Test method for hardenability of steel for bearing ring

Abstract

The invention discloses a method for testing the hardenability of steel for a bearing ring, and relates to the technical field of metal heat treatment and bearing manufacturing. The method comprises the following steps: preparing an integrated test ferrule; processing and forming at least three test areas with different wall thicknesses on the ring along the circumferential direction, wherein each wall thickness value corresponds to different wall thickness specifications of the bearing ring; performing synchronous heat treatment on the whole ferrule according to an actual production heat treatment process; sampling from the center position of the radial section in the middle of each test area to detect performance indexes; and the hardenability of the steel under different wall thicknesses is evaluated according to the corresponding relation between the wall thicknesses and the performance indexes. Multi-wall-thickness synchronous heat treatment is achieved through the integrated ferrule, process errors are eliminated, and test results are accurately matched with actual products; multi-wall-thickness hardenability detection is completed through one test, the period is short, and the cost is low; and the adaptability of the heat treatment process can be synchronously evaluated, and the method is suitable for detection and production guidance of high-carbon chromium bearing steel such as GCr15, GCr15SiMn and GCr18Mo.

Description

Technical Field

[0001] This invention relates to the fields of metal heat treatment and bearing manufacturing technology, specifically to a test method for the hardenability of steel used in bearing rings. Background Technology

[0002] High-carbon chromium bearing steel is a key material for manufacturing core components such as bearing rings and rolling elements. With the increasing size of major mechanical equipment such as tunnel boring machines, wind turbines, rolling mills, and marine engineering equipment, bearing dimensions are also increasing, placing higher demands on the hardenability of the steel. Hardenability is a core technological property of steel, referring to the ability of steel to obtain the depth of a hardened layer during quenching, directly determining the uniformity of hardness, wear resistance, and service life of bearing products.

[0003] In existing technologies, the mainstream method for evaluating the hardenability of steel is the end-quenching test (Jominy test), and the standard method can be found in GB / T 225-2006 "End-quenching test method for hardenability of steel". This method involves heating a cylindrical specimen with a diameter of 25×100mm to a specified temperature, spraying water onto its end face for quenching, and then measuring the hardness change along the length of the specimen to obtain the hardenability curve.

[0004] However, the end-quench test method has the following inherent defects in practical applications: (1) The end-quench test specimen is a simple cylindrical shape, which cannot simulate the annular structure characteristics of bearing rings. The arc structure and wall thickness variation of ring-type products have a significant impact on the cooling rate distribution during the quenching process. The end-quench test is difficult to reflect this geometric effect, resulting in a low degree of matching between the test results and actual production. (2) If it is necessary to study the hardenability of materials under different wall thicknesses, the traditional method requires processing multiple test bars of different specifications and performing heat treatments separately. This not only increases the workload of the test, but also the fluctuation of process parameters (such as heating time, cooling medium temperature, etc.) between different batches of heat treatment will lead to poor consistency of test results, making it difficult to accurately judge the true hardenability of materials under different wall thicknesses. (3) The end-quench test can only give the hardenability curve of the material, and cannot simultaneously evaluate the matching degree between a specific heat treatment process (such as heating temperature, holding time, cooling method in actual production) and the material. In actual production, it is often necessary to determine the appropriate process parameters through multiple "trial and error" processes, which is time-consuming and labor-intensive, and seriously affects the product development cycle and production efficiency.

[0005] To address the aforementioned issues, there is an urgent need for a testing method that can simulate the characteristics of actual products, enable simultaneous testing of multiple wall thicknesses, and rapidly and accurately evaluate the hardenability and process adaptability of steel. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a test method for the hardenability of steel for bearing rings. The method uses an integral test ring as the base to process regions with different wall thicknesses, and achieves hardenability testing for multiple wall thicknesses in one test through synchronous heat treatment, effectively shortening the test cycle and improving the matching degree between test results and actual production.

