treatment and other methods, effectively reducing the expansion of surface cracks and further improving the fatigue resistance of the forging. Through this treatment, the hardness and toughness of the surface layer are significantly improved, thereby increasing the fatigue life of the forging in a long-term working environment;

[0049] Heating and detecting temperature field: During the heating process, temperature detection equipment is used to monitor the surface and internal temperature of the billet in real time, and the temperature field distribution of the billet is accurately calculated through the temperature field calculation module. This process ensures the uniformity of temperature distribution during the heating process, avoids internal stress concentration caused by uneven temperature, and thus affects the overall quality and performance of the forging. Real-time temperature data can dynamically adjust the forging process to ensure that the billet is forged within the optimal temperature range, thereby improving the comprehensive mechanical properties of the forging;

[0050] Through the above steps, the present invention provides a precise, controllable and efficient forging process for optimizing the anti-fatigue performance of the output shaft of wind power equipment, which not only effectively improves the anti-fatigue performance and service life of the forging, but also ensures its long-term stability under harsh working conditions.

[0051] When heating the blank, the heating temperature is set to 1050°C to 1100°C and the heating time is 60 to 70 minutes.

[0052] The temperature detection equipment includes a high-precision temperature sensor for real-time detection of the surface and internal temperature of the blank;

[0053] The temperature field calculation module calculates the temperature distribution based on real-time data.

[0054] The temperature distribution is calculated using the following formula:

[0055]

[0056] Where: T is the temperature field, which indicates the change of the temperature inside and on the surface of the blank with time and space; α is the thermal diffusivity, in m 2 / s, is the Laplace operator of temperature, which describes the change of temperature in space. During the whole forging process, the forging parameters are dynamically adjusted based on the real-time temperature field distribution data provided by the temperature detection equipment to further improve the comprehensive mechanical properties and fatigue life of the forgings.

[0057] In the present invention, when the blank is heated, the forgeability of the blank is improved by precisely controlling the heating temperature and heating time, providing an ideal basis for the subsequent forging process. Specifically, the blank is heated to 1050°C to 1100°C for 60 to 70 minutes. This temperature range can ensure the optimization of the blank structure, so that it has the best processing performance when entering the forging stage, and avoid uneven heating or excessive heating to cause adverse effects on subsequent processes;

[0058] During the heating process, the present invention uses a high-precision temperature detection device to monitor the temperature of the blank in real time. The device includes a temperature sensor that can simultaneously detect the temperature of the surface and the inside of the blank to ensure uniform temperature distribution. Through the feedback of real-time data, the system can adjust the heating process in time to avoid stress concentration or structural defects caused by local temperature differences, thereby improving the overall quality of the blank;

[0059] In order to further optimize the heating control, the present invention also uses a temperature field calculation module to calculate the temperature distribution based on real-time data. This calculation process can accurately grasp the temperature changes of the blank during the heating process and ensure that the temperature of each part is uniform, avoiding forging defects caused by uneven temperature. By dynamically adjusting the heating parameters, the blank is ensured to reach the ideal state during the heating stage, thus providing a solid foundation for the subsequent forging process.

[0060] Hot forging is divided into three stages:

[0061] Rough forging stage: Rough forging is performed through a large deformation to obtain the initial shape of the blank and avoid internal stress concentration;

[0062] Fine forging stage: fine processing of the blank to eliminate rough forging defects and further refine the grains;

[0063] Detail forging stage: The forgings are finally processed through a small deformation to ensure the surface quality and dimensional accuracy of the forgings.

[0064] Rough forging stage: heat the billet to 1000℃~1100℃, and the deformation rate is 10~12mm / s;

[0065] Precision forging stage: heat the blank to 950℃~1050℃, and the deformation rate is 7~5mm / s;

[0066] Detail forging stage: heat the billet to 900℃~1000℃, and the deformation rate is 4~6mm / s.

[0067] In the present invention, the hot forging process is divided into three stages to gradually refine the grains of the billet, eliminate forging defects, and optimize the quality and performance of the forging;

[0068] Rough forging stage: In this stage, the billet is rough forged with a large deformation, the main purpose of which is to obtain the initial shape of the billet and avoid internal stress concentration. To this end, the billet is heated to 1000℃~1100℃ and forged at a deformation rate of 10~12mm / s. The goal of this stage is to eliminate the general defects in the billet and ensure the initial shaping of the billet to provide a suitable base for the subsequent fine forging and detail forging stages;

