Heat treatment device for forging test of bearing steel for wind power main shaft bearing

Abstract

The invention discloses a heat treatment device for a forging test of bearing steel for a wind power main shaft bearing, which comprises a plurality of phase change balls which are arranged in a thermal protection heat insulation pipe at intervals and are made of phase change heat absorption materials, and a plurality of hot air flow transfer holes which are formed in the pipe wall of the thermal protection heat insulation pipe at intervals, the phase change balls and the hot air flow transfer holes are sequentially and alternately arranged in the axial direction, and a test block placing space for placing a heat treatment test block is formed in a space between every two adjacent phase change balls in the thermal protection heat insulation pipe; a hot air flow baffle is arranged at the position of a hole opening of the hot air flow transfer hole, a distance used for limiting passing of hot air flow is arranged between the hot air flow baffle and the hole opening of the hot air flow transfer hole, and the distances between the hot air flow baffles on the same thermal protection heat insulation pipe and the hole opening of the hot air flow transfer hole are different from one another. The forging performance of the bearing steel for the wind power main shaft bearing is improved, the cost of a forging test is reduced, and the period of the forging test is shortened.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of February 7, 2025, application number 202510134040.3, and invention name: A forging method for bearing steel for wind turbine main shaft bearings based on forging tests. Technical Field

[0002] The present invention relates to the field of forging technology, and in particular to a forging method for bearing steel for a wind turbine main shaft bearing based on a forging test, and also to a heat treatment device for forging tests of bearing steel for a wind turbine main shaft bearing. Background Art

[0003] Bearing steel forgings are widely used in various industries, and typical applications include new energy fields such as large bearing steel forgings for wind turbine main shaft bearings.

[0004] The manufacturing of bearing steel forgings involves a series of processes, from molten steel smelting to billet formation, forging, heat treatment, and ring rolling. To meet the needs of bearings in various applications, customers often impose stringent performance requirements on bearing steel forgings. For example, bearing steel forgings for wind turbine main shaft bearings in a certain application must meet application requirements such as tensile strength ≥900 MPa, cross-sectional reduction rate ≥48%, and grain size ≥7. Conventional forging processes may not be able to meet these various performance requirements, or even if they can be met, the product qualification rate is low.

[0005] To this end, technicians must research and optimize forging process parameters, reduce defects, and improve the quality and overall performance of bearing steel forgings. Furthermore, researching and optimizing forging process parameters typically requires forging tests. However, for large bearing steel forgings, forging tests are costly and time-consuming. Summary of the Invention

[0006] To address the above-mentioned issues, the present invention proposes a forging method for wind turbine main shaft bearing steel based on forging tests. The method aims to obtain optimized forging process parameters through forging tests, thereby improving the forging performance of the bearing steel for wind turbine main shaft bearings and reducing the cost and cycle of forging tests. The specific technical solution is as follows: A forging method for bearing steel for wind turbine main shaft bearings based on forging tests includes conducting forging tests on a number of bearing steel forgings under different forging process parameters, sampling the forgings obtained from the forging tests to obtain a large number of test specimens; then testing and performance evaluation are performed on the test specimens, and optimized forging process parameters are obtained based on the performance evaluation results, and the optimized forging process parameters are used as forging process parameters for formal forging of the bearing steel for wind turbine main shaft bearings; 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: A finite element model of a bearing steel forging is established. The performance indicators of the bearing steel forging are used as optimization targets. The initial values ​​of the forging process parameters are set. Based on the initial values ​​of the forging process parameters, the forging process parameters are preliminarily optimized through thermal simulation of the forging process and finite element analysis calculations to obtain the theoretical forging process parameters of the bearing steel forging. The performance indicators of the bearing steel forging include tensile strength, cross-sectional shrinkage, and grain size. 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 forged, and based on the theoretical forging process parameters of the bearing steel forgings, set the upper and lower floating ranges of the forging process parameters during the forging test, assign values ​​to the forging process parameters of each bearing steel forging that needs to be forged, and make the assigned values ​​of the forging process parameters of each bearing steel forging different from each other within the upper and lower floating ranges, so as to obtain the test forging process parameters of each bearing steel forging; the test forging process parameters include the test forging heating temperature and the test post-forging heat treatment temperature; Among them, the values ​​assigned to the forging process parameters of the bearing steel forgings are different from each other within the upper and lower floating ranges, which may be different forging heating temperatures or different post-forging heat treatment temperatures; that is, it is necessary to ensure that the values ​​of at least one of the experimental forging process parameters, the forging heating temperature and the post-forging heat treatment temperature, are different.

[0007] Preferably, the test forging heating temperature and the test post-forging heat treatment temperature of each bearing steel forging can be varied within a temperature range of ±25°C.

[0008] (3) Forging test: According to the forging process parameters 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 roughing molten steel in an electric arc furnace, refining molten steel outside the furnace, and vacuum carbon deoxidation treatment, and then formed into a number of prefabricated steel billets by casting or continuous casting; wherein, during the roughing molten steel in the electric arc furnace, refining molten steel outside the furnace, and vacuum carbon deoxidation treatment processes, molten steel smelting quality control points are set at various key process nodes. By setting the molten steel smelting quality control points, the process parameters of the molten steel smelting are controlled within the set range, thereby controlling the stability of the quality of the molten steel smelting billets; S2. Heating before forging: Place the prefabricated steel billet in a forging heating furnace and heat it to the forging heating temperature set in the forging test planning design; S3. Forging: The steel billet in the forging heating furnace is removed and transferred to a forging press for forging, punching, and finishing 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 a fine and uniform internal structure and heal 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 formed into a ring-shaped forging blank by ring rolling; S5. Making heat treatment test pieces: cutting the forging blank and rolling 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 plan design; S7. Forging Sampling and Testing: Samples are collected from heat-treated test blocks of bearing steel forgings using different experimental forging process parameters to obtain a number of test specimens, and each test specimen is tested. The test items include A, B, and C, where A represents tensile strength data, B represents cross-sectional reduction data, and C represents grain size data obtained through metallographic structure testing. S8. Data collation and classification: For each test sample, if any one of the three test items A, B, and C is unqualified, the forging process parameters of the corresponding test sample will be classified as unqualified forging process parameters; if all three test items A, B, and C are 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 for subsequent forging performance evaluation; the data of the test samples corresponding to the unqualified forging process parameters will be eliminated; S9. Establish a forging performance evaluation model and obtain the optimization of 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 forging performance evaluation formula M=(α×A+β×B+γ×C)÷(A+B+C); among them, 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 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 when forging bearing steel for wind turbine main shaft bearings.