[0007] To achieve the above objectives, the specific solution adopted by the present invention is as follows: A test method for the hardenability of steel for bearing rings includes the following steps: Step (1) Preparation of an integrated test ring: Select the steel to be tested and process it into an integrated test ring; Step (2) Processing to form test areas: M test areas with different wall thicknesses are processed along the circumference on the test ring, M≥3, and the wall thickness value of each test area corresponds to the different wall thickness specifications of the bearing ring made of the steel to be tested; Step (3), synchronous heat treatment: Place the test rings that have been processed in the test area into a heat treatment furnace and perform heat treatment according to the actual production heat treatment process of the bearing rings; Step (4), performance testing: On the heat-treated test ring, samples are taken from the center of the radial section in the middle of each test area to test its performance indicators; Step (5) Result evaluation: Based on the correspondence between the wall thickness of each test area and the performance of its corresponding position, evaluate the hardenability of the steel under different wall thicknesses.

[0008] Furthermore, in step (2), the chord length of the test area is 3 to 6 times the wall thickness of the test area.

[0009] Furthermore, in step (2), the chord length of the test area is 4 times the wall thickness of the test area.

[0010] Furthermore, before step (1), a design step is also included: determining the size of the test ring, the number M of test areas, and the chord length of each test area, so that all test areas can be arranged circumferentially on the test ring.

[0011] Furthermore, in step (2), test areas with different wall thicknesses are formed by cutting the inner or outer surface of the test ring, and the adjacent test areas are transitioned by a circular arc.

[0012] Furthermore, in step (3), the heat treatment includes heating, holding, quenching and tempering processes performed sequentially.

[0013] Furthermore, in step (4), the performance indicators include hardness indicators and / or microstructure indicators.

[0014] Furthermore, the steel to be tested is high-carbon chromium bearing steel, which is any steel grade from the GCr15, GCr15SiMn, GCr18Mo or GCr18MnMo1 series.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following beneficial effects: (1) This invention adopts an integrated test ring design, processing multiple test areas with different wall thicknesses on the same ring and performing heat treatment simultaneously. This design fundamentally eliminates the process parameter errors (such as heating temperature fluctuations, holding time differences, and cooling medium temperature changes) introduced by different heat treatment batches in traditional multi-test bar tests, ensuring that the heat treatment process of each wall thickness area is completely consistent. At the same time, the structural form of the test ring matches the actual bearing ring product, and the chord length of the test area is determined according to 3-6 times the wall thickness, making the structural characteristics of the test part closer to the arc cross-section of the actual product. The test results can truly reflect the hardening behavior of the material under actual production conditions, and the matching degree between the test results and the actual product is greatly improved.

[0016] (2) The present invention can simultaneously complete the hardenability test of multiple wall thicknesses (at least 3) in one test, without the need to process multiple test bars separately or perform multiple furnace heat treatments. Compared with the traditional end-quench test, the test cycle can be shortened by more than 60%, and the labor cost, material cost and energy cost are significantly reduced. For research and development projects that need to study the hardenability of materials in a wide range of wall thicknesses, the efficiency advantage of the present invention is particularly prominent.

[0017] (3) This invention can not only evaluate the hardenability grade of steel under different wall thicknesses, but also simultaneously evaluate the compatibility of specific heat treatment processes with materials. Since the experiment strictly adopts the actual production heat treatment process of the product under study, the test results can directly determine the applicable wall thickness range of the material, judge the rationality of the current heat treatment process, and provide a clear decision-making basis for whether the process needs to be adjusted or the material needs to be replaced. This functional integration characteristic enables the test results to directly serve key production links such as product design, process optimization and quality control, significantly enhancing the engineering application value of this invention.

[0018] (4) The method of the present invention has a clear process and well-defined steps. Each step (ring processing, test area formation, heat treatment, and sampling and testing) adopts mature conventional technology, requiring no special equipment or complex operation, which facilitates its application in industrial production. At the same time, the test parameters can be flexibly adjusted according to the wall thickness requirements of different products, making it widely applicable and universal.

