A method for numerical simulation of duplex stainless steel cutting process

Abstract

The present invention relates to the technical field of high-speed cutting simulation, and discloses a method for numerical simulation of the cutting process of duplex stainless steel, S1, according to the microstructure characteristics of the duplex material and the law of change of flow stress with strain rate, select a viscosity constitutive equation suitable for the duplex material; S2, based on the electron backscatter diffraction technology EBSD image data, obtain the microstructure information of the duplex material, and use the Python program to extract the microstructure distribution and orientation of the two phases, etc., and import them into ABAQUS for modeling; S3, through the VUHARD subroutine, the MTS constitutive equation of the duplex material is secondary developed, and the different physical properties of the two phases are respectively given properties that conform to the actual material; S4, design a cutting experiment, and verify the accuracy of the simulation model by comparing the cutting force collected by the cutting experiment with the cutting force extracted by the simulation. The present invention solves the problem that the existing method ignores the microstructure distribution, orientation and material properties of the duplex material, thereby affecting the accuracy of the simulation process.

Description

Technical Field

[0001] The invention belongs to the technical field of high-speed cutting simulation, and in particular relates to a method for numerical simulation of a duplex stainless steel cutting process. Background Art

[0002] Traditional metal cutting experiments are time-consuming and laborious, and require a lot of financial resources to produce expensive test pieces. In order to obtain accurate data, advanced data measurement and acquisition equipment is needed, and the experimental data obtained is subject to large errors due to the influence of operating level and environment. With the improvement of finite element simulation, its accuracy and credibility are getting higher and higher. Compared with traditional experiments, finite elements can express the relationship between strain, strain rate and cutting temperature of various materials through constitutive equations, so as to intuitively analyze the changes of various physical quantities in the actual cutting process.

[0003] Existing methods for establishing material microscopic models mainly include finite element models based on Voronoi diagrams, cell models, and chessboard finite element models based on finite element networks. However, the completely random algorithm of the Voronoi model is difficult to control the size and distribution of grains, the cell model is only applicable to materials with periodic structures, and the approximation of the shape of the chessboard model causes differences between the model and the actual structure, resulting in simulation errors.

[0004] At present, finite element simulation research is mainly focused on single-phase materials, while research on dual-phase materials is relatively rare; in ABAQUS software, the material property module only comes with the JC constitutive model, lacking secondary development. This single model is difficult to meet the analysis needs of complex dual-phase materials. The methods for establishing finite element analysis models for dual-phase materials are also relatively limited, which has certain limitations in practical engineering applications.

[0005] Therefore, in view of the above problems, the present invention proposes a method for numerical simulation of duplex stainless steel cutting process. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, the present invention proposes a method for numerical simulation of a duplex stainless steel cutting process.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for numerical simulation of a duplex stainless steel cutting process comprises the following steps:

[0009] S1. According to the microstructure characteristics of the duplex material and the variation law of flow stress with strain rate, the viscous constitutive equation suitable for the duplex material is selected. The duplex material is S32760 duplex stainless steel, and the S32760 duplex stainless steel uses the S32760 duplex constitutive model considering the viscosity effect;

[0010] S2. Based on the EBSD image data, the microstructure information of the two-phase material is obtained, and the distribution and orientation of the two-phase microstructure are extracted using the Python program and imported into ABAQUS for modeling;

[0011] S3, the S32760 two-phase constitutive model considering the viscosity effect established in S1 is secondary developed by using the corresponding yield function to obtain the derivative of equivalent plastic strain, strain rate and temperature, and is written into the ABAQUS simulation model established in S2 in the form of VUHARD subroutine using FORTRAN language for finite element simulation;

[0012] S4. Design a cutting experiment and verify the accuracy of the simulation model by comparing the cutting force collected from the cutting experiment with the cutting force extracted from the simulation.

