A forging method of bearing steel for wind power spindle bearings based on forging tests

Abstract

The present invention discloses a forging method for bearing steel used in wind power spindle bearings based on forging tests, which includes conducting forging tests on a certain number of bearing steel forgings and detecting and evaluating them after the forging tests under different forging process parameters to obtain the optimized forging process parameters; setting the weight coefficients α, β, and γ for three detection items A, B, and C for evaluating the performance of forgings according to different bearing application scenarios and working conditions, and establishing a formula for evaluating the performance of forgings as M = (α×A + β×B + γ×C) ÷ (A + B + C); where M is the comprehensive evaluation value of the forging performance considering the weights, and taking the forging heating temperature and the post-forging heat treatment temperature used in the test corresponding to the test sample with the largest M value as the forging process parameters when forging the bearing steel for wind power spindle bearings. The present invention improves the forging performance of the bearing steel used in wind power spindle bearings and reduces the cost and cycle of forging tests.

Description

Technical Field

[0001] The present invention relates to the technical field of forging, and particularly to a forging method of bearing steel for wind power spindle bearings based on forging tests. Background Art

[0002] Forged bearing steel parts are widely used in various industries. A relatively typical example is in new energy fields such as large forged bearing steel parts for wind power spindle bearings.

[0003] The manufacturing of forged bearing steel parts involves processes such as steel melting and billet making, forging, heat treatment, ring rolling, etc. To meet the requirements of bearings in various application scenarios, customers usually put forward some strict performance indicators for forged bearing steel parts. For example, for the forged parts of bearing steel for wind power spindle bearings in a certain application scenario, it is required to meet the application requirements such as tensile strength ≥ 900 MPa, reduction of area ≥ 48%, and grain size ≥ grade 7. For various performance requirements of such forged bearing steel parts put forward by customers, conventional forging processes may not be able to meet them, or although they can meet them, the product qualification rate is low.

[0004] Therefore, researching and optimizing the forging process parameters during forging, reducing defects during forging, and improving the quality and comprehensive performance of forged bearing steel parts are technical problems that technicians must face. In addition, the research and optimization of forging process parameters usually involve conducting forging tests. However, for large forged bearing steel parts, the cost of their forging tests is high and the cycle is long. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a forging method of bearing steel for wind power spindle bearings based on forging tests, aiming to obtain optimized forging process parameters through forging tests, thereby improving the performance of forged parts of bearing steel for wind power spindle bearings and reducing the cost and cycle of forging tests. The specific technical solutions are as follows:

[0006] A forging method of bearing steel for wind power spindle bearings based on forging tests includes conducting forging tests on a certain number of forged bearing steel parts under different forging process parameters, sampling the forged parts obtained from the forging tests to obtain a relatively large number of test specimens for detection; then detecting and evaluating the performance of the test specimens, and correspondingly obtaining the optimized forging process parameters according to the performance evaluation results, and using the optimized forging process parameters as the forging process parameters for the formal forging of bearing steel for wind power spindle bearings; the specific method for obtaining the optimized forging process parameters includes the following steps set in sequence:

[0007] (1) Modeling analysis and preliminary optimization of forging process parameters: Establish a finite element model of bearing steel forgings, taking the performance indicators of bearing steel forgings as the optimization objectives, setting the initial values of forging process parameters, and based on the initial values of forging process parameters, preliminarily optimizing the forging process parameters through thermal simulation and finite element analysis calculation of the forging process to obtain the theoretical forging process parameters of bearing steel forgings; among them, the performance indicators of the bearing steel forgings include tensile strength index, reduction of area index, and grain size index; the forging process parameters include forging heating temperature and post-forging heat treatment temperature;

[0008] (2) Forging test planning and design: Set the number of bearing steel forgings that need to be subjected to forging tests, based on the theoretical forging process parameters of bearing steel forgings, set the upper and lower floating ranges of the values of forging process parameters during forging tests, assign values to the forging process parameters of each bearing steel forging that needs to be subjected to forging tests, and make the assigned values of the forging process parameters of each bearing steel forging different from each other within the said 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 test forging heating temperature and test post-forging heat treatment temperature;

[0009] Among them, the assigned values of the forging process parameters of each bearing steel forging are different from each other within the said upper and lower floating ranges, which can be different forging heating temperatures or different post-forging heat treatment temperatures; that is, at least one of the test forging process parameters of forging heating temperature and post-forging heat treatment temperature should be ensured to have different values.

[0010] Preferably, the settings of the test forging heating temperature and test post-forging heat treatment temperature of each bearing steel forging can be changed within the temperature range of ±25°C of floating up and down.

[0011] (3) Forging test: According to the test forging process parameters set in the forging test planning and design, conduct forging tests on each bearing steel forging. The forging test process of the bearing steel forging includes the following steps:

[0012] S1. Molten steel smelting and blank making: After the steel materials are proportioned, they go through rough smelting of molten steel in an electric arc furnace, secondary refining of molten steel, vacuum carbon deoxidation treatment in sequence, and then form a number of precast steel blanks through casting or continuous casting; among them, during the processes of rough smelting of molten steel in the electric arc furnace, secondary refining of molten steel, and vacuum carbon deoxidation treatment, set quality control points for molten steel smelting at each key process node. By setting quality control points for molten steel smelting, control the process parameters of molten steel smelting within the set range, so as to control the stability of the quality of molten steel smelting and blank making;

[0013] S2. Pre-forging heating: Place the precast steel blank into a forging heating furnace and heat it to the forging heating temperature set in the forging test planning and design;

[0014] S3. Forging: Take out the steel billet in the forging heating furnace, transfer it to the forging press, and perform forging, punching, and finishing processes in sequence to form a forging blank with a central through-hole; during forging, adopt the forging process with a large anvil width ratio, large reduction ratio, and multi-pass non-uniform temperature deformation forging process to achieve the effect of fine and uniform internal structure and healing of internal defects;

[0015] S4. Ring rolling of forging blank: Red-hot transfer the forging blank with a central through-hole to the ring rolling machine in a hot state, and form a ring-shaped forging blank through ring rolling;

[0016] S5. Making heat treatment specimens: Cut the ring-rolled forging blank and divide it into several heat treatment test blocks;

[0017] S6. Heat treatment of test blocks: Use a heat treatment furnace, and each heat treatment test block is subjected to post-forging heat treatment according to the post-forging heat treatment temperature set in the forging test plan design;

