Method for determining relationship between workpiece diameter change and processed workpiece surface performance parameters

Abstract

The invention discloses a method for determining the relationship between workpiece diameter variation and treated workpiece surface performance parameters, which is applied to the field of metal material performance detection and comprises the following steps: establishing a quantitative relationship model between the workpiece diameter variation of a workpiece and the workpiece grain size of the treated workpiece; performing surface nanocrystallization treatment on the workpiece to obtain workpiece grain sizes of the treated workpiece corresponding to different workpiece diameter variations, and obtaining a plurality of groups of experimental data; experimental data are substituted into the quantitative relation model, model parameters are fitted through a least square method, and the model parameters comprise to-be-calibrated material constants related to the to-be-tested workpiece material; and according to the model parameters, the relation between the workpiece grain size of the processed workpiece and the workpiece diameter variation is determined. According to the method provided by the invention, the industrial implementability of the workpiece surface nanocrystallization treatment can be remarkably improved, the performance detection efficiency of the treated workpiece is improved, and the comprehensive cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of metal material performance detection, and in particular to a method for determining the relationship between a workpiece diameter change and surface performance parameters of the workpiece after treatment. Background Art

[0002] Bearing steel rolls (such as GCr15SiMn and M50) achieve a hardness of 60-65HRC after surface tempering, but their hardness and wear resistance still have significant room for improvement. Through surface nano-crystallization, severe plastic deformation (SPD) is used to induce a gradient structure on the surface. Under the action of stress (shear and compressive stress) and deformation, the originally coarse grains are gradually elongated axially into thin ribbons, forming a fibrous structure. The dislocation density within the material increases dramatically, and some grains are broken down. Under continuous action, the grain size gradually refines, significantly enhancing hardness, fatigue resistance, and wear resistance.

[0003] In the related art, methods for measuring the surface grain size of gradient nanostructures typically include transmission electron microscopy, X-ray diffraction peak broadening analysis, and ultrasonic surface wave testing. Hardness is measured using indentation or impact methods such as Vickers, Rockwell, Leeb, and Shore. However, these methods have the following disadvantages:

[0004] 1. Hardness testing has requirements on the shape and size of the sample, especially for complex shapes and medium and large workpieces (such as rollers), which are hindered and the testing process is cumbersome;

[0005] 2. Sampling, press-in and impact measurement methods will destroy the surface integrity of the workpiece;

[0006] 3. Sample preparation and testing take a long time and are costly, which is not conducive to timely testing in industry.

[0007] Therefore, how to effectively improve the efficiency of judging the performance parameters of workpiece grains is a technical problem that those skilled in the art currently need to solve. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for determining the relationship between the diameter change of a workpiece and the surface performance parameters of the workpiece after processing, which is used to quickly and accurately judge the workpiece grain parameter information and is convenient for operation.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for determining the relationship between a workpiece diameter change and a surface performance parameter of the workpiece after treatment, comprising the following steps:

[0011] Establish the workpiece diameter variation of the workpiece The grain size of the workpiece after processing Quantitative relationship model between

[0012] The workpiece is subjected to surface nano-processing to obtain different diameter changes of the workpiece The corresponding grain size of the workpiece after processing , and obtained several sets of experimental data;

[0013] Substituting the experimental data into the quantitative relationship model, and fitting the model parameters by the least square method, wherein the model parameters include material constants to be calibrated related to the material of the workpiece to be measured;

[0014] Determine the grain size of the processed workpiece according to the model parameters The change in the workpiece diameter The relationship between them.

[0015] On the other hand, the quantitative relationship model is:

[0016] (1)

[0017] in: ;

[0018] is the volume strain;

[0019] is the change in workpiece diameter;

[0020] is the workpiece diameter before processing;

[0021] is the workpiece grain size of the workpiece before processing;

[0022] is the workpiece grain size of the processed workpiece;

[0023] is the surface residual compressive stress of the workpiece after treatment;

[0024] 、 、 It is the material constant to be calibrated related to the workpiece material to be measured.

