Forging method of bearing steel for wind power main shaft bearing based on forging test

Abstract

The invention discloses a forging test-based method for forging bearing steel for a wind power main shaft bearing, which comprises the following steps of: under different forging process parameters, carrying out forging tests on a plurality of bearing steel forgings and detecting and evaluating after the forging tests to obtain optimized forging process parameters; according to different bearing application occasions and working conditions, weight coefficients alpha, beta and gamma of three detection items A, B and C for forging performance evaluation are set, and a forging performance evaluation formula M = (alpha * A + beta * B + gamma * C) / (A + B + C) is established; wherein M is a forging performance comprehensive evaluation value based on weight consideration, and the test forging heating temperature and the test post-forging heat treatment temperature corresponding to the detection sample with the maximum M value serve as forging process parameters during forging of the bearing steel for the wind power main shaft bearing. The forging performance of the bearing steel for the wind power main shaft bearing is improved, the cost of a forging test is reduced, and the period of the forging test is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of forging, and in particular to a forging method for bearing steel for a wind turbine main shaft bearing based on a forging test. Background Art

[0002] Bearing steel forgings are widely used in various industries, and typical applications include new energy fields such as large bearing steel forgings for wind turbine main shaft bearings.

[0003] The manufacturing of bearing steel forgings involves processes such as molten steel smelting, billet making, forging, heat treatment, and ring rolling. In order to meet the needs of bearings in various applications, customers usually put forward some hard indicators for the performance of bearing steel forgings. For example, the bearing steel forgings for wind turbine main shaft bearings in a certain application need to meet the application requirements of tensile strength ≥ 900 MPa, cross-sectional shrinkage ≥ 48%, and grain size ≥ 7. The various performance requirements of such bearing steel forgings proposed by customers may not be met by conventional forging processes, or even if they can be met, the product qualification rate is low.

[0004] Therefore, it is a technical problem that technicians must face to study and optimize the forging process parameters in the forging process, reduce defects in the forging process, and improve the quality and comprehensive performance of bearing steel forgings. In addition, the research and optimization of forging process parameters usually requires forging tests. However, for large bearing steel forgings, the forging test is costly and has a long cycle. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a forging method for bearing steel for wind turbine main shaft bearings based on forging tests, aiming to obtain optimized forging process parameters through forging tests, thereby improving the forging performance of bearing steel for wind turbine main shaft bearings and reducing the cost and cycle of forging tests. The specific technical solutions are as follows: A forging method for bearing steel for wind turbine main shaft bearings based on forging tests, comprising: conducting forging tests on a number of bearing steel forgings under different forging process parameters, sampling the forgings obtained from the forging tests to obtain a large number of test specimens; then testing and performance evaluation of the test specimens, and obtaining optimized forging process parameters according to the performance evaluation results, and using the optimized forging process parameters as forging process parameters for formal forging of bearing steel for wind turbine main shaft bearings; the specific method for obtaining the optimized forging process parameters comprises the following steps arranged in sequence: (1) Modeling analysis and preliminary optimization of forging process parameters: Establish a finite element model of the bearing steel forging, take the performance index of the bearing steel forging as the optimization target, set the initial values ​​of the forging process parameters, and based on the initial values ​​of the forging process parameters, preliminarily optimize the forging process parameters through thermal simulation of the forging process and finite element analysis calculation to obtain the theoretical forging process parameters of the bearing steel forging; wherein the performance index of the bearing steel forging includes tensile strength index, cross-sectional shrinkage index and grain size index; the forging process parameters include forging heating temperature and post-forging heat treatment temperature; (2) Forging test planning and design: Set the number of bearing steel forgings that need to be subjected to forging tests, set the upper and lower floating ranges of the forging process parameter values ​​during the forging test based on the theoretical forging process parameters of the bearing steel forgings, assign values ​​to the forging process parameters of each bearing steel forging that needs to be subjected to forging tests, and make the values ​​of the forging process parameters of each bearing steel forging different from each other within the upper and lower floating ranges, so as to obtain the test forging process parameters of each bearing steel forging; the test forging process parameters include the test forging heating temperature and the test post-forging heat treatment temperature; Among them, the values ​​assigned to the forging process parameters of the bearing steel forgings are different from each other within the upper and lower floating range, which may be different forging heating temperatures or different post-forging heat treatment temperatures; that is, it is necessary to ensure that at least one of the test forging process parameters, the forging heating temperature and the post-forging heat treatment temperature, has a different value.

[0006] Preferably, the test forging heating temperature and the test post-forging heat treatment temperature of each bearing steel forging can be changed within a temperature range of ±25°C.

[0007] (3) Forging test: According to the forging process parameters for the test set in the forging test planning design, the forging test of each bearing steel forging is carried out. The forging test process of the bearing steel forging includes the following steps: S1. Molten steel smelting and billet making: after the steel material is batched, it is sequentially subjected to rough molten steel in an electric arc furnace, refined molten steel outside the furnace, and vacuum carbon deoxidation treatment, and then cast or continuously cast to form a number of prefabricated steel billets; wherein, during the rough molten steel in an electric arc furnace, refined molten steel outside the furnace, and vacuum carbon deoxidation treatment, molten steel smelting quality control points are set at each key process node, and by setting the molten steel smelting quality control points, the process parameters of molten steel smelting are controlled within the set range, thereby controlling the stability of the quality of molten steel smelting billets; S2. Heating before forging: placing the prefabricated steel billet in a forging heating furnace and heating it to the forging heating temperature set in the forging test planning design; S3, forging: the steel billet in the forging heating furnace is taken out and transferred to the forging press for forging, punching and finishing treatment in sequence to form a forging billet with a central through hole; during forging, a large anvil width ratio, a large reduction forging process and a multi-pass non-uniform temperature deformation forging process are adopted to achieve the effect of fine uniformity of the internal structure and healing of the core defects; S4, forging blank ring rolling: the forging blank with a central through hole is transferred to the ring rolling machine in a hot state, and is formed into a ring-shaped forging blank by ring rolling; S5. Making heat treatment test pieces: cutting the forging blank rolled ring into a number of heat treatment test pieces; S6. Heat treatment of test blocks: using a heat treatment furnace, each heat treatment test block is subjected to post-forging heat treatment according to the test post-forging heat treatment temperature set in the forging test planning design; S7. Sampling and testing of forgings: Samples are taken from heat-treated test blocks of bearing steel forgings with different forging process parameters for testing to obtain a number of test specimens, and each test specimen is tested; the test items include A, B, and C, where A is the tensile strength data, B is the cross-sectional shrinkage data, and C is the grain size data obtained through metallographic structure testing; S8. Data sorting and classification: For each test sample, if one of the three test contents A, B, and C is unqualified, the forging process parameters of the corresponding test sample will be classified as unqualified forging process parameters; if the three test contents A, B, and C are all qualified, the forging process parameters of the corresponding test sample will be classified as qualified forging process parameters, and the test sample will be retained and the subsequent forging performance evaluation will be carried out on it; the data of the test sample corresponding to the unqualified forging process parameters will be eliminated; S9. Establish a forging performance evaluation model to obtain the optimization of forging process parameters: According to the different bearing application scenarios and working conditions, reasonably set the weight coefficients α, β and γ for forging performance evaluation, and establish the forging performance evaluation formula M=(α×A+β×B+γ×C)÷(A+B+C); where M is the comprehensive evaluation value of forging performance based on weight considerations, α is the tensile strength weight coefficient, β is the cross-sectional shrinkage weight coefficient, and γ is the grain size weight coefficient; by calculating the size of the comprehensive evaluation value M of forging performance of each test sample, screen out the test sample with the largest comprehensive evaluation value M of forging performance, and use the test forging heating temperature and test post-forging heat treatment temperature corresponding to the test sample with the largest M value as the forging process parameters when forging bearing steel for wind turbine main shaft bearings.

[0008] Preferably, in the forging test of step (3), a multi-joint forging operating manipulator is further provided, which can realize the sequential transfer of forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling machine, and the multi-joint forging operating manipulator is movably arranged on a guide rail in the workshop; a clamp for clamping the bearing steel forging is arranged on the front end mechanical arm of the multi-joint forging operating manipulator, and a hot transfer heat protection device for preventing the temperature of the forging from decreasing during the transfer process is also arranged on the front end mechanical arm of the multi-joint forging operating manipulator; the hot transfer heat protection device comprises a telescopic bellows assembly arranged on the front end mechanical arm of the multi-joint forging operating manipulator, which can surround and remove the bearing steel forging clamped by the clamp from the periphery, and the telescopic bellows assembly has a built-in radiation heater for radiant heating of the forging.

[0009] Preferably, the clamp is a finger cylinder.