[0069] Fine forging stage: The main task of the fine forging stage is to eliminate the defects of the rough forging stage, further refine the grains, and improve the mechanical properties of the forgings. In this stage, the temperature of the billet is controlled between 950℃ and 1050℃, and the deformation rate is 7-5mm / s. Through fine processing, the unevenness and defects in the billet are gradually eliminated, and its surface quality is further improved;

[0070] Detail forging stage: The goal of this stage is to perform final processing on the forgings through a smaller deformation to ensure the surface quality and dimensional accuracy of the forgings. The billet is heated to 900℃~1000℃ in this stage and forged at a deformation rate of 4~6mm / s. The key to the detail forging stage is to accurately control the deformation during the forging process to optimize the final size and surface quality of the forgings;

[0071] Through the gradual processing of these three stages, the present invention can effectively improve the comprehensive mechanical properties, surface quality and fatigue resistance of the forgings, ensuring that the output shaft of the wind power equipment has higher reliability and durability during use.

[0072] After hot forging, the blank is cooled to room temperature and then cold forged. The specific steps include:

[0073] Cool the blank to room temperature, and control the cooling rate at 10-30℃ / s;

[0074] When the temperature of the billet drops to 100-150°C, cold forging is carried out with a cold forging pressure of 50-100 MPa and a deformation rate of 1-1.5 mm / s, which is used to optimize the surface hardness and fatigue resistance of the forging.

[0075] When the forging is subjected to surface residual compressive stress treatment, an ultrasonic generator is used to perform ultrasonic impact treatment on the forging, and the frequency range is 20 to 40 kHz, and the treatment efficiency is 0.5 to 0.8 m 2 / min.

[0076] After the surface residual compressive stress treatment, the forging is subjected to low temperature tempering treatment, the forging is heated to 200-300°C and kept warm for 30-60 minutes to stabilize the internal metallographic structure and residual stress field.

[0077] In the present invention, after hot forging, the blank is cooled to room temperature and cold forged to further optimize the surface hardness and fatigue resistance of the forging. The specific steps of cold forging are as follows:

[0078] Cooling the blank to room temperature: First, after hot forging, the blank is cooled to room temperature, and the cooling rate is controlled at 10-30℃ / s to ensure uniform temperature distribution inside the blank and avoid internal stress caused by too fast cooling;

[0079] Cold forging: When the temperature of the blank drops to 100-150°C, cold forging begins. At this time, the cold forging pressure is 50-100MPa, and the deformation rate is 1-1.5mm / s. The main purpose of cold forging is to optimize the surface hardness and fatigue resistance of the forging through appropriate deformation, thereby improving the durability and strength of the forging;

[0080] Surface residual compressive stress treatment: In order to further enhance the fatigue resistance of forgings, the forgings are subjected to surface residual compressive stress treatment after cold forging. During this treatment, an ultrasonic generator is used to perform ultrasonic impact treatment on the forgings, with a frequency range of 20 to 40 kHz and a treatment efficiency of 0.5 to 0.8 m 2 / min. Ultrasonic impact can effectively improve the structure of the surface layer of forgings, reduce residual tensile stress, and improve surface hardness and fatigue resistance;

[0081] Low temperature tempering treatment: Finally, after the surface residual compressive stress treatment, the forging will be subjected to low temperature tempering treatment. The forging is heated to 200-300℃ and kept for 30-60min to stabilize the internal metallographic structure and residual stress field of the forging. Low temperature tempering helps to eliminate the internal stress generated during the cooling process, while improving the toughness and fatigue life of the forging; through cold forging and post-treatment processes, the surface quality and mechanical properties of the forging are significantly improved, ensuring that the output shaft of the wind power equipment has high fatigue tolerance and long life during operation.

[0082] Example 2: Comparative experiment to verify the advantages of staged forging, cold forging and ultrasonic impact treatment

[0083] The purpose of this experiment is to verify the advantages of cold forging and ultrasonic impact treatment after staged forging on the fatigue resistance of the output shaft of wind power equipment. By setting up different experimental groups, the differences in fatigue resistance of each group are systematically compared.

[0084] Experimental group design

[0085] Experimental Group 1: Traditional forging process

[0086] Process: Traditional forging in stages

[0087] Process parameters:

[0088] Rough forging stage: the billet is heated to 1000℃ and the deformation rate is 11mm / s

[0089] Precision forging stage: the billet is heated to 1000°C and the deformation rate is 6mm / s

[0090] Detailed forging stage: the blank is heated to 950℃ and the deformation rate is 5mm / s

[0091] Cooling treatment: No

[0092] Ultrasonic shock: No

[0093] Experimental group 2: staged forging + cold forging after staged forging

[0094] Process: Forging in stages, followed by cold forging after each stage

[0095] Process parameters:

[0096] Rough forging stage: the billet is heated to 1000℃ and the deformation rate is 11mm / s

[0097] Precision forging stage: the billet is heated to 1000°C and the deformation rate is 6mm / s

[0098] Detailed forging stage: the blank is heated to 950℃ and the deformation rate is 5mm / s

[0099] Cooling treatment: After the blank is cooled to room temperature, the cooling rate is controlled at 10℃ / s. After cooling to 100℃, cold forging is performed. The cold forging pressure is 60MPa and the deformation rate is 1.3mm / s.