[0025] On the other hand, substituting the experimental data into the quantitative relationship model and fitting the model parameters by the least squares method includes:

[0026] According to the formula (1), the change in the diameter of the workpiece is determined The grain size of the workpiece after processing The relationship between:

[0027] (2)

[0028] According to formula (2), formula (3) is obtained as follows:

[0029] (3)

[0030] Simplifying the formula (3), we get the formula (4), as follows:

[0031] (4)

[0032] in:

[0033] .

[0034] For each set of experimental data, an equation can be obtained; after conducting N sets of experiments, the equation system is obtained as follows:

[0035] (5)

[0036] Convert the equation group (5) into matrix form and construct the matrix equation Y=X*θ, with parameters ,in:

[0037] ;

[0038] ;

[0039] Least squares fitting 、 and value.

[0040] On the other hand, the different workpiece diameter changes are obtained The corresponding grain size of the workpiece after processing , and obtained several sets of experimental data including:

[0041] Obtain the grain size of the workpiece before processing using a metallographic microscope or electron backscatter diffraction (EBSD) , the grain size of the workpiece after processing was analyzed by TEM sampling ; Use X-ray diffraction or neutron diffraction to measure the surface residual compressive stress of the treated workpiece ; Use a laser diameter gauge to measure the diameter of the workpiece before processing And the workpiece diameter of the processed workpiece , and according to the workpiece diameter of the workpiece before processing and the workpiece diameter of the workpiece after the treatment , calculate the change in the workpiece diameter .

[0042] On the other hand, the surface nano-processing includes at least one of surface grinding, surface rolling, shot peening, laser shock, and ultrasonic rolling.

[0043] On the other hand, before performing the surface nano-processing on the workpiece, the method further comprises:

[0044] A bearing steel roller that has been subjected to quenching and tempering treatment is selected as the workpiece. The structure of the workpiece is martensite, and the grain size of the workpiece is within the range of 0.8-5 μm.

[0045] On the other hand, the surface nano-processing of the workpiece further comprises:

[0046] By adjusting the pressure, feed rate, speed and / or pass number of the workpiece, multiple groups of surface nano-processing are performed on the workpiece to obtain multiple groups of different values ​​of workpiece diameter changes. , and the change in diameter of each workpiece The corresponding grain size of the workpiece after processing .

[0047] On the other hand, it also includes:

[0048] Determine the surface hardness of the workpiece after treatment based on the Hall-Petch relationship The grain size of the workpiece after processing The relationship between the workpiece surface hardness before treatment is obtained by fitting the experimental data. Constants related to material properties ;

[0049] According to the surface hardness of the workpiece before the treatment Constants related to the material properties , determine the surface hardness of the workpiece after treatment The grain size of the workpiece after processing the relationship between;

[0050] According to the grain size of the workpiece after processing The change in the workpiece diameter The relationship between the workpiece surface hardness after treatment is determined The change in the workpiece diameter The relationship between them.

[0051] On the other hand, the surface hardness of the workpiece after the treatment is The surface grain size of the workpiece after treatment The relationship between them is:

[0052] (6)

[0053] in:

[0054] : Surface hardness of workpiece before treatment;

[0055] : constants related to material properties;

[0056] : Workpiece grain size of the workpiece after processing.

[0057] On the other hand, the surface hardness of the workpiece before treatment is obtained by fitting the experimental data. Constants related to material properties Previously also included:

[0058] Use a hardness tester to measure the surface hardness of the workpiece after each group of treatment .