[0010] Preferably, the radiation heater includes a number of annular carbon heating tubes, the telescopic bellows assembly includes a flange ring fixed on the front end mechanical arm of the multi-joint forging operating robot and located at the rear side of the clamp, a metal bellows connected to the front end surface of the flange ring, a reflective film coated on the inner wall of the metal bellows, and a number of annular carbon heating tubes coaxially arranged near the inner wall of the metal bellows and arranged at intervals along the axial direction, a pair of servo electric push rods connected to the controller of the multi-joint forging operating robot are provided at the rear end of the flange ring, and the front end of the telescopic rod of the servo electric push rod is connected to the front end of the metal bellows; wherein, the power of the annular carbon heating tube near the front end of the metal bellows is greater than the power of the annular carbon heating tubes at other positions.

[0011] In the present invention, the telescopic rod of the servo electric push rod is located outside the metal bellows, and a joystick connected to the front end of the metal bellows is transversely arranged at the front end of the telescopic rod of the servo electric push rod. When the telescopic rod of the servo electric push rod is telescopically moved, the joystick drives the front end of the metal bellows to move synchronously together, and when the front end of the metal bellows moves forward, the bearing steel forging on the clamp can be surrounded from the periphery, and when the front end of the metal bellows moves backward, the bearing steel forging on the clamp can be completely exposed.

[0012] In the present invention, an automatic heating tube distributor is also provided between the telescopic rod of the servo electric push rod and the metal bellows for realizing automatic spacing and uniform distribution of the annular carbon heating tubes inside the metal bellows along the axial direction; the automatic heating tube distributor includes a number of sliding sleeves movably arranged on the outer circle of the telescopic rod of the servo electric push rod, a moving rod fixed on the sliding sleeve and laterally arranged relative to the telescopic rod of the servo electric push rod, a hook hole arranged at the cantilever end of the moving rod, and a number of rod body mounting through holes correspondingly opened on the tube wall of the metal bellows, the cantilever end of the moving rod passes through the rod body mounting through hole of the metal bellows and enters the interior of the metal bellows, and each of the annular carbon heating tubes is correspondingly hung on the hook hole of the cantilever end of the moving rod at the corresponding position through a metal wire.

[0013] Preferably, the heating power of each of the annular carbon heating tubes is adjustable.

[0014] Preferably, a number of sliders are movably arranged on the outer circle of the telescopic rod of the servo electric push rod, the slider is connected to a U-shaped bracket, the U-shaped bracket is connected to a hollow tube body transversely arranged relative to the telescopic rod of the servo electric push rod, a number of tube body mounting through holes are arranged on the tube wall of the metal bellows, the cantilever end of the hollow tube body passes through the tube body mounting through hole and enters the interior of the metal bellows, an infrared temperature detection sensor is inserted into the interior of the hollow tube body at one end of the hollow tube body connected to the U-shaped bracket, the infrared detection light of the infrared temperature detection sensor passes through the inner hole of the hollow tube body and enters the interior of the metal bellows; the infrared temperature detection sensor is connected to the controller of the multi-joint forging operation manipulator, when the transportation distance of the bearing steel forging is long, the multi-joint forging operation manipulator senses the temperature of different areas of the forging through the infrared temperature detection sensor, and ensures that the surface temperature of the forging reaches the set value during the transportation process by adjusting the heating power of each annular carbon heating tube and realizes the temperature balance of various places on the surface of the forging.

[0015] Preferably, the rod body mounting through hole and the tube body mounting through hole are respectively opened at the V-shaped fold of the metal bellows.

[0016] Preferably, an annular heat radiation reflection cover is also provided at the front end portion of the metal bellows for enhancing the heating and insulation effect of the front end face of the bearing steel forging. The annular heat radiation reflection cover is fixed on the operating rod at the front end of the servo electric push rod, and the reflecting surface of the annular heat radiation reflection cover is inclined relative to the operating rod towards the direction away from the mouth of the metal bellows.

[0017] When the transfer distance of the forging is long, the multi-joint forging operation robot senses the temperature of different areas of the forging through the infrared temperature detection sensor, and adjusts the heating power of each annular carbon heating tube to ensure that the surface temperature of the forging reaches the set value during the transfer process and achieves temperature balance at various locations on the forging surface.

[0018] As a further improvement of the present invention, in the step S9, forging performance evaluation and forging process parameter optimization, an artificial intelligence AI data analysis prediction model is also used to further optimize and set the forging process parameters of the bearing steel forgings. The specific optimization setting method includes the following steps: T1. Selection of artificial intelligence AI model: Select an artificial intelligence AI data analysis and prediction model as a training model for optimizing forging process parameters; the artificial intelligence AI data analysis and prediction model includes a forging process data input layer, a hidden layer based on an artificial neural network topology structure, and a forging performance data output layer, which are sequentially arranged and connected; T2. Obtain training sample data: select all test samples with qualified forging process parameters in the data sorting and classification in step S8, and use the forging heating temperature data and post-forging heat treatment temperature data corresponding to all these test samples as the training sample data of the forging process data input layer of the AI ​​data analysis and prediction model, and use the corresponding forging performance comprehensive evaluation value M as the training sample data of the forging performance data output layer of the AI ​​data analysis and prediction model; T3, AI training: Feed the training sample data into the artificial intelligence (AI) data analysis and prediction model for training to obtain an artificial intelligence (AI) data analysis and prediction model after one iteration; T4. Prediction, verification and optimization: Based on the AI ​​data analysis prediction model after one iteration, the size of the training sample data of the forging process data input layer is fine-tuned several times, and according to the training sample data after each fine-tuning, the output layer of the artificial intelligence AI data analysis prediction model is used to output the predicted value of the comprehensive evaluation value M of the forging performance; compare the predicted value of each M with the original maximum M value. If it is larger than the maximum M value in step S9, the training sample data of the forging process data input layer corresponding to the larger M value is verified through actual forging. If the verification is qualified, the final optimized forging process parameters with a larger M value are obtained, which are used as the forging process parameters for forging bearing steel for wind turbine main shaft bearings for formal production.

[0019] Preferably, in the step S1, when molten steel is smelted to form billets, a number of prefabricated steel billets with slightly changed chemical composition contents are prepared in advance; at the same time, in the step T2, when obtaining training sample data, a forging chemical composition detector is used to detect each test sample with a slight change in chemical composition content, to obtain the chemical composition content data corresponding to each test sample, and the chemical composition content data of each test sample is added to the training sample data of the forging process data input layer of the AI ​​data analysis and prediction model.

[0020] Preferably, the forging chemical composition detector can be a spectrometer, an atomic absorption spectrometer or other detection instruments.

[0021] As a further improvement of the present invention, in the step S1, during the molten steel smelting and billet making, the molten steel smelting quality control points at each key process node include the molten steel casting or continuous casting temperature quality control points during molten steel casting or continuous casting, the molten steel casting or continuous casting speed quality control points during molten steel casting or continuous casting, and the molten steel casting or continuous casting cooling speed quality control points after molten steel casting or continuous casting; in the forging test process of the step (3), the training sample data required in the step T2, obtaining the training sample data, is obtained by adopting an economical and cheap method for obtaining training sample data; the economical and cheap method for obtaining training sample data includes, in the step S1, during the molten steel smelting and billet making, in order to economically and cheaply obtain each test sample with slight changes in chemical composition content and reduce the test furnaces of molten steel smelting, during casting or continuous casting, the molten steel casting or continuous casting temperature quality control points are controlled. The method comprises the following steps: performing reverse negative intervention on at least one of the quality control points, the molten steel casting or continuous casting speed quality control point and the molten steel casting or continuous casting cooling speed quality control point; that is, appropriately relaxing the relatively strict quality control parameters in the quality control points that were originally used to improve the uniformity of the internal chemical composition distribution of the precast steel billet, allowing the quality control parameters to fluctuate within a wider range, so as to appropriately increase the negative effect of the uneven distribution of the internal chemical composition of the precast steel billet, so that when making the heat treatment test piece in step S5, the internal chemical compositions of the heat treatment test blocks cut from the forging billet rolling ring and the internal chemical compositions of the test samples obtained in step S7, the forging sampling and testing, show slight differences from each other; thereby achieving a large number of training samples with fine-tuned changes in the chemical composition content of the precast steel billet prepared from the same batch of molten steel.

[0022] Preferably, the reverse negative intervention measures of the molten steel casting or continuous casting temperature quality control point include relaxing the variation range of the molten steel casting or continuous casting temperature, or manually intervening in the control of the molten steel casting or continuous casting temperature, thereby affecting the distribution of solutes inside the prefabricated steel billet after casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting speed quality control point include appropriately increasing or decreasing the molten steel casting or continuous casting speed, or manually intervening in the molten steel casting or continuous casting speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting sends dendrite segregation; wherein, the manual intervention in the molten steel casting or continuous casting speed includes adopting variable speed intermittent casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting cooling speed quality control point include relaxing the variation range of the molten steel casting or continuous casting cooling speed, or manually intervening in the control of the variation range of the molten steel casting or continuous casting cooling speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting segregates.

