An electromagnetic-assisted heat treatment method for aero-engine bearing steel

Abstract

The present invention provides an electromagnetic-assisted heat treatment method for aero-engine bearing steel, which relates to the technical field of heat treatment and includes the following steps: S1: Heat the aero-engine bearing steel to a preset austenitizing temperature T A , and hold for a preset time t q . After austenitization, put the aero-engine bearing steel into a salt bath for isothermal quenching; S2: After quenching, place the aero-engine bearing steel in an electromagnetic energy generator and perform alternating electromagnetic field treatment on the aero-engine bearing steel; S3: Perform a single tempering heat treatment on the aero-engine bearing steel. The present invention combines ultrafine-grained duplex quenching, microstructure stabilization electromagnetic field regulation, and simplified tempering, reasonably matches the process conditions of the alternating electromagnetic field and heat treatment, and realizes the stabilization of retained austenite in the bearing and the improvement of strength and toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment, and particularly relates to an electromagnetic-assisted heat treatment method for aero-engine bearing steel. Background Art

[0002] Aero-engine bearings are key high-speed rotating components, with extremely high requirements for their material properties. Especially in high-temperature and high-speed working environments, they need to have excellent strength and toughness. Traditional heat treatment methods such as martensitic quenching and high-temperature tempering are often used to improve the properties of bearing steel, but there are some problems. During the quenching process, rapid cooling leads to the formation of martensite structure, and the high-temperature tempering treatment eliminates the retained austenite. These processes will reduce the toughness of the bearing steel and increase the risk of brittle fracture. In addition, the traditional heat treatment method adopts a process plan of quenching plus three times of tempering, which is time-consuming, energy-consuming, and inefficient, and it is difficult to meet the requirements of modern aero-engine manufacturing. Summary of the Invention

[0003] In view of this, the present invention provides an electromagnetic-assisted heat treatment method for aero-engine bearing steel, which combines ultrafine-grained duplex quenching, microstructure stabilization electromagnetic field regulation, and simplified tempering, reasonably matches the process conditions of alternating electromagnetic field and heat treatment, and realizes the stabilization of retained austenite in the bearing and the improvement of strength and toughness.

[0004] The technical object of the present invention is achieved as follows:

[0005] The present invention provides an electromagnetic-assisted heat treatment method for aero-engine bearing steel, including the following steps:

[0006] S1: Heat the aero-engine bearing steel to a preset austenitizing temperature T A , and hold for a preset time t q , and then put the austenitized aero-engine bearing steel into a salt bath for isothermal quenching;

[0007] S2: After quenching, place the aero-engine bearing steel in an electromagnetic energy generator and perform alternating electromagnetic field treatment on the aero-engine bearing steel;

[0008] S3: Perform a single tempering heat treatment on the aero-engine bearing steel.

[0009] On the basis of the above technical solution, preferably, step S2 includes:

[0010] S21: Divide the aero-engine bearing steel into N p zones along the cross-section;

[0011] S22: Select one zone N i ;

[0012] S23: Set the parameters of the alternating electromagnetic field treatment, and pass the electromagnetic energy generator to the zone N iPerform processing according to the parameters of the alternating electromagnetic field;

[0013] S24: Repeat step S23 at time intervals of t 1 seconds until the partition N i is subjected to N times of alternating electromagnetic field processing;

[0014] S25: Repeat steps S22 - S24 until all p N partitions are processed.

[0015] Based on the above technical solution, preferably, the parameters of the alternating electromagnetic field processing include the electromagnetic energy loading method, the electromagnetic energy loading frequency, and the pulse waveform of the electromagnetic energy.

[0016] Based on the above technical solution, preferably, the electromagnetic energy loading method includes a single electric field, a single magnetic field, and an electromagnetic composite field;

[0017] The electromagnetic energy loading frequency f is set to f =(0.1 - 0.6) f r , with the unit of Hz, where f r is the resonance frequency of the aero-engine bearing steel;

[0018] The pulse waveform of the electromagnetic energy includes a sine wave, a square wave, and a triangular wave.

[0019] Based on the above technical solution, preferably, in each alternating electromagnetic field processing, the number of electromagnetic pulses applied is 5 - 10.

[0020] Based on the above technical solution, preferably, when the electromagnetic energy loading method is a single electric field, under the electric field loading, the current density is set to , with the unit of A / mm 2 , where is the current density coefficient, is the electromagnetic energy loading frequency, is the specific heat capacity of the aero-engine bearing steel, is the electromagnetic energy loading area.