[0059] The method for determining the relationship between the workpiece diameter change and the surface performance parameters of the workpiece after treatment provided by the present invention comprises the following steps: establishing the workpiece diameter change The grain size of the workpiece after processing The workpiece is subjected to surface nano-processing to obtain different diameter changes of the workpiece. The corresponding grain size of the workpiece after processing , and obtain several sets of experimental data; substitute the experimental data into the quantitative relationship model, and fit the model parameters by the least square method, wherein the model parameters include the material constants to be calibrated related to the workpiece material to be measured; determine the workpiece grain size after processing according to the model parameters The change in the workpiece diameter The method provided by the present invention can establish a relationship between the change in the workpiece diameter of the workpiece and the workpiece grain size of the workpiece after treatment. After the workpiece is subjected to surface nano-processing, it is only necessary to measure the workpiece diameter of the workpiece. By calculating the change in the workpiece diameter, the workpiece grain size of the workpiece after treatment can be quickly obtained. There is no need to use transmission electron microscopy (TEM) or X-ray grain size measurement to detect the workpiece grain size after treatment. This can significantly improve the industrial feasibility of workpiece surface nano-processing, improve the efficiency of performance detection of treated workpieces, and reduce overall costs.

[0060] In one embodiment, the method further includes determining the surface hardness of the workpiece after processing according to the Hall-Petch relationship. The grain size of the workpiece after processing The relationship between the workpiece surface hardness before treatment is obtained by fitting the experimental data. Constants related to material properties ; According to the surface hardness of the workpiece before the treatment Constants related to the material properties , determine the surface hardness of the workpiece after treatment The grain size of the workpiece after processing According to the relationship between the workpiece grain size after processing The change in the workpiece diameter The relationship between the workpiece surface hardness after treatment is determined The change in the workpiece diameter The above method is to measure the surface hardness of the workpiece after treatment. The grain size of the workpiece after processing The relationship between the workpiece and the grain size of the workpiece after processing is determined The change in the workpiece diameter The relationship between the surface hardness of the workpiece after treatment is obtained The change in the workpiece diameter The relationship between the surface hardness of the workpiece after treatment It can also be quickly calculated by the change in workpiece diameter, without the need for hardness measurement to measure the surface hardness of the processed workpiece. Carrying out inspection can further reduce the overall cost and improve the performance inspection efficiency of the processed workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0062] Figure 1 A flowchart of a specific embodiment of the method for determining the relationship between the workpiece diameter change and the surface performance parameters of the workpiece after treatment provided by the present invention;

[0063] Figure 2 This is a flow chart of another specific embodiment of the method for determining the relationship between the workpiece diameter change and the surface performance parameters of the processed workpiece provided by the present invention. DETAILED DESCRIPTION

[0064] The core of the present invention is to provide a method for determining the relationship between the change in workpiece diameter and the surface performance parameters of the processed workpiece, which can significantly reduce the overall cost and improve feasibility.

[0065] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0066] Please refer to Figure 1 , Figure 1 The present invention provides a method for determining the relationship between a workpiece diameter change and surface performance parameters of the workpiece after treatment.

[0067] In this embodiment, the method for determining the relationship between the workpiece diameter change and the surface performance parameters of the processed workpiece includes:

[0068] Step S1: Establish the workpiece diameter variation of the workpiece The grain size of the workpiece after processing Quantitative relationship model between

[0069] Step S2: Perform surface nano-processing on the workpiece to obtain different diameter changes of the workpiece The corresponding grain size of the workpiece after processing , and obtained several sets of experimental data;

[0070] Step S3: Substitute the experimental data into the quantitative relationship model and fit the model parameters by the least square method. The model parameters include the material constants to be calibrated related to the material of the workpiece to be measured;

[0071] Step S4: Determine the grain size of the processed workpiece based on the model parameters The change in the workpiece diameter The relationship between them.

[0072] Specifically, due to the related art's limitations on the grain size of the processed workpiece, When obtaining the data, it is necessary to use transmission electron microscopy (TEM) or X-ray measurement, which results in a long cycle and high cost. In this application, the diameter change of the workpiece is established based on the surface volume change caused by plastic deformation, which in turn causes the diameter change. The grain size of the workpiece after processing The quantitative relationship model between the diameter of the workpiece is obtained Calculate the workpiece grain size after processing The calculation formula for the change in workpiece diameter is The acquisition method is simple, efficient and low-cost; after surface nano-treatment, the mechanical properties of metal materials, including surface hardness, wear resistance, corrosion resistance and fatigue resistance, can be greatly improved, the material utilization rate becomes higher, and the cost can be effectively reduced.