[0023] In the present invention, the hot-sending heat transfer protection device used in the forging test of step (3) is used for forging of bearing steel for wind turbine main shaft bearings for formal production; the process of formal production of bearing steel forgings for wind turbine main shaft bearings adopts the forging process of steps S1 to S4, and the following process steps are added after step S1, molten steel smelting and blanking, and before step S2, pre-forging heating: S1A, electroslag remelting: The precast steel billet obtained by casting or continuous casting is subjected to secondary refining in a crystallizer of an Ar gas-protected electroslag remelting furnace under an Ar gas-protected atmosphere, and is cooled and demolded in the crystallizer to form a refined and purified precast steel billet of bearing steel.

[0024] As a further improvement of the present invention, the economical and cheap acquisition method of training sample data also includes in the step S6, in order to economically and cheaply obtain each test sample with a slight change in heat treatment temperature and reduce the number of test heats of heat treatment, a heat treatment temperature variable temperature control rack capable of achieving fine adjustment of temperature changes at various locations and a high-temperature furnace temperature tracker equipped with the heat treatment temperature variable temperature control rack are used, and all heat treatment test blocks are placed in different positions in the heat treatment temperature variable temperature control rack, and then the heat treatment temperature variable temperature control rack with all heat treatment test blocks and the high-temperature furnace temperature tracker are placed together in the same heat treatment. The heat treatment furnace is used to heat the test blocks, and each heat treatment test block is connected to each thermocouple led out from the high-temperature furnace temperature tracker for measuring the actual heat treatment temperature of each heat treatment test block; by placing each heat treatment test block together in a heat treatment temperature variable temperature control rack, the actual heat treatment temperature of each heat treatment test block has a temperature difference with the temperature inside the heat treatment furnace, and the actual heat treatment temperature of each heat treatment test block is different, thereby realizing a large number of heat treatment process parameter training samples in which each heat treatment test block in the heat treatment test conducted in the same heat treatment furnace has different heat treatment temperatures (the temperature of each heat treatment test block is changed and fine-tuned).

[0025] Preferably, the heat treatment temperature variable temperature control rack includes a rack, a number of heat protection insulation tubes arranged at intervals on the rack, a number of phase change balls arranged in the heat protection insulation tube at intervals along the axial direction of the heat protection insulation tube and made of phase change heat absorption material, a number of heat flow transfer holes arranged on the tube wall of the heat protection insulation tube at intervals along the axial direction of the heat protection insulation tube, and the phase change balls and the heat flow transfer holes are alternately arranged in sequence along the axial direction, the heat flow transfer hole is arranged on the tube wall of the heat protection insulation tube located between two adjacent phase change balls, and the space between two adjacent phase change balls inside the heat protection insulation tube forms a test block placement space for placing a heat treatment test block; a heat flow baffle is arranged at the orifice position of the heat flow transfer hole, and a spacing for limiting the passage of hot air is arranged between the heat flow baffle and the orifice of the heat flow transfer hole, and the spacing between each of the heat flow baffles and the orifice of the heat flow transfer hole on the same heat protection insulation tube is different from each other.

[0026] In the present invention, a thermocouple mounting hole for inserting a thermocouple to measure the heat treatment temperature inside the thermal protection insulation pipe is also provided on the outer circle of the thermal protection insulation pipe.

[0027] Preferably, an adapting hole may be provided on the heat treatment test block, and the thermocouple may be directly and completely contacted with the adapting hole of the heat treatment test block.

[0028] Preferably, the heat treatment of the heat-treated test block may be performed by isothermal spheroidizing annealing heat treatment.

[0029] In the present invention, the hot air flow baffle is fixed to the tube wall of the heat protection insulation tube by means of screws.

[0030] Taking into account that the temperature of isothermal spheroidizing annealing heat treatment usually involves the heating and holding temperature of the first stage of heat treatment and the isothermal transformation holding temperature of the second stage of heat treatment, in order to achieve fine-tuning combined changes of the heating and holding temperature and the isothermal transformation holding temperature of each heat treatment specimen, so as to obtain more sample data of different heat treatment temperature combinations (heating and holding temperature and isothermal transformation holding temperature) of the heat treatment specimens, the hot air flow baffle adopts a bimetallic hot air flow baffle, and the bimetallic hot air flow baffle is fixedly connected to the outer pipe wall of the thermal protection insulation pipe through a cantilever installation method.

[0031] Preferably, a spherical cap sheet body is provided on one side of the bimetallic hot air flow baffle facing the hot air flow transfer hole, and a distance is provided between the spherical cap sheet body and the orifice of the hot air flow transfer hole.

[0032] Preferably, according to the direction of the thermal deformation of the bimetallic hot air flow baffle, the bimetallic hot air flow baffle can be installed in a forward direction to achieve the deformation of the bimetallic hot air flow baffle toward the direction close to the orifice when the temperature in the furnace increases, or can be installed in a reverse direction to achieve the deformation of the bimetallic hot air flow baffle toward the direction away from the orifice when the temperature in the furnace increases, thereby achieving the adjustment of the heat transfer airflow volume in the heat treatment furnace and the thermal protection insulation tube, and then achieving fine-tuning of the increase and decrease of the heat treatment temperature inside the thermal protection insulation tube, thereby obtaining more heat treatment temperature data samples with different heat treatment temperature combinations of the heat treatment test blocks.

[0033] Preferably, a flexible high-temperature fire-resistant insulation layer is provided on the outer side of the bimetallic hot air flow baffle facing away from the hot air flow transfer hole.

[0034] By setting a bimetallic hot air flow baffle, the combined change of the heating insulation temperature in the first stage and the isothermal transformation insulation temperature in the second stage during the isothermal spheroidizing annealing heat treatment can be further realized, thereby collecting more heat treatment process parameter sample data with fine-tuning changes in the heat treatment temperature.

[0035] In the present invention, the diameter setting of the phase change ball can be obtained through thermodynamic calculations to ensure that the phase change ball has sufficient heat storage performance during the entire heat treatment process, so that the temperature inside the thermal protection insulation tube will not be out of control within the specified heat treatment time, and the temperature relative to the temperature outside the thermal protection insulation tube (i.e., the internal temperature of the heat treatment furnace) can always maintain a relatively constant temperature difference.

[0036] By setting the distances between the hot air flow baffle and the hot air flow transfer holes on the heat protection insulation pipe to be different from each other, the temperatures of the test block placement spaces inside the heat protection insulation pipe for placing heat treatment test blocks are different.

[0037] Furthermore, by setting the spacing between the hot air flow baffle and the orifice of the hot air flow transfer hole on the thermal protection insulation pipe to be different from each other, and setting the hot air flow baffle to be a bimetallic hot air flow baffle, different heat treatment temperature combinations of the heat treatment test blocks can be achieved, that is, different combinations of heating temperature rise and insulation temperature and isothermal transformation insulation temperature, so that each heat treatment test block placed in the same heat treatment furnace has a different heat treatment temperature combination (different combinations of heating temperature rise and insulation temperature and isothermal transformation insulation temperature), thereby obtaining a large number of heat treatment process parameter sample data.

[0038] Preferably, the phase change ball can be an aluminum alloy ball whose phase change temperature is lower than the heat treatment temperature of the bearing steel forging, or a phase change ball made of other materials with a relatively lower phase change temperature, and the minimum diameter of the phase change ball is determined by thermodynamic calculation.

[0039] Preferably, the phase change ball may also be a composite phase change ball with an aluminum alloy shell filled with paraffin phase change material.

[0040] In the present invention, the phase change ball is fixed to the heat protection insulation tube by screws.

[0041] Preferably, the heat treatment temperature variable temperature control rack of the present invention is also provided with a station for openly placing heat treatment test blocks.

[0042] Preferably, the heat protection insulation pipe includes a metal pipe body, a detachable pipe cover plate arranged at both ends of the metal pipe body, and a high-temperature refractory fiber insulation layer respectively arranged on the outer surface of the metal pipe body and the outer side of the pipe cover plate.

[0043] The high-temperature refractory fiber insulation layer on the outer surface of the above-mentioned thermal protection insulation tube can effectively reduce the heat transfer from the heat treatment furnace to the inside of the thermal protection insulation tube. It cooperates with the phase change ball arranged inside the thermal protection insulation tube and the bimetallic hot air flow baffle arranged at the orifice of the thermal protection insulation tube to realize the regulation of the hot air flow entering the thermal protection insulation tube, thereby effectively regulating the heat treatment temperature in the thermal protection insulation tube, thereby obtaining training sample data for each heat treatment test block with fine-tuning changes in the heat treatment temperature.

[0044] The forging method of bearing steel for wind turbine main shaft bearing based on forging test of the present invention can also be applied to the forging of various bearing forgings in other industries.