[0100] Ultrasonic shock: No

[0101] Experimental group 3: staged forging + cold forging after stage + ultrasonic impact treatment

[0102] Process: Forging in stages, cold forging after stages, combined with ultrasonic impact treatment

[0103] Process parameters:

[0104] Rough forging stage: the billet is heated to 1000℃ and the deformation rate is 11mm / s

[0105] Precision forging stage: the billet is heated to 1000°C and the deformation rate is 6mm / s

[0106] Detailed forging stage: the blank is heated to 950℃ and the deformation rate is 5mm / s

[0107] Cooling treatment: After the blank is cooled to room temperature, the cooling rate is controlled at 10℃ / s. After cooling to 100℃, cold forging is performed. The cold forging pressure is 60MPa and the deformation rate is 1.3mm / s.

[0108] Ultrasonic impact treatment: using an ultrasonic generator with a frequency range of 30kHz and a treatment efficiency of 0.7m 2 / min

[0109] Experimental group 4: staged forging + cold forging after staged forging + ultrasonic impact treatment (cold forging parameters are lower than the range value)

[0110] Process: Same as experimental group 3, the only difference is that during cold forging, the cooling rate is 5℃ / s, cold forging is performed after cooling to 100℃, the cold forging pressure is 50MPa, and the deformation rate is 1.1mm / s

[0111] Experimental group 5: staged forging + cold forging after staged forging + ultrasonic impact treatment (cold forging parameters are higher than the range value)

[0112] Process: Same as experimental group 3, the only difference is that during cold forging, the cooling rate is 30℃ / s, cold forging is performed after cooling to 100℃, the cold forging pressure is 70MPa, and the deformation rate is 1.5mm / s

[0113] Experimental group 6: staged forging + cold forging after staged forging + low-frequency ultrasonic impact treatment

[0114] Process: Same as experimental group 3, the only difference is that the frequency of ultrasonic impact is 20kHz and the treatment efficiency is 0.5m 2 / min

[0115] Experimental group 7: staged forging + cold forging after staged forging + high-frequency ultrasonic impact treatment

[0116] Process: Same as experimental group 3, the only difference is that the frequency of ultrasonic impact is 40kHz and the processing efficiency is 0.8m 2 / min

[0117] Fatigue detection methods and equipment

[0118] Fatigue testing equipment:

[0119] The fatigue test of each experimental group of samples was carried out using a vibration fatigue testing machine: MTS810 series.

[0120] A high-frequency fatigue test mode is used to simulate the actual working environment of wind power equipment bearings.

[0121] The operating frequency of the testing machine is set to 50 Hz, and the test stress range is set to 400-600 MPa (depending on the design of different specimens).

[0122] Testing steps:

[0123] The forgings of each experimental group were cut into standard fatigue specimens.

[0124] Each sample was subjected to 10 6 Load the cracks for several times and record the number of cycles to generate cracks to evaluate the fatigue life.

[0125] The crack morphology of the samples was observed, the crack propagation stage was tested, and the fatigue limit value of each experimental group was recorded.

[0126] Use an electron microscope (such as SEM) to analyze the fatigue fracture and observe its microscopic characteristics and fatigue failure mode.

[0127] Data recording and analysis:

[0128] Fatigue life (Nf): The number of fractures of samples in each experimental group.

[0129] Fatigue Strength: Fatigue strength is evaluated through maximum stress and sample crack growth data.

[0130] Fatigue limit: Evaluate the fatigue limit of each test group (i.e. the maximum cyclic stress that cannot produce cracks).

[0131] The experimental results are summarized in Table 1.

[0132] Table 1

[0133]

[0134] Results Analysis

[0135] According to the experimental results, experimental group 3 (staged forging + cold forging after staged hot forging + ultrasonic impact treatment) showed significant advantages. Comparing the performance differences between experimental group 3 and other experimental groups, the synergistic effect of cold forging after staged hot forging and ultrasonic impact treatment was clearly verified.