[0073] The method provided by the present invention can establish a relationship between the change in workpiece diameter and the workpiece grain size of the treated workpiece. After the workpiece is subjected to surface nano-processing, it is only necessary to measure the workpiece diameter. By calculating the change in workpiece diameter, the workpiece grain size of the treated workpiece can be quickly obtained. There is no need to use transmission electron microscopy or X-ray grain size measurement to detect the workpiece grain size after treatment. This can significantly improve the industrial feasibility of workpiece surface nano-processing, increase the efficiency of performance testing of treated workpieces, and reduce overall costs.

[0074] The method for determining the relationship between the workpiece diameter change and the surface performance parameters of the processed workpiece is not only applicable to the inspection of complex-shaped and medium-to-large workpieces (such as rolling mills), but the workpiece diameter change can also be replaced by the change in other appearance dimensions, which is also applicable to other types of workpieces.

[0075] In some embodiments, the surface nano-processing includes at least one of surface rolling, surface rolling, shot peening, laser shock, and ultrasonic rolling. The specific method can be selected according to needs, and a combination of multiple methods can be selected to prepare a gradient structure on the surface of the bearing steel workpiece, and by adjusting the process parameters corresponding to the method, different degrees of plastic deformation, that is, different changes in the diameter of the workpiece, can be obtained. samples.

[0076] In some embodiments, before performing surface nano-processing on the workpiece, the method further includes:

[0077] A bearing steel roller that has undergone quenching and tempering treatment is selected as the workpiece. The workpiece structure is martensite and the grain size of the workpiece is in the range of 0.8-5μm. Of course, in the actual detection process, the corresponding material should be selected for surface nano-treatment according to the actual workpiece material type, and the required experimental data should be obtained.

[0078] In some embodiments, performing surface nano-processing on the workpiece further includes:

[0079] By adjusting the pressure, feed rate, speed and / or pass number of the workpiece, multiple groups of surface nano-processing are performed on the workpiece to obtain multiple groups of different values ​​of workpiece diameter changes. , and the diameter changes of each workpiece The corresponding grain size of the workpiece after processing Specifically, in order to better obtain experimental data, after completing different groups of experimental surface nano-processing, the workpiece diameter change should be different. In order to ensure that the workpiece diameter change in different groups of experiments is different, the pressure, feed rate, speed or number of passes of the workpiece during the surface nano-processing process can be changed to obtain multiple groups of different workpiece diameter changes. , and its corresponding grain size of the processed workpiece .

[0080] In some embodiments, volumetric strain is established Grain refinement and residual stress Correlation, thus determining the quantitative relationship model as:

[0081] (1)

[0082] in: ;

[0083] is the volume strain;

[0084] is the change in workpiece diameter;

[0085] is the workpiece diameter before processing;

[0086] is the workpiece grain size of the workpiece before processing;

[0087] is the workpiece grain size of the processed workpiece;

[0088] is the surface residual compressive stress of the workpiece after treatment;

[0089] 、 、 It is the material constant to be calibrated related to the workpiece material to be measured.

[0090] In some embodiments, substituting experimental data into a quantitative relationship model and fitting model parameters by least squares method comprises:

[0091] According to formula (1), the change in workpiece diameter is determined The grain size of the workpiece after processing The relationship between:

[0092] (2)

[0093] According to formula (2), multiply both sides , we get the linear expression, namely formula (3), as follows:

[0094] (3)

[0095] Simplifying formula (3), we get formula (4), as follows:

[0096] (4)

[0097] in:

[0098] .