[0019] (5) This invention is not only applicable to high carbon chromium bearing steel series such as GCr15, GCr15SiMn, GCr18Mo, GCr18MnMo1, etc., but can also be extended to the research and testing of quenching and tempering heat treatment of alloy structural steels such as 42CrMo and 50CrMo. It has good versatility and promotion value. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the test ring in Example 1. Figure 2 This is a schematic diagram of the test ring in Example 2. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] To enable those skilled in the art to fully understand and implement the present invention, the technical solution of the present invention will be described in detail below.

[0023] First, the experimental design phase Before conducting the experiment, a design scheme is required. The core task of the design phase is to ensure that the selected test area can be reasonably arranged on the test ring. The specific design principles are as follows: (1) Regarding the wall thickness value The wall thickness value of the test area should be determined based on the actual wall thickness range of the product under study. For example, if the product wall thickness range is 30~50mm, several representative wall thickness values ​​can be selected within this range. The following principles should be followed when selecting the values: ① The wall thickness values ​​should cover the entire wall thickness range of the product, including the minimum wall thickness, the maximum wall thickness, and intermediate key points; ② There should be an appropriate interval (generally 5~10mm) between adjacent wall thickness values ​​to facilitate observation of the hardenability variation with wall thickness; ③ The number of wall thickness values ​​M should be no less than 3. The reason for taking M as 3 is that only two wall thickness points can reflect the trend and cannot determine the nonlinear characteristics of hardenability variation; while when M≥3, at least three data points can be obtained, thus enabling a preliminary fitting of the "wall thickness-hardness" variation curve and determination of the material's hardenability limit.

[0024] (2) Regarding the determination of chord length The chord length refers to the length of the chord corresponding to the test area in the circumferential direction, and it is a key parameter determining the circumferential dimension of the test area. In this invention, the chord length L and the wall thickness t satisfy: L = k × t, where k is a multiple. The value of the multiple k ranges from 3 to 6, preferably 4. This range is determined based on the following considerations: If the chord length is too short (k < 3), the circumferential dimension of the test area is too small, and the detection point may be affected by boundary effects, failing to represent the overall hardening effect of the wall thickness area; at the same time, a short chord length also makes sampling and testing difficult. Therefore, to ensure the representativeness of the test results, k must be no less than 3. If the chord length is too long (k > 6), the test area occupies too much circumferential space, which will limit the number of test areas that can be set when the ring size is fixed; at the same time, an excessively long chord length will lead to an excessively large circumferential dimension of the test area, which may introduce uneven cooling in the circumferential direction, thus affecting the accuracy of the test results. Numerous experiments have shown that k in the range of 3 to 6 can ensure both the representativeness of the test and the flexibility of the test area layout. When k=4, the ratio of chord length to wall thickness of the test area is 4:1. This ratio makes the structural shape of the test area closest to the arc-shaped characteristics of the actual bearing ring product. Under this ratio, the cooling conditions at the test point are closest to the core cooling conditions of the actual product, and the test results have the strongest guiding significance for actual production. Therefore, this invention uses k=4 as the most preferred embodiment.

[0025] (3) Feasibility of Circumferential Space After determining the M wall thickness values ​​and corresponding chord lengths, it is necessary to verify whether all test areas can be arranged circumferentially on the test ring. The verification method is as follows: based on the chord length and the diameter of the test ring, calculate the central angle and arc length corresponding to each test area. The sum of the arc lengths of all areas (including the length of the transition zone) should be less than or equal to the circumference of the ring. If the sum of the arc lengths exceeds the circumference of the ring, adjustments are required. There are three adjustment methods: ①Increase the size of the test ring: By increasing the size of the ring, the arrangement requirements can be met without changing the number of test areas M and the chord length multiple k; ② Reduce the number of test areas M: While ensuring coverage of the product wall thickness range, the number of wall thickness values ​​can be appropriately reduced, for example from 5 to 4; ③ Appropriately reduce the chord length multiple k: If necessary, k can be reduced from 4 to 3, but it must not be less than 3.