[0136] 1. Comparison of fatigue life (Nf)

[0137] Fatigue life is an important indicator to measure the fatigue resistance of forgings, representing the service life of the material under alternating loads. According to the table:

[0138] The fatigue life of experimental group 1 (conventional forging process) is 1.2×10 6 times, which is the baseline value.

[0139] The fatigue life of experimental group 2 (stage forging + cold forging treatment) was improved to 1.5×10 6 This was an increase of 25% compared to the experimental group.

[0140] The fatigue life of experimental group 3 (stage forging + cold forging + ultrasonic impact treatment) is 2.0×10 6 times, an increase of 66.7% compared to experimental group one and 33.3% compared to experimental group two.

[0141] This indicates that cold forging alone can improve fatigue life, and after adding ultrasonic impact treatment, the fatigue life is further significantly improved, proving the synergistic effect of cold forging and ultrasonic impact treatment.

[0142] 2. Comparison of fatigue strength (MPa)

[0143] Fatigue strength refers to the ability of a material to withstand alternating loads and is usually characterized by maximum stress. In this experiment:

[0144] The fatigue strength of experimental group 1 is 520MPa.

[0145] The fatigue strength of the experimental group 2 (stage forging + cold forging treatment) is 540 MPa, which is 3.8% higher than that of the experimental group 1.

[0146] The fatigue strength of experimental group three (stage forging + cold forging treatment + ultrasonic impact treatment) is 580 MPa, which is 11.5% higher than that of experimental group one and 7.4% higher than that of experimental group two.

[0147] Although cold forging improves fatigue strength, the addition of ultrasonic impact treatment leads to a greater improvement in fatigue strength. This shows that ultrasonic impact treatment plays an important role in improving the surface quality of materials, removing tiny cracks, and improving overall fatigue resistance.

[0148] 3. Comparison of fatigue limit (MPa)

[0149] The fatigue limit is the maximum stress value that a material can withstand repeated stress without fatigue fracture. It is one of the key indicators for evaluating fatigue resistance:

[0150] The fatigue limit of experimental group 1 is 450MPa.

[0151] The fatigue limit of experimental group 2 (stage forging + cold forging treatment) is 470 MPa, which is 4.4% higher than that of experimental group 1.

[0152] The fatigue limit of experimental group three (stage forging + cold forging treatment + ultrasonic impact treatment) is 500 MPa, which is 11.1% higher than that of experimental group one and 6.4% higher than that of experimental group two.

[0153] In terms of improving the fatigue limit, ultrasonic impact treatment once again played a significant role, indicating that it plays a key role in improving the internal structure of the material, eliminating surface defects and improving fatigue resistance.

[0154] 4. Analysis of synergistic effects of each experimental group

[0155] From the experimental results, it can be seen that the synergy of cold forging after staged hot forging and ultrasonic impact treatment brings the following advantages:

[0156] Improvement of fatigue life: From the comparison of fatigue life, it can be seen that ultrasonic impact treatment plays a decisive role in improving fatigue life. Cold forging can effectively improve the surface hardness and toughness of the material, but ultrasonic impact treatment can effectively remove surface microcracks and increase compressive stress by performing high-frequency impact on the surface of the forging, thereby further improving fatigue life.

[0157] Improvement of fatigue strength: Although cold forging can improve the hardness and wear resistance of materials, the addition of ultrasonic impact treatment makes the surface of the material smoother, and the crack propagation is suppressed, which greatly enhances the fatigue strength. Ultrasonic impact treatment helps to distribute stress more evenly, reduce local stress concentration, and avoid early fatigue fracture caused by surface defects.

[0158] Improvement of fatigue limit: Ultrasonic impact treatment has a particularly prominent effect on improving fatigue limit. Through the impact of high-frequency ultrasonic waves, the surface microstructure is optimized, the density and compressive stress of the surface layer of the material are strengthened, and the fatigue resistance of the material is improved. The combination of cold forging and ultrasonic impact treatment shows a synergistic effect in improving fatigue limit, which is significantly better than cold forging or forging alone.

[0159] 5. Potential for optimization and practical application

[0160] Based on the results of experimental group 3, the following conclusions can be drawn:

[0161] Manifestation of synergistic effect: The combination of cold forging after staged forging and ultrasonic impact treatment has obvious synergistic effect in improving the fatigue life, fatigue strength and fatigue limit of materials. This comprehensive optimization process can significantly improve the service life and reliability of key components such as the output shaft of wind power equipment, especially in high-load and long-term working environments.