[0099] For each set of experimental data, an equation can be obtained; after conducting N sets of experiments, the equation system is obtained as follows:

[0100] (5)

[0101] Convert equation group (5) into matrix form and construct the matrix equation ,parameter ,in:

[0102] ;

[0103] ;

[0104] Least squares fitting 、 and value.

[0105] Specifically, the number of experimental groups can be selected as needed. In order to save costs and improve efficiency, two groups of experiments are generally selected and two groups of experimental data are obtained. Of course, the larger the number of experimental groups, the better the fitting results. 、 and The more precise the value, for example, you can select four groups of experiments and obtain four groups of experimental data.

[0106] In some embodiments, different workpiece diameter variations are obtained. The corresponding grain size of the workpiece after processing , and obtained several sets of experimental data including:

[0107] Obtain the grain size of the workpiece before processing using a metallographic microscope or electron backscatter diffraction (EBSD) , the grain size of the workpiece after processing was analyzed by TEM sampling ; Use X-ray diffraction or neutron diffraction to measure the surface residual compressive stress of the treated workpiece ; Use a laser diameter gauge to measure the diameter of the workpiece before processing And the workpiece diameter of the processed workpiece , and according to the workpiece diameter before processing and the workpiece diameter of the processed workpiece , calculate the change in workpiece diameter . Grain size of workpiece before processing , the grain size of the workpiece after processing , Surface residual compressive stress of the workpiece after treatment , Workpiece diameter before processing And the workpiece diameter of the processed workpiece In addition to the above methods, the acquisition can also be carried out by any means that can meet the detection requirements.

[0108] Please refer to Figure 2 , Figure 2 This is a flow chart of another specific embodiment of the method for determining the relationship between the workpiece diameter change and the surface performance parameters of the processed workpiece provided by the present invention.

[0109] In some embodiments, further comprising:

[0110] Step S5: Determine the surface hardness of the workpiece after treatment based on the Hall-Petch relationship The grain size of the workpiece after processing The relationship between the workpiece surface hardness before treatment is obtained by fitting the experimental data. Constants related to material properties ;

[0111] Step S6: Based on the surface hardness of the workpiece before treatment Constants related to material properties , determine the surface hardness of the workpiece after treatment The grain size of the workpiece after processing the relationship between;

[0112] Step S7: Based on the grain size of the workpiece after processing Change in workpiece diameter The relationship between the workpiece surface hardness after treatment is determined Change in workpiece diameter The relationship between them.

[0113] The above method is to measure the surface hardness of the workpiece after treatment. The grain size of the workpiece after processing The relationship between the workpiece and the grain size of the workpiece after processing is determined Change in workpiece diameter The relationship between the surface hardness of the workpiece after treatment is obtained Change in workpiece diameter The relationship between the surface hardness of the workpiece after treatment It can also be quickly calculated by the change in workpiece diameter, without the need for hardness measurement to measure the surface hardness of the processed workpiece. Carrying out inspection can further reduce the overall cost and improve the performance inspection efficiency of the processed workpiece.

[0114] In some embodiments, the surface hardness of the workpiece after treatment is The surface grain size of the workpiece after treatment The relationship between them is:

[0115] (6)

[0116] in:

[0117] : Surface hardness of workpiece before treatment;

[0118] : constants related to material properties;

[0119] : Workpiece grain size of the processed workpiece (unit: nm).

[0120] Specifically, experimental data fitting and , construct the matrix equation:

[0121] (7)

[0122] The solution process of and k is the same as above 、 and value, and finally obtain and That's it.

[0123] In some embodiments, the surface hardness of the workpiece before treatment is obtained by fitting experimental data. Constants related to material properties Previously also included:

[0124] Use a hardness tester to measure the surface hardness of the workpiece after each group of treatment , of course, the surface hardness of the workpiece after treatment It can also be obtained through other means, not limited to measurement with a hardness tester.

[0125] It should be noted that the surface hardness of the workpiece before treatment given in this application is It is obtained by fitting experimental data. This setting is to reduce the surface hardness of the workpiece before processing. The detection process can further improve efficiency.