[0013] Preferably, in step S1, during high-speed cutting, the material undergoes a process of large strain, high strain rate, and high temperature. 4 s -1 Under the condition of strain rate above 0.04, the viscosity effect is obvious. Therefore, in order to consider the viscosity behavior of the processed material, the S32760 duplex stainless steel is used with the S32760 duplex constitutive model considering the viscosity effect. The constitutive equation selected in the simulation is as follows:

[0014] Austenite:

[0015] Ferrite:

[0016] Where σ is the yield stress; σ 1 is the non-thermal stress constant of austenite phase; σ 2 is the non-thermal stress constant of ferrite phase; is the ferrite hardening coefficient; ε is the equivalent plastic strain; n 1 is the austenite strain sensitivity index; n 2 is the ferrite strain sensitivity index; is the austenite hardening coefficient; is the reference value of the ferrite saturation threshold stress at T = 0K; β is a constant determined by the reference thermal activation energy and the Boltzmann constant; T is the temperature; is the equivalent plastic strain rate; is the reference strain rate; p and q are constants; α is a constant determined by the Burgers vector and shear modulus; is the reference saturation strain rate; μ 1 is the austenite viscosity effect coefficient; μ 2 is the ferrite viscosity effect coefficient.

[0017] Preferably, in step S2, based on the EBSD image data of S32760, the microstructure information of the duplex material is obtained, the microstructure information of the EBSD image data of the S32760 duplex stainless steel is extracted by digital image processing technology, and a geometric model based on the material microstructure is established; step S2 includes the following specific steps:

[0018] 2.1. Use EBSD technology to obtain the microstructure image of duplex stainless steel matrix;

[0019] 2.2. Identify the microstructure of the material, extract the microstructure information of the EBSD image data of S32760 duplex stainless steel through digital image processing technology, and establish a geometric model based on the material microstructure;

[0020] 2.3. Further process the established model, create materials in the material library and name them as aus, fe, and tool, and make corresponding material assignments to provide a basis for assigning material properties to subsequent subroutines.

[0021] Preferably, the step S3 performs secondary development on the S32760 duplex stainless steel MTS constitutive model considering the viscosity effect established in step S1, and writes it into ABAQUS in the form of a VUHARD subroutine using FORTRAN language for finite element simulation, including the following specific steps:

[0022] 3.1. Write the program interface in the subroutine;

[0023] 3.2. Define three variables: equivalent plastic strain ε, equivalent plastic strain rate Temperature T, store it in the corresponding array;

[0024] 3.3. Derivative the two-phase constitutive equation with respect to different variables, including calculating the derivative of the constitutive equation with respect to the equivalent plastic strain, the derivative of the constitutive equation with respect to the equivalent plastic strain rate, and the derivative of the constitutive equation with respect to the temperature, and then store the results in the corresponding array;

[0025] The specific equations and storage locations are as follows:

[0026] Austenite phase constitutive equation, obtain the yield stress and store it in the yield stress array yield:

[0027]

[0028] The derivative of the austenite yield function with respect to the equivalent plastic strain ε is stored in the first column of the array of yield function derivatives with respect to the equivalent plastic strain dieldDeqps:

[0029]

[0030] Austenite yield function versus equivalent plastic strain rate The derivative of the yield function is stored in the second column of the array dyeldDeqps of the yield function derivative of the equivalent plastic strain:

[0031]

[0032] The derivative of the austenite yield function with respect to temperature T: The results are stored in the array of yield function derivatives with respect to temperature dieldDtemp:

[0033]

[0034] Finally, the above four-column array and the strain array, a total of five columns, are converted into units and summarized into the new state variable array stateNew for storage.

[0035] Similarly, the constitutive equation of ferrite phase is:

[0036]

[0037] The derivative of the ferrite yield function with respect to the equivalent plastic strain ε is:

[0038]

[0039] Ferrite yield function versus equivalent plastic strain rate The derivative of :

[0040]

[0041] The derivative of the ferrite yield function with respect to temperature T is:

[0042]

[0043] 3.4. Select the constitutive model of the corresponding phase according to the material name, calculate and store the corresponding calculation results in a specific array, and assign material properties to the two-phase materials and simulate them;

[0044] 3.5. When running the simulation, select the VUHARD subroutine to implement the finite element calculation solution for distinguishing the two-phase material;

[0045] 3.6. After the solution is completed, the cutting force is obtained.