[0162] Potential for extensive applications: The process of combining hot forging, cold forging and ultrasonic impact treatment in stages can not only improve the fatigue resistance of the material, but also improve the surface quality and mechanical properties of the material, which is particularly important for wind power equipment that requires high fatigue resistance and long-term stability. The implementation of this process can effectively extend the service life of the equipment, reduce maintenance costs, and improve the overall efficiency of the wind power industry.

[0163] 6. Summary

[0164] The results of experimental group 3 show that the synergistic effect of cold forging after staged hot forging and ultrasonic impact treatment significantly improves the fatigue resistance of the output shaft of wind power equipment, and shows superiority in key indicators such as fatigue life, fatigue strength and fatigue limit. This process provides strong technical support for improving the reliability, stability and durability of wind power equipment, and can be widely used in the production of other key components in the wind power field.

[0165] 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 forging process for optimizing the fatigue resistance of a wind power equipment output shaft, characterized in that: The following steps are involved: Heating the blank to a preset temperature improves the forgeability of the blank and provides a base for subsequent forging; Hot forging uses a staged forging process to gradually refine the grains and remove forging defects; Cold forging, cooling the blank to room temperature for cold forging, is used to optimize the surface hardness and toughness of the forging and further enhance the fatigue resistance; After final forging and cold forging, the residual compressive stress on the forging surface is treated; Heating and detecting the temperature field: During the heating process, the temperature of the blank is detected in real time by the temperature detection equipment, and the temperature field is calculated to ensure uniform temperature distribution.

2. A forging process for optimizing the fatigue resistance of a wind power equipment output shaft according to claim 1, characterized in that: When heating the blank, the heating temperature is set to 1050°C to 1100°C and the heating time is 60 to 70 minutes.

3. The forging process for optimizing the fatigue resistance of the output shaft of a wind power equipment according to claim 1 is characterized in that: The temperature detection device includes a high-precision temperature sensor for detecting the surface and internal temperature of the blank in real time; The temperature field calculation module calculates the temperature distribution based on real-time data.

4. A forging process for optimizing the fatigue resistance of a wind power equipment output shaft according to claim 3, characterized in that: The temperature distribution is calculated by the following formula: Where: T is the temperature field, which indicates the change of the temperature inside and on the surface of the blank with time and space; α is the thermal diffusivity, in m 2 / s, is the Laplace operator of temperature, which describes the change of temperature in space.

5. The forging process for optimizing the fatigue resistance of the output shaft of a wind power equipment according to claim 1 is characterized in that: The hot forging is divided into three stages: Rough forging stage: Rough forging is performed through a large deformation to obtain the initial shape of the blank and avoid internal stress concentration; Fine forging stage: fine processing of the blank to eliminate rough forging defects and further refine the grains; Detail forging stage: The forgings are finally processed through a small deformation to ensure the surface quality and dimensional accuracy of the forgings.

6. A forging process for optimizing the fatigue resistance of a wind power equipment output shaft according to claim 5, characterized in that: Rough forging stage: heat the billet to 1000℃~1100℃, and the deformation rate is 10~12mm / s; Precision forging stage: heat the blank to 950℃~1050℃, and the deformation rate is 7~5mm / s; Detail forging stage: heat the billet to 900℃~1000℃, and the deformation rate is 4~6mm / s.

7. A forging process for optimizing the fatigue resistance of a wind power equipment output shaft according to claim 1, characterized in that: After hot forging, the blank is cooled to room temperature and then cold forged. The specific steps include: Cool the blank to room temperature, and control the cooling rate at 10-30℃ / s; When the temperature of the billet drops to 100-150°C, cold forging is carried out with a cold forging pressure of 50-100 MPa and a deformation rate of 1-1.5 mm / s, which is used to optimize the surface hardness and fatigue resistance of the forging.

8. The forging process for optimizing the fatigue resistance of the output shaft of a wind power equipment according to claim 1 is characterized in that: When the forging is subjected to surface residual compressive stress treatment, an ultrasonic generator is used to perform ultrasonic impact treatment on the forging, and the frequency range is 20 to 40 kHz, and the treatment efficiency is 0.5 to 0.8 m 2 / min.

9. A forging process for optimizing the fatigue resistance of a wind power equipment output shaft according to claim 1, characterized in that: After the surface residual compressive stress treatment, the forging is subjected to low temperature tempering treatment, the forging is heated to 200-300°C and kept warm for 30-60 minutes to stabilize the internal metallographic structure and residual stress field.

10. A forging process for optimizing the fatigue resistance of a wind power equipment output shaft according to claim 4, characterized in that: During the whole forging process, the forging parameters are dynamically adjusted based on the real-time temperature field distribution data provided by the temperature detection equipment to further improve the comprehensive mechanical properties and fatigue life of the forgings.

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