Construction method of cold speed-microstructure-strength three-field coupling of railway wheel

Abstract

The application discloses a construction method of cold speed-structure-strength three-field coupling of a railway wheel, and is based on the principle of consistency (equivalence), that is, the cooling rate / temperature field change of the ferrite-pearlite two-phase material with the same chemical composition and different cooling conditions must be the same or equivalent at the consistent place of structure and performance. The actual production process is used to prepare a physical wheel, which is used as a reference. Microstructure and static strength data of a plurality of characteristic points on a certain path of the wheel rim are collected. A new method of instrumented indentation for measuring static strength and quantitative analysis of microstructure are used under laboratory conditions. Through the two media of microstructure and static strength, the correspondence between the production actuality and the laboratory under two different heat treatment cooling conditions is established. Finally, a high-efficiency and low-cost characterization method of railway wheel heat treatment "cold speed-structure-strength" three-field coupling is formed.

Description

Technical Field

[0001] This invention belongs to the field of multi-field coupling technology for heat treatment and cooling of railway wheels. More specifically, this invention relates to a method for constructing a three-field coupling of cooling rate, microstructure, and strength for railway wheels. Background Technology

[0002] Intelligent research is a hot topic and a future development direction in the field of heat treatment. Its core foundation is the digitization of the heat treatment process, and the difficulty lies in the digitization of the cooling process. In the past, the establishment of digital models for heat treatment usually adopted numerical simulation methods based on specific industrial simulation software. First, the temperature field distribution and variation characteristics were obtained, and then coupled with the supercooled austenite phase transformation characteristics of the material to obtain the microstructure transformation process and the final microstructure composition. A multi-field coupled mathematical model of temperature-microstructure-property was established to predict the microstructure and properties, and then the model was corrected or reconstructed through physical verification.

[0003] For pearlitic railway wheels, heat treatment cooling is the core process that determines phase change products and mechanical properties. With the support of databases of material properties (phase change, thermal properties, etc.) and heat transfer characteristics, the heat treatment process can be automatically designed, executed and controlled based on chemical composition by comparing the microstructure and performance control targets through digital models. However, the accuracy of the model established by simply using numerical simulation is limited by the following factors: (1) It is difficult to accurately measure the heat transfer coefficient under water spray cooling conditions on the wheel tread surface, which directly leads to inaccurate simulation of temperature field distribution and changes, and thus the accuracy of microstructure and performance prediction is difficult to meet the needs of industrial production; (2) The heat transfer coefficient also varies depending on the wheel steel material, wheel specifications and tread surface shape and boundary cooling conditions. The workload of establishing a heat transfer coefficient database using conventional methods is large and the accuracy is uncontrollable; (3) Multi-field coupling simulation requires the determination of phase change kinetic parameters, thermal property parameters and mechanical properties of each basic phase of the material. The testing workload is large, the accuracy requirements are high, it depends on special instruments and equipment, and the established database is only for specific materials, so the application of the process simulation numerical model is singular.

[0004] The journal article "Finite Element Simulation of Novel Heat Treatment Cooling Process for High Carbon Steel Road Wheels" (Journal of Materials Heat Treatment), 2021, 42(1):182-189, proposed a finite element numerical model for tread quenching (CVQ) based on MSC.Marc and Thermal Prophet for heavy-duty high carbon steel wheels. The model was verified by physical testing. However, this method requires the establishment of a material phase transformation and thermal property database, back-calculation of boundary heat transfer coefficients using on-site temperature measurement, input of the obtained parameters and boundary conditions into commercial software for modeling and solving, and finally physical verification, comparison and correction. This method has the problems of long modeling process, high cost and dependence on professional equipment and software. Summary of the Invention

[0005] This invention provides a method for constructing railway wheels using a three-field coupling of cold speed, microstructure, and strength, aiming to improve the aforementioned problems.

[0006] This invention is implemented as follows: a method for constructing a three-field coupling of cold speed, microstructure, and strength in railway wheels, the method comprising the following steps:

[0007] S1. The wheel A to be tested is heated, quenched and completely cooled at the production site to obtain a heat-treated cooled blank wheel.

[0008] S2. Take a rim test block from the wheel B to be tested, and heat, quench and cool the rim test block under laboratory conditions to obtain a heat-treated and cooled blank rim test block.

[0009] S3. Cut the rim of the blank wheel radially, take a cross-sectional sample, and take feature point 1 at different depths from the tread surface radially. Test the static strength and microstructure at each feature point 1.