[0045] The beneficial effects of the present invention are: First, the forging method of the bearing steel for wind turbine main shaft bearing based on forging test of the present invention preliminarily optimizes the forging process parameters through thermal simulation and finite element analysis calculation of the forging process, and then uses a large reduction forging process based on a large anvil width ratio to conduct actual forging tests, and evaluates the sample data of the forging test through a comprehensive forging performance evaluation model to obtain forging process parameters with better forging performance, and applies the better forging process parameters to the formal forging process of bearing steel forgings. In this way, the forging performance of the bearing steel for wind turbine main shaft bearing can be improved.

[0046] Secondly, the present invention provides a forging method for bearing steel for wind turbine main shaft bearings based on forging tests. During the forging process, a forging operation robot with a hot transfer heat protection device is used to perform the transfer operation of the forgings, which can ensure that the forging heating equipment, the forging press and the ring rolling machine are relatively far apart and that the temperature of the forgings does not drop when the ambient temperature is low, and can balance the temperature of the forgings on the surface, thereby effectively reducing forging defects and improving the stability of the forging quality.

[0047] Third, the forging method of bearing steel for wind turbine main shaft bearings based on forging tests of the present invention obtains more sample data of forging process parameters through forging tests. After the sample data is trained by using an AI data analysis and prediction model, the AI ​​data analysis and prediction model can further predict forging process parameters with better forging performance. And when the training sample contains sample data of the chemical composition of the forging, it is possible to find a forging component formula with a slight change in chemical composition but better comprehensive performance of the forging through AI data analysis and prediction, which provides a new solution for the research and development of forgings with better comprehensive performance. The forging process parameters obtained by AI data analysis and prediction can be put into production after verification.

[0048] Fourth, the forging method of bearing steel for wind turbine main shaft bearing based on forging test of the present invention adopts reverse negative intervention measures of quality control points when molten steel is smelted and made into billets to realize economical and cheap acquisition of training samples; it increases the unevenness of the chemical composition distribution of molten steel by adopting reverse negative intervention measures, so that when sampling is carried out in the prefabricated steel billet after casting or continuous casting, more various test samples with fine-tuning changes in chemical composition content can be obtained, thereby overcoming the disadvantage that when the same batch of molten steel is conventionally cast or continuously cast, its chemical composition content is relatively uniformly distributed inside the prefabricated steel billet, making it difficult to obtain more various test sample data with fine-tuning changes in chemical composition content, thereby greatly reducing the cost of forging tests and the production cycle of forging tests.

[0049] Fifth, the forging method of bearing steel for wind turbine main shaft bearing based on forging test of the present invention adopts a specially designed temperature control rack with variable heat treatment temperature when heat treating the test blocks. It can realize that when a large number of heat treatment test blocks are placed in the same heat treatment furnace for heat treatment, the heat treatment temperature of each heat treatment test block is different (with slight changes compared with the pre-set heat treatment temperature), so as to obtain more sample data of test specimens with heat treatment temperature (including the heating and holding temperature of the first stage of heat treatment and the isothermal transformation holding temperature of the second stage of heat treatment), thereby further greatly reducing the cost of forging test and the production cycle of forging test. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a process flow diagram of a forging method for a bearing steel for a wind turbine main shaft bearing based on a forging test of the present invention; Figure 2 It is a structural schematic diagram of a hot transfer heat protection device provided on the front end mechanical arm of a forging operation manipulator; Figure 3 Figure 2 A partial enlarged view of Figure 4 It is a schematic diagram of the structure of a temperature control rack with a variable temperature for heat treatment; Figure 5 yes Figure 4 Schematic diagram of the structure of the thermal protection insulation pipe part involved.

[0051] In the figure: 1, front end mechanical arm, 2, bearing steel forging, 3, heat treatment test block, 4, clamp, 5, radiation heater, 6, flange ring, 7, metal bellows, 8, annular carbon heating tube, 9, servo electric push rod, 10, joystick, 11, sliding sleeve, 12, moving rod, 13, slider, 14, U-shaped bracket, 15, hollow tube body, 16, infrared temperature detection sensor, 17, annular thermal radiation reflector, 18, high temperature resistant furnace temperature tracker, 19, thermocouple, 20, rack, 21, thermal protection insulation tube, 22, phase change ball, 23, hot air flow transfer hole, 24, hot air flow baffle, 25, screw, 26, metal tube body, 27, tube body cover, 28, high temperature refractory fiber insulation layer, 29, ball crown sheet. DETAILED DESCRIPTION

[0052] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0053] like Figures 1 to 5 The forging method of a bearing steel for a wind turbine main shaft bearing based on a forging test is shown as an embodiment of the present invention, which includes conducting forging tests on a number of bearing steel forgings under different forging process parameters, and sampling the forgings obtained from the forging test to obtain a large number of test specimens; then testing and performance evaluation are performed on the test specimens, and optimal forging process parameters are obtained according to the performance evaluation results, and the optimal forging process parameters are used as forging process parameters for formal forging of bearing steel for wind turbine main shaft bearings; the specific method for obtaining the optimal forging process parameters includes the following steps set in sequence: (1) Modeling analysis and preliminary optimization of forging process parameters: Establish a finite element model of the bearing steel forging, take the performance index of the bearing steel forging as the optimization target, set the initial values ​​of the forging process parameters, and based on the initial values ​​of the forging process parameters, preliminarily optimize the forging process parameters through thermal simulation of the forging process and finite element analysis calculation to obtain the theoretical forging process parameters of the bearing steel forging; wherein the performance index of the bearing steel forging includes tensile strength index, cross-sectional shrinkage index and grain size index; the forging process parameters include forging heating temperature and post-forging heat treatment temperature; (2) Forging test planning and design: Set the number of bearing steel forgings that need to be subjected to forging tests, set the upper and lower floating ranges of the forging process parameter values ​​during the forging test based on the theoretical forging process parameters of the bearing steel forgings, assign values ​​to the forging process parameters of each bearing steel forging that needs to be subjected to forging tests, and make the values ​​of the forging process parameters of each bearing steel forging different from each other within the upper and lower floating ranges, so as to obtain the test forging process parameters of each bearing steel forging; the test forging process parameters include the test forging heating temperature and the test post-forging heat treatment temperature; Among them, the values ​​assigned to the forging process parameters of the bearing steel forgings are different from each other within the upper and lower floating range, which may be different forging heating temperatures or different post-forging heat treatment temperatures; that is, it is necessary to ensure that at least one of the test forging process parameters, the forging heating temperature and the post-forging heat treatment temperature, has a different value.

[0054] Preferably, the test forging heating temperature and the test post-forging heat treatment temperature of each bearing steel forging can be changed within a temperature range of ±25°C.

[0055] (3) Forging test: According to the forging process parameters for the test set in the forging test planning design, the forging test of each bearing steel forging is carried out. The forging test process of the bearing steel forging includes the following steps: S1. Molten steel smelting and billet making: after the steel material is batched, it is sequentially subjected to rough molten steel in an electric arc furnace, refined molten steel outside the furnace, and vacuum carbon deoxidation treatment, and then cast or continuously cast to form a number of prefabricated steel billets; wherein, during the rough molten steel in an electric arc furnace, refined molten steel outside the furnace, and vacuum carbon deoxidation treatment, molten steel smelting quality control points are set at each key process node, and by setting the molten steel smelting quality control points, the process parameters of molten steel smelting are controlled within the set range, thereby controlling the stability of the quality of molten steel smelting billets; S2. Heating before forging: placing the prefabricated steel billet in a forging heating furnace and heating it to the forging heating temperature set in the forging test planning design; S3, forging: the steel billet in the forging heating furnace is taken out and transferred to the forging press for forging, punching and finishing treatment in sequence to form a forging billet with a central through hole; during forging, a large anvil width ratio, a large reduction forging process and a multi-pass non-uniform temperature deformation forging process are adopted to achieve the effect of fine uniformity of the internal structure and healing of the core defects; S4, forging blank ring rolling: the forging blank with a central through hole is transferred to the ring rolling machine in a hot state, and is formed into a ring-shaped forging blank by ring rolling; S5. Making heat treatment test pieces: cutting the forging blank rolled ring into a number of heat treatment test pieces; S6. Heat treatment of test blocks: using a heat treatment furnace, each heat treatment test block is subjected to post-forging heat treatment according to the test post-forging heat treatment temperature set in the forging test planning design; S7. Sampling and testing of forgings: Samples are taken from heat-treated test blocks of bearing steel forgings with different forging process parameters for testing to obtain a number of test specimens, and each test specimen is tested; the test items include A, B, and C, where A is the tensile strength data, B is the cross-sectional shrinkage data, and C is the grain size data obtained through metallographic structure testing; S8. Data sorting and classification: For each test sample, if one of the three test contents A, B, and C is unqualified, the forging process parameters of the corresponding test sample will be classified as unqualified forging process parameters; if the three test contents A, B, and C are all qualified, the forging process parameters of the corresponding test sample will be classified as qualified forging process parameters, and the test sample will be retained and the subsequent forging performance evaluation will be carried out on it; the data of the test sample corresponding to the unqualified forging process parameters will be eliminated; S9. Establish a forging performance evaluation model to obtain the optimization of forging process parameters: According to the different bearing application scenarios and working conditions, reasonably set the weight coefficients α, β and γ for forging performance evaluation, and establish the forging performance evaluation formula M=(α×A+β×B+γ×C)÷(A+B+C); where M is the comprehensive evaluation value of forging performance based on weight considerations, α is the tensile strength weight coefficient, β is the cross-sectional shrinkage weight coefficient, and γ is the grain size weight coefficient; by calculating the size of the comprehensive evaluation value M of forging performance of each test sample, screen out the test sample with the largest comprehensive evaluation value M of forging performance, and use the test forging heating temperature and test post-forging heat treatment temperature corresponding to the test sample with the largest M value as the forging process parameters when forging bearing steel for wind turbine main shaft bearings.