[0021] Based on the above technical solution, preferably, when the electromagnetic energy loading method is a single magnetic field, under the magnetic field loading, the magnetic field strength is set to , with the unit of A / mm, where is the magnetic field strength coefficient, is the electromagnetic energy loading frequency, is the specific heat capacity of the aero-engine bearing steel, is the electromagnetic energy loading area.

[0022] Based on the above technical solution, preferably, when the electromagnetic energy loading method is an electromagnetic composite field, under the loading of the electromagnetic composite field, the current density is set to , and its unit is A / mm 2 , where I is the current density set in a single electric field; the magnetic field intensity is set to , and its unit is A / mm, where H is the magnetic field intensity set in a single magnetic field.

[0023] Based on the above technical solution, preferably, in step S1, the preset austenitizing temperature Acm is the austenite transformation temperature of the aero-engine bearing steel; the preset time , is the heat preservation coefficient, is the density of the aero-engine bearing steel, is the volume of the aero-engine bearing steel; the temperature of the salt bath is T q , , refers to the starting temperature of the transformation of the aero-engine bearing steel from austenite to martensite.

[0024] Based on the above technical solution, preferably, in step S21, the number of partitions , is the cross-sectional area of the aero-engine bearing steel, is the electromagnetic energy loading area;

[0025] In step S23, the number of times i of performing alternating electromagnetic field treatment on partition N , is the conductivity of the aero-engine bearing steel;

[0026] In step S24, the time interval t 1 is 2 - 6 seconds.

[0027] The method of the present invention has the following beneficial effects compared with the prior art:

[0028] (1) The present invention combines ultra-fine grain duplex quenching, microstructure stabilization electromagnetic field regulation, and simplified tempering, greatly reducing the heat treatment time and energy consumption, giving full play to the advantages of electromagnetic field regulation, and at the same time making up for the limitations of traditional heat treatment methods;

[0029] (2) By adopting reasonable parameters of alternating electromagnetic field, the present invention realizes the stabilization of retained austenite in aero-engine bearing steel. Since the massive retained austenite in the aero-engine bearing steel continues to nucleate and form fine lath martensite under the action of alternating electromagnetic field treatment, the growth space of martensite during subsequent tempering is restricted, thus overall refining the structure of the aero-engine bearing steel; the electromagnetic field regulation will further promote the transfer of supersaturated carbon in martensite to retained austenite, and then promote the enrichment of carbon in retained austenite. Therefore, the retained austenite has better thermal and mechanical stability, and finally makes the aero-engine bearing steel have better strength and toughness after tempering;

[0030] (3) By introducing electromagnetic field regulation between quenching and tempering, the present invention directly promotes the decomposition of retained austenite and stabilizes the metastable structure. Originally, three high-temperature temperings were required, but now only one high-temperature tempering is needed, which greatly improves the production efficiency and product quality. Brief Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 is the method flow chart of the embodiment of the present invention;

[0033] Figure 2 is the process flow schematic diagram of the embodiment of the present invention;

[0034] Figure 3 is the comparison chart of heat treatment analysis results of the embodiment of the present invention. Detailed Embodiments

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] As Figure 1 shown, the present invention provides an electromagnetic-assisted heat treatment method for aero-engine bearing steel, including the following steps:

[0037] S1: Heat the aero-engine bearing steel to a preset austenitizing temperature T A , and hold for a preset time t q, the austenitized aero-engine bearing steel is put into a salt bath for isothermal quenching;

[0038] S2: After quenching, the aero-engine bearing steel is placed in an electromagnetic energy generator, and the aero-engine bearing steel is subjected to an alternating electromagnetic field treatment;

[0039] S3: The aero-engine bearing steel is subjected to a single tempering heat treatment.

[0040] The main purpose of the present invention is to provide an electromagnetic-assisted heat treatment method for aero-engine bearing steel, which combines ultrafine-grained duplex quenching, microstructure stabilization electromagnetic field regulation, and simplified tempering, reasonably matches the process conditions of the alternating electromagnetic field and heat treatment, and realizes the stabilization of retained austenite in the bearing and the improvement of strength and toughness. The process is as Figure 2 shown.