[0010] S4. Cut the blank wheel rim test block radially, take cross-sectional specimens, and take more feature points 2 at different depths from the tread surface radially to test the static strength at each feature point 2 position.

[0011] S5. Find a matching feature point in feature point 2 that matches the static strength of feature point 1;

[0012] S6. Pre-embed thermocouples at the matching feature point positions in the wheel rim test block, heat and quench the wheel rim test block completely under laboratory conditions, read the cooling curve of the matching feature point, and fit the cooling rate, microstructure and static strength of the matching feature point to form a coupling curve of cooling rate-microstructure-static strength.

[0013] Furthermore, the wheel or rim test block is completely cooled after quenching when the rim temperature does not exceed 100°C.

[0014] Furthermore, the radial depth of the feature point from the tread surface is 10mm to 60mm.

[0015] Furthermore, the procedure includes the following steps after step S5 and before step S6:

[0016] S7. Take a cross-sectional sample from the radial direction of the blank wheel rim test block, measure the microstructure at the matching feature point position in the cross-sectional sample, and check whether it is equivalent to the microstructure at the corresponding feature point 1 position on the blank wheel. If it is equivalent, proceed to step S6.

[0017] Furthermore, static strength is characterized by yield strength and tensile strength.

[0018] Furthermore, the microstructure was characterized using the ferrite volume fraction and pearlite lamellar spacing.

[0019] Furthermore, in feature point 2, we find feature points whose static strength deviation from feature point 1 is less than 5%. Feature point 2 with the smallest deviation is the matching feature point of feature point 1.

[0020] Furthermore, the specific method for determining the pre-embedded location of the thermocouple is as follows:

[0021] The radial embedment depth is the radial depth of the matching feature point, and the arc length of the embedment position of the adjacent thermocouple in the circumferential direction is 20mm to 30mm.

[0022] Furthermore, the wheel is a ferrite-pearlite two-phase material wheel.

[0023] The method for constructing railway wheels using a three-field coupling of cold speed, microstructure, and strength provided by this invention has the following beneficial effects:

[0024] 1) By using microstructure and static strength as two “mediums”, the correlation between laboratory and actual field cooling is established, forming a set of efficient, low-cost, and independently controllable standardized implementation specifications for the characterization of the “cooling rate-structure-strength” three-field coupling of railway wheel heat treatment, which has practical engineering value;

[0025] 2) It does not require special precision instruments, extensive material parameter testing, or complex cooling and heat transfer boundary condition testing, calculation, and correction, thus overcoming the shortcomings of traditional methods such as high cost and long cycle. Attached Figure Description

[0026] Figure 1 A flowchart illustrating the construction method of the cold speed-structure-strength three-field coupling of railway wheels provided in an embodiment of the present invention;

[0027] Figure 2 The yield strength of the wheel and rail contact center area (i.e., 80 mm from the inner rim surface) of the actual wheel obtained by the instrumented indentation method in the embodiments of the present invention at radial distances of 15, 25, 35, 45, and 55 mm from the tread surface, respectively.

[0028] Figure 3 The tensile strength of the wheel and rail contact center area (i.e., 80 mm from the inner rim surface) of the actual wheel obtained by the instrumented indentation method in the embodiments of the present invention at radial distances of 15, 25, 35, 45, and 55 mm from the tread surface, respectively.

[0029] Figure 4 The results of quantitative analysis of the microstructure at radial distances of 15, 25, 35, 45, and 55 mm from the tread surface in the central area of ​​the wheel-rail contact zone (i.e., 80 mm from the inner rim surface) of the actual wheel provided in the embodiments of the present invention.

[0030] Figure 5 The location for embedding thermocouples at characteristic points of a 1 / 8 rim test block provided in this embodiment of the invention;

[0031] Figure 6 The temperature drop curve measured at a characteristic point on a 1 / 8 rim test block in the laboratory provided in this embodiment of the invention;

[0032] Figure 7 The cooling rate gradient obtained under laboratory conditions provided in this embodiment of the invention is the relationship between the cooling rate and the depth from the tread surface, wherein the cooling rate at the feature point is taken as the effective average cooling rate in the range of 800 to 600°C.

[0033] Figure 8 The three-field coupled characterization curves of microstructure-static strength-cooling rate provided in the embodiments of the present invention. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0035] Figure 1 The flowchart illustrates the construction method of the cold speed-microstructure-strength three-field coupling of railway wheels provided in this embodiment of the invention. The method specifically includes the following steps:

[0036] S1. The wheel A to be tested is heated, quenched and completely cooled at the production site to obtain a heat-treated cooled blank wheel.