[0126] Specifically, in a specific embodiment, the material of the workpiece is selected to be GCr15 bearing steel, the workpiece type is a roller, and the workpiece surface is subjected to high-frequency quenching and tempering treatment; initial parameter measurement: the workpiece grain size before treatment is obtained by EBSD , use micrometer and other means to measure the workpiece diameter before processing , use the micro Vickers hardness tester to measure the surface hardness of the workpiece before treatment ; Use the surface mechanical rolling treatment (SMRT) process to perform surface nano-processing on the workpiece surface to obtain different degrees of plastic deformation, that is, the change in workpiece diameter The samples are 0.1mm, 0.15mm, 0.2mm, and 0.25mm respectively;

[0127] Measure the sample parameters of different workpiece diameter changes: TEM sampling and analysis of the gradient nanostructure of the workpiece surface with different workpiece diameter changes to determine the grain size of the workpiece after treatment. ; Use X-ray diffraction or neutron diffraction to measure the surface residual compressive stress of the treated workpiece , the unit is , using dimensional measurement including laser diameter gauge to measure the workpiece diameter after processing , thereby obtaining the workpiece diameter change , use the micro Vickers hardness tester to measure the surface hardness of the workpiece after treatment , the specific values ​​are shown in Table 1.

[0128] Table 1 Sample parameters of workpieces in each group of experiments

[0129]

[0130] According to the experimental data in Table 1, we can calculate 、 、 The numerical values ​​of the values ​​are obtained according to formula (3), Table 2.

[0131] Table 2 Calculated from experimental data of each group , , , The value of

[0132]

[0133] According to the data in Table 2, we can get , and then calculate ;

[0134] Then according to formula (6), calculate and , formula (6) can be written as ; The calculation process is:

[0135]

[0136] Therefore, we get .

[0137] The above model was verified and the experimental values ​​were used for calculation to obtain the error range, as shown in Table 3.

[0138] Table 3 Error values ​​of calculation results in each group of experiments

[0139]

[0140] It can be seen from Table 3 that the change in workpiece diameter in each group of experiments The error value and the surface hardness of the workpiece after treatment The error values ​​are all within the allowable range.

[0141] The above is a detailed introduction to a method for determining the relationship between a change in workpiece diameter and the surface performance parameters of the workpiece after treatment, provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the method of the present invention and its core concept. It should be pointed out that, for those skilled in the art, several improvements and modifications may be made to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A method for determining the relationship between workpiece diameter change and surface performance parameters of the workpiece after treatment, characterized in that: The following steps are involved: Establish the workpiece diameter change of the workpiece ( ) and the workpiece grain size after processing ( ) quantitative relationship model between them; The workpiece is subjected to surface nano-processing to obtain different workpiece diameter changes ( ) corresponds to the grain size of the processed workpiece ( ), and obtain several sets of experimental data; Substituting the experimental data into the quantitative relationship model, and fitting the model parameters by the least square method, wherein the model parameters include material constants to be calibrated related to the material of the workpiece to be measured; According to the model parameters, the workpiece grain size of the processed workpiece is determined ( ) and the workpiece diameter change ( ) between them.

2. The method for determining the relationship between the workpiece diameter change and the surface performance parameters of the workpiece after treatment according to claim 1, characterized in that: The quantitative relationship model is: （1） in: ; : volumetric strain; : Change in workpiece diameter; : workpiece diameter of the workpiece before processing; : Workpiece grain size of the workpiece before processing; : Workpiece grain size of the workpiece after processing; : Surface residual compressive stress of the workpiece after treatment; 、 、 It is the material constant to be calibrated related to the workpiece material to be measured.