[0041] Specifically, in an embodiment of the present invention, step S1 is ultrafine-grained duplex quenching, and the process includes:

[0042] The aero-engine bearing steel is heated to a preset austenitizing temperature T A , Acm is the austenite transformation temperature of the aero-engine bearing steel; and it is held for a preset time t q , , is the holding coefficient, is the density of the aero-engine bearing steel, is the volume of the aero-engine bearing steel; to austenitize the aero-engine bearing steel. Subsequently, the austenitized aero-engine bearing steel is put into a salt bath at a temperature of for isothermal quenching, where refers to the starting temperature of the transformation of the aero-engine bearing steel from austenite to martensite.

[0043] The purpose of step S1 is to obtain an ultrafine austenite and martensite mixed structure. During heat treatment, when heated to a certain temperature, the aero-engine bearing steel will undergo a phase transformation, changing from body-centered cubic ferrite to face-centered cubic austenite. This transformation temperature range has a starting temperature and an ending temperature, and the austenite transformation ending temperature of the aero-engine bearing steel is related to factors such as its chemical composition and heating rate. For different aero-engine bearing steels, Acm is used to represent its austenite transformation ending temperature, and in the present invention, the preset austenitizing temperature is set to , to ensure that the aero-engine bearing steel can be completely transformed into the austenite state. And Ms refers to the starting temperature of the transformation of the aero-engine bearing steel from austenite to martensite. Martensite is a metal microstructure that is formed by rapid cooling (quenching). When austenite reaches a certain temperature during cooling, it will start to transform into martensite, and this temperature is defined as Ms. The aero-engine bearing steel is heated to After that, austempering treatment is carried out, and the quenching temperature is . Select as the austempering temperature to control the process of martensite transformation and the final microstructure state. Isothermal holding at the Ms temperature can make the transformation of austenite to martensite proceed slowly and achieve a certain degree of incompleteness of the transformation, thereby obtaining a duplex microstructure (i.e., a microstructure in which austenite and martensite coexist).

[0044] Specifically, in one embodiment of the present invention, step S2 includes:

[0045] S21: Divide the aero-engine bearing steel along the cross-section into N p zones;

[0046] S22: Select one zone N i ;

[0047] S23: Set the alternating electromagnetic field treatment parameters, and process zone N i according to the alternating electromagnetic field treatment parameters through an electromagnetic energy generator;

[0048] S24: Repeat step S23 at time intervals of t 1 seconds until zone N i is subjected to N times of alternating electromagnetic field treatment;

[0049] S25: Repeat steps S22 - S24 until all N p zones are processed.

[0050] Specifically, the aero-engine bearing steel is divided along the cross-section into N p zones, and the number of zones , is the cross-sectional area of the aero-engine bearing steel, is the electromagnetic energy loading area. The purpose of zoning is to perform electromagnetic field treatment on the bearing steel more evenly and specifically. The number of zones is related to and , making the area of each zone reasonable to avoid uneven treatment due to too large a zone or reduced efficiency due to too small a zone; each zone is subjected to N times of alternating electromagnetic field treatment through an electromagnetic energy generator, , is the conductivity of the aero-engine bearing steel. The choice of the number of treatments N takes into account the response degree of the material to the electromagnetic field and the saturation effect of the treatment; the time interval t 1 between two consecutive alternating electromagnetic field treatments is 2 - 6 seconds. This interval allows the material to have time to respond and recover, avoiding fatigue or damage to the material caused by overly frequent treatment.

[0051] Specifically, when performing the alternating electromagnetic field treatment once, the set parameters of the alternating electromagnetic field treatment include the electromagnetic energy loading method, the electromagnetic energy loading frequency, and the pulse waveform of the electromagnetic energy. The electromagnetic energy loading method includes a single electric field, a single magnetic field, and an electromagnetic composite field; the electromagnetic energy loading frequency f is set to f =(0.1 - 0.6) f r , with the unit of Hz, where f r is the resonance frequency of the aero-engine bearing steel; the pulse waveform of the electromagnetic energy includes a sine wave, a square wave, and a triangular wave.

[0052] Specifically, when the electromagnetic energy loading method is a single electric field, under the electric field loading, the current density is set to , with the unit of A / mm 2 , where is the current density coefficient, is the electromagnetic energy loading frequency, is the specific heat capacity of the aero-engine bearing steel, is the electromagnetic energy loading area.

[0053] Specifically, when the electromagnetic energy loading method is a single magnetic field, under the magnetic field loading, the magnetic field intensity is set to , with the unit of A / mm, where is the magnetic field intensity coefficient, is the electromagnetic energy loading frequency, is the specific heat capacity of the aero-engine bearing steel, is the electromagnetic energy loading area.