[0037] In this embodiment of the invention, a rolled wheel, designated A, is taken and, at the production site, undergoes a certain process flow, including full austenitization heating, quenching, and complete cooling to obtain a heat-treated cooled blank wheel.

[0038] S2. Take a rim test block from the wheel B to be tested, and heat, quench and cool the rim test block under laboratory conditions to obtain a heat-treated and cooled blank rim test block.

[0039] In this embodiment of the invention, another rolled wheel, designated B, is taken as the test piece. Two 1 / 8 rim test blocks are cut from this wheel and designated B1 and B2, respectively. The rim test block designated B1 is used in a laboratory setting to obtain a heat-treated and cooled blank rim test block according to the process described in step S1. The homogenization temperature and holding time in the rim test block process are the same as in step S1. However, due to practical reasons, the cooling water flow rate and other conditions in the laboratory are not consistent with the water flow rate in the production site. Therefore, the correspondence between the microstructure, static strength properties, and radial feature point depth of the cross-section of the rim test block obtained in the laboratory will inevitably differ from that of the blank wheel. Furthermore, the quenching and cooling time described in steps S1 and S2 is sufficiently long to ensure not only that the entire cross-section of the rim has undergone microstructural transformation but also to achieve a "thorough cooling" effect, ensuring that the overall temperature recovery of the rim does not exceed 100°C, reducing the "self-tempering" effect caused by temperature recovery after quenching, and preserving the quenched and cooled microstructure to the maximum extent.

[0040] S3. Cut the rim of the blank wheel radially, take a cross-sectional sample, and take feature point 1 at different depths from the tread surface in the wheel-rail contact area. Test the static strength of each feature point and test the microstructure of other cross-sectional samples at the feature point locations.

[0041] In this embodiment of the invention, the rim of the blank wheel is radially cut open, and a cross-sectional sample (25-30 mm thick) is taken. Both sides are machined to be flat and smooth. Then, in the middle of the tread surface, i.e., the wheel-rail contact area, along a certain path in the radial direction, a feature point 1 is randomly selected at a distance of 10-20 mm, 20-30 mm, 30-40 mm, 40-50 mm, and 50-60 mm from the tread surface, and numbered #1, #2, #3, #4, and #5 respectively. The corresponding depths from the tread surface are recorded as h1, h2, h3, h4, and h5 (mm). According to GB / T 39635-2020 "Metallic Materials - Instrumented Indentation Method for Determination of Indentation Tensile Properties and Residual Stress", the yield strength and tensile strength of the feature points numbered #1 to #5 are collected using the instrumented indentation method to obtain the static strength results at the corresponding feature points along the path. Take another cross-sectional sample (15-20 mm thick) from the radial direction of the rim of the blank wheel. Prepare a metallographic sample on the sample block. Extract the volume fraction of ferrite in the microstructure at feature points #1 to #5 under an optical microscope with a built-in scale. At the same time, measure the interlamellar spacing of pearlite in the microstructure at feature points #1 to #5 under a scanning electron microscope to obtain the quantitative results of the microstructure at the feature points along this path.

[0042] The reason why the "microstructure-static strength" coupling data characterizing the heat-treated blank wheel within 10mm of the tread surface was not tested is because this area is a dense non-pearlitic harmful structure area, which needs to be removed by subsequent machining after heat treatment. The reason why the "microstructure-static strength" coupling data characterizing the heat-treated wheel beyond 60mm of the tread surface was not tested is because this area is beyond the wear limit area, and the actual service wheel is scrapped at this point, so studying this area is not of practical significance.

[0043] S4. Cut the blank wheel rim test block radially, take cross-sectional samples, and take more feature points 2 at different depths from the tread surface in the wheel-rail contact area radially, and test the static strength of each feature point 2.

[0044] Cut the wheel rim test block numbered B1 radially and take one cross-sectional sample (thickness 25-30mm). Process both sides to be flat and smooth. Along the path described in step S3, starting from a point 10-15mm away from the tread surface, perform high-throughput instrumented indentation method yield strength and tensile strength tests radially according to the test method described in GB / T 39635-2020. The distance between the test feature points is 3mm-4mm, and the total test path is 60mm-70mm away from the tread surface. Establish the static strength at a series of feature points along this path.