[0056] Preferably, in the forging test of step (3), a multi-joint forging operating manipulator is further provided, which can realize the sequential transfer of forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling machine, and the multi-joint forging operating manipulator is movably arranged on the guide rails of the workshop site; a clamp 4 for clamping the bearing steel forging 2 is arranged on the front end mechanical arm 1 of the multi-joint forging operating manipulator, and a hot transfer heat protection device for preventing the temperature of the forging from decreasing during the transfer process is also arranged on the front end mechanical arm 1 of the multi-joint forging operating manipulator; the hot transfer heat protection device comprises a telescopic bellows assembly arranged on the front end mechanical arm 1 of the multi-joint forging operating manipulator, which can surround and remove the bearing steel forging 2 clamped by the clamp 4 from the periphery, and the telescopic bellows assembly has a built-in radiation heater 5 for radiant heating of the forging.

[0057] Preferably, the clamp 4 is a finger cylinder.

[0058] Preferably, the radiation heater 5 includes a number of annular carbon heating tubes 8, and the telescopic bellows assembly includes a flange ring 6 fixed on the front end mechanical arm 1 of the multi-joint forging operation manipulator and located at the rear side of the clamp 4, a metal bellows 7 connected to the front end surface of the flange ring 6, a reflective film coated on the inner wall of the metal bellows 7, and a number of annular carbon heating tubes 8 coaxially arranged near the inner wall of the metal bellows 7 and arranged at intervals along the axial direction, and a pair of servo electric push rods 9 connected to the controller of the multi-joint forging operation manipulator are provided at the rear end of the flange ring 6, and the front end of the telescopic rod of the servo electric push rod 9 is connected to the front end of the metal bellows 7; wherein, the power of the annular carbon heating tube 8 near the front end of the metal bellows 7 is greater than the power of the annular carbon heating tubes at other positions.

[0059] In this embodiment, the telescopic rod of the servo electric push rod 9 is located outside the metal bellows 7, and a joystick 10 connected to the front end of the metal bellows 7 is transversely arranged at the front end of the telescopic rod of the servo electric push rod 9. When the telescopic rod of the servo electric push rod 9 is telescopically moved, the joystick 10 drives the front end of the metal bellows 7 to move synchronously together, and when the front end of the metal bellows 7 moves forward, the bearing steel forging 2 on the clamp 4 can be surrounded from the outside, and when the front end of the metal bellows 7 moves backward, the bearing steel forging 2 on the clamp 4 can be completely exposed.

[0060] In this embodiment, an automatic heating tube distributor is also provided between the telescopic rod of the servo electric push rod 9 and the metal bellows 7 for realizing automatic and uniform distribution of the annular carbon heating tubes 8 inside the metal bellows 7 along the axial direction; the automatic heating tube distributor includes a number of sliding sleeves 11 movably arranged on the outer circle of the telescopic rod of the servo electric push rod 9, a moving rod 12 fixed on the sliding sleeve 11 and laterally arranged relative to the telescopic rod of the servo electric push rod 9, a hook hole arranged at the cantilever end of the moving rod 12, and a number of rod body mounting through holes correspondingly opened on the tube wall of the metal bellows 7, the cantilever end of the moving rod 12 passes through the rod body mounting through hole of the metal bellows 7 and enters the interior of the metal bellows 7, and each of the annular carbon heating tubes 8 is correspondingly hung on the hook hole of the cantilever end of the moving rod 12 at the corresponding position through a metal wire.

[0061] Preferably, the heating power of each of the annular carbon heating tubes 8 is adjustable.

[0062] Preferably, a number of sliders 13 are also movably arranged on the outer circle of the telescopic rod of the servo electric push rod 9, and a U-shaped bracket 14 is connected to the slider 13. A hollow tube body 15 is connected to the U-shaped bracket 14 and is transversely arranged relative to the telescopic rod of the servo electric push rod 9. A number of tube body mounting through holes are arranged on the tube wall of the metal bellows 7. The cantilever end of the hollow tube body 15 passes through the tube body mounting through hole and enters the interior of the metal bellows 7. One end of the hollow tube body 15 connected to the U-shaped bracket 14 is inserted into the interior of the hollow tube body 15. There is an infrared temperature detection sensor 16, and the infrared detection light of the infrared temperature detection sensor 16 passes through the inner hole of the hollow tube body 15 into the interior of the metal bellows 7; the infrared temperature detection sensor 16 is connected to the controller of the multi-joint forging operation robot. When the transportation distance of the bearing steel forging 2 is long, the multi-joint forging operation robot senses the temperature of different areas of the forging through the infrared temperature detection sensor 16, and adjusts the heating power of each annular carbon heating tube 8 to ensure that the surface temperature of the forging reaches the set value during the transportation process and achieves the balance of temperature at various locations on the surface of the forging.

[0063] Preferably, the rod body mounting through hole and the tube body mounting through hole are respectively opened at the V-shaped fold of the metal bellows 7 .

[0064] Preferably, an annular heat radiation reflection cover 17 is also provided at the front end portion of the metal bellows 7 for enhancing the heating and insulation effect of the front end face of the bearing steel forging 2. The annular heat radiation reflection cover 17 is fixed on the operating rod 10 at the front end of the servo electric push rod 9, and the reflecting surface of the annular heat radiation reflection cover 17 is inclined relative to the operating rod towards the direction away from the mouth of the metal bellows.

[0065] When the transportation distance of the forging is long, the multi-joint forging operation robot senses the temperature of different areas of the forging through the infrared temperature detection sensor 16, and adjusts the heating power of each annular carbon heating tube 8 to ensure that the surface temperature of the forging reaches the set value during the transportation process and achieves temperature balance at various locations on the forging surface.

[0066] As a further improvement of this embodiment, in the step S9, forging performance evaluation and forging process parameter optimization, an artificial intelligence AI data analysis prediction model is also used to further optimize and set the forging process parameters of the bearing steel forgings. The specific optimization setting method includes the following steps: T1. Selection of artificial intelligence AI model: Select an artificial intelligence AI data analysis and prediction model as a training model for optimizing forging process parameters; the artificial intelligence AI data analysis and prediction model includes a forging process data input layer, a hidden layer based on an artificial neural network topology structure, and a forging performance data output layer, which are sequentially arranged and connected; T2. Obtain training sample data: select all test samples with qualified forging process parameters in the data sorting and classification in step S8, and use the forging heating temperature data and post-forging heat treatment temperature data corresponding to all these test samples as the training sample data of the forging process data input layer of the AI ​​data analysis and prediction model, and use the corresponding forging performance comprehensive evaluation value M as the training sample data of the forging performance data output layer of the AI ​​data analysis and prediction model; T3, AI training: Feed the training sample data into the artificial intelligence (AI) data analysis and prediction model for training to obtain an artificial intelligence (AI) data analysis and prediction model after one iteration; T4. Prediction, verification and optimization: Based on the AI ​​data analysis prediction model after one iteration, the size of the training sample data of the forging process data input layer is fine-tuned several times, and according to the training sample data after each fine-tuning, the output layer of the artificial intelligence AI data analysis prediction model is used to output the predicted value of the comprehensive evaluation value M of the forging performance; compare the predicted value of each M with the original maximum M value. If it is larger than the maximum M value in step S9, the training sample data of the forging process data input layer corresponding to the larger M value is verified through actual forging. If the verification is qualified, the final optimized forging process parameters with a larger M value are obtained, which are used as the forging process parameters for forging bearing steel for wind turbine main shaft bearings for formal production.

[0067] Preferably, in the step S1, when molten steel is smelted to form billets, a number of prefabricated steel billets with slightly changed chemical composition contents are prepared in advance; at the same time, in the step T2, when obtaining training sample data, a forging chemical composition detector is used to detect each test sample with a slight change in chemical composition content, to obtain the chemical composition content data corresponding to each test sample, and the chemical composition content data of each test sample is added to the training sample data of the forging process data input layer of the AI ​​data analysis and prediction model.

[0068] Preferably, the forging chemical composition detector can be a spectrometer, an atomic absorption spectrometer or other detection instruments.