[0054] Specifically, when the electromagnetic energy loading method is an electromagnetic composite field, under the electromagnetic composite field loading, the current density is set to , with the unit of A / mm 2 , where I is the current density set when it is a single electric field; the magnetic field intensity is set to , with the unit of A / mm, where H is the magnetic field intensity set when it is a single magnetic field.

[0055] Specifically, step S2 is the process of regulating the stable electromagnetic field of the structure. In this process, each partition is subjected to the alternating electromagnetic field treatment for multiple times (N times). The purpose is to promote the homogenization and stabilization of the material structure through the repeated action of the electromagnetic field.

[0056] When performing the N - time alternating electromagnetic field treatment on a single partition, the loading method of the electromagnetic field each time can be the same or different. For example:

[0057] 1) In all N treatments, the same electromagnetic field loading method (such as electromagnetic composite field loading) is adopted, and parameters such as the loading frequency and pulse waveform are kept the same. Its advantages are simple process and easy control, and it is suitable for materials with relatively stable responses to electromagnetic fields.

[0058] 2) In the N treatments, two or more different electromagnetic field loading methods are adopted (such as alternately using electromagnetic composite field loading and electromagnetic torsion field loading), or the loading frequency, pulse waveform and other parameters are changed under the same loading method. This scheme can achieve more refined microstructure control through the superposition of different electromagnetic field effects, and is suitable for materials that are relatively sensitive to electromagnetic fields.

[0059] 3) In the N treatments, the electromagnetic field loading method or parameters are gradually changed to achieve the progressive optimization of the electromagnetic field action. For example, a lower frequency and smaller pulse amplitude can be adopted in the initial stage, and then the frequency and amplitude can be gradually increased to adapt to the changes in the material microstructure.

[0060] Specifically, in the N times of alternating electromagnetic field treatments for each partition, a certain number of electromagnetic pulses will be applied. In the present invention, the number of electromagnetic pulses applied in each alternating electromagnetic field treatment is set to be 5 - 10.

[0061] An electromagnetic pulse refers to a high-intensity electromagnetic field applied in a short time, which can affect the microstructure and properties of materials. By controlling the number of pulses in each alternating electromagnetic field treatment, the effect of the electromagnetic field on the material can be optimized. If the number of pulses is too small, it may not be sufficient to cause significant changes in the material microstructure and properties; while if the number of pulses is too large, it may lead to excessive energy concentration and cause local damage to the material. Therefore, controlling the number of pulses in each alternating electromagnetic field treatment between 5 and 10 can ensure the full action of the electromagnetic field on the material while avoiding the negative impacts brought by over-treatment.

[0062] It should be noted that in each alternating electromagnetic field treatment, first, parameters such as the electromagnetic field loading method (such as electromagnetic composite field loading), loading frequency (such as 0.2fr) and pulse waveform (such as triangular wave) are set. Then, according to these parameters, a continuous alternating electromagnetic field is applied to the material. In this continuous process, the intensity of the electromagnetic field will change periodically according to the set waveform (such as triangular wave), and each cycle can be regarded as a "pulse". The number of pulses also refers to the number of times the electromagnetic field intensity changes periodically during the continuous process. For example: when the set loading frequency is 0.2fr, then the period of each "pulse" is 1 / (0.2fr). If 8 "pulses" are applied in an alternating electromagnetic field treatment, then the total duration of this treatment is 8 / (0.2fr).

[0063] In the present invention, the main purpose of the electromagnetic field regulation for tissue stabilization is to improve the tissue stability of aero-engine bearing steel, thereby enhancing its service performance and lifespan. 1. Improving the microstructure of the material: By precisely controlling the parameters of the electromagnetic field, such as frequency, intensity, waveform, etc., selective interaction with the microstructure of the material can be achieved. This interaction can promote the formation of beneficial phases and inhibit the generation of harmful phases, thus optimizing the microstructure of the material. The optimized microstructure has higher stability and can better resist various damages and degradations. 2. Reducing residual stresses: During the production and processing of aero-engine bearing steel, residual stresses are often introduced, which may have a negative impact on the performance and lifespan of the material. Through electromagnetic field regulation, these residual stresses can be effectively reduced or eliminated, putting the material in a more stable state. The reduction of residual stresses can improve the fatigue resistance of the material and extend its lifespan. 3. Promoting the uniform distribution of alloying elements: Aero-engine bearing steel usually contains multiple alloying elements, and the distribution of these elements has an important impact on the performance of the material. Electromagnetic field regulation can promote the diffusion and redistribution of alloying elements in the material, making their distribution more uniform. A uniform distribution of alloying elements can improve the mechanical properties of the material, such as strength, toughness, etc., and also enhance the corrosion resistance and oxidation resistance of the material. 4. Enhancing the thermal stability of the material: Aero-engine bearing steel needs to have good thermal stability. Through electromagnetic field regulation, the phase transformation temperature of the material can be increased, delaying the tissue evolution and performance degradation at high temperatures. This improvement in thermal stability enables the material to maintain good mechanical properties and dimensional stability at high temperatures, thus meeting the demanding working conditions of aero-engines.