[0018] S7. Sampling and testing of forgings: Sampling is carried out separately for the heat treatment test blocks of bearing steel forgings using different test forging process parameters to obtain a number of test specimens, and each test specimen is tested; The test items include three items A, B, and C, where A is the tensile strength data, B is the reduction of area data, and C is the data of the grain size grade obtained through metallographic structure detection;

[0019] S8. Data sorting and classification: For each test specimen, if one of the three test contents A, B, and C is unqualified, the forging process parameters of the corresponding test specimen are classified as unqualified forging process parameters; if all three test contents A, B, and C are qualified, the forging process parameters of the corresponding test specimen are classified as qualified forging process parameters, and the corresponding test specimen is retained and its subsequent forging performance evaluation is carried out; The data of the test specimens corresponding to the unqualified forging process parameters are excluded;

[0020] S9. Establish a forging performance evaluation model and obtain optimized forging process parameters: According to the different bearing application occasions and working conditions, reasonably set the weight coefficients α, β, and γ for forging performance evaluation, and establish the forging performance evaluation formula as M = (α×A + β×B + γ×C) ÷ (A + B + C); where, M is the comprehensive forging performance evaluation value considering weights, α is the tensile strength weight coefficient, β is the reduction of area weight coefficient, and γ is the grain size weight coefficient; By calculating the size of the comprehensive forging performance evaluation value M of each test specimen, screen out the test specimen with the largest comprehensive forging performance evaluation value M, and use the test forging heating temperature and test post-forging heat treatment temperature corresponding to the test specimen with the largest M value as the forging process parameters during the forging of bearing steel for wind power spindle bearings.

[0021] Preferably, in the forging test of step (3), a multi-joint forging operation manipulator capable of sequentially transferring forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling machine is also provided. The multi-joint forging operation manipulator is movably arranged on the guide rail of the workshop site. A clamp for clamping the bearing steel forging is arranged on the front end robotic arm of the multi-joint forging operation manipulator. A red-hot transfer heat protection device for preventing the temperature of the forging from decreasing during transfer is also arranged on the front end robotic arm of the multi-joint forging operation manipulator. The red-hot transfer heat protection device includes a telescopic bellows assembly arranged on the front end robotic arm of the multi-joint forging operation manipulator, which can surround and withdraw from the periphery the bearing steel forging clamped by the clamp. The telescopic bellows assembly is internally provided with a radiation heater for radiantly heating the forging.

[0022] Preferably, the clamp uses a finger cylinder.

[0023] Preferably, the radiation heater includes a plurality of annular carbon heating tubes. The telescopic bellows assembly includes a flange ring fixed on the front end robotic arm of the multi-joint forging operation manipulator and located at the rear side position of the clamp, a metal bellows connected to the front end face of the flange ring, a reflective film coated on the inner wall of the metal bellows, and a plurality of annular carbon heating tubes coaxially arranged at the inner wall part of the metal bellows and spaced axially. 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. The front end of the telescopic rod of the servo electric push rod is connected to the front end part of the metal bellows. Among them, the power of the annular carbon heating tube at the front port part of the metal bellows is greater than that of the annular carbon heating tubes at other positions.

[0024] In the present invention, the telescopic rod of the servo electric push rod is located at the outer side position of the metal bellows. A control rod connected to the front end part of the metal bellows is horizontally 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 expands and contracts, the control rod drives the front end part of the metal bellows to move synchronously. When the front end of the metal bellows moves forward, it can surround the bearing steel forging on the clamp from the periphery. When the front end of the metal bellows moves backward, it can completely expose the bearing steel forging on the clamp.

[0025] In the present invention, a heating tube automatic distribution device is further provided between the telescopic rod of the servo electric push rod and the metal bellows for realizing the axial automatic and evenly spaced distribution of the annular carbon heating tubes inside the metal bellows; the heating tube automatic distribution device includes a plurality of sliding sleeves movably arranged on the outer circumference of the telescopic rod of the servo electric push rod, a moving rod fixed on the sliding sleeve and horizontally 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 plurality of rod body installation through holes correspondingly opened on the pipe wall of the metal bellows. The cantilever end of the moving rod passes through the rod body installation through hole of the metal bellows and enters the inside of the metal bellows, and each of the annular carbon heating tubes is respectively hung on the hook holes at the cantilever ends of the moving rods at corresponding positions through metal wires.

[0026] Preferably, the heating power of each of the annular carbon heating tubes is adjustable.

[0027] Preferably, a plurality of sliders are further movably arranged on the outer circumference of the telescopic rod of the servo electric push rod. A U-shaped bracket is connected to the slider, and a hollow tube body horizontally arranged relative to the telescopic rod of the servo electric push rod is connected to the U-shaped bracket. A plurality of tube body installation through holes are arranged on the pipe wall of the metal bellows. The cantilever end of the hollow tube body passes through the tube body installation through hole and enters the inside of the metal bellows. An infrared temperature detection sensor is inserted into the end of the hollow tube body connected to the U-shaped bracket and facing the inside of the hollow tube body. The infrared detection light of the infrared temperature detection sensor passes through the inner hole of the hollow tube body and enters the inside of the metal bellows; the infrared temperature detection sensor is connected to the controller of the multi-joint forging manipulator. When the transfer distance of the bearing steel forging is relatively long, the multi-joint forging 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 transfer process and realizes the balance of the surface temperature of each part of the forging by adjusting the heating power of each annular carbon heating tube.

[0028] Preferably, the rod body installation through holes and the tube body installation through holes are respectively opened at the V-shaped folding part of the metal bellows.

[0029] Preferably, an annular heat radiation reflection cover for strengthening the heating and heat preservation effect of the front end face of the bearing steel forging is further arranged at the front end part of the metal bellows. The annular heat radiation reflection cover is fixed on the operating rod at the front end of the servo electric push rod, and the reflection surface of the annular heat radiation reflection cover is inclined relative to the operating rod in a direction away from the mouth of the metal bellows.

[0030] When the transfer distance of the forging is relatively 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 transfer process and realizes the temperature balance of each part of the forging surface by adjusting the heating power of each annular carbon heating tube.

[0031] 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 the forging process parameters of the bearing steel forging. The specific optimization setting method includes the following steps:

[0032] T1. Selection of the artificial intelligence AI model: Select the artificial intelligence AI data analysis prediction model as the training model for optimizing the forging process parameters; the artificial intelligence AI data analysis prediction model includes a forging process data input layer, a hidden layer based on the artificial neural network topology structure, and a forging performance data output layer that are sequentially set and connected.