[0026] Only after making the above adjustments and meeting the feasibility requirements of the circular space can we proceed to the next step.

[0027] Second, preparation of the test rings. Based on the ring dimensions determined by the design scheme, the steel to be tested is selected and processed into a one-piece test ring. During processing, the following should be noted: ① The ring blank should be free of forging defects, segregation, inclusions, and other metallurgical defects; ② Stress-relieving annealing should be performed after rough machining to eliminate processing stress; ③ Finish machining should ensure dimensional accuracy and surface quality, and the concentricity and roundness of each part should meet the requirements. "One-piece" means that the entire test ring is processed from a single piece of raw material, forming a single structure, rather than being assembled from multiple parts. This is an important prerequisite for ensuring consistent heat treatment conditions in all test areas.

[0028] To facilitate manufacturing, the initial wall thickness of the test rings is usually taken as the maximum value within the range of bearing ring wall thicknesses of the product under study. In this way, the wall thickness of all test areas can be obtained by thinning the rings, eliminating the need for thickening and simplifying the manufacturing process.

[0029] Third, processing to form a test area M test areas with different wall thicknesses are machined circumferentially on the test ring. Specifically, the test ring has an initial wall thickness, which is greater than the wall thickness of all test areas to be machined; typically, this initial thickness is the maximum value within the range of bearing ring wall thicknesses of the product under study. Based on this, the test areas with each target wall thickness are obtained by machining (thinning) the inner or outer surface of the ring.

[0030] To simplify the machining process, it is preferable to use the method of turning the outer surface, that is, keeping the inner diameter unchanged, and obtaining each target wall thickness by turning the outer surface of the test ring. For example, if the initial wall thickness of the test ring is 50mm (inner diameter 180mm, outer diameter 280mm), if a test area with a wall thickness of 40mm is to be obtained, the outer diameter needs to be turned to 260mm, while the inner diameter remains unchanged at 180mm; if a test area with a wall thickness of 30mm is to be obtained, the outer diameter needs to be turned to 240mm, while the inner diameter remains unchanged at 180mm.

[0031] The test areas are arranged sequentially along the circumference, with adjacent areas connected by a rounded transition. The radius of the transition fillet is generally 2-5 mm, with the specific value determined based on the size of the raceway. The purpose of setting the rounded transition is to avoid stress concentration caused by abrupt changes in wall thickness and to prevent cracks from forming in the transition zone during heat treatment.

[0032] Fourth, simultaneous heat treatment The test rings, after processing in the test areas, are placed in a heat treatment furnace and heat-treated according to the actual production heat treatment process of the product under study. Simultaneous heat treatment means that the entire ring undergoes simultaneous heating, holding, quenching, and tempering processes to ensure that the heat treatment process parameters for all test areas are completely consistent.

[0033] It should be noted that "according to the actual production heat treatment process" means that all parameters of the heat treatment process (heating temperature, heating rate, holding time, cooling method, cooling medium, cooling rate, tempering temperature, tempering time, etc.) should be strictly consistent with the actual production process of the product. This is crucial to ensuring that the test results can directly guide production. For example, if the product uses salt bath quenching, then the test should also use salt bath quenching; if the product uses vacuum quenching, then the test should also use vacuum quenching; if the product uses bainitic isothermal quenching, then the test should also use bainitic isothermal quenching.

[0034] Fifth, performance testing After heat treatment, samples were taken from each test area to test its performance indicators.