3. The method for determining the relationship between the workpiece diameter change and the surface performance parameters of the workpiece after treatment according to claim 2, characterized in that: Substituting the experimental data into the quantitative relationship model and fitting the model parameters by the least squares method includes: According to the formula (1), the change in the diameter of the workpiece is determined ( ) and the workpiece grain size after processing ( ) between: （2） According to formula (2), the formula is as follows: （3） Simplifying the formula (3), we get the formula (4), as follows: （4） in: ； For each set of experimental data, an equation can be obtained; after conducting N sets of experiments, the equation system is obtained as follows: （5） Convert the equation group (5) into matrix form and construct the matrix equation Y=X*θ, with parameters ,in: ； ； Least squares fitting 、 and value.

4. The method for determining the relationship between the change in workpiece diameter and the surface performance parameters of the workpiece after treatment according to claim 2, characterized in that: The different workpiece diameter changes ( ) corresponds to the grain size of the processed workpiece ( ), and obtained several sets of experimental data including: The grain size of the workpiece before processing is obtained by metallographic microscope or electron backscatter diffraction (EBSD) ), the grain size of the workpiece after processing was analyzed by TEM sampling ( ); Use X-ray diffraction or neutron diffraction to measure the surface residual compressive stress of the treated workpiece ( ); Use a laser diameter gauge to measure the workpiece diameter before processing ( ) and the workpiece diameter of the processed workpiece ( ), and according to the workpiece diameter of the workpiece before the treatment ( ) and the workpiece diameter of the workpiece after the treatment ( ), calculate the change in the workpiece diameter ( ).

5. The method for determining the relationship between the diameter change of a workpiece and the surface performance parameters of the workpiece after treatment according to claim 1, characterized in that: The surface nano-processing includes at least one of surface grinding, surface rolling, shot peening, laser shock, and ultrasonic rolling.

6. The method for determining the relationship between workpiece diameter change and surface performance parameters of the workpiece after treatment according to claim 1, characterized in that: Before the workpiece is subjected to surface nano-processing, the following steps are further included: A bearing steel roller that has been subjected to quenching and tempering treatment is selected as the workpiece. The structure of the workpiece is martensite, and the grain size of the workpiece is within the range of 0.8-5 μm.

7. The method for determining the relationship between workpiece diameter change and surface performance parameters of the workpiece after treatment according to claim 1, characterized in that: The surface nano-processing of the workpiece further comprises: By adjusting the pressure, feed rate, rotation speed and / or pass number of the workpiece, multiple groups of surface nano-processing are performed on the workpiece to obtain multiple groups of different values ​​of workpiece diameter changes ( ), and the change in diameter of each workpiece ( ) corresponds to the grain size of the processed workpiece ( ).

8. A method for determining the relationship between a workpiece diameter change and a surface performance parameter of the workpiece after treatment according to any one of claims 1 to 7, characterized in that: Also includes: According to the Hall-Petch relationship, the surface hardness of the workpiece after treatment is determined ( ) and the workpiece grain size after processing ( ) and the surface hardness of the workpiece before treatment was obtained by fitting the experimental data ( ) and material property related constants ( ); According to the surface hardness of the workpiece before the treatment ( ) and the material property related constants ( ), determine the surface hardness of the workpiece after treatment ( ) and the workpiece grain size after processing ( ) According to the grain size of the workpiece after processing ( ) and the workpiece diameter change ( ) to determine the surface hardness of the workpiece after treatment ( ) and the workpiece diameter change ( ) between them.

9. The method for determining the relationship between the workpiece diameter change and the surface performance parameters of the workpiece after treatment according to claim 8, characterized in that: The surface hardness of the workpiece after the treatment ( ) and the surface grain size of the workpiece after treatment ( ) is: （6） in: : Surface hardness of workpiece before treatment; : constants related to material properties; : Workpiece grain size of the workpiece after processing.

10. The method for determining the relationship between the workpiece diameter change and the surface performance parameters of the workpiece after treatment according to claim 8, characterized in that: The surface hardness of the workpiece before treatment is obtained by fitting the experimental data ( ) and material property related constants ( ) also includes: Use a hardness tester to measure the surface hardness of the workpiece after each group of treatment ( ).

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