[0046] Preferably, in step S4, a piezoelectric dynamometer is used to measure the force, and after the cutting force is collected, the collected cutting force needs to be filtered.

[0047] Compared with the prior art, the technical effects and advantages of the present invention are:

[0048] 1. The present invention discloses a method for numerical simulation of the cutting process of duplex stainless steel. Based on the metal microstructure, the image can be accurately vectorized through image recognition and processing to obtain a two-dimensional RVE model of the metal based on the material microstructure, which plays an important role in the finite element simulation analysis of duplex stainless steel S32760.

[0049] 2. The present invention discloses a method for numerical simulation of the cutting process of duplex stainless steel. By writing the VUHARD subroutine, the user-defined material constitutive model is imported into ABAQUS through secondary development. According to the material performance data and deformation of the specific material, the deformation hardening behavior of the material is defined, thereby realizing a detailed simulation and prediction of the behavior of the material during the deformation process. It plays an important role in the cutting simulation of duplex stainless steel S32760. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a logic block diagram of the present invention;

[0051] Figure 2 EBSD image of the duplex stainless steel S32760 of the present invention;

[0052] Figure 3 The image is preliminarily processed by MATLAB according to the present invention;

[0053] Figure 4 A model diagram of the present invention in which a surface is divided according to a phase boundary curve;

[0054] Figure 5 A model diagram of a divided material set of the present invention;

[0055] Figure 6 Schematic diagram of initial geometry and boundary conditions of the model of the present invention;

[0056] Figure 7 is a cutting force result curve diagram of the present invention;

[0057] Figure 8 FIG. 4 is a diagram of the experimental equipment of the present invention.

[0058] In the figure: 1. tool handle; 2. milling cutter; 3. blade; 4. workpiece; 5. vise; 6. dynamometer. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] The existing methods for establishing material microscopic models mainly include finite element models based on Voronoi diagrams, cell models, and chessboard finite element models based on finite element networks. However, the completely random algorithm of the Voronoi model is difficult to control the size and distribution of grains. The cell model is only applicable to materials with periodic structures, and the approximation of the shape of the chessboard model causes the difference between the model and the real structure, resulting in simulation errors. In order to be closer to reality, it has become a common method to use the microstructure of the material to establish a simulation model. The modeling method disclosed in the present invention extracts the material microstructure information by identifying its EBSD image data for duplex materials, and the established model is more in line with the material microstructure. An effective simulation model establishment method is provided for the subsequent finite element analysis of duplex stainless steel materials.

[0061] Existing constitutive model solution methods focus on the perspective of single-phase materials, while there are few studies on the constitutive models of duplex composite materials. Due to its own structural characteristics, duplex stainless steel has both austenite and ferrite phases. S32760 duplex stainless steel shows strong temperature sensitivity and strain rate sensitivity, and is also affected by viscosity effects. Most existing models cannot accurately simulate the deformation behavior of complex materials. The present invention conducts secondary development of the viscosity constitutive equation of duplex materials by writing the VUHARD subroutine, assigns material properties to the two-phase materials respectively, and defines the deformation hardening behavior of the material according to the material performance data and the actual deformation situation, thereby realizing the fine simulation and prediction of the material's behavior during the deformation process, and providing an effective numerical simulation method for the cutting process for the finite element analysis of duplex stainless steel materials.

[0062] The following is combined with Figure 1-8 Provide further details of this application;

[0063] like Figure 1 As shown, a method for numerical simulation of duplex stainless steel cutting process comprises the following steps:

[0064] S1. According to the microstructural characteristics of the two-phase material and the variation law of flow stress with strain rate, a viscous constitutive equation suitable for the two-phase material is selected.