[0035] The sampling location is the center of the radial section in the middle of each test area. "Middle" refers to the midpoint along the chord length of the test area, away from the boundary to avoid the influence of boundary effects on the test results. "Radial section" refers to the cross-section perpendicular to the ring's axis, i.e., the ring's annular cross-section. "Center location" refers to the geometric center point of the radial section, i.e., the midpoint along the wall thickness direction. The core of hardenability evaluation is whether the material's core is hardened; therefore, the test point should be taken at the core.

[0036] Sampling can be performed using wire cutting or slicing methods. Sufficient cooling is essential during sampling to prevent heat from affecting the hardness of the test points. Hardness is the primary testing indicator, with Rockwell hardness (HRC) or Vickers hardness (HV) being preferred.

[0037] To further evaluate the quenching effect comprehensively, metallographic samples can be prepared from various testing locations to observe the microstructure. Microstructure observation indicators include: martensite level, bainite level, troostite level, and carbide distribution.

[0038] Sixth, Results Evaluation Based on the test data, a correlation was established between the wall thickness t of each test area and the corresponding core performance.

[0039] Determine the hardenability grade of this steel for different wall thicknesses by referring to the product technical standards (such as JB / T 1255-2014 "Technical Conditions for Heat Treatment of High Carbon Chromium Bearing Steel Parts for Rolling Bearings"). The determination principle is as follows: If the core hardness of a certain wall thickness meets the technical standard requirements (e.g., ≥58HRC) and the microstructure is qualified, it indicates that the wall thickness is within the hardenability range of the material. If the core hardness of a certain wall thickness is lower than the technical standard requirement, or if a large amount of unquenched structure appears (such as the troostite level exceeding the standard), it indicates that the wall thickness has exceeded the hardenability of the material.

[0040] Based on the test results for each wall thickness, the maximum applicable wall thickness range of the material can be determined, as well as the compatibility between the current heat treatment process and the material.

[0041] The technical solution of the present invention will be further described below with reference to specific embodiments. Example 1

[0042] This embodiment uses GCr18Mo high-carbon chromium bearing steel as the test material, and the bearing ring wall thickness of the product under study ranges from 30mm to 50mm. The test method is as follows: (1) Experimental design: Five representative wall thickness values ​​were selected, namely 30mm, 35mm, 40mm, 45mm and 50mm. The chord length multiple was taken as 4, and the chord lengths of each region were calculated to be 120mm, 140mm, 160mm, 180mm and 200mm respectively; the outer diameter of the test ring was taken as 350mm and the inner diameter as 250mm, which met the feasibility requirements of the circumferential space. (2) Preparation of test rings: GCr18Mo high carbon chromium bearing steel round bars were selected, and after forging and annealing, they were processed into one-piece test rings. The initial wall thickness was taken as the maximum value of 50 mm in all test areas, corresponding to an inner diameter of 250 mm and an outer diameter of 350 mm, and the ring width was 60 mm; (3) Processing to form test areas: Five test areas are sequentially processed along the circumference of the ring, with wall thicknesses of 50mm, 45mm, 40mm, 35mm and 30mm for each area, as follows: Figure 1 As shown. To simplify the machining process, the outer surface is turned, meaning the inner diameter of 250mm is kept constant, and the target wall thickness is obtained by turning the outer diameter. Specific machining parameters are as follows: 50mm wall thickness area: Maintain initial state, outer diameter 350mm, inner diameter 250mm; 45mm wall thickness area: machine the outer diameter to 340mm, and keep the inner diameter at 250mm; For the 40mm wall thickness area: machine the outer diameter to 330mm, while keeping the inner diameter at 250mm; 35mm wall thickness area: machine the outer diameter to 320mm, while keeping the inner diameter at 250mm; 30mm wall thickness area: machine the outer diameter to 310mm, and keep the inner diameter at 250mm; Adjacent wall thickness areas are connected by a 3mm radius arc to avoid stress concentration during heat treatment. (4) Synchronous heat treatment: The test rings that have been processed in the test area are placed in a heat treatment furnace and treated according to the actual production heat treatment process of GCr18Mo bearing rings. The specific process parameters are: heating to 870℃, holding for 1.5 hours, then quenching in a 190℃ salt bath, cooling and then tempering at 200℃ for 6 hours, and finally air cooling to room temperature. (5) Performance Testing: After heat treatment, samples were taken from the center of the radial section in the middle of each test area to test Rockwell hardness and microstructure. The test results showed: The core hardness of the 30mm wall thickness area is 61.5HRC, and the microstructure consists of fine lower bainite with residual carbides and no unquenched structure. The core hardness of the 35mm wall thickness region is 60.8HRC. The microstructure consists of fine lower bainite with residual carbides. A small amount of troostite is present in the core, and the troostite rating is grade 1. The core hardness of the 40mm wall thickness region is 59HRC, the microstructure is lower bainite plus residual carbides, and there is a lot of troostite in the core, with a troostite rating of grade 2. The core hardness of the 45mm wall thickness region is 55HRC, the microstructure is lower bainite plus residual carbides, and there is a large amount of troostite in the core, with a troostite rating of more than 2. The core hardness of the 50mm wall thickness region is 52HRC, the microstructure is lower bainite plus residual carbides, and there is a large amount of troostite in the core, with a troostite rating of more than 2. (6) Result evaluation: According to the test results, the core hardness of the GCr18Mo bearing steel is not lower than 58HRC and the troostite level does not exceed 2 within the wall thickness range of 30mm to 40mm. When the wall thickness exceeds 40mm, the core hardness decreases significantly and the troostite level increases significantly, indicating that the hardenability of the material is insufficient under the wall thickness condition. Example 2