[0033] T2. Obtaining training sample data: Select all the test specimens with qualified forging process parameters in the step S8, data sorting and classification, and use the forging heating temperature data and post-forging heat treatment temperature data corresponding to all these test specimens as the training sample data of the forging process data input layer of the AI data analysis prediction model. At the same time, use the comprehensive evaluation value M of the forging performance corresponding to it as the training sample data of the forging performance data output layer of the AI data analysis prediction model.

[0034] T3. AI training: Feed the training sample data into the artificial intelligence AI data analysis prediction model for training to obtain the artificial intelligence AI data analysis prediction model after one iteration.

[0035] T4. Prediction, verification and optimization: Based on the AI data analysis prediction model after one iteration, make several fine-tuning settings on the size of the training sample data of the forging process data input layer, and according to the training sample data after each fine-tuning, output the predicted value of the comprehensive evaluation value M of the forging performance through the output layer of the artificial intelligence AI data analysis prediction model; Compare the predicted values of each M with the original maximum M value. If a value larger than the maximum M value in step S9 appears, verify the training sample data of the forging process data input layer corresponding to the larger M value through actual forging. If the verification is qualified, obtain the final optimized forging process parameters with a larger M value, and use them as the forging process parameters when forging the bearing steel for the wind power spindle bearing used in formal production.

[0036] Preferably, in the step S1 of smelting molten steel into billets, a plurality of prefabricated steel billets with slightly varying chemical composition contents are prepared in advance; at the same time, in the step T2 of obtaining training sample data, a forging chemical composition detector is also used to detect each test sample with a slightly varying chemical composition content, and the chemical composition content data corresponding to each test sample is obtained, 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.

[0037] Preferably, the forging chemical composition detector can adopt detection instruments such as spectrometers and atomic absorption spectrometers.

[0038] As a further improvement of the present invention, in the step S1 of smelting molten steel into billets, the molten steel smelting quality control points at each key process node include the molten steel casting or continuous casting temperature quality control point, the molten steel casting or continuous casting speed quality control point, and the molten steel casting or continuous casting cooling speed quality control point during molten steel casting or continuous casting; during the forging test process in the step (3), by adopting the training sample data economic and inexpensive acquisition method, the training sample data required in the step T2 of obtaining training sample data is obtained; the training sample data economic and inexpensive acquisition method includes, in the step S1 of smelting molten steel into billets, in order to economically and inexpensively obtain each test sample with a slightly varying chemical composition content and reduce the number of test furnaces for molten steel smelting, during casting or continuous casting, at least one of the molten steel casting or continuous casting temperature quality control point, the molten steel casting or 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 used to improve the internal chemical composition distribution uniformity of the prefabricated steel billet are appropriately relaxed, allowing the quality control parameters to fluctuate within a wider range, so as to achieve the negative effect of appropriately increasing the internal chemical composition distribution non-uniformity of the prefabricated steel billet, so that when making heat treatment specimens in the step S5, the internal chemical compositions of each heat treatment test block obtained by cutting from the forged ring and each test sample obtained during the forging sample detection in the step S7 are slightly different from each other; thus, a large number of training samples with slightly varying chemical composition contents can be obtained by sampling on the prefabricated steel billets prepared from the molten steel of the same furnace.

[0039] Preferably, the reverse negative intervention measures for 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 to control the molten steel casting or continuous casting temperature, so as to affect the distribution of solutes inside the precast steel billet after casting or continuous casting; the reverse negative intervention measures for 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 dendritic segregation occurs in the internal structure of the precast steel billet after casting or continuous casting; wherein, the manual intervention in the molten steel casting or continuous casting speed includes using variable-speed intermittent casting or continuous casting; the reverse negative intervention measures for 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 to control the variation range of the molten steel casting or continuous casting cooling speed, so that segregation occurs in the internal structure of the precast steel billet after casting or continuous casting.

[0040] In the present invention, the redelivery transfer heat protection device used in the forging test in step (3) is used for forging bearing steel for wind power spindle bearings for formal production; when carrying out the forging process for the bearing steel forgings for wind power spindle bearings in formal production, the forging process of steps S1 to S4 is adopted, and the following process steps are added before step S1, molten steel smelting and billet making and before step S2, pre-forging heating:

[0041] S1A. Electroslag remelting: Using the precast steel billet obtained by casting or continuous casting as the object, in an Ar gas protection atmosphere, secondary refining is carried out in the crystallizer of an Ar gas protection electroslag remelting furnace, and after cooling and demolding in the crystallizer, a refined and purified precast steel billet for bearing steel is formed.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] Preferably, the heat treatment of the heat-treated test block may be performed by isothermal spheroidizing annealing heat treatment.

[0047] In the present invention, the hot air baffle is fixed to the tube wall of the thermal protection and heat insulation tube by screws.

[0048] Considering that the temperature of isothermal spheroidizing annealing heat treatment usually involves the heating, temperature rising and heat preservation temperature in the first stage of heat treatment and the isothermal transformation heat preservation temperature in the second stage of heat treatment, in order to realize the fine-tuning combined change of the heating, temperature rising and heat preservation temperature and the isothermal transformation heat preservation temperature of each heat treatment specimen, so as to obtain more sample data of different heat treatment temperature combinations (heating, temperature rising and heat preservation temperature and isothermal transformation heat preservation temperature) of heat treatment specimens, the hot air baffle adopts a bimetallic hot air baffle, and the bimetallic hot air baffle is fixedly connected to the outer tube wall of the thermal protection and heat insulation tube by a cantilever mounting method.

[0049] Preferably, a spherical crown body is arranged on the side of the bimetallic hot air baffle facing the hot air transfer hole, and there is a spacing between the spherical crown body and the orifice of the hot air transfer hole.

[0050] Preferably, according to the direction of thermal deformation of the bimetallic hot air baffle, the bimetallic hot air baffle can be installed forward to realize that when the temperature in the furnace rises, the bimetallic hot air baffle deforms towards the direction close to the orifice, or can be installed reversely to realize that when the temperature in the furnace rises, the bimetallic hot air baffle deforms towards the direction away from the orifice, so as to realize the adjustment of the heat transfer air flow rate in the heat treatment furnace and inside the thermal protection and heat insulation tube, and further realize the fine-tuning increase and fine-tuning decrease of the heat treatment temperature inside the thermal protection and heat insulation tube, thereby obtaining more heat treatment temperature data samples of different heat treatment temperature combinations of heat treatment specimens.

[0051] Preferably, a layer of flexible high-temperature refractory heat insulation layer is arranged on the outer side surface of the bimetallic hot air baffle facing away from the hot air transfer hole.