[0064] Specifically, in an embodiment of the present invention, step S3 is simplified tempering, which performs a single tempering heat treatment on the aero-engine bearing steel. Specifically, the aero-engine bearing steel is heated to 530°C - 550°C and held for 2 hours, followed by one tempering.

[0065] The purpose of step S3 is to further optimize the microstructure and performance of the aero-engine bearing steel, eliminate residual stresses, and improve the stability and reliability of the material. The tempering temperature is set at 530°C - 550°C. This temperature range is lower than the austenitization temperature of the aero-engine bearing steel, so it will not cause significant phase transformations. This temperature range can promote the atomic diffusion and rearrangement inside the material, but will not lead to significant grain growth or performance degradation. Compared with the traditional multi-step tempering process, single tempering can significantly simplify the heat treatment process, improve production efficiency, and reduce energy consumption and costs. This is due to the fact that the above-mentioned electromagnetic field treatment has completed the main tissue optimization and performance regulation, so the subsequent tempering treatment can be simplified to a single step.

[0066] The present invention combines ultrafine-grained duplex quenching, electromagnetic field regulation for tissue stabilization, and simplified tempering, greatly reducing the heat treatment time and energy consumption, giving full play to the advantages of electromagnetic field regulation, and at the same time making up for the limitations of traditional heat treatment methods. By adopting reasonable alternating electromagnetic field parameters, the stabilization of retained austenite in aero-engine bearing steel is achieved. Due to the continued nucleation of massive retained austenite in aero-engine bearing steel under the action of alternating electromagnetic field treatment to form fine lath martensite structure, the growth space of martensite during subsequent tempering is restricted, thus overall refining the structure of aero-engine bearing steel; the electromagnetic field regulation will further promote the transfer of supersaturated carbon in martensite to retained austenite, thereby promoting the enrichment of carbon in retained austenite, so the retained austenite has better thermal and mechanical stability, and finally making the aero-engine bearing steel have better strength and toughness after tempering. At the same time, by introducing electromagnetic field regulation between quenching and tempering, the decomposition of retained austenite is directly promoted and the metastable structure is stabilized. Originally, three high-temperature temperings were required, but now only one high-temperature tempering is needed, greatly improving the production efficiency and product quality.

[0067] The heat treatment method of the present invention will be described in detail below with a specific embodiment:

[0068] Taking the electromagnetic-assisted heat treatment of a certain type of aero-engine bearing steel as an example, an electromagnetic-assisted heat treatment method for aero-engine bearing steel is implemented according to the following steps:

[0069] S1. Ultrafine-grained duplex quenching: Heat the aero-engine bearing steel to 1088 °C and hold for 30 minutes for austenitization. Subsequently, quickly place the austenitized aero-engine bearing steel into a salt bath at a temperature of Ms-(10~60 °C) for isothermal quenching, and finally water-cool to room temperature;

[0070] S2. Electromagnetic field regulation for tissue stabilization: After quenching, quickly clamp the aero-engine bearing steel at the middle position between the two fixtures of the electromagnetic energy generator. The cross-sectional area of the fixture is 50 mm 2 . Divide the aero-engine bearing steel into 4 zones along the cross-section. Perform 3 times of alternating electromagnetic field treatment on each zone through the electromagnetic energy generator, with an interval time of 5 s. The parameters of a single alternating electromagnetic field treatment are: the electromagnetic energy loading method is single electric field loading, the electromagnetic energy pulse frequency is 50 Hz, the pulse waveform is triangular wave, the current density is set to 75 A / mm 2 , and the number of pulse actions in one alternating electromagnetic field treatment is 5;

[0071] S3. Simplified tempering: Heat the aero-engine bearing steel to the tempering temperature of 550 °C and hold for 2 hours.