[0043] This embodiment uses GCr18MnMo1 high hardenability bearing steel as the test material, and the bearing ring wall thickness of the product under study ranges from 45mm to 60mm. The test method is as follows: (1) Experimental design: Four representative wall thickness values ​​were selected, namely 45mm, 50mm, 55mm and 60mm. The chord length multiple was taken as 4, and the chord lengths of each region were calculated to be 180mm, 200mm, 220mm and 240mm respectively; the outer diameter of the test ring was taken as 360mm and the inner diameter as 240mm to meet the feasibility requirements of the circumferential space. (2) Preparation of test rings: GCr18MnMo1 bearing steel round bars were selected, and after forging and annealing, they were processed into one-piece test rings. The initial wall thickness was taken as the maximum value of 60mm in all test areas, corresponding to an inner diameter of 240mm and an outer diameter of 360mm, and the ring width was 60mm; (3) Processing to form test areas: Four test areas are processed sequentially along the circumference of the ring, with wall thicknesses of 60mm, 55mm, 50mm and 45mm for each area, as follows: Figure 2 As shown. The machining method involves turning the outer surface, keeping the inner diameter constant at 240mm, and obtaining the target wall thickness by turning the outer diameter. Specific machining parameters are as follows: 60mm wall thickness area: Maintain initial state, outer diameter 360mm, inner diameter 240mm; 55mm wall thickness area: machine the outer diameter to 350mm, while keeping the inner diameter at 240mm; 50mm wall thickness area: machine the outer diameter to 340mm, while keeping the inner diameter at 240mm; 45mm wall thickness area: machine the outer diameter to 330mm, and keep the inner diameter at 240mm; Adjacent wall thickness areas are connected by a 3mm radius arc. (4) Simultaneous heat treatment: The test rings with completed test area processing are placed in a heat treatment furnace and treated according to the recommended heat treatment process for GCr18MnMo1 bearing rings. The specific process parameters are: heating to 890℃, holding for 2 hours, then quenching in a 190℃ salt bath, cooling and then tempering at 200℃ for 6 hours, and finally air cooling to room temperature. (5) Performance Testing: After heat treatment, samples were taken from the center of the radial section in the middle of each test area to test Rockwell hardness and microstructure. The test results showed: The core hardness of the 45mm wall thickness region is 61.2HRC, and the microstructure consists of lower bainite with a small amount of carbides and no troostite. The core hardness of the 50mm wall thickness region is 60.5HRC, and the microstructure consists of lower bainite with a small amount of carbides and no troostite. The core hardness of the 55mm wall thickness region is 58.7HRC, and the microstructure consists of lower bainite with a small amount of troostite, with a troostite rating of grade 1. The core hardness of the 60mm wall thickness region is 57.3HRC, and the microstructure is lower bainite with more troostite, with a troostite rating of grade 2. (6) Result Evaluation: According to the test results, the core hardness of the GCr18MnMo1 bearing steel is not lower than 57HRC within a wall thickness range of 60mm, the troostite level does not exceed level 2, and the hardenability is good, which can meet the technical requirements of the product. The heat treatment process adopted in this embodiment is qualified for the heat treatment quality of this material under various wall thickness conditions, and can be directly used to guide the heat treatment process of bearing rings with a wall thickness of 60mm or less in actual production.