[0065] During high-speed cutting, the material undergoes a process of large strain, high strain rate, and high temperature. 4 s -1 Under the condition of strain rate above 0.5, the viscosity effect is obvious. Therefore, in order to consider the viscosity behavior of the processed material, the S32760 two-phase constitutive model considering the viscosity effect should be used.

[0066] According to relevant literature, the constitutive equation selected in the simulation is as follows:

[0067] Austenite:

[0068] Ferrite:

[0069] Where σ is the yield stress; σ 1 is the non-thermal stress constant of austenite phase; σ 2 is the non-thermal stress constant of ferrite phase; is the ferrite hardening coefficient; ε is the equivalent plastic strain; n 1 is the austenite strain sensitivity index; n 2 is the ferrite strain sensitivity index; is the austenite hardening coefficient; is the reference value of the ferrite saturation threshold stress at T = 0K; β is a constant determined by the reference thermal activation energy and the Boltzmann constant; T is the temperature; is the equivalent plastic strain rate; is the reference strain rate; p and q are constants; α is a constant determined by the Burgers vector and shear modulus; is the reference saturation strain rate; μ 1 is the austenite viscosity effect coefficient; μ 2 is the ferrite viscosity effect coefficient.

[0070] S2. Obtain the microstructure information of the duplex material based on the EBSD image data of S32760. The microstructure information of the EBSD image data of S32760 duplex stainless steel is extracted by digital image processing technology, and a geometric model based on the material microstructure is established.

[0071] The EBSD technique can be used to obtain images of the microstructure of the duplex stainless steel matrix, such as Figure 2 As shown, this is the EBSD image of duplex stainless steel S32760. From the image, the austenite phase and the ferrite phase can be clearly distinguished. The red phase is the austenite phase and the blue phase is the ferrite phase.

[0072] The microstructure of the material is identified, and the steps of extracting the microstructure information of the EBSD image data of S32760 duplex stainless steel by digital image processing technology and establishing a geometric model based on the material microstructure are as follows:

[0073] (1) Read the EBSD image of the microstructure and use MATLAB to process the image. First, convert the image into a grayscale image and then perform a median filter to remove noise. Next, perform binary processing on the digital image and perform Gaussian blur and sharpening. Fill in small internal defects to remove small features that have little effect on the simulation results; the processed image is as follows: Figure 3 As shown, Figure 3This is the image after preliminary processing by MATLAB;

[0074] (2) The acquired image is further processed through the Python program, and all the contours of the binarized image are found and saved through graphics methods.

[0075] (3) Find the contour information in the binarized image, convert it into an array list, and store it in the variable rings. Finally, store the coordinate array information as a text file named by sequence number in the specified folder for subsequent program calls.

[0076] (4) Use Python program and ABAQUS software to create a model. First, ensure that relevant modules and libraries are introduced to use the functions of ABAQUS. Next, draw a two-dimensional rectangular plane model as the basic shell, and create a part object with a dimension of two-dimensional plane and a type of deformable. Read the coordinate data in the text file named by the serial number and use the coordinate points to create a spline curve on the new sketch, and then divide the surface according to the sketch. Obtain a model with the surface divided according to the phase boundary curve obtained from the EBSD image data, such as Figure 4 As shown, Figure 4 This is a model that has been divided into surfaces according to the phase boundary curve.

[0077] (5) Further process the established model. First, scale and adjust it to make it consistent with the actual size. Then create the tool component TOOL and perform meshing. Next, use the collection tool to create an austenite (AUS) collection, and select all faces corresponding to austenite according to the EBSD image data and add them to the collection. Create the remaining faces as a ferrite collection (FE). Create materials in the material library and name them aus, fe, and tool, and assign corresponding materials to provide a basis for assigning material properties to subsequent subroutines. The model with the divided material collection is as follows: Figure 5 As shown, Figure 5 A model for partitioning a collection of materials.

[0078] S3. The S32760 duplex stainless steel MTS constitutive model considering the viscosity effect established in S1 is secondary developed and written into the ABAQUS simulation model established in S2 in the form of a VUHARD subroutine using FORTRAN language for finite element simulation.