[0045] S5. Find a matching feature point in feature point 2 that matches the static strength of feature point 1. The microstructure of feature point 1 is the microstructure of the corresponding matching feature point.

[0046] The static strength at a series of characteristic points measured on the blank wheel rim test block was compared with the static strength at characteristic points #1 to #5 measured on the blank wheel. With the deviation being less than 5%, five characteristic points that highly matched the characteristic points #1 to #5 were selected from the many characteristic points on the blank wheel rim test block and numbered #1', #2', #3', #4', and #5' respectively. The depths h1', h2', h3', h4', and h5' (mm) of each characteristic point from the tread surface were recorded.

[0047] S6. Pre-embed thermocouples at matching feature points in the rim test block, heat and quench the rim test block completely under laboratory conditions, read the cooling curves of the matching feature points, and fit the cooling rate, microstructure, and static strength of the matching feature points to form a coupling curve of cooling rate, microstructure, and static strength.

[0048] Take a 1 / 8 rim specimen (B2), and use an EDM drill in the laboratory to locate and determine the depth of feature points #1' to #5' at their distances from the tread surface (h1' to h5'). Insert thermocouples into the corresponding positions and secure them tightly. Then, in the laboratory, heat-treat the rim specimen with the embedded thermocouples according to the process described in step S2, performing heating, quenching, and complete cooling. Thermocouples are used for temperature-time data acquisition throughout the heat treatment process. Based on the principle of "consistency (equivalence)," feature points with consistent microstructure and properties should also have consistent cooling rates. Therefore, the cooling curves at the five feature points obtained in this step correspond to the cooling temperature field distribution along the corresponding path of the actual wheel rim in production, as shown in step S1. Thus, through the two "mediums" of microstructure and static strength, a correspondence between actual production and laboratory heat treatment cooling conditions has been established.

[0049] When measuring the temperature field change at a feature point under laboratory conditions, in order to reduce the influence of drilling on the temperature field between different feature points, holes are drilled at a fixed depth and offset from each other along the circumferential direction on the inner side of the rim, with an arc length spacing of 20mm to 30mm between the holes.

[0050] Based on the principle of "consistency (equivalence)," this invention states that for ferrite-pearlite two-phase materials with the same chemical composition but different cooling conditions (such as water flow), the cooling rate / temperature field changes at points with consistent microstructure and properties must be the same or equivalent. First, a physical wheel is fabricated according to the actual production process and used as a benchmark. Microstructure and static strength data are collected at several characteristic points along a radial path of the wheel rim. Then, under laboratory conditions, a new method for measuring static strength using instrumented indentation and quantitative analysis of microstructure are employed. Through these two "mediums" of microstructure and static strength, the correspondence between actual production and laboratory heat treatment cooling conditions is established. Ultimately, a highly efficient and low-cost characterization method for the "cooling rate-microstructure-strength" three-field coupling of railway wheel heat treatment is formed.

[0051] In this embodiment of the invention, after step S5 and before step S6, the method further includes:

[0052] S7. Take another cross-sectional sample from the rim test block along the radial direction and measure the ferrite volume fraction and pearlite lamellar spacing in the microstructure at the characteristic points numbered #1' to #5'. Check whether they are equivalent to the quantitative analysis results of the microstructure at the characteristic points numbered #1 to #5. If they are equivalent, proceed to step S6. If they are not equivalent, repeat step S4.

[0053] According to the principle of "consistency (equivalence)," for ferrite-pearlite type wheels, the microstructure composition of characteristic points with equivalent mechanical properties should also be equivalent. Therefore, the quantitative analysis results of the microstructure at characteristic points #1' to #5' should be equivalent to the quantitative analysis results of the microstructure at characteristic points #1 to #5.

[0054] Two rolled wheels from the same heat number and batch were selected and labeled A and B, respectively. Their main chemical components (by mass percentage) were: C 0.75; Si 0.84; Mn 0.86; Cr 0.13; Ni 0.02; V 0.05; P≤0.020; S≤0.015 and C 0.74; Si 0.84; Mn 0.85; Cr 0.15; Ni 0.03; V 0.06; P≤0.020; S≤0.015, with the remainder being Fe and unavoidable impurities. At the production site, wheel A underwent homogenization at 870±10℃ for 2.5 hours, followed by quenching and complete cooling to obtain a heat-treated cooled blank wheel, with a strong water spraying time of 999 seconds. Two 1 / 8 rim test blocks were taken from wheel B, labeled B1 and B2 respectively. Test block B1 was heat-treated and cooled in the laboratory by homogenization at 870±10℃ for 2.5h, followed by quenching and complete cooling, resulting in a heat-treated and cooled wheel. A strong water spraying time of 720s was applied. It was ensured that the overall temperature recovery after quenching and cooling of wheel A and the 1 / 8 rim test block B1 did not exceed 100℃ to reduce the "self-tempering" effect caused by temperature recovery and to preserve the quenched and cooled microstructure to the maximum extent.