[0052] By setting the bimetallic hot air baffle, the combined change of the heating and heat preservation temperature in the first stage and the isothermal transformation heat preservation temperature in the second stage during isothermal spheroidizing annealing heat treatment can be further realized, so as to collect more sample data of heat treatment process parameters with fine-tuning changes in heat treatment temperature.

[0053] In the present invention, the diameter of the phase change ball can be obtained through thermodynamic calculation to ensure that during the whole process of heat treatment, the phase change ball has sufficient heat storage performance, so as not to cause the out-of-control of the temperature inside the thermal protection and heat insulation tube within the specified heat treatment time, and it can always maintain a relatively constant temperature difference relative to the temperature outside the thermal protection and heat insulation tube (i.e., the internal temperature of the heat treatment furnace).

[0054] By setting the distances between the hot air baffle and the orifices of the hot air transfer holes on the thermal protection and heat insulation tube to be different from each other, the temperatures of the respective specimen placement spaces inside the thermal protection and heat insulation tube for placing heat treatment specimens are made different.

[0055] Furthermore, by setting the distances between the hot air baffle and the orifices of the hot air transfer holes on the thermal protection and heat insulation tube to be different from each other, and by setting the hot air baffle as a bimetallic hot air baffle, different heat treatment temperature combinations for the heat treatment specimens can be achieved, that is, the combinations of heating-up temperature, holding temperature, and isothermal transformation holding temperature are different. Thus, each heat treatment specimen placed in the same heat treatment furnace has different heat treatment temperature combinations (different combinations of heating-up temperature, holding temperature, and isothermal transformation holding temperature), so as to obtain a relatively large number of sample data of heat treatment process parameters.

[0056] Preferably, the phase change balls can be made of aluminum alloy balls with a phase change temperature lower than the heat treatment temperature of the bearing steel forging, or can be made of phase change balls made of other materials with a relatively lower phase change temperature, and the minimum diameter of the phase change balls is determined through thermodynamic calculations.

[0057] Preferably, the phase change balls can also be composite phase change balls with an aluminum alloy ball shell filled with paraffin phase change material inside.

[0058] In the present invention, the phase change balls are fixed to the thermal protection and heat insulation tube by screws.

[0059] Preferably, a work station for openly placing heat treatment specimens is further provided on the heat treatment temperature variable control rack of the present invention.

[0060] Preferably, the thermal protection and heat insulation tube includes a metal tube body, tube body covers detachably arranged at both ends of the metal tube body, and high-temperature refractory fiber heat insulation layers respectively arranged on the outer surface of the metal tube body and the outer side of the tube body cover.

[0061] The high-temperature refractory fiber heat insulation layer on the outer surface of the above-mentioned thermal protection and heat insulation tube can effectively reduce the transfer of heat in the heat treatment furnace to the inside of the thermal protection and heat insulation tube. It cooperates with the phase change balls arranged inside the thermal protection and heat insulation tube and the bimetallic hot air baffle arranged at the orifice of the thermal protection and heat insulation tube to realize the regulation of the hot air flow rate entering the inside of the thermal protection and heat insulation tube, so as to effectively control the heat treatment temperature inside the thermal protection and heat insulation tube, and thus obtain sample data for training of each heat treatment specimen with slightly adjusted heat treatment temperature.

[0062] A forging method of bearing steel for a wind power spindle bearing based on a forging test according to the present invention can also be applied to the forging of various bearing forgings in other industries.

[0063] The beneficial effects of the present invention are:

[0064] First, for the forging method of bearing steel for wind power spindle bearings based on forging tests in the present invention, the forging process parameters are preliminarily optimized through the thermal simulation and finite element analysis calculation of the forging process. Then, the actual forging test is carried out by adopting the large reduction forging process based on the large anvil width ratio. The sample data of the forging test is evaluated through the comprehensive evaluation model of forging performance, so as to obtain the forging process parameters with better forging performance, and the better forging process parameters are applied to the formal forging process of bearing steel forgings. Thus, the forging performance of bearing steel for wind power spindle bearings can be improved.

[0065] Second, for the forging method of bearing steel for wind power spindle bearings based on forging tests in the present invention, during the forging process, the forging operation manipulator with a redelivery transfer heat protection device is used to carry out the transfer operation of the forgings, which can ensure that the temperature of the forgings does not drop when the distance between the forging heating equipment, the forging press and the ring rolling mill is relatively far and the ambient temperature is relatively low, and can make the temperature of each part of the forging surface balanced. Thus, forging defects can be effectively reduced and the stability of forging quality can be improved.

[0066] Third, for the forging method of bearing steel for wind power spindle bearings based on forging tests in the present invention, a relatively large number of sample data of forging process parameters are obtained through forging tests. After the sample data is trained by adopting the AI data analysis prediction model, the AI data analysis prediction model can further predict the forging process parameters with better forging performance. And when the sample data of the chemical composition of the forgings is included in the training samples, it is possible to find through AI data analysis prediction the forging component formula with slightly changed chemical composition but better comprehensive performance of the forgings, providing a new solution for the research and development of forgings with better comprehensive performance. The forging process parameters obtained through AI data analysis prediction can be put into production and use after verification.

[0067] Fourth, for the forging method of bearing steel for wind power spindle bearings based on forging tests in the present invention, the economic and inexpensive acquisition of training samples is realized by adopting the quality control point reverse negative intervention measures during the steelmaking and billet making process; by adopting the reverse negative intervention measures to increase the non-uniformity of the distribution of the chemical composition of the molten steel, when sampling from the precast steel billets after casting or continuous casting, more various test specimens with slightly adjusted chemical composition content can be obtained, thus overcoming the drawback that when the molten steel of the same heat is cast or continuously cast by the conventional method, the distribution of the chemical composition content in the precast steel billets is relatively uniform inside, making it difficult to obtain more data of various test specimens with slightly adjusted chemical composition content. Thus, the cost of forging tests and the production cycle of forging tests are greatly reduced.