[0044] In summary, the hardenability testing method for high-carbon chromium bearing steel of this invention can be widely applied in the research, development, production, and testing of bearing rings in the bearing manufacturing industry. This method can rapidly and accurately test the hardenability of steel at different wall thicknesses, while simultaneously evaluating the suitability of heat treatment processes. It has significant industrial application value for improving the quality stability of bearing products, reducing production costs, and shortening the research and development cycle. Furthermore, this method can also be extended to the research and testing of quenching and tempering heat treatment for alloy structural steels such as 42CrMo and 50CrMo, demonstrating broad prospects for widespread application.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention in any way. All equivalent transformations or modifications made in accordance with the essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A test method for the hardenability of steel for bearing rings, characterized in that, Includes the following steps: Step (1) Preparation of an integrated test ring: Select the steel to be tested and process it into an integrated test ring; Step (2) Processing to form test areas: M test areas with different wall thicknesses are processed along the circumference on the test ring, M≥3, and the wall thickness value of each test area corresponds to the different wall thickness specifications of the bearing ring made of the steel to be tested; Step (3), synchronous heat treatment: Place the test rings that have been processed in the test area into a heat treatment furnace and perform heat treatment according to the actual production heat treatment process of the bearing rings; Step (4), performance testing: On the heat-treated test ring, samples are taken from the center of the radial section in the middle of each test area to test its performance indicators; Step (5) Result evaluation: Based on the correspondence between the wall thickness of each test area and the performance of its corresponding position, evaluate the hardenability of the steel under different wall thicknesses.

2. The test method for the hardenability of bearing ring steel according to claim 1, characterized in that, In step (2), the chord length of the test area is 3 to 6 times the wall thickness of the test area.

3. The test method for the hardenability of bearing ring steel according to claim 2, characterized in that, In step (2), the chord length of the test area is 4 times the wall thickness of the test area.

4. The test method for the hardenability of bearing ring steel according to claim 2, characterized in that, Before step (1), a design step is also included: determining the size of the test ring, the number M of test areas and the chord length of each test area, so that all test areas can be arranged circumferentially on the test ring.

5. The test method for the hardenability of bearing ring steel according to claim 1, characterized in that, In step (2), test areas with different wall thicknesses are formed by cutting the inner or outer surface of the test ring, and the adjacent test areas are transitioned by a circular arc.

6. The test method for the hardenability of bearing ring steel according to claim 1, characterized in that, In step (3), the heat treatment includes heating, holding, quenching and tempering processes performed sequentially.

7. The test method for the hardenability of bearing ring steel according to claim 1, characterized in that, In step (4), the performance indicators include hardness indicators and / or microstructure indicators.

8. The test method for the hardenability of bearing ring steel according to claim 1, characterized in that, The steel to be tested is high-carbon chromium bearing steel, which is any steel grade in the GCr15, GCr15SiMn, GCr18Mo or GCr18MnMo1 series.

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