[0079] The specific steps are as follows:

[0080] Write the program interface in the subroutine, then define three variables and store them in the corresponding arrays:

[0081] Equivalent plastic strain ε, expressed as eps = eqps (km); equivalent plastic strain rate Its expression is epsr=max(eqpsRate(km),1000.); temperature T, its expression is t=tempOld(km).

[0082] When VUHARD is called, the material of each point is processed through a loop. In each loop, we can select the appropriate constitutive equation by judging whether the material name of the current calculation point is aus. If it is austenite, the austenite phase equation is applied to obtain the corresponding output value; if not, it is ferrite, then the ferrite phase equation is applied to obtain the corresponding output value. The output values ​​are stored in the corresponding variables to create an array, including yield (yield stress array), dyedDtemp (yield function derivative array for temperature), and dyedDeqps (yield function derivative array for equivalent plastic strain). Finally, these values ​​are summarized and saved in stateNew (new state variable array).

[0083] In addition, to obtain the data in the above array, we need to differentiate the two-phase constitutive equation with respect to different variables, including calculating the derivative of the constitutive equation with respect to the equivalent plastic strain, the derivative of the constitutive equation with respect to the equivalent plastic strain rate, and the derivative of the constitutive equation with respect to temperature.

[0084] Through such loops and processing, we can effectively process the properties of each material point and obtain the corresponding output results.

[0085] The specific equations and storage locations are as follows:

[0086] Austenite phase constitutive equation, obtain the yield stress and store it in the yield stress array yield:

[0087]

[0088] The derivative of the austenite yield function with respect to the equivalent plastic strain ε is stored in the first column of the array of yield function derivatives with respect to the equivalent plastic strain dieldDeqps:

[0089]

[0090] Austenite yield function versus equivalent plastic strain rate The derivative of the yield function is stored in the second column of the array dyeldDeqps of the yield function derivative of the equivalent plastic strain:

[0091]

[0092] The derivative of the austenite yield function with respect to temperature T is stored in the yield function derivative array with respect to temperature, dieldDtemp:

[0093]

[0094] Finally, the result data obtained from the above four equations and the corresponding strains, a total of five arrays, are converted into units and summarized into a new state variable array stateNew for storage.

[0095] Similarly, for the constitutive equation of the ferrite phase, the yield stress is obtained and stored in the yield stress array yield:

[0096]

[0097] The derivative of the ferrite yield function with respect to the equivalent plastic strain ε is stored in the first column of the array of yield function derivatives with respect to the equivalent plastic strain dyeldDeqps:

[0098]

[0099] Ferrite yield function versus equivalent plastic strain rate The derivative of the yield function is stored in the second column of the array dyeldDeqps of the yield function derivative of the equivalent plastic strain:

[0100]

[0101] The derivative of the ferrite yield function with respect to temperature T is stored in the yield function derivative array with respect to temperature, dieldDtemp:

[0102]

[0103] Through program definition, it is possible to select the constitutive model of the corresponding phase by judging whether the material name of the current operation point is aus, calculate and store the corresponding calculation results in a specific array, and thus realize finite element calculation and solution by assigning material properties to the two-phase materials respectively.

[0104] After the program is written and saved, establish the analysis step and create boundary conditions, such as Figure 6 The figure shows the initial geometry and boundary conditions of the model. The bottom edge and the left side are completely fixed. Create a tool reference point, set the speed to the cutting speed, and the direction to the cutting direction. Set the material internal surface contact and interaction properties. Select the VUHARD subroutine in the subroutine option to achieve the finite element calculation solution for distinguishing the two-phase material.

[0105] After the solution is completed, the cutting force curve can be viewed, such as Figure 7 As shown in Figure 2, the red color represents the cutting force in the x-direction and the blue color represents the cutting force in the y-direction.