[0055] The rim of wheel A (as described above) is radially cut open, and a cross-sectional sample with a thickness of 25-30 mm is taken. Both sides are machined to be flat and smooth. Along the central contact area of ​​the wheel track (i.e., 80 mm from the inner rim surface), starting from the tread surface downwards, one "point" is taken at distances of 15 mm, 25 mm, 35 mm, 45 mm, and 55 mm from the tread surface, and numbered #1, #2, #3, #4, and #5 respectively. Following GB / T 39635-2020 "Instrumented Indentation Method for Determination of Indentation Tensile Properties and Residual Stress of Metallic Materials," the instrumented indentation method is used. The indenter is a WC material ball head with a diameter of 1 mm. Yield strength (through the segmentation point of the elastic-plastic curve) and tensile strength (principle of tensile instability) tests are performed on the above-mentioned "points" #1 to #5 to obtain the static strength results at the corresponding characteristic points along this path. Figure 2 , Figure 3 As shown.

[0056] A 15-20 mm thick cross-sectional sample was taken from the rim of the aforementioned wheel A. A metallographic sample was prepared, and the ferrite volume fraction at the aforementioned feature points #1-#5 was extracted using a grayscale + binary method under an optical microscope with a built-in scale. Simultaneously, the pearlite lamellar spacing at the aforementioned feature points #1-#5 was measured under scanning electron microscopy. The quantitative results of the microstructure at the five feature points along this path are shown in Table 1. Figure 4 For ferrite-pearlite two-phase material wheels, the sum of the volume fractions of ferrite and pearlite is 100%.

[0057] Table 1. Microstructure and static strength results at 5 characteristic points on the actual wheel rim.

[0058]

[0059]

[0060] Cut the 1 / 8 rim test block (B1) radially and take a cross-sectional sample with a thickness of 25-30 mm. Process both sides to be flat and smooth. Along the central area of ​​the wheel-rail contact (i.e., 80 mm from the inner rim surface), from the tread surface downwards, perform high-throughput instrumented indentation method yield strength and tensile strength tests according to the test method described in GB / T 39635-2020. The spacing between characteristic points is 3 mm, the total test path is 66 mm from the tread surface, and the total number of characteristic points is 22. Establish the static strength results at the series of characteristic points measured along this path. The static strength results at the series of characteristic points were compared with the static strength results at the actual wheel at characteristic points #1 to #5. With a deviation of less than 5%, five characteristic points that closely matched the numbered #1 to #5 were selected from the numerous test points and numbered #1', #2', #3', #4', and #5' respectively. The depths from the tread surface to each characteristic point were recorded as h1', h2', h3', h4', and h5' (mm). A cross-sectional sample with a thickness of 15 to 20 mm was taken from the 1 / 8 rim test block numbered B1 to prepare a metallographic sample. The ferrite volume fraction and pearlite lamellar spacing in the microstructure at characteristic points #1' to #5' were measured to obtain the quantitative results of the microstructure at the five characteristic points along this path, as shown in Table 2.

[0061] Table 2. Quantitative analysis of microstructure and instrumented indentation strength measurement results at 5 corresponding characteristic points on a 1 / 8 rim specimen from the laboratory.

[0062]

[0063] Take another 1 / 8 rim test block, numbered B2, and in the laboratory, according to... Figure 5The method shown involves using an electrical discharge machining (EDM) machine to locate and define the depth on the inner surface of the wheel rim. The outer diameter of the copper electrode is 2mm, and the hole depth is 80mm. To minimize the impact of drilling on the temperature field between different "points," the five feature points, numbered #1' to #5', are staggered circumferentially along the inner surface of the wheel rim, with an arc length spacing of 25mm between the holes. A 1.6mm diameter thermocouple is inserted to the corresponding depth and securely sealed. In the laboratory, heat treatment heating and complete cooling are performed according to the above process. Thermocouples are used to collect temperature-time data during the heat treatment process, with a data acquisition interval of 1 second. The obtained cooling curves at the five "points" correspond to the cooling temperature field distribution along the corresponding path of the actual wheel. Figure 6 As shown. The effective average cooling rate within the 800–600℃ range is taken as the cooling rate at the corresponding characteristic "point," and a cooling rate gradient is established, i.e., the relationship between cooling rate and depth from the tread surface. The results are as follows. Figure 7 As shown. Thus, based on the principle of "consistency (equivalence)," the correspondence between actual production and different heat treatment cooling conditions in the laboratory was established through the two "mediums" of microstructure and static strength.