[0069] As a further improvement of the present invention, in the step S1, during the molten steel smelting and billet making, the molten steel smelting quality control points at each key process node include the molten steel casting or continuous casting temperature quality control points during molten steel casting or continuous casting, the molten steel casting or continuous casting speed quality control points during molten steel casting or continuous casting, and the molten steel casting or continuous casting cooling speed quality control points after molten steel casting or continuous casting; in the forging test process of the step (3), the training sample data required in the step T2, obtaining the training sample data, is obtained by adopting an economical and cheap method for obtaining training sample data; the economical and cheap method for obtaining training sample data includes, in the step S1, during the molten steel smelting and billet making, in order to economically and cheaply obtain each test sample with slight changes in chemical composition content and reduce the test furnaces of molten steel smelting, during casting or continuous casting, the molten steel casting or continuous casting temperature quality control points are controlled. The method comprises the following steps: performing reverse negative intervention on at least one of the quality control points, the molten steel casting or continuous casting speed quality control point and the molten steel casting or continuous casting cooling speed quality control point; that is, appropriately relaxing the relatively strict quality control parameters in the quality control points that were originally used to improve the uniformity of the internal chemical composition distribution of the precast steel billet, allowing the quality control parameters to fluctuate within a wider range, so as to appropriately increase the negative effect of the uneven distribution of the internal chemical composition of the precast steel billet, so that when making the heat treatment test piece in step S5, the internal chemical compositions of the heat treatment test blocks cut from the forging billet rolling ring and the internal chemical compositions of the test samples obtained in step S7, the forging sampling and testing, show slight differences from each other; thereby achieving a large number of training samples with fine-tuned changes in the chemical composition content of the precast steel billet prepared from the same batch of molten steel.

[0070] Preferably, the reverse negative intervention measures of the molten steel casting or continuous casting temperature quality control point include relaxing the variation range of the molten steel casting or continuous casting temperature, or manually intervening in the control of the molten steel casting or continuous casting temperature, thereby affecting the distribution of solutes inside the prefabricated steel billet after casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting speed quality control point include appropriately increasing or decreasing the molten steel casting or continuous casting speed, or manually intervening in the molten steel casting or continuous casting speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting sends dendrite segregation; wherein, the manual intervention in the molten steel casting or continuous casting speed includes adopting variable speed intermittent casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting cooling speed quality control point include relaxing the variation range of the molten steel casting or continuous casting cooling speed, or manually intervening in the control of the variation range of the molten steel casting or continuous casting cooling speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting segregates.

[0071] In this embodiment, the hot-sending heat transfer protection device used in the forging test of step (3) is used for forging the bearing steel for wind turbine main shaft bearings for formal production; the process of formal production of the bearing steel forging 2 for wind turbine main shaft bearings adopts the forging process of steps S1 to S4, and the following process steps are added after step S1, molten steel smelting and blanking, and before step S2, pre-forging heating: S1A, electroslag remelting: The precast steel billet obtained by casting or continuous casting is subjected to secondary refining in a crystallizer of an Ar gas-protected electroslag remelting furnace under an Ar gas-protected atmosphere, and is cooled and demolded in the crystallizer to form a refined and purified precast steel billet of bearing steel.

[0072] As a further improvement of the present embodiment, the economical and cheap method for acquiring training sample data also includes, in the step S6, in order to economically and cheaply acquire each test sample with a slight change in heat treatment temperature and reduce the number of heat treatment test furnaces, using a heat treatment temperature variable temperature control rack capable of achieving fine-tuning of temperature changes at various locations and a high-temperature resistant furnace temperature tracker 18 provided in conjunction with the heat treatment temperature variable temperature control rack, placing all the heat treatment test blocks 3 at different positions in the heat treatment temperature variable temperature control rack, and then placing the heat treatment temperature variable temperature control rack with all the heat treatment test blocks and the high-temperature resistant furnace temperature tracker 18 together in the same heat treatment The heat treatment furnace is used for heat treatment of test blocks 3, and each heat treatment test block 3 is connected to each thermocouple 19 led out from the high temperature resistant furnace temperature tracker 18 for measuring the actual heat treatment temperature of each heat treatment test block 3; by placing each heat treatment test block 3 together in a heat treatment temperature variable temperature control rack, the actual heat treatment temperature of each heat treatment test block 3 has a temperature difference with the temperature inside the heat treatment furnace, and the actual heat treatment temperature of each heat treatment test block is different, thereby realizing a large number of heat treatment process parameter training samples in which each heat treatment test block 3 in the heat treatment test conducted in the same heat treatment furnace has different heat treatment temperatures (the temperature of each heat treatment test block 3 is changed and fine-tuned).

[0073] Preferably, the heat treatment temperature variable temperature control rack includes a rack 20, a number of heat protection insulation tubes 21 arranged at intervals on the rack 20, a number of phase change balls 22 arranged in the heat protection insulation tube 21 along the axial direction of the heat protection insulation tube 21 and made of phase change heat absorbing material, a number of hot air flow transfer holes 23 arranged on the tube wall of the heat protection insulation tube 21 along the axial direction of the heat protection insulation tube 21, and the phase change balls 22 and the hot air flow transfer holes 23 are alternately arranged in sequence along the axial direction, and the hot air flow transfer holes 23 are arranged On the tube wall of the heat protection insulation tube 21 located between two adjacent phase change balls 22, a test block placement space for placing the heat treatment test block 3 is formed in the space inside the heat protection insulation tube 21 between two adjacent phase change balls 22; a heat flow baffle 24 is arranged at the orifice position of the heat flow transfer hole 23, and a spacing for limiting the passage of hot air flow is arranged between the heat flow baffle 24 and the orifice of the heat flow transfer hole 23, and the spacing between each of the heat flow baffles 24 and the orifice of the heat flow transfer hole 23 on the same heat protection insulation tube 21 is different from each other.

[0074] In this embodiment, a thermocouple mounting hole for inserting a thermocouple 19 to measure the internal heat treatment temperature of the thermal protection insulation tube 21 is further provided on the outer circle of the thermal protection insulation tube 21 .

[0075] Preferably, an adapting hole may be provided on the heat treatment test block 3, so that the thermocouple is directly and completely in contact with the adapting hole of the heat treatment test block.

[0076] Preferably, the heat treatment of the heat-treated test block 3 may be performed by isothermal spheroidizing annealing heat treatment.

[0077] In this embodiment, the hot air flow baffle 24 is fixed to the tube wall of the heat protection insulation tube 21 by means of screws 25 .

[0078] Taking into account that the temperature of isothermal spheroidizing annealing heat treatment usually involves the heating and holding temperature of the first stage of heat treatment and the isothermal transformation holding temperature of the second stage of heat treatment, in order to achieve fine-tuning combined changes in the heating and holding temperature and the isothermal transformation holding temperature of each heat treatment specimen, so as to obtain more sample data of different heat treatment temperature combinations (heating and holding temperature and isothermal transformation holding temperature) of the heat treatment specimen 3, the hot air flow baffle 24 adopts a bimetallic hot air flow baffle, and the bimetallic hot air flow baffle is fixedly connected to the outer pipe wall of the thermal protection insulation tube 21 by a cantilever installation method.

[0079] Preferably, a spherical cap sheet 29 is provided on one side of the bimetallic hot air flow baffle 24 facing the hot air flow transfer hole, and a distance is provided between the spherical cap sheet 29 and the opening of the hot air flow transfer hole 23 .

[0080] Preferably, according to the direction of the heat deformation of the bimetallic hot air flow baffle 24, the bimetallic hot air flow baffle 24 can be installed in a forward direction to achieve the deformation of the bimetallic hot air flow baffle 24 in the direction close to the orifice when the temperature in the furnace increases, or can be installed in a reverse direction to achieve the deformation of the bimetallic hot air flow baffle 24 in the direction away from the orifice when the temperature in the furnace increases, thereby achieving the adjustment of the heat transfer airflow volume in the heat treatment furnace and the thermal protection insulation tube, and then achieving the fine-tuning of the increase and decrease of the heat treatment temperature inside the thermal protection insulation tube 21, thereby obtaining more heat treatment temperature data samples of different heat treatment temperature combinations of the heat treatment test blocks 3.

[0081] Preferably, a flexible high-temperature fire-resistant insulation layer is provided on the outer side of the bimetallic hot air flow baffle 24 facing away from the hot air flow transfer hole 24 .

[0082] By setting the bimetallic hot air flow baffle 24, the combined change of the heating insulation temperature in the first stage and the isothermal transformation insulation temperature in the second stage during the isothermal spheroidizing annealing heat treatment can be further realized, thereby collecting more heat treatment process parameter sample data with fine-tuning changes in the heat treatment temperature.