[0068] Fifth, for the forging method of bearing steel for wind power spindle bearings based on forging tests in the present invention, when heat-treating the test blocks, a heat treatment temperature variable control rack with a special design is adopted. When a relatively large number of heat treatment test blocks are placed in the same heat treatment furnace for heat treatment, the heat treatment temperatures of the respective heat treatment test blocks are different (with fine-tuning changes relative to the preset heat treatment temperature), so as to obtain more sample data of the test specimens for detecting heat treatment temperatures (including the heating, temperature-rising, heat-preserving temperatures in the first stage of heat treatment and the isothermal transformation heat-preserving temperatures in the second stage of heat treatment). Thereby, the cost of forging tests and the production cycle of forging tests are further greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is a process flow schematic diagram of the forging method of bearing steel for wind power spindle bearings based on forging tests in the present invention;

[0070] Figure 2 is a schematic structural diagram of a red transfer heat protection device arranged on the front end robotic arm of a forging operation manipulator;

[0071] Figure 3 Figure 2 partial enlarged view;

[0072] Figure 4 is a schematic structural diagram of a heat treatment temperature variable control rack;

[0073] Figure 5 is Figure 4 a schematic structural diagram of the part related to the heat protection and heat insulation tube in

[0074] In the figures: 1, front end robotic arm; 2, bearing steel forging; 3, heat treatment test block; 4, clamp; 5, radiant heater; 6, flange ring; 7, metal bellows; 8, annular carbon heating tube; 9, servo electric push rod; 10, operating rod; 11, sliding sleeve; 12, moving rod; 13, slider; 14, U-shaped bracket; 15, hollow tube body; 16, infrared temperature detection sensor; 17, annular heat radiation reflection cover; 18, high-temperature furnace temperature tracker; 19, thermocouple; 20, frame; 21, heat protection and heat 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 plate; 28, high-temperature refractory fiber heat insulation layer; 29, spherical crown sheet body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0075] The following combines the drawings and embodiments to further describe the specific embodiments of the present invention. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0076] As Figures 1 to 5The following is an embodiment of the forging method of bearing steel for wind power main shaft bearings based on forging tests according to the present invention, including 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 relatively large number of test specimens; then detecting and evaluating the performance of the test specimens, and correspondingly obtaining the optimized forging process parameters according to the performance evaluation results, and using the optimized forging process parameters as the forging process parameters for the official forging of bearing steel for wind power main shaft bearings; the specific method for obtaining the optimized forging process parameters includes the following steps set in sequence:

[0077] (1) Modeling analysis and preliminary optimization of forging process parameters: Establish a finite element model of the bearing steel forging, taking the performance indicators of the bearing steel forging as the optimization goal, setting the initial values of the forging process parameters, and based on the initial values of the forging process parameters, preliminarily optimizing the forging process parameters through thermal simulation and finite element analysis calculation of the forging process to obtain the theoretical forging process parameters of the bearing steel forging; wherein, the performance indicators of the bearing steel forging include tensile strength index, reduction of area index and grain size index; the forging process parameters include forging heating temperature and post-forging heat treatment temperature;

[0078] (2) Forging test planning and design: Set the number of bearing steel forgings for which forging tests need to be conducted, based on the theoretical forging process parameters of the bearing steel forging, set the upper and lower floating ranges of the numerical values of the forging process parameters during the forging test, assign values to the forging process parameters of each bearing steel forging to be tested, and make the assigned values of the forging process parameters of each bearing steel forging different from each other within the above-mentioned floating range, so as to obtain the test forging process parameters of each bearing steel forging; the test forging process parameters include test forging heating temperature and test post-forging heat treatment temperature;

[0079] Among them, the assigned values of the forging process parameters of each bearing steel forging are different from each other within the above-mentioned floating range, which can be that the forging heating temperature is different, or the post-forging heat treatment temperature is different; that is, at least one of the test forging process parameters of the forging heating temperature and the post-forging heat treatment temperature should be ensured to have different numerical values.

[0080] Preferably, the settings of the test forging heating temperature and the test post-forging heat treatment temperature of each bearing steel forging can be changed within the temperature range of ±25°C of floating up and down.

[0081] (3) Forging test: According to the test forging process parameters set in the forging test planning and design, conduct forging tests on each bearing steel forging, and the forging test process of the bearing steel forging includes the following steps:

[0082] S1. Molten steel smelting and billet making: After the steel materials are proportioned, they go through rough smelting of molten steel in an electric arc furnace, secondary refining of molten steel, and vacuum carbon deoxidation treatment in sequence, and then several precast steel billets are formed through casting or continuous casting; among them, during the processes of rough smelting of molten steel in the electric arc furnace, secondary refining of molten steel, and vacuum carbon deoxidation treatment, molten steel smelting quality control points are set at each key process node. 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 and billet making.

[0083] S2. Pre-forging heating: Place the precast steel billet into a forging heating furnace and heat it to the forging heating temperature set in the forging test planning and design.

[0084] S3. Forging: Take out the steel billet in the forging heating furnace and transfer it to a forging press for successive forging, punching, and finishing treatments to form a forged billet with a central through-hole; during forging, by adopting a forging process with a large anvil width ratio, a large reduction ratio, and a multi-pass non-uniform temperature deformation forging process, the internal structure is made fine and uniform and the defects in the core are healed.

[0085] S4. Ring rolling of the forged billet: Transfer the forged billet with a central through-hole to a ring rolling machine in a hot state and form a ring-shaped forged billet through ring rolling.

[0086] S5. Making heat treatment specimens: Cut the ring-rolled forged billet and divide it into several heat treatment test blocks.

[0087] S6. Heat treatment of test blocks: Use a heat treatment furnace, and each heat treatment test block is subjected to post-forging heat treatment according to the post-forging heat treatment temperature set in the forging test planning and design.

[0088] S7. Sampling and testing of forgings: Sampling is carried out separately for the heat treatment test blocks of bearing steel forgings using different test forging process parameters to obtain several test specimens for testing, and each test specimen is tested; the test items include three contents A, B, and C, where A is the tensile strength data, B is the reduction of area data, and C is the data of the grain size grade obtained through metallographic structure testing.

[0089] S8. Data sorting and classification: For each test specimen, if one of the three test contents A, B, and C is unqualified, the forging process parameters corresponding to the test specimen are classified as unqualified forging process parameters; if all three test contents A, B, and C are qualified, the forging process parameters corresponding to the test specimen are classified as qualified forging process parameters, and the test specimen is retained and its subsequent forging performance evaluation is carried out; the data of the test specimens corresponding to the unqualified forging process parameters are excluded.

[0090] S9. Establish a forging performance evaluation model to obtain optimized forging process parameters: According to the different application scenarios and working conditions of the bearings, reasonably set the weight coefficients α, β, and γ for forging performance evaluation, and establish the formula for forging performance evaluation as M = (α×A + β×B + γ×C) ÷ (A + B + C); where M is the comprehensive forging performance evaluation value considering weights, α is the weight coefficient of tensile strength, β is the weight coefficient of reduction of area, and γ is the weight coefficient of grain size; by calculating the size of the comprehensive forging performance evaluation value M of each test specimen, screen out the test specimen with the largest comprehensive forging performance evaluation value M, and use the forging heating temperature and post-forging heat treatment temperature of the test specimen corresponding to the largest M value as the forging process parameters when forging bearing steel for wind power spindle bearings.

[0091] Preferably, in the forging test of step (3), a multi-joint forging operation manipulator capable of sequentially transferring forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling mill is also provided. The multi-joint forging operation manipulator is movably arranged on the guide rail of the workshop site; a clamp 4 for clamping the bearing steel forging 2 is provided on the front end robotic arm 1 of the multi-joint forging operation manipulator, and a red-hot transfer heat protection device for preventing the temperature of the forging from decreasing during transfer is also provided on the front end robotic arm 1 of the multi-joint forging operation manipulator; the red-hot transfer heat protection device includes a telescopic bellows assembly provided on the front end robotic arm 1 of the multi-joint forging operation manipulator that can surround and withdraw from the periphery the bearing steel forging 2 clamped by the clamp 4, and a radiation heater 5 for radiatively heating the forging is built into the telescopic bellows assembly.

[0092] Preferably, the clamp 4 uses a finger cylinder.

[0093] Preferably, the radiation heater 5 includes a plurality of annular carbon heating tubes 8. The telescopic bellows assembly includes a flange ring 6 fixed on the front end robotic 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 face of the flange ring 6, a reflective film coated on the inner wall of the metal bellows 7, a plurality of annular carbon heating tubes 8 coaxially arranged at the inner wall part of the metal bellows 7 and spaced axially, 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 part of the metal bellows 7; among them, the power of the annular carbon heating tube 8 at the front port part of the metal bellows 7 is greater than the power of the annular carbon heating tubes at other positions.

[0094] In this embodiment, the telescopic rod of the servo electric push rod 9 is located outside the metal bellows 7. A joystick 10 connected to the front end of the metal bellows 7 is horizontally 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 expands and contracts, the joystick 10 drives the front end part of the metal bellows 7 to move synchronously. When the front end of the metal bellows 7 moves forward, it can surround the bearing steel forging 2 on the clamp 4 from the periphery. When the front end of the metal bellows 7 moves backward, the bearing steel forging 2 on the clamp 4 can be completely exposed.

[0095] In this embodiment, a heating tube automatic equalizer for realizing the axial automatic and evenly spaced distribution of the annular carbon heating tubes 8 inside the metal bellows 7 is further arranged between the telescopic rod of the servo electric push rod 9 and the metal bellows 7. The heating tube automatic equalizer includes a plurality 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 horizontally arranged relative to the telescopic rod of the servo electric push rod 9, a hook hole arranged at the cantilever end part of the moving rod 12, and a plurality of rod body installation through holes correspondingly opened on the pipe wall of the metal bellows 7. The cantilever end of the moving rod 12 passes through the rod body installation through hole of the metal bellows 7 and enters the inside of the metal bellows 7. Each of the annular carbon heating tubes 8 is respectively hung on the hook hole at the cantilever end of the corresponding moving rod 12 through a metal wire.

[0096] Preferably, the heating power of each of the annular carbon heating tubes 8 is adjustable.

[0097] Preferably, a plurality of sliders 13 are further movably arranged on the outer circle of the telescopic rod of the servo electric push rod 9. A U-shaped bracket 14 is connected to the slider 13. A hollow tube body 15 horizontally arranged relative to the telescopic rod of the servo electric push rod 9 is connected to the U-shaped bracket 14. A plurality of tube body installation through holes are arranged on the pipe wall of the metal bellows 7. The cantilever end of the hollow tube body 15 passes through the tube body installation through hole and enters the inside of the metal bellows 7. An infrared temperature detection sensor 16 is inserted into the end of the hollow tube body 15 connected to the U-shaped bracket 14 towards the inside of the hollow tube body 15. The infrared detection light of the infrared temperature detection sensor 16 passes through the inner hole of the hollow tube body 15 and enters the inside of the metal bellows 7. The infrared temperature detection sensor 16 is connected to the controller of the multi-joint forging operation manipulator. When the transfer distance of the bearing steel forging 2 is relatively long, the multi-joint forging operation manipulator senses the temperature of different areas of the forging through the infrared temperature detection sensor 16 and ensures that the surface temperature of the forging reaches the set value during the transfer process of the forging and realizes the balance of the surface temperature of each part of the forging by adjusting the heating power of each annular carbon heating tube 8.

[0098] 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 .

[0099] 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.

[0100] 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.

[0101] 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:

[0102] 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;

[0103] 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;

[0104] 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;

[0105] T4, Prediction, Verification and Optimization: Based on the AI data analysis prediction model after one iteration, make several fine-tuning settings on the size of the training sample data in the input layer of the forging process data, and according to the training sample data after each fine-tuning, through the output layer of the artificial intelligence AI data analysis prediction model, output the predicted value of the comprehensive evaluation value M of the forging performance; compare each predicted value of M with the original maximum M value. If a value larger than the maximum M value in step S9 appears, then use the training sample data of the forging process data input layer corresponding to the larger M value for verification through actual forging. If the verification is qualified, obtain the final optimized forging process parameters with a larger M value and use them as the forging process parameters when forging bearing steel for wind power spindle bearings for formal production.

[0106] Preferably, in step S1, when preparing the steel billet by smelting molten steel, prepare several prefabricated steel billets with slightly varying chemical composition contents in advance; at the same time, in step T2, when obtaining the training sample data, also use a forging chemical composition detector to detect each test sample with a slightly varying chemical composition content, obtain the chemical composition content data corresponding to each test sample, and add the chemical composition content data of each test sample to the training sample data in the input layer of the forging process data of the AI data analysis prediction model.

[0107] Preferably, the forging chemical composition detector can adopt detection instruments such as spectrometers and atomic absorption spectrometers.

[0108] As a further improvement of the present invention, in the step S1 of smelting molten steel into billets, the quality control points of molten steel smelting at each key process node include the quality control point of the molten steel casting or continuous casting temperature during molten steel casting or continuous casting, the quality control point of the molten steel casting or continuous casting speed during molten steel casting or continuous casting, and the quality control point of the molten steel casting or continuous casting cooling speed after molten steel casting or continuous casting; during the forging test process in the step (3), by adopting the training sample data economic and cheap acquisition method, the training sample data required in the step T2 of obtaining training sample data is obtained; the training sample data economic and cheap acquisition method includes, when smelting molten steel into billets in the step S1, in order to economically and cheaply obtain each test sample with a slight change in the chemical composition content, reducing the number of test furnace charges for molten steel smelting, during casting or continuous casting, performing reverse negative intervention on at least one of the quality control points of the molten steel casting or continuous casting temperature, the molten steel casting or continuous casting speed, and the molten steel casting or continuous casting cooling speed; that is, appropriately relaxing the relatively strict quality control parameters originally used to improve the uniformity of the internal chemical composition distribution of the prefabricated steel billet at the quality control point, allowing the quality control parameters to fluctuate within a wider range, so as to achieve the negative effect of appropriately increasing the non-uniformity of the internal chemical composition distribution of the prefabricated steel billet, so that when making heat treatment specimens in the step S5, the internal chemical compositions of each heat treatment test block obtained by cutting from the forged billet ring rolling and each test sample obtained during the forging sample detection in the step S7 have slight differences from each other; thus, a large number of training samples with slightly varying chemical composition contents can be obtained by sampling on the prefabricated steel billets prepared from the molten steel of the same furnace charge.

[0109] Preferably, the reverse negative intervention measures for the quality control point of the molten steel casting or continuous casting temperature include relaxing the variation range of the molten steel casting or continuous casting temperature, or artificially intervening to control the molten steel casting or continuous casting temperature, so as to affect the distribution of solutes inside the prefabricated steel billet after casting or continuous casting; the reverse negative intervention measures for the quality control point of the molten steel casting or continuous casting speed include appropriately increasing or decreasing the molten steel casting or continuous casting speed, or artificially intervening in the molten steel casting or continuous casting speed, so that dendritic segregation occurs in the internal structure of the prefabricated steel billet after casting or continuous casting; wherein, the artificial intervention in the molten steel casting or continuous casting speed includes adopting variable-speed intermittent casting or continuous casting; the reverse negative intervention measures for the quality control point of the molten steel casting or continuous casting cooling speed include relaxing the variation range of the molten steel casting or continuous casting cooling speed, or artificially intervening to control the variation range of the molten steel casting or continuous casting cooling speed, so that segregation occurs in the internal structure of the prefabricated steel billet after casting or continuous casting.

[0110] 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:

[0111] 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.

[0112] 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).

[0113] Preferably, the heat treatment temperature variable control rack includes a rack 20, a number of heat protection and heat insulation tubes 21 spaced on the rack 20, a number of phase change balls 22 arranged at intervals along the axial direction of the heat protection and heat insulation tubes 21 and made of a phase change heat absorption material, and a number of hot air flow transfer holes 23 spaced along the axial direction of the heat protection and heat insulation tubes 21 on the tube walls of the heat protection and heat insulation tubes 21. The phase change balls 22 and the hot air flow transfer holes 23 are alternately arranged in sequence along the axial direction. The hot air flow transfer holes 23 are arranged on the tube walls of the heat protection and heat insulation tubes 21 between two adjacent phase change balls 22. A test block placement space for placing a heat treatment test block 3 is formed in the space between two adjacent phase change balls 22 inside the heat protection and heat insulation tubes 21; a hot air flow baffle 24 is arranged at the orifice position of the hot air flow transfer holes 23, and a spacing for restricting the passage of hot air is arranged between the hot air flow baffle 24 and the orifice of the hot air flow transfer holes 23, and the spacings between the hot air flow baffles 24 and the orifices of the hot air flow transfer holes 23 on the same heat protection and heat insulation tube 21 are different from each other.

[0114] In this embodiment, a thermocouple installation hole for inserting a thermocouple 19 to measure the heat treatment temperature inside the heat protection and heat insulation tube 21 is further arranged on the outer circle of the heat protection and heat insulation tube 21.

[0115] Preferably, an adaptation hole can be arranged on the heat treatment test block 3, and the thermocouple is directly in full contact with the adaptation hole of the heat treatment test block.

[0116] Preferably, the heat treatment of the heat treatment test block 3 can adopt isothermal spheroidizing annealing heat treatment.

[0117] In this embodiment, the hot air flow baffle 24 is fixed to the tube wall of the heat protection and heat insulation tube 21 by screws 25.

[0118] Considering that the temperature of isothermal spheroidizing annealing heat treatment usually involves the heating, rising, and holding temperature in the first stage of heat treatment and the isothermal transformation and holding temperature in the second stage of heat treatment, in order to realize the fine-tuning combined change of the heating, rising, and holding temperature and the isothermal transformation and holding temperature of each heat treatment test block, so as to obtain more sample data of different heat treatment temperature combinations (heating, rising, and holding temperature and isothermal transformation and holding temperature) of the heat treatment test block 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 tube wall of the heat protection and heat insulation tube 21 by a cantilever mounting method.

[0119] Preferably, a spherical crown sheet body 29 is arranged on the surface of the bimetallic hot air flow baffle 24 facing the hot air flow transfer hole, and a spacing is arranged between the spherical crown sheet body 29 and the orifice of the hot air flow transfer hole 23.

[0120] Preferably, according to the direction of thermal deformation of the bimetallic hot gas flow baffle 24, the bimetallic hot gas flow baffle 24 can be installed in the forward direction to cause the bimetallic hot gas flow baffle 24 to deform towards the orifice when the temperature in the furnace rises, or it can be installed in the reverse direction to cause the bimetallic hot gas flow baffle 24 to deform away from the orifice when the temperature in the furnace rises, so as to adjust the heat transfer gas flow rate between the inside of the heat treatment furnace and the inside of the heat protection and heat insulation tube, and further achieve fine adjustment of the increase and decrease of the heat treatment temperature inside the heat protection and heat insulation tube 21, thereby obtaining more heat treatment temperature data samples of different heat treatment temperature combinations of the heat treatment specimens 3.

[0121] Preferably, a layer of flexible high-temperature refractory heat insulation layer is provided on the outer side of the bimetallic hot gas flow baffle 24 facing away from the hot gas flow transfer hole 23.

[0122] By providing the bimetallic hot gas flow baffle 24, it is further possible to realize the combined change of the heating and holding temperature in the first stage and the isothermal transformation and holding temperature in the second stage during isothermal spheroidizing annealing heat treatment, so as to collect more sample data of heat treatment process parameters with fine adjustment changes in heat treatment temperature.

[0123] In this embodiment, the diameter of the phase change ball 22 can be obtained through thermodynamic calculation to ensure that during the whole process of heat treatment, the phase change ball has sufficient heat storage performance, so as not to cause the out-of-control of the temperature inside the heat protection and heat insulation tube within the specified heat treatment time, and it can always maintain a relatively constant temperature difference relative to the temperature outside the heat protection and heat insulation tube (i.e., the internal temperature of the heat treatment furnace).

[0124] By setting the different distances between the hot gas flow baffle 24 and the orifice of the hot gas flow transfer hole 23 on the heat protection and heat insulation tube 21, the temperatures of the respective specimen placement spaces for placing the heat treatment specimens 3 inside the heat protection and heat insulation tube 21 are different.

[0125] Furthermore, by setting the different distances between the hot gas flow baffle 24 and the orifice of the hot gas flow transfer hole 23 on the heat protection and heat insulation tube 21, and setting the hot gas flow baffle 24 as a bimetallic hot gas flow baffle, different heat treatment temperature combinations of the heat treatment specimens 3 can be realized, that is, different combinations of heating-up and holding temperatures and isothermal transformation and holding temperatures, so that each heat treatment specimen 3 placed in the same heat treatment furnace has different heat treatment temperature combinations (different combinations of heating-up and holding temperatures and isothermal transformation and holding temperatures), thereby obtaining a relatively large number of sample data of heat treatment process parameters.

[0126] Preferably, the phase change balls 22 can be made of aluminum alloy balls with a phase change temperature lower than the heat treatment temperature of the bearing steel forgings, or can be made of phase change balls made of other materials with a relatively lower phase change temperature, and the minimum diameter of the phase change balls is determined through thermodynamic calculations.

[0127] Preferably, the phase change balls 22 can also be composite phase change balls with a paraffin phase change material filled inside an aluminum alloy spherical shell.

[0128] In this embodiment, the phase change balls 22 are fixed to the thermal protection and heat insulation tube 21 through screws 25.

[0129] Preferably, a work station for openly placing the heat treatment test block 3 is further provided on the heat treatment temperature variable control rack of this embodiment.

[0130] Preferably, the thermal protection and heat insulation tube 21 includes a metal tube body 26, tube body covers 27 detachably arranged at both ends of the metal tube body 26, and high-temperature refractory fiber heat insulation layers 28 respectively arranged on the outer surface of the metal tube body 26 and the outer sides of the tube body covers 27.

[0131] The high-temperature refractory fiber heat insulation layer on the outer surface of the above-mentioned thermal protection and heat insulation tube 21 can effectively reduce the transfer of heat in the heat treatment furnace to the inside of the thermal protection and heat insulation tube. It cooperates with the phase change balls 22 arranged inside the thermal protection and heat insulation tube 21 and the bimetallic hot air flow baffle 24 arranged at the orifice of the thermal protection and heat insulation tube 21 to realize the regulation of the hot air flow entering the inside of the thermal protection and heat insulation tube 21, so as to effectively control the heat treatment temperature inside the thermal protection and heat insulation tube 21, and thus obtain the training sample data of each heat treatment test block 3 with a fine-tuning change in the heat treatment temperature.

[0132] The forging method of bearing steel for wind power spindle bearings based on forging tests in this embodiment can also be applied to the forging of various bearing forgings in other industries.

[0133] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope 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 comprises the following steps: performing forging tests on a number of bearing steel forgings under different forging process parameters, sampling the forgings obtained from the forging tests, and obtaining 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 optimized 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 optimized forging process parameters comprises cutting the forging blank after ring rolling, dividing it into a number of heat treatment test blocks, and then performing post-forging heat treatment on the heat treatment test blocks; then For the heat treatment test blocks of bearing steel forgings with different experimental forging process parameters, samples are taken respectively to obtain a number of test samples, and each test sample is tested to screen out the test sample with the largest comprehensive evaluation value of forging performance, and the test forging heating temperature and the test post-forging heat treatment temperature corresponding to the test sample with the largest comprehensive evaluation value of forging performance are used as the forging process parameters when forging bearing steel for wind turbine main shaft bearings; more sample data of forging process parameters are obtained through forging tests, and the sample data is trained by using an AI data analysis and prediction model, and the AI ​​data analysis and prediction model further predicts the sample data with Forging process parameters for better forging performance; wherein, the 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 heat treatment of the test block, in order to economically and cheaply obtain each test sample with a slight change in heat treatment temperature and reduce the number of test furnaces for heat treatment, using a heat treatment temperature variable temperature control rack that can achieve fine-tuning of temperature changes at various locations and a high-temperature resistant furnace temperature tracker that is matched with the heat treatment temperature variable temperature control rack, placing all the 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 the heat treatment test blocks and a high-temperature furnace temperature tracker are placed in the same heat treatment furnace, and each heat treatment test block is respectively 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 with different heat treatment temperatures for each heat treatment test block in the heat treatment test carried out together in the same heat treatment furnace.

2. A forging method for bearing steel for wind turbine main shaft bearing based on forging test according to claim 1, characterized in that: The specific method for obtaining the optimized forging process parameters includes 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; (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.

3. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 2, 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 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.

4. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 3, 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.

5. The forging method for bearing steel for wind turbine main shaft bearing based on forging test according to claim 2 is 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.

6. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 5, 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.

7. A forging method for a wind turbine main shaft bearing steel based on a forging test according to claim 6, 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.

8. A forging method for a bearing steel for a wind turbine main shaft bearing based on a forging test according to claim 7, 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.

9. A forging method for a bearing steel for a wind turbine main shaft bearing based on a forging test according to claim 2, 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.

10. A forging method for bearing steel for wind turbine main shaft bearing based on forging test according to claim 1, characterized in that: 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 along the axial direction of the heat protection insulation tube and made of phase change heat absorption material, a number of hot air 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 hot air flow transfer holes are alternately arranged in sequence along the axial direction, the hot air flow transfer holes are arranged on the tube wall of the heat protection insulation tube between two adjacent phase change balls, and the heat protection insulation tube is arranged in the heat protection insulation tube. The space inside the tube between two adjacent phase change balls forms a test block placement space for placing a heat treatment test block; a hot air flow baffle is arranged at the orifice position of the hot air flow transfer hole, and a spacing for limiting the passage of hot air flow is arranged between the hot air flow baffle and the orifice of the hot air flow transfer hole, and the spacings between each hot air flow baffle and the orifice of the hot air flow transfer hole on the same heat protection insulation tube are different from each other; 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 tube wall of the heat protection insulation tube by a cantilever installation method.

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