[0106] S4. Conduct a right-angle cutting experiment and use a dynamometer to measure the cutting force during the right-angle cutting process. Compare the cutting force obtained from the right-angle cutting experiment with the cutting force obtained from the finite element model established above to verify the accuracy of the finite element model.

[0107] Schematic diagram of the right-angle cutting experimental device Figure 8 As shown, the blade rake angle is 15°, the blade thickness is 3.97mm, and the cutting edge length is 9.525mm. In order to only consider the influence of cutting amount and tool angle on the cutting process, the blade is not coated. The blade 3 is installed on the milling cutter disc 2, and the tool cutting edge is parallel to the machine tool spindle direction. The milling cutter disc 2 is connected to the machine tool using the BT40 tool holder 1. The rake angles of the blade 3 and the milling cutter disc 2 are 0°, 4°, 8°, and 12° respectively.

[0108] Wire cutting technology is used to cut rectangular blocks with length, width and height of 16mm, 3mm and 60mm respectively from the S32760 duplex stainless steel bar. The surface of 16x3mm is the surface that needs to be cut. The workpiece 4 is clamped with a vise 5, and then the vise 5 is connected to the dynamometer 6 with bolts to collect the cutting force.

[0109] A piezoelectric dynamometer is used, and the dynamometer model is 9139AA. In order to eliminate the influence of tool wear on the experimental results, each group of experiments needs to replace a new blade 3 for processing, and only one blade 3 is installed at a time.

[0110] Taking cutting speed, feed rate and tool rake angle as experimental variables, a three-factor four-level orthogonal experiment was designed. The cutting parameters table of the cutting experiment is shown in Table 1.

[0111] Table 1 Cutting amount for cutting experiment

[0112]

[0113]

[0114] After the cutting force is collected, it is necessary to filter the collected cutting force to finally obtain the cutting force experimental test data. The cutting force measured by the cutting experiment is compared with the cutting force obtained by the finite element simulation to verify the accuracy of the finite element simulation model. The comparison between the experimental cutting force and the simulated cutting force is shown in Table 2.

[0115] Table 2 Comparison of experimental cutting force and simulated cutting force

[0116]

[0117]

[0118] It can be seen from Table 2 that the maximum error in Fx is 21.4%, the minimum error is 3.5%, and the average error is 12.99%; the maximum error in Fy is 26.7%, the minimum error is 1.8%, and the average error is 12.36%. The errors are all within 15%, which shows that the prediction results of the finite element model are relatively accurate and can simulate the cutting of S32760 steel well.

[0119] In summary, the modeling method disclosed in the present invention extracts material microstructure information through image recognition for duplex materials, and the established model is more consistent with the material microstructure; by writing the VUHARD subroutine, the two-phase materials are respectively assigned material properties, and the deformation hardening behavior of the material is defined according to the material performance data and the actual deformation situation, thereby realizing the fine simulation and prediction of the material behavior. It provides an effective numerical simulation method for the cutting process for the finite element analysis of duplex stainless steel materials.

[0120] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for numerical simulation of duplex stainless steel cutting process, characterized in that: The steps include: S1. According to the microstructure characteristics of the duplex material and the variation law of flow stress with strain rate, the viscous constitutive equation suitable for the duplex material is selected. The duplex material is S32760 duplex stainless steel, and the S32760 duplex stainless steel uses the S32760 duplex constitutive model considering the viscosity effect; S2. Based on the EBSD image data, the microstructure information of the two-phase material is obtained, and the distribution and orientation of the two-phase microstructure are extracted using the Python program and imported into ABAQUS for modeling; S3, the S32760 two-phase constitutive model considering the viscosity effect established in S1 is secondary developed by using the corresponding yield function to obtain the derivative of equivalent plastic strain, strain rate and temperature, and is written into the ABAQUS simulation model established in S2 in the form of VUHARD subroutine using FORTRAN language for finite element simulation; S4. Design a cutting experiment and verify the accuracy of the simulation model by comparing the cutting force collected by the cutting experiment with the cutting force extracted by the simulation; The constitutive equation of