[0083] In this embodiment, the diameter setting of the phase change ball 22 can be obtained through thermodynamic calculations to ensure that during the entire heat treatment process, the phase change ball has sufficient heat storage performance, so that the temperature inside the thermal protection insulation tube will not be out of control within the specified heat treatment time, and the temperature relative to the temperature outside the thermal protection insulation tube (i.e., the internal temperature of the heat treatment furnace) can always maintain a relatively constant temperature difference.

[0084] By setting the distances between the hot air flow baffle 24 and the hot air flow transfer holes 23 on the heat protection insulation tube 21 to be different from each other, the temperatures of the various test block placement spaces inside the heat protection insulation tube 21 for placing the heat treatment test blocks 3 are different.

[0085] Furthermore, by setting the spacing between the hot air flow baffle 24 and the opening of the hot air flow transfer hole 23 on the thermal protection insulation tube 21 to be different from each other, and setting the hot air flow baffle 24 to be a bimetallic hot air flow baffle, different heat treatment temperature combinations of the heat treatment test block 3 can be achieved, that is, different combinations of the heating temperature rise insulation temperature and the isothermal transformation insulation temperature, so that each heat treatment test block 3 placed in the same heat treatment furnace has a different heat treatment temperature combination (different combinations of the heating temperature rise insulation temperature and the isothermal transformation insulation temperature), thereby obtaining a large number of heat treatment process parameter sample data.

[0086] Preferably, the phase change ball 22 can be an aluminum alloy ball with a phase change temperature lower than the heat treatment temperature of the bearing steel forging, or a phase change ball made of other materials with a relatively lower phase change temperature, and the minimum diameter of the phase change ball is determined by thermodynamic calculation.

[0087] Preferably, the phase change ball 22 may also be a composite phase change ball with an aluminum alloy shell filled with paraffin phase change material.

[0088] In this embodiment, the phase change ball 22 is fixed to the heat protection insulation tube 21 by means of screws 25 .

[0089] Preferably, the heat treatment temperature variable temperature control rack of this embodiment is also provided with a station for openly placing the heat treatment test block 3.

[0090] Preferably, the heat protection insulation pipe 21 includes a metal pipe body 26, a detachable pipe cover plate 27 arranged at both ends of the metal pipe body 26, and a high-temperature refractory fiber insulation layer 28 respectively arranged on the outer surface of the metal pipe body 26 and the outer side of the pipe cover plate 27.

[0091] The high-temperature refractory fiber insulation layer on the outer surface of the above-mentioned thermal protection insulation tube 21 can effectively reduce the heat transfer from the heat treatment furnace to the inside of the thermal protection insulation tube. It cooperates with the phase change ball 22 arranged inside the thermal protection insulation tube 21 and the bimetallic hot air flow baffle 24 arranged at the orifice of the thermal protection insulation tube 21 to achieve the regulation of the hot air flow entering the thermal protection insulation tube 21, so as to effectively control the heat treatment temperature in the thermal protection insulation tube 21, thereby obtaining training sample data for each heat treatment test block 3 with fine-tuning changes in the heat treatment temperature.

[0092] The forging method of bearing steel for wind turbine main shaft bearing based on forging test in this embodiment can also be applied to the forging of various bearing forgings in other industries.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A forging method for a bearing steel for a wind turbine main shaft bearing based on a forging test, characterized in that: The method includes conducting forging tests on a number of bearing steel forgings under different forging process parameters, sampling the forgings obtained from the forging tests to obtain a large number of test specimens; then testing and evaluating the performance of the test specimens, and obtaining the optimal forging process parameters according to the performance evaluation results, and using the optimal forging process parameters as the forging process parameters for the formal forging of bearing steel for wind turbine main shaft bearings; the specific method for obtaining the optimal forging process parameters includes the following steps set in sequence: (1) Modeling analysis and preliminary optimization of forging process parameters: Establish a finite element model of the bearing steel forging, take the performance index of the bearing steel forging as the optimization target, set the initial values ​​of the forging process parameters, and based on the initial values ​​of the forging process parameters, preliminarily optimize the forging process parameters through thermal simulation of the forging process and finite element analysis calculation to obtain the theoretical forging process parameters of the bearing steel forging; wherein the performance index of the bearing steel forging includes tensile strength index, cross-sectional shrinkage index and grain size index; the forging process parameters include forging heating temperature and post-forging heat treatment temperature; (2) Forging test planning and design: Set the number of bearing steel forgings that need to be subjected to forging tests, set the upper and lower floating ranges of the forging process parameter values ​​during the forging test based on the theoretical forging process parameters of the bearing steel forgings, assign values ​​to the forging process parameters of each bearing steel forging that needs to be subjected to forging tests, and make the values ​​of the forging process parameters of each bearing steel forging different from each other within the upper and lower floating ranges, so as to obtain the test forging process parameters of each bearing steel forging; the test forging process parameters include the test forging heating temperature and the test post-forging heat treatment temperature; (3) Forging test: According to the forging process parameters for the test set in the forging test planning design, the forging test of each bearing steel forging is carried out. The forging test process of the bearing steel forging includes the following steps: S1. Molten steel smelting and billet making: after the steel material is batched, it is sequentially subjected to rough molten steel in an electric arc furnace, refined molten steel outside the furnace, and vacuum carbon deoxidation treatment, and then cast or continuously cast to form a number of prefabricated steel billets; wherein, during the rough molten steel in an electric arc furnace, refined molten steel outside the furnace, and vacuum carbon deoxidation treatment, molten steel smelting quality control points are set at each key process node, and by setting the molten steel smelting quality control points, the process parameters of molten steel smelting are controlled within the set range, thereby controlling the stability of the quality of molten steel smelting billets; S2. Heating before forging: placing the prefabricated steel billet in a forging heating furnace and heating it to the forging heating temperature set in the forging test planning design; S3, forging: the steel billet in the forging heating furnace is taken out and transferred to the forging press for forging, punching and finishing treatment in sequence to form a forging billet with a central through hole; during forging, a large anvil width ratio, a large reduction forging process and a multi-pass non-uniform temperature deformation forging process are adopted to achieve the effect of fine uniformity of the internal structure and healing of the core defects; S4, forging blank ring rolling: the forging blank with a central through hole is transferred to the ring rolling machine in a hot state, and is formed into a ring-shaped forging blank by ring rolling; S5. Making heat treatment test pieces: cutting the forging blank rolled ring into a number of heat treatment test pieces; S6. Heat treatment of test blocks: using a heat treatment furnace, each heat treatment test block is subjected to post-forging heat treatment according to the test post-forging heat treatment temperature set in the forging test planning design; S7. Sampling and testing of forgings: Samples are taken from heat-treated test blocks of bearing steel forgings with different forging process parameters for testing to obtain a number of test specimens, and each test specimen is tested; the test items include A, B, and C, where A is the tensile strength data, B is the cross-sectional shrinkage data, and C is the grain size data obtained through metallographic structure testing; S8. Data sorting and classification: For each test sample, if one of the three test contents A, B, and C is unqualified, the forging process parameters of the corresponding test sample will be classified as unqualified forging process parameters; if the three test contents A, B, and C are all qualified, the forging process parameters of the corresponding test sample will be classified as qualified forging process parameters, and the test sample will be retained and the subsequent forging performance evaluation will be carried out on it; the data of the test sample corresponding to the unqualified forging process parameters will be eliminated; S9. Establish a forging performance evaluation model to obtain the optimization of forging process parameters: According to the different bearing application scenarios and working conditions, reasonably set the weight coefficients α, β and γ for forging performance evaluation, and establish the forging performance evaluation formula M=(α×A+β×B+γ×C)÷(A+B+C); where M is the comprehensive evaluation value of forging performance based on weight considerations, α is the tensile strength weight coefficient, β is the cross-sectional shrinkage weight coefficient, and γ is the grain size weight coefficient; by calculating the size of the comprehensive evaluation value M of forging performance of each test sample, screen out the test sample with the largest comprehensive evaluation value M of forging performance, and use the test forging heating temperature and test post-forging heat treatment temperature corresponding to the test sample with the largest M value as the forging process parameters when forging bearing steel for wind turbine main shaft bearings.

2. A forging method for bearing steel for wind turbine main shaft bearing based on forging test according to claim 1, characterized in that: In the forging test of step (3), a multi-joint forging operating manipulator is also provided, which can realize the sequential transfer of forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling machine. The multi-joint forging operating manipulator is movably arranged on the guide rails of the workshop site; a clamp for clamping the bearing steel forging is arranged on the front end mechanical arm of the multi-joint forging operating manipulator, and a hot transfer heat protection device for preventing the temperature of the forging from decreasing during the transfer process is also arranged on the front end mechanical arm of the multi-joint forging operating manipulator; the hot transfer heat protection device includes a telescopic bellows assembly sleeve arranged on the front end mechanical arm of the multi-joint forging operating manipulator, which can surround and remove the bearing steel forging clamped by the clamp from the periphery, and the telescopic bellows assembly has a built-in radiation heater for radiant heating of the forging.

3. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 2, characterized in that: The radiation heater includes a number of annular carbon heating tubes, and the telescopic bellows assembly includes a flange ring fixed on the front end mechanical arm of the multi-joint forging operation manipulator and located at the rear side of the clamp, a metal bellows connected to the front end surface of the flange ring, a reflective film coated on the inner wall of the metal bellows, and a number of annular carbon heating tubes coaxially arranged near the inner wall of the metal bellows and arranged at intervals along the axial direction. A pair of servo electric push rods connected to the controller of the multi-joint forging operation manipulator are arranged at the rear end of the flange ring, and the front end of the telescopic rod of the servo electric push rod is connected to the front end of the metal bellows; wherein, the power of the annular carbon heating tube near the front end of the metal bellows is greater than the power of the annular carbon heating tubes at other positions.

4. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 3, characterized in that: In the step S9, forging performance evaluation and forging process parameter optimization, an artificial intelligence AI data analysis prediction model is also used to further optimize and set the forging process parameters of the bearing steel forgings. The specific optimization setting method includes the following steps: T1. Selection of artificial intelligence AI model: Select an artificial intelligence AI data analysis and prediction model as a training model for optimizing forging process parameters; the artificial intelligence AI data analysis and prediction model includes a forging process data input layer, a hidden layer based on an artificial neural network topology structure, and a forging performance data output layer, which are sequentially arranged and connected; T2. Obtain training sample data: select all test samples with qualified forging process parameters in the data sorting and classification in step S8, and use the forging heating temperature data and post-forging heat treatment temperature data corresponding to all these test samples as the training sample data of the forging process data input layer of the AI ​​data analysis and prediction model, and use the corresponding forging performance comprehensive evaluation value M as the training sample data of the forging performance data output layer of the AI ​​data analysis and prediction model; T3, AI training: Feed the training sample data into the artificial intelligence (AI) data analysis and prediction model for training to obtain an artificial intelligence (AI) data analysis and prediction model after one iteration; T4. Prediction, verification and optimization: Based on the AI ​​data analysis prediction model after one iteration, the size of the training sample data of the forging process data input layer is fine-tuned several times, and according to the training sample data after each fine-tuning, the output layer of the artificial intelligence AI data analysis prediction model is used to output the predicted value of the comprehensive evaluation value M of the forging performance; compare the predicted value of each M with the original maximum M value. If it is larger than the maximum M value in step S9, the training sample data of the forging process data input layer corresponding to the larger M value is verified through actual forging. If the verification is qualified, the final optimized forging process parameters with a larger M value are obtained, which are used as the forging process parameters for forging bearing steel for wind turbine main shaft bearings for formal production.

5. A forging method for bearing steel for wind turbine main shaft bearing based on forging test according to claim 4, characterized in that: In the step S1, when molten steel is smelted to form billets, a number of prefabricated billets with slightly changed chemical composition contents are prepared in advance; at the same time, in the step T2, when obtaining training sample data, a forging chemical composition detector is used to detect each test sample with a slight change in chemical composition content, to obtain the chemical composition content data corresponding to each test sample, and the chemical composition content data of each test sample is added to the training sample data of the forging process data input layer of the AI ​​data analysis and prediction model.

6. A forging method for bearing steel for wind turbine main shaft bearing based on forging test according to claim 5, characterized in that: In the step S1, during the molten steel smelting and billet making, the molten steel smelting quality control points at each key process node include the molten steel casting or continuous casting temperature quality control point during molten steel casting or continuous casting, the molten steel casting or continuous casting speed quality control point during molten steel casting or continuous casting, and the molten steel casting or continuous casting cooling speed quality control point after molten steel casting or continuous casting; in the step (3), during the forging test, the training sample data required in the step T2, obtaining the training sample data, is obtained by adopting an economical and cheap method for obtaining training sample data; the economical and cheap method for obtaining training sample data includes, in the step S1, during the molten steel smelting and billet making, in order to economically and cheaply obtain each test sample with slight changes in chemical composition content and reduce the test furnaces of molten steel smelting, during casting or continuous casting, the molten steel casting or continuous casting temperature quality control point, the molten steel casting speed quality control point, and the molten steel casting cooling speed quality control point are controlled. Or at least one of the continuous casting speed quality control point and the molten steel casting or continuous casting cooling speed quality control point is subjected to reverse negative intervention; that is, the relatively strict quality control parameters originally specified in the quality control points for improving the uniformity of the internal chemical composition distribution of the precast steel billet are appropriately relaxed, and the quality control parameters are allowed to fluctuate within a wider range, so as to appropriately increase the negative effect of the uneven distribution of the internal chemical composition of the precast steel billet, so that when the heat treatment test piece is made in step S5, the internal chemical composition of each heat treatment test block cut from the forging billet rolling ring and the internal chemical composition of each test sample obtained in step S7, the forging sampling test, are slightly different from each other; thereby, a large number of training samples with fine-tuned changes in the chemical composition content can be obtained by sampling on the precast steel billet prepared from the same batch of molten steel.

7. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 6, characterized in that: The reverse negative intervention measures of the molten steel casting or continuous casting temperature quality control point include relaxing the variation range of the molten steel casting or continuous casting temperature, or manually intervening in the control of the molten steel casting or continuous casting temperature, thereby affecting the distribution of solutes inside the prefabricated steel billet after casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting speed quality control point include appropriately increasing or decreasing the molten steel casting or continuous casting speed, or manually intervening in the molten steel casting or continuous casting speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting sends dendrite segregation; wherein, the manual intervention in the molten steel casting or continuous casting speed includes adopting variable speed intermittent casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting cooling speed quality control point include relaxing the variation range of the molten steel casting or continuous casting cooling speed, or manually intervening in the control of the variation range of the molten steel casting or continuous casting cooling speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting segregates.

8. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 3, characterized in that: The hot-sending heat transfer protection device used in the forging test of step (3) is used for forging the bearing steel for wind turbine main shaft bearings for formal production; the process for formal production of the bearing steel forgings for wind turbine main shaft bearings adopts the forging process of steps S1 to S4, and the following process steps are added after step S1, molten steel smelting and blanking and before step S2, pre-forging heating: S1A, electroslag remelting: The precast steel billet obtained by casting or continuous casting is subjected to secondary refining in a crystallizer of an Ar gas-protected electroslag remelting furnace under an Ar gas-protected atmosphere, and is cooled and demolded in the crystallizer to form a refined and purified precast steel billet of bearing steel.

9. A forging method for a bearing steel for a wind turbine main shaft bearing based on a forging test according to claim 6, characterized in that: The economical and cheap acquisition method of training sample data also includes, in the step S6, in order to economically and cheaply obtain each test sample with a slight change in heat treatment temperature and reduce the number of test heats of heat treatment, using a heat treatment temperature variable temperature control rack capable of achieving fine adjustment of temperature changes at various locations and a high-temperature furnace temperature tracker equipped with the heat treatment temperature variable temperature control rack, placing all heat treatment test blocks at different positions in the heat treatment temperature variable temperature control rack, and then placing the heat treatment temperature variable temperature control rack with all heat treatment test blocks and the high-temperature furnace temperature tracker together in the same A heat treatment furnace is provided, and each heat treatment test block is respectively connected to each thermocouple led out from a high temperature resistant furnace temperature tracker for measuring the actual heat treatment temperature of each heat treatment test block; by placing each heat treatment test block together in a heat treatment temperature variable temperature control rack, the actual heat treatment temperature of each heat treatment test block has a temperature difference with the temperature inside the heat treatment furnace, and the actual heat treatment temperature of each heat treatment test block is different, thereby realizing a large number of heat treatment process parameter training samples with different heat treatment temperatures for each heat treatment test block in the heat treatment test conducted in the same heat treatment furnace.

10. A forging method for a bearing steel for a wind turbine main shaft bearing based on a forging test according to claim 9, characterized in that: The heat treatment temperature variable temperature control rack includes a rack, a number of heat protection insulation tubes arranged on the rack at intervals, a number of phase change balls arranged in the heat protection insulation tube along the axial direction of the heat protection insulation tube and made of phase change heat absorption material, a number of heat flow transfer holes arranged on the tube wall of the heat protection insulation tube along the axial direction of the heat protection insulation tube, and the phase change balls and the heat flow transfer holes are alternately arranged in sequence along the axial direction, the heat flow transfer hole is arranged on the tube wall of the heat protection insulation tube between two adjacent phase change balls, and the space between two adjacent phase change balls inside the heat protection insulation tube forms a test block placement space for placing a heat treatment test block; a heat flow baffle is arranged at the orifice position of the heat flow transfer hole, and a spacing for limiting the passage of the heat flow is arranged between the heat flow baffle and the orifice of the heat flow transfer hole, and the spacing between each of the heat flow baffles and the orifice of the heat flow transfer hole on the same heat protection insulation tube is different from each other.

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