[0072] Through the above high-strength and tough electromagnetic-assisted heat treatment method for aero-engine bearing steel, the tensile strength and impact absorption work of a certain type of aero-engine bearing steel before and after electromagnetic-assisted heat treatment were tested, and the performance results were compared with those of traditional heat treatment as shown in Table 1.

[0073] Table 1 Performance test results of traditional heat treatment and heat treatment of the present invention

[0074]

[0075] As can be seen from Table 1, by using the heat treatment method of the present invention, the ultimate tensile strength of the aero-engine bearing steel is increased by 75 MPa, and the impact absorption energy is increased by 24.1%, thus confirming the technical effect of the heat treatment method of the present invention.

[0076] The materials of traditional heat treatment and heat treatment of the present invention were respectively analyzed by EBSD (Electron Backscatter Diffraction), and the analysis results are as Figure 3 shown. Figure 3 In (a), it is the diffraction image of the aero-engine bearing steel material obtained by the traditional heat treatment method, which is an IPF (Inverse Pole Figure). Figure 3 In (c), it is the EBSD phase size distribution map of the aero-engine bearing steel material obtained by the traditional heat treatment method. Figure 3 In (b), it is the diffraction image of the aero-engine bearing steel material obtained by the heat treatment method of the present invention, which is an IPF (Inverse Pole Figure). Figure 3 In (d), it is the EBSD phase size distribution map of the aero-engine bearing steel material obtained by the heat treatment method of the present invention. It can be seen from Figure 3 this that by using the electromagnetic-assisted heat treatment method of the present invention, the average phase size of the aero-engine bearing steel can be decreased from 1.71 μm to 1.34 μm, and the size is significantly refined. The finer phase structure has a higher interface density, which is beneficial to improving the strength and toughness of the material.

[0077] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electromagnetic assisted heat treatment method for aircraft engine bearing steel, characterized in that: The steps include: S1: Heat the aero engine bearing steel to the preset austenitizing temperature T A , and keep warm for preset time t q , the austenitized aero-engine bearing steel is placed in a salt bath for isothermal quenching; S2: After quenching, the aero-engine bearing steel is placed in an electromagnetic energy generator and subjected to alternating electromagnetic field treatment. The electromagnetic energy loading method is an electromagnetic composite field. In each alternating electromagnetic field treatment, the number of electromagnetic pulses applied is 5-10. S21: The aero engine bearing steel is divided into N p Partitions; S22: Select a partition N i ; S23: Set the alternating electromagnetic field processing parameters, and use the electromagnetic energy generator to treat the partition N i The processing is performed according to the alternating electromagnetic field processing parameters; the alternating electromagnetic field processing parameters include the electromagnetic energy loading method, the electromagnetic energy loading frequency and the electromagnetic energy pulse waveform; the electromagnetic energy loading frequency f is set to f = (0.1-0.6)f r , whose unit is Hz, where f r is the resonance frequency of the aero-engine bearing steel; the pulse waveforms of the electromagnetic energy include sine wave, square wave and triangle wave; under the electromagnetic composite field loading, the current density is set to Its unit is A / mm 2 , the magnetic field strength is set to Its unit is A / mm, where α is the current density coefficient, β is the magnetic field intensity coefficient, f is the electromagnetic energy loading frequency, and c is the p is the specific heat capacity of aero-engine bearing steel, S e is the electromagnetic energy loading area; S24: Repeat step S23 at a time interval of t1 seconds until the partition N i Performing N alternating electromagnetic field treatments; S25: Repeat steps S22-S24 until N p All partitions have been processed; S3: Single tempering heat treatment of aero engine bearing steel.

2. The electromagnetic assisted heat treatment method for aircraft engine bearing steel according to claim 1, characterized in that: In step S1, the austenitizing temperature T is preset. A =Acm+20℃, Acm is the austenite transformation temperature of the aero engine bearing steel; preset time k is the insulation coefficient, ρ is the density of the aero-engine bearing steel, V is the volume of the aero-engine bearing steel; the temperature of the salt bath is T q , T q =Ms-10℃, Ms refers to the starting temperature of the transformation of austenite to martensite of aircraft engine bearing steel.

3. The electromagnetic assisted heat treatment method for aircraft engine bearing steel according to claim 1, characterized in that: In step S21, the number of partitions S is the cross-sectional area of ​​the aero-engine bearing steel, S e is the electromagnetic energy loading area; In step S23, partition N i Number of alternating electromagnetic field treatments σ is the electrical conductivity of aero-engine bearing steel; In step S24, the time interval t1 is 2-6 seconds.

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