[0064] The coupled data of the "cooling rate-structure-strength" three fields are processed to obtain the corresponding fitted curve data package, such as... Figure 8 The figure shows the cooling process of wheel heat treatment under certain working conditions. The absolute deviation of static strength between the characteristic points #1' to #5' of the laboratory 1 / 8 wheel rim specimen and the characteristic points #1 to #5' of the actual wheel rim is calculated as follows:

[0065] Characteristic point #1': Yield strength deviation |(825-828) / 828×100%| = 0.36%, tensile strength deviation |(1261-1268) / 1268×100%| = 0.55%;

[0066] Characteristic point #2': Yield strength deviation |(790-792) / 792×100%| = 0.25%, tensile strength deviation |(1228-1234) / 1234×100%| = 0.49%;

[0067] Characteristic point #3': Yield strength deviation |(769-779) / 779×100%| = 1.28%, tensile strength deviation |(1211-1223) / 1223×100%| = 0.98%;

[0068] Characteristic point #4': Yield strength deviation |(760-771) / 771×100%| = 1.43%, tensile strength deviation |(1204-1216) / 1216×100%| = 0.99%;

[0069] Characteristic point #5': Yield strength deviation |(752-763) / 763×100%| = 1.44%, tensile strength deviation |(1182-1210) / 1210×100%| = 2.31%.

[0070] It can be seen that the maximum absolute deviation of yield strength at the corresponding characteristic point is 1.44%, and the maximum absolute deviation of tensile strength is 2.31%, both of which are less than the target deviation of 5%, and meet the design requirements.

[0071] The present invention has been described by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels, characterized in that, The method includes the following steps: S1. The wheel A to be tested is heated, quenched and completely cooled at the production site to obtain a heat-treated cooled blank wheel. S2. Take a rim test block from the wheel B to be tested, and heat, quench and cool the rim test block under laboratory conditions to obtain a heat-treated and cooled blank rim test block. S3. Cut the rim of the blank wheel radially, take a cross-sectional sample, and take feature point 1 at different depths from the tread surface radially. Test the static strength and microstructure at each feature point 1. S4. Cut the blank wheel rim test block radially, take cross-sectional specimens, and take more feature points 2 at different depths from the tread surface radially to test the static strength at each feature point 2 position. S5. Find a matching feature point in feature point 2 that matches the static strength of feature point 1; S6. Pre-embed thermocouples at the matching feature point positions in the wheel rim test block, heat and quench the wheel rim test block completely under laboratory conditions, read the cooling curve of the matching feature point, and fit the cooling rate, microstructure and static strength of the matching feature point to form a coupling curve of cooling rate-microstructure-static strength.

2. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, When the rim temperature does not exceed 100℃, the wheel or rim test block to be tested is quenched and completely cooled.

3. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, The radial depth of the feature point from the tread surface is 10mm to 60mm.

4. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, The steps following step S5 and before step S6 include: S7. Take a cross-sectional sample from the radial direction of the blank wheel rim test block, measure the microstructure at the matching feature point position in the cross-sectional sample, and check whether it is equivalent to the microstructure at the corresponding feature point 1 position on the blank wheel. If it is equivalent, proceed to step S6.

5. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, Static strength is characterized by yield strength and tensile strength.

6. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, The microstructure was characterized by the ferrite volume fraction and the pearlite lamellar spacing.

7. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, Find feature points in feature point 2 whose static strength deviation from feature point 1 is less than 5%. Feature point 2 with the smallest deviation is the matching feature point of feature point 1.

8. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, The specific method for determining the pre-embedded location of thermocouples is as follows: The radial embedment depth is the radial depth of the matching feature point, and the arc length of the embedment position of the adjacent thermocouple in the circumferential direction is 20mm to 30mm.

9. The method for constructing a three-field coupling of cold speed, microstructure, and strength for railway wheels as described in claim 1, characterized in that, The wheel is made of a ferrite-pearlite two-phase material.

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