[0009] Preferably, in the forging test of step (3), a multi-joint forging operation manipulator is further provided which can realize the transfer of forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling machine in sequence, and the multi-joint forging operation manipulator is movably provided on the guide rails of the workshop site; a clamp for clamping the bearing steel forgings is provided on the front end manipulator arm of the multi-joint forging operation manipulator, and a hot transfer heat protection device for preventing the temperature of the forgings from decreasing during the transfer process is also provided on the front end manipulator arm of the multi-joint forging operation manipulator; the hot transfer heat protection device includes a telescopic bellows assembly provided on the front end manipulator arm of the multi-joint forging operation manipulator, which can surround and remove the bearing steel forgings clamped by the clamp from the periphery, and the telescopic bellows assembly is equipped with a radiation heater for radiant heating of the forgings.

[0010] Preferably, the clamp is a finger cylinder.

[0011] Preferably, 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 operating robot and located at the rear side of the clamp, a metal bellows connected to the front end surface of the flange ring, a reflective film coated on the inner wall of the metal bellows, and a number of annular carbon heating tubes coaxially arranged near the inner wall of the metal bellows and arranged at intervals along the axial direction. The rear end of the flange ring is provided with a pair of servo electric push rods connected to the controller of the multi-joint forging operating robot, 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.

[0012] In the present invention, the telescopic rod of the servo electric linear actuator is located outside the metal bellows. A joystick is laterally disposed at the front end of the telescopic rod, connected to the front end of the metal bellows. When the telescopic rod of the servo electric linear actuator is extended or retracted, the joystick drives the front end of the metal bellows to move synchronously. When the front end of the metal bellows moves forward, it can enclose the bearing steel forging on the clamp from the outside. When the front end of the metal bellows moves backward, it can completely expose the bearing steel forging on the clamp.

[0013] In the present invention, a heating tube automatic distributor is further provided between the telescopic rod of the servo electric push rod and the metal bellows for realizing automatic and uniform distribution of the annular carbon heating tubes inside the metal bellows along the axial direction; the heating tube automatic distributor includes a number of sliding sleeves movably arranged on the outer circle of the telescopic rod of the servo electric push rod, a moving rod fixed on the sliding sleeve and arranged transversely relative to the telescopic rod of the servo electric push rod, a hook hole arranged at the cantilever end of the moving rod, and a number of rod body mounting through holes correspondingly opened on the tube wall of the metal bellows. The cantilever end of the moving rod passes through the rod body mounting through hole of the metal bellows and enters the interior of the metal bellows, and each of the annular carbon heating tubes is correspondingly hung on the hook hole of the cantilever end of the moving rod at the corresponding position through a metal wire.

[0014] Preferably, the heating power of each of the annular carbon heating tubes is adjustable.

[0015] Preferably, a number of sliders are movably provided on the outer circle of the telescopic rod of the servo electric push rod, the slider is connected to a U-shaped bracket, and the U-shaped bracket is connected to a hollow tube body arranged transversely relative to the telescopic rod of the servo electric push rod, and a number of tube body mounting through holes are provided on the tube wall of the metal bellows, and the cantilever end of the hollow tube body passes through the tube body mounting through holes and enters the interior of the metal bellows, and an infrared temperature detection sensor is inserted into the interior of the hollow tube body at one end of the hollow tube body connected to the U-shaped bracket, and the infrared detection light of the infrared temperature detection sensor passes through the inner hole of the hollow tube body and enters the interior of the metal bellows; the infrared temperature detection sensor is connected to the controller of the multi-joint forging operation robot. When the transportation distance of the bearing steel forging is long, the multi-joint forging operation robot senses the temperature of different areas of the forging through the infrared temperature detection sensor, and ensures that the surface temperature of the forging reaches the set value during the transportation process by adjusting the heating power of each annular carbon heating tube and achieves temperature balance at various locations on the surface of the forging.

[0016] 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.

[0017] Preferably, an annular heat radiation reflector is provided at the front end of the metal bellows for enhancing the heating and insulation effect of the front end face of the bearing steel forging. The annular heat radiation reflector is fixed on the operating rod at the front end of the servo electric push rod, and the reflecting surface of the annular heat radiation reflector is inclined relative to the operating rod toward the direction away from the mouth of the metal bellows.

[0018] 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, and adjusts the heating power of each annular carbon heating tube to ensure that the surface temperature of the forging reaches the set value during the transportation process and achieves temperature balance at all locations on the forging surface.

[0019] 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 and prediction model is further 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 an artificial intelligence (AI) model: An artificial intelligence (AI) data analysis and prediction model is selected as the 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, and a forging performance data output layer, which are sequentially arranged and connected. T2. Obtaining 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 training sample data for the forging process data input layer of the AI ​​data analysis and prediction model. At the same time, use the corresponding forging performance comprehensive evaluation value M as training sample data for 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 the artificial intelligence (AI) data analysis and prediction model after one iteration; T4. Prediction, verification and optimization: Based on the AI ​​data analysis and 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 and prediction model is used to output the predicted value of the comprehensive evaluation value M of the forging performance; the predicted value of each M is compared 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 the larger M value are obtained, and they are used as the forging process parameters when forging bearing steel for wind turbine main shaft bearings for formal production.

[0020] Preferably, in the step S1, when molten steel is smelted to form billets, a number of prefabricated steel billets with slightly changed chemical composition contents are prepared in advance; at the same time, in the step T2, when obtaining training sample data, a forging chemical composition detector is used to detect each test sample with slightly changed chemical composition contents, 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.

[0021] Preferably, the forging chemical composition detector can be a spectrometer, an atomic absorption spectrometer or other detection instruments.

[0022] As a further improvement of the present invention, in the step S1, 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 forging test process of the step (3), the training sample data required in the step T2, obtaining the training sample data, is obtained by adopting an economical and cheap method for obtaining training sample data; the economical and cheap method for obtaining training sample data includes, in the step S1, 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 heats of molten steel smelting, when casting or continuous casting is carried out, the molten steel casting or continuous casting temperature quality control point is controlled. The method comprises the following steps: performing reverse negative intervention on at least one of the quality control points, the molten steel casting or continuous casting speed quality control point and the molten steel casting or continuous casting cooling speed quality control point; that is, appropriately relaxing the stricter 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, allowing the quality control parameters to fluctuate within a wider range, so as to appropriately increase the negative effect of the uneven distribution of the internal chemical composition of the precast steel billet, so that when step S5, when making the heat treatment test piece, there are slight differences in the internal chemical composition of each heat treatment test block cut from the forging billet rolling ring and each test sample obtained when step S7, when sampling and testing the forging, so that a large number of training samples with fine-tuned changes in the chemical composition content can be obtained by sampling the precast steel billets prepared from the same batch of molten steel.

[0023] Preferably, the reverse negative intervention measures of the molten steel casting or continuous casting temperature quality control point include relaxing the variation range of the molten steel casting or continuous casting temperature, or manually intervening in the control of the molten steel casting or continuous casting temperature, thereby affecting the distribution of solutes inside the prefabricated steel billet after casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting speed quality control point include appropriately increasing or decreasing the molten steel casting or continuous casting speed, or manually intervening in the molten steel casting or continuous casting speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting sends dendrite segregation; wherein, the manual intervention in the molten steel casting or continuous casting speed includes adopting variable speed intermittent casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting cooling speed quality control point include relaxing the variation range of the molten steel casting or continuous casting cooling speed, or manually intervening in the control of the variation range of the molten steel casting or continuous casting cooling speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting segregates.

[0024] In the present invention, the hot-steam transfer heat protection device used in the forging test of step (3) is used for forging bearing steel for wind turbine main shaft bearings for formal production; the process for formal production of bearing steel forgings for wind turbine main shaft bearings adopts the forging process of steps S1 to S4, and the following process steps are added after step S1, molten steel smelting and blanking, and before step S2, pre-forging heating: S1A, Electroslag Remelting: The precast steel billet obtained by casting or continuous casting is subjected to secondary refining in the crystallizer of an Ar gas-protected electroslag remelting furnace under an Ar gas-protected atmosphere. After cooling and demoulding in the crystallizer, a refined and purified precast steel billet of bearing steel is formed.

[0025] 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 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 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 resistant furnace temperature tracker are placed together in the same heat treatment rack. 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).

[0026] 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 holes are arranged on the tube wall of the heat protection insulation tube between two adjacent phase change balls, and the space between two adjacent phase change balls inside the heat protection insulation tube forms a test block placement space for placing a heat treatment test block; a heat flow baffle is provided at the orifice position of the heat flow transfer hole, and a spacing for limiting the passage of hot air is provided between the heat flow baffle and the orifice of the heat flow transfer hole, and the spacing between each heat flow baffle and the orifice of the heat flow transfer hole on the same heat protection insulation tube is different from each other.

[0027] 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 further provided on the outer circle of the thermal protection insulation pipe.

[0028] Preferably, an adapting hole may be provided on the treatment test block 3, so that the thermocouple is directly and completely in contact with the adapting hole of the heat treatment test block.

[0029] Preferably, the heat treatment of the heat-treated test block may be performed by isothermal spheroidizing annealing.

[0030] In the present invention, the hot air flow baffle is fixed to the tube wall of the heat protection insulation tube by screws.

[0031] Taking into account that the temperature of isothermal spheroidizing annealing heat treatment usually involves the heating and holding temperature of the first stage of heat treatment and the isothermal transformation holding temperature of the second stage of heat treatment, in order to achieve fine-tuning combined changes of the heating and holding temperature and the isothermal transformation holding temperature of each heat treatment specimen, so as to obtain more sample data of different heat treatment temperature combinations (heating and holding temperature and isothermal transformation holding temperature) of the heat treatment specimens, the hot air flow baffle adopts a bimetallic hot air flow baffle, and the bimetallic hot air flow baffle is fixedly connected to the outer pipe wall of the thermal protection insulation pipe through a cantilever installation method.

[0032] Preferably, a spherical cap sheet is provided on a side of the bimetallic hot air flow baffle facing the hot air flow transfer hole, and a distance is provided between the spherical cap sheet and the orifice of the hot air flow transfer hole.

[0033] Preferably, according to the direction of deformation of the bimetallic hot air flow baffle due to heat, the bimetallic hot air flow baffle can be installed in a forward direction so that the bimetallic hot air flow baffle is deformed in a direction close to the orifice when the temperature in the furnace rises, or can be installed in a reverse direction so that the bimetallic hot air flow baffle is deformed in a direction away from the orifice when the temperature in the furnace rises, thereby realizing the adjustment of the heat transfer airflow volume in the heat treatment furnace and the thermal protection insulation tube, and then realizing the fine-tuning of the increase and decrease of the heat treatment temperature inside the thermal protection insulation tube, thereby obtaining more heat treatment temperature data samples with different heat treatment temperature combinations of the heat treatment test blocks.

[0034] Preferably, a flexible high-temperature fire-resistant insulation layer is provided on the outer side of the bimetallic hot air flow baffle facing away from the hot air flow transfer hole.

[0035] By setting a bimetallic hot air flow baffle, the combined changes of the heating and holding temperature in the first stage and the isothermal transformation and holding temperature in the second stage during the isothermal spheroidizing annealing heat treatment can be further realized, thereby collecting more heat treatment process parameter sample data with fine-tuning changes in the heat treatment temperature.

[0036] In the present invention, the diameter setting of the phase change ball can be obtained through thermodynamic calculations to ensure that the phase change ball has sufficient heat storage performance during the entire heat treatment process, so that the temperature inside the thermal protection insulation tube will not be out of control within the specified heat treatment time, and it can always maintain a relatively constant temperature difference relative to the temperature outside the thermal protection insulation tube (i.e., the internal temperature of the heat treatment furnace).

[0037] By setting the distances between the hot air flow baffle and the hot air flow transfer holes on the heat protection insulation pipe to be different, the temperatures of the various test block placement spaces inside the heat protection insulation pipe for placing heat treatment test blocks are different.

[0038] Furthermore, by setting the distances between the hot air flow baffle and the orifice of the hot air flow transfer hole on the thermal protection insulation tube to be different, and setting the hot air flow baffle to a bimetallic hot air flow baffle, different heat treatment temperature combinations of the heat treatment test blocks can be achieved, that is, different combinations of heating and heating insulation temperatures and isothermal transformation insulation temperatures, so that each heat treatment test block placed in the same heat treatment furnace has a different heat treatment temperature combination (different combinations of heating and heating insulation temperatures and isothermal transformation insulation temperatures), thereby obtaining a larger number of heat treatment process parameter sample data.

[0039] Preferably, the phase change ball can be an aluminum alloy ball with a phase change temperature lower than the heat treatment temperature of the bearing steel forging, or a phase change ball made of other materials with a relatively lower phase change temperature, and the minimum diameter of the phase change ball is determined by thermodynamic calculation.

[0040] Preferably, the phase change ball may also be a composite phase change ball in which an aluminum alloy shell is filled with a paraffin phase change material.

[0041] In the present invention, the phase change ball is fixed to the heat protection insulation tube by screws.

[0042] Preferably, the heat treatment temperature variable temperature control rack of the present invention is further provided with a station for openly placing heat treatment test blocks.

[0043] Preferably, the heat protection insulation pipe includes a metal pipe body, a detachable pipe cover plate arranged at both ends of the metal pipe body, and a high-temperature refractory fiber insulation layer respectively arranged on the outer surface of the metal pipe body and the outer side of the pipe cover plate.

[0044] The high-temperature refractory fiber insulation layer on the outer surface of the above-mentioned thermal protection insulation tube can effectively reduce the heat transfer from the heat treatment furnace to the inside of the thermal protection insulation tube. It cooperates with the phase change ball arranged inside the thermal protection insulation tube and the bimetallic hot air flow baffle arranged at the orifice of the thermal protection insulation tube to realize the regulation of the hot air flow entering the thermal protection insulation tube, thereby effectively regulating the heat treatment temperature in the thermal protection insulation tube, thereby obtaining training sample data for each heat treatment test block with fine-tuning changes in the heat treatment temperature.

[0045] The forging method of bearing steel for wind turbine main shaft bearings based on forging tests of the present invention can also be applied to the forging of various bearing forgings in other industries.

[0046] The beneficial effects of the present invention are: First, the present invention provides a forging method for wind turbine main shaft bearing steel based on forging tests. Forging process parameters are initially optimized through thermal simulation and finite element analysis of the forging process. Actual forging tests are then conducted using a high-reduction forging process based on a large anvil width ratio. Sample data from the forging tests is evaluated using a comprehensive forging performance evaluation model to obtain forging process parameters with improved forging performance. These optimized forging process parameters are then applied to the actual forging process for bearing steel forgings. This improves the forging performance of bearing steel forgings used in wind turbine main shaft bearings.

[0047] Second, the present invention provides a forging method for bearing steel for wind turbine main shaft bearings based on forging tests. During the forging process, a forging operation robot that replaces a red-hot transfer heat protection device is used to perform the transfer operation of the forgings. This can ensure that the distances between the forging heating equipment, the forging press and the ring rolling machine are relatively far, and that the temperature of the forgings does not drop when the ambient temperature is low. It can also balance the temperature of various parts of the forging surface, thereby effectively reducing forging defects and improving the stability of the forging quality.

[0048] Third, the present invention provides a forging method for bearing steel for wind turbine main shaft bearings based on forging tests. This method obtains a large amount of sample data for forging process parameters through forging tests. This sample data is trained using an AI data analysis and prediction model, which can then be used to further predict forging process parameters with better forging performance. Furthermore, when the training samples include sample data on the chemical composition of forgings, it is possible to use AI data analysis and prediction to find a forging composition formula with slight changes in chemical composition but better overall forging performance, providing a new solution for the research and development of forgings with better overall performance. The forging process parameters predicted through AI data analysis can be put into production after verification.

[0049] Fourth, the present invention provides a forging method for bearing steel for wind turbine main shaft bearings based on forging tests. When molten steel is smelted and made into billets, reverse negative intervention measures of quality control points are adopted to achieve economical and cheap acquisition of training samples. The reverse negative intervention measures are adopted to increase the unevenness of the chemical composition distribution of the molten steel, so that when sampling is performed in the prefabricated steel billet after casting or continuous casting, more various test samples with fine-tuning changes in chemical composition content can be obtained. This overcomes the disadvantage that when the same batch of molten steel is conventionally cast or continuously cast, its chemical composition content is relatively uniformly distributed inside the prefabricated steel billet, making it difficult to obtain more various test sample data with fine-tuning changes in chemical composition content. This greatly reduces the cost of the forging test and the production cycle of the forging test.

[0050] Fifth, the present invention provides a forging method for bearing steel for wind turbine main shaft bearings based on a forging test. During heat treatment of the test blocks, a specially designed temperature control rack with variable heat treatment temperature is adopted. This can achieve that when a large number of heat treatment test blocks are placed in the same heat treatment furnace for heat treatment, the heat treatment temperature of each heat treatment test block is different (with fine-tuning changes relative to the pre-set heat treatment temperature), thereby obtaining more sample data of test specimens with heat treatment temperatures (including the heating and holding temperature of the first stage of heat treatment and the isothermal transformation holding temperature of the second stage of heat treatment), thereby further significantly reducing the cost of the forging test and the production cycle of the forging test. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram of a process flow of a forging method for a wind turbine main shaft bearing steel based on a forging test of the present invention; Figure 2 This is a schematic diagram of the structure of a hot-transfer heat protection device installed on the front end arm of a forging operation manipulator; Figure 3 Figure 2 A partial enlarged view of Figure 4 This is a schematic diagram of the structure of a temperature control rack with variable heat treatment temperature; Figure 5 yes Figure 3 Schematic diagram of the structure of the thermal protection insulation pipe part.

[0052] In the figure: 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. Joystick, 11. Sleeve, 12. Moving rod, 13. Slider, 14. U-shaped bracket, 15. Hollow tube, 16. Infrared temperature detection sensor, 17. Annular thermal radiation reflector, 18. High-temperature furnace temperature tracker, 19. Thermocouple, 20. Rack, 21. Thermal protection insulation tube, 22. Phase change ball, 23. Hot air flow transfer hole, 24. Hot air flow baffle, 25. Screw, 26. Metal tube, 27. Tube cover, 28. High-temperature refractory fiber insulation layer, 29. Ball cap sheet. DETAILED DESCRIPTION

[0053] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0054] like Figures 1 to 5 The present invention shows an embodiment of a forging method for bearing steel for wind turbine main shaft bearings based on forging tests. The method includes conducting forging tests on a number of bearing steel forgings under different forging process parameters, sampling the forgings obtained from the forging tests, and obtaining a large number of test specimens. The test specimens are then tested and performance evaluated, and optimized forging process parameters are obtained based on the performance evaluation results. The optimized forging process parameters are used as 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 includes the following steps set in sequence: (1) Modeling analysis and preliminary optimization of forging process parameters: A finite element model of a bearing steel forging is established. The performance indicators of the bearing steel forging are used as optimization targets. The initial values ​​of the forging process parameters are set. Based on the initial values ​​of the forging process parameters, the forging process parameters are preliminarily optimized through thermal simulation of the forging process and finite element analysis calculations to obtain the theoretical forging process parameters of the bearing steel forging. The performance indicators of the bearing steel forging include tensile strength, cross-sectional shrinkage, and grain size. 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 forged, and based on the theoretical forging process parameters of the bearing steel forgings, set the upper and lower floating ranges of the forging process parameters during the forging test, assign values ​​to the forging process parameters of each bearing steel forging that needs to be forged, and make the assigned values ​​of the forging process parameters of each bearing steel forging different from each other within the upper and lower floating ranges, so as to obtain the test forging process parameters of each bearing steel forging; the test forging process parameters include the test forging heating temperature and the test post-forging heat treatment temperature; Among them, the values ​​assigned to the forging process parameters of the bearing steel forgings are different from each other within the upper and lower floating ranges, which may be different forging heating temperatures or different post-forging heat treatment temperatures; that is, it is necessary to ensure that the values ​​of at least one of the experimental forging process parameters, the forging heating temperature and the post-forging heat treatment temperature, are different.

[0055] Preferably, the test forging heating temperature and the test post-forging heat treatment temperature of each bearing steel forging can be varied within a temperature range of ±25°C.

[0056] (3) Forging test: According to the forging process parameters 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 roughing molten steel in an electric arc furnace, refining molten steel outside the furnace, and vacuum carbon deoxidation treatment, and then formed into a number of prefabricated steel billets by casting or continuous casting; wherein, during the roughing molten steel in the electric arc furnace, refining molten steel outside the furnace, and vacuum carbon deoxidation treatment processes, molten steel smelting quality control points are set at various key process nodes. By setting the molten steel smelting quality control points, the process parameters of the molten steel smelting are controlled within the set range, thereby controlling the stability of the quality of the molten steel smelting billets; S2. Heating before forging: Place the prefabricated steel billet in a forging heating furnace and heat it to the forging heating temperature set in the forging test planning design; S3. Forging: The steel billet in the forging heating furnace is removed and transferred to a forging press for forging, punching, and finishing 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 a fine and uniform internal structure and heal 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 formed into a ring-shaped forging blank by ring rolling; S5. Making heat treatment test pieces: cutting the forging blank and rolling 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 plan design; S7. Forging Sampling and Testing: Samples are collected from heat-treated test blocks of bearing steel forgings using different experimental forging process parameters to obtain a number of test specimens, and each test specimen is tested. The test items include A, B, and C, where A represents tensile strength data, B represents cross-sectional reduction data, and C represents grain size data obtained through metallographic structure testing. S8. Data collation and classification: For each test sample, if any one of the three test items A, B, and C is unqualified, the forging process parameters of the corresponding test sample will be classified as unqualified forging process parameters; if all three test items A, B, and C are 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 for subsequent forging performance evaluation; the data of the test samples corresponding to the unqualified forging process parameters will be eliminated; S9. Establish a forging performance evaluation model and obtain the optimization of 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 forging performance evaluation formula M=(α×A+β×B+γ×C)÷(A+B+C); among them, 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 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 when forging bearing steel for wind turbine main shaft bearings.

[0057] Preferably, in the forging test of step (3), a multi-joint forging operation manipulator is further provided which can realize the transfer of forgings from the forging heating furnace to the forging press and from the forging press to the ring rolling machine in sequence, and the multi-joint forging operation manipulator is movably provided on the guide rail of the workshop site; a clamp 4 for clamping the bearing steel forging 2 is provided on the front end manipulator arm 1 of the multi-joint forging operation manipulator, and a hot transfer heat protection device for preventing the temperature of the forging from decreasing during the transfer process is also provided on the front end manipulator arm 1 of the multi-joint forging operation manipulator; the hot transfer heat protection device includes a telescopic bellows assembly provided on the front end manipulator arm 1 of the multi-joint forging operation manipulator, which can surround and remove the bearing steel forging 2 clamped by the clamp 4 from the periphery, and the telescopic bellows assembly has a built-in radiation heater 5 for radiant heating of the forging.

[0058] Preferably, the clamper 4 is a finger cylinder.

[0059] Preferably, the radiation heater 5 includes a number of annular carbon heating tubes 8, and the telescopic bellows assembly includes a flange ring 6 fixed on the front end robot arm 1 of the multi-joint forging operation robot and located at the rear side of the clamp 4, a metal bellows 7 connected to the front end surface of the flange ring 6, a reflective film coated on the inner wall of the metal bellows 7, and a number of annular carbon heating tubes 8 coaxially arranged near the inner wall of the metal bellows 7 and arranged at intervals along the axial direction. The rear end of the flange ring 6 is provided with a pair of servo electric push rods 9 connected to the controller of the multi-joint forging operation robot, and the front end of the telescopic rod of the servo electric push rod 9 is connected to the front end of the metal bellows 7; wherein, the power of the annular carbon heating tube 8 near the front end of the metal bellows 7 is greater than the power of the annular carbon heating tubes at other positions.

[0060] In this embodiment, the telescopic rod of the servo electric linear actuator 9 is located outside the metal bellows 7. A joystick 10 is laterally disposed at the front end of the telescopic rod of the servo electric linear actuator 9 and is connected to the front end of the metal bellows 7. When the telescopic rod of the servo electric linear actuator 9 is extended or retracted, the joystick 10 drives the front end 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 outside. When the front end of the metal bellows 7 moves backward, it can completely expose the bearing steel forging 2 on the clamp 4.

[0061] In this embodiment, a heating tube automatic distributor is also provided between the telescopic rod of the servo electric push rod 9 and the metal bellows 7 for automatically and evenly distributing the annular carbon heating tubes 8 inside the metal bellows 7 along the axial direction; the heating tube automatic distributor includes a number of sliding sleeves 11 movably arranged on the outer circle of the telescopic rod of the servo electric push rod 9, a moving rod 12 fixed on the sliding sleeve 11 and arranged transversely relative to the telescopic rod of the servo electric push rod 9, a hook hole provided at the cantilever end of the moving rod 12, and a number of rod body mounting through holes correspondingly opened on the tube wall of the metal bellows 7. The cantilever end of the moving rod 12 passes through the rod body mounting through hole of the metal bellows 7 and enters the interior of the metal bellows 7. Each of the annular carbon heating tubes 8 is respectively hung on the hook hole of the cantilever end of the moving rod 12 at the corresponding position through a metal wire.

[0062] Preferably, the heating power of each of the annular carbon heating tubes 8 is adjustable.

[0063] Preferably, a number of sliders 13 are also movably provided on the outer circle of the telescopic rod of the servo electric push rod 9, and a U-shaped bracket 14 is connected to the slider 13. The U-shaped bracket 14 is connected to a hollow tube body 15 arranged transversely relative to the telescopic rod of the servo electric push rod 9. A number of tube body mounting through holes are provided on the tube wall of the metal bellows 7. The cantilever end of the hollow tube body 15 passes through the tube body mounting through hole and enters the interior of the metal bellows 7. The end of the hollow tube body 15 connected to the U-shaped bracket 14 is inserted into the interior of the hollow tube body 15. There is an infrared temperature detection sensor 16, and the infrared detection light of the infrared temperature detection sensor 16 passes through the inner hole of the hollow tube body 15 and enters the interior of the metal bellows 7; the infrared temperature detection sensor 16 is connected to the controller of the multi-joint forging operation robot. When the transportation distance of the bearing steel forging 2 is long, the multi-joint forging operation robot senses the temperature of different areas of the forging through the infrared temperature detection sensor 16, and adjusts the heating power of each annular carbon heating tube 8 to ensure that the surface temperature of the forging reaches the set value during the transportation process and achieves temperature balance at various locations on the surface of the forging.

[0064] 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 .

[0065] 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 toward the direction away from the mouth of the metal bellows.

[0066] 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 transportation and achieves temperature balance at various locations on the forging surface.

[0067] As a further improvement of this embodiment, in step S9, forging performance evaluation and forging process parameter optimization, an artificial intelligence (AI) data analysis and prediction model is further 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 an artificial intelligence (AI) model: An artificial intelligence (AI) data analysis and prediction model is selected as the 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, and a forging performance data output layer, which are sequentially arranged and connected. T2. Obtaining 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 training sample data for the forging process data input layer of the AI ​​data analysis and prediction model. At the same time, use the corresponding forging performance comprehensive evaluation value M as training sample data for 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 the artificial intelligence (AI) data analysis and prediction model after one iteration; T4. Prediction, verification and optimization: Based on the AI ​​data analysis and 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 and prediction model is used to output the predicted value of the comprehensive evaluation value M of the forging performance; the predicted value of each M is compared 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 the larger M value are obtained, and they are used as the forging process parameters when forging bearing steel for wind turbine main shaft bearings for formal production.

[0068] Preferably, in the step S1, when molten steel is smelted to form billets, a number of prefabricated steel billets with slightly changed chemical composition contents are prepared in advance; at the same time, in the step T2, when obtaining training sample data, a forging chemical composition detector is used to detect each test sample with slightly changed chemical composition contents, 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.

[0069] Preferably, the forging chemical composition detector can be a spectrometer, an atomic absorption spectrometer or other detection instruments.

[0070] As a further improvement of the present invention, in the step S1, 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 forging test process of the step (3), the training sample data required in the step T2, obtaining the training sample data, is obtained by adopting an economical and cheap method for obtaining training sample data; the economical and cheap method for obtaining training sample data includes, in the step S1, 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 heats of molten steel smelting, when casting or continuous casting is carried out, the molten steel casting or continuous casting temperature quality control point is controlled. The method comprises the following steps: performing reverse negative intervention on at least one of the quality control points, the molten steel casting or continuous casting speed quality control point and the molten steel casting or continuous casting cooling speed quality control point; that is, appropriately relaxing the stricter 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, allowing the quality control parameters to fluctuate within a wider range, so as to appropriately increase the negative effect of the uneven distribution of the internal chemical composition of the precast steel billet, so that when step S5, when making the heat treatment test piece, there are slight differences in the internal chemical composition of each heat treatment test block cut from the forging billet rolling ring and each test sample obtained when step S7, when sampling and testing the forging, so that a large number of training samples with fine-tuned changes in the chemical composition content can be obtained by sampling the precast steel billets prepared from the same batch of molten steel.

[0071] Preferably, the reverse negative intervention measures of the molten steel casting or continuous casting temperature quality control point include relaxing the variation range of the molten steel casting or continuous casting temperature, or manually intervening in the control of the molten steel casting or continuous casting temperature, thereby affecting the distribution of solutes inside the prefabricated steel billet after casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting speed quality control point include appropriately increasing or decreasing the molten steel casting or continuous casting speed, or manually intervening in the molten steel casting or continuous casting speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting sends dendrite segregation; wherein, the manual intervention in the molten steel casting or continuous casting speed includes adopting variable speed intermittent casting or continuous casting; the reverse negative intervention measures of the molten steel casting or continuous casting cooling speed quality control point include relaxing the variation range of the molten steel casting or continuous casting cooling speed, or manually intervening in the control of the variation range of the molten steel casting or continuous casting cooling speed, so that the internal structure of the prefabricated steel billet after casting or continuous casting segregates.

[0072] In this embodiment, the hot-steam transfer heat 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 forging 2 for wind turbine main shaft bearings adopts the forging process of steps S1 to S4, and the following process steps are added after step S1, molten steel smelting and blanking, and before step S2, pre-forging heating: S1A, Electroslag Remelting: The precast steel billet obtained by casting or continuous casting is subjected to secondary refining in the crystallizer of an Ar gas-protected electroslag remelting furnace under an Ar gas-protected atmosphere. After cooling and demoulding in the crystallizer, a refined and purified precast steel billet of bearing steel is formed.

[0073] As a further improvement of this embodiment, the economical and cheap acquisition method of the 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 that can achieve fine-tuning of temperature changes at various locations and a high-temperature resistant furnace temperature tracker 18 that is matched with the heat treatment temperature variable temperature control rack are used, and all the heat treatment test blocks 3 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 the heat treatment test blocks and the high-temperature resistant furnace temperature tracker 18 are placed together in the same heat treatment. The heat treatment test blocks 3 are placed in the furnace, 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 has different heat treatment temperatures (the temperature of each heat treatment test block 3 is changed and fine-tuned) in the heat treatment test conducted in the same heat treatment furnace.

[0074] Preferably, the heat treatment temperature variable temperature control rack includes a rack 20, a number of heat protection insulation tubes 21 spaced apart on the rack 20, a number of phase change balls 22 arranged in the heat protection insulation tube 21 along the axial direction of the heat protection insulation tube 21 and made of phase change heat absorbing material, a number of hot air flow transfer holes 23 spaced apart on the tube wall of the heat protection insulation tube 21 along the axial direction of the heat protection insulation tube 21, and the phase change balls 22 and the hot air flow transfer holes 23 are alternately arranged in sequence along the axial direction, and the hot air flow transfer holes 23 are arranged On the tube wall of the heat protection insulation tube 21 located between two adjacent phase change balls 22, a test block placement space for placing the heat treatment test block 3 is formed in the space inside the heat protection insulation tube 21 between two adjacent phase change balls 22; a heat flow baffle 24 is provided at the orifice position of the heat flow transfer hole 23, and a spacing for limiting the passage of the heat flow is provided between the heat flow baffle 24 and the orifice of the heat flow transfer hole 23, and the spacing between each of the heat flow baffles 24 and the orifice of the heat flow transfer hole 23 on the same heat protection insulation tube 21 is different from each other.

[0075] In this embodiment, a thermocouple mounting hole for inserting a thermocouple 19 to measure the heat treatment temperature inside the thermal protection insulation tube 21 is further provided on the outer circle of the thermal protection insulation tube 21 .

[0076] Preferably, an adapting hole may be provided on the treatment test block 3, so that the thermocouple is directly and completely in contact with the adapting hole of the heat treatment test block.

[0077] Preferably, the heat treatment of the heat-treated test block 3 may be performed by isothermal spheroidizing annealing.

[0078] In this embodiment, the hot air flow baffle 24 is fixed to the tube wall of the heat protection insulation tube 21 by screws 25 .

[0079] Taking into account that the temperature of the isothermal spheroidizing annealing heat treatment usually involves the heating and holding temperature of the first stage of heat treatment and the isothermal transformation holding temperature of the second stage of heat treatment, in order to achieve fine-tuning combined changes of the heating and holding temperature and the isothermal transformation holding temperature of each heat treatment specimen, so as to obtain more sample data of different heat treatment temperature combinations (heating and holding temperature and isothermal transformation holding temperature) of the heat treatment specimen 3, the hot air flow baffle 24 adopts a bimetallic hot air flow baffle, and the bimetallic hot air flow baffle is fixedly connected to the outer pipe wall of the thermal protection insulation pipe 21 through a cantilever installation method.

[0080] Preferably, a spherical cap sheet 29 is provided on a side of the bimetallic hot air flow baffle 24 facing the hot air flow transfer hole, and a distance is provided between the spherical cap sheet 29 and the opening of the hot air flow transfer hole 23 .

[0081] Preferably, according to the direction of deformation of the bimetallic hot air flow baffle 24 due to heat, the bimetallic hot air flow baffle 24 can be installed in a forward direction so that the bimetallic hot air flow baffle 24 is deformed in a direction close to the orifice when the temperature in the furnace rises, or can be installed in a reverse direction so that the bimetallic hot air flow baffle 24 is deformed in a direction away from the orifice when the temperature in the furnace rises, thereby realizing the adjustment of the heat transfer airflow volume in the heat treatment furnace and the thermal protection insulation tube, and then realizing the fine-tuning of the increase and decrease of the heat treatment temperature inside the thermal protection insulation tube 21, thereby obtaining more heat treatment temperature data samples of different heat treatment temperature combinations of the heat treatment test blocks 3.

[0082] Preferably, a flexible high-temperature fire-resistant insulation layer is provided on the outer side of the bimetallic hot air flow baffle 24 facing away from the hot air flow transfer hole 24 .

[0083] By setting the bimetallic hot air flow baffle 24, the combined changes of the heating and holding temperature in the first stage and the isothermal transformation and holding temperature in the second stage during the isothermal spheroidizing annealing heat treatment can be further realized, thereby collecting more heat treatment process parameter sample data with fine-tuning changes in the heat treatment temperature.

[0084] In this embodiment, the diameter setting of the phase change ball 22 can be obtained through thermodynamic calculations to ensure that the phase change ball has sufficient heat storage performance during the entire heat treatment process, so that the temperature inside the thermal protection insulation tube will not be out of control within the specified heat treatment time, and it can always maintain a relatively constant temperature difference relative to the temperature outside the thermal protection insulation tube (i.e., the internal temperature of the heat treatment furnace).

[0085] By setting the distances between the hot air flow baffle 24 and the hot air flow transfer holes 23 on the heat protection insulation tube 21 to be different, the temperatures of the various test block placement spaces inside the heat protection insulation tube 21 for placing the heat treatment test blocks 3 are different.

[0086] Furthermore, by setting the distances between the hot air flow baffle 24 and the orifice of the hot air flow transfer hole 23 on the thermal protection insulation tube 21 to be different from each other, and setting the hot air flow baffle 24 to be a bimetallic hot air flow baffle, different heat treatment temperature combinations of the heat treatment test block 3 can be achieved, that is, different combinations of heating and heating insulation temperature and isothermal transformation insulation temperature, so that each heat treatment test block 3 placed in the same heat treatment furnace has a different heat treatment temperature combination (different combinations of heating and heating insulation temperature and isothermal transformation insulation temperature), thereby obtaining a larger number of heat treatment process parameter sample data.

[0087] Preferably, the phase change ball 22 can be an aluminum alloy ball with a phase change temperature lower than the heat treatment temperature of the bearing steel forging, or a phase change ball made of other materials with a relatively lower phase change temperature, and the minimum diameter of the phase change ball is determined by thermodynamic calculation.

[0088] Preferably, the phase change ball 22 may also be a composite phase change ball having an aluminum alloy shell filled with paraffin phase change material.

[0089] In this embodiment, the phase change ball 22 is fixed to the thermal protection insulation tube 21 by screws 25 .

[0090] Preferably, the heat treatment temperature variable temperature control rack of this embodiment is further provided with a station for openly placing the heat treatment test block 3.

[0091] Preferably, the thermal protection insulation pipe 21 includes a metal pipe body 26, a detachable pipe cover plate 27 arranged at both ends of the metal pipe body 26, and a high-temperature refractory fiber insulation layer 28 respectively arranged on the outer surface of the metal pipe body 26 and the outer side of the pipe cover plate 27.

[0092] The high-temperature refractory fiber insulation layer on the outer surface of the above-mentioned thermal protection insulation tube 21 can effectively reduce the heat transfer from the heat treatment furnace to the inside of the thermal protection insulation tube. It cooperates with the phase change ball 22 arranged inside the thermal protection insulation tube 21 and the bimetallic hot air flow baffle 24 arranged at the orifice of the thermal protection insulation tube 21 to realize the regulation of the hot air flow entering the thermal protection insulation tube 21, thereby effectively regulating the heat treatment temperature in the thermal protection insulation tube 21, thereby obtaining training sample data for each heat treatment test block 3 with fine-tuning changes in the heat treatment temperature.

[0093] The forging method of bearing steel for wind turbine main shaft bearings based on forging tests in this embodiment can also be applied to the forging of various bearing forgings in other industries.

[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A heat treatment device for forging test of bearing steel for wind turbine main shaft bearing, characterized in that: The heat protection insulation tube includes a heat protection insulation tube for placing heat treatment test blocks, 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, and 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 holes are arranged on the tube wall of the heat protection insulation tube between two adjacent phase change balls, and the space between two adjacent phase change balls inside the heat protection insulation tube forms a test block placement space for placing the heat treatment test blocks; a heat flow baffle is provided at the orifice position of the heat flow transfer hole, and a distance for limiting the passage of hot air is provided between the heat flow baffle and the orifice of the heat flow transfer hole, and the distances between each heat flow baffle and the orifice of the heat flow transfer hole on the same heat protection insulation tube are different from each other.

2. A heat treatment device for forging test of bearing steel for wind turbine main shaft bearings according to claim 1, characterized in that: There are multiple thermal protection insulation tubes, and the multiple thermal protection insulation tubes are arranged at intervals on the rack, thereby forming a temperature control rack with variable heat treatment temperature; during the heat treatment test, each heat treatment test block is placed in each test block placement space of the thermal protection insulation tube.

3. The heat treatment device for forging test of bearing steel for wind turbine main shaft bearing according to claim 1, characterized in that: It is also equipped with a high-temperature resistant furnace temperature tracker; a thermocouple mounting hole for inserting a thermocouple to measure the heat treatment temperature inside the thermal protection insulation tube is also provided on the outer circle of the thermal protection insulation tube; each heat treatment test block is respectively connected to each thermocouple led out from the high-temperature resistant furnace temperature tracker for measuring the actual heat treatment temperature of each heat treatment test block.

4. The heat treatment device for forging test of bearing steel for wind turbine main shaft bearing according to claim 1, characterized in that: The hot air flow baffle is a bimetallic hot air flow baffle, and the bimetallic hot air flow baffle is fixedly connected to the outer pipe wall of the heat protection insulation pipe through a cantilever installation method.

5. A heat treatment device for forging test of bearing steel for wind turbine main shaft bearing according to claim 4, characterized in that: A spherical cap sheet body is provided on one side of the bimetallic hot air flow baffle facing the hot air flow transfer hole, and a distance is provided between the spherical cap sheet body and the orifice of the hot air flow transfer hole.

6. A heat treatment device for forging test of bearing steel for wind turbine main shaft bearings according to claim 4, characterized in that: The bimetallic hot air flow baffle is installed in a forward direction so that when the temperature in the furnace increases, the bimetallic hot air flow baffle is deformed toward the direction close to the orifice, thereby achieving fine adjustment of the increase in the heat treatment temperature inside the thermal protection insulation pipe.

7. A heat treatment device for forging test of bearing steel for wind turbine main shaft bearings according to claim 4, characterized in that: The bimetallic hot air flow baffle is installed in reverse so that when the temperature in the furnace increases, the bimetallic hot air flow baffle is deformed in a direction away from the orifice, thereby achieving a fine-tuning of the heat treatment temperature inside the thermal protection insulation tube.

8. The heat treatment device for forging test of bearing steel for wind turbine main shaft bearing according to claim 4, characterized in that: A flexible high-temperature fire-resistant insulation layer is provided on the outer side of the bimetallic hot air flow baffle facing away from the hot air flow transfer hole.

9. The heat treatment device for forging test of bearing steel for wind turbine main shaft bearing according to claim 1, characterized in that: The phase change ball is an aluminum alloy ball whose phase change temperature is lower than the heat treatment temperature of the bearing steel forging, or the phase change ball is a composite phase change ball with an aluminum alloy shell filled with paraffin phase change material.

10. The heat treatment device for forging test of bearing steel for wind turbine main shaft bearing according to claim 1, characterized in that: The heat protection insulation pipe includes a metal pipe body, detachable pipe cover plates arranged at both ends of the metal pipe body, and high-temperature fire-resistant fiber insulation layers respectively arranged on the outer surface of the metal pipe body and the outer side of the pipe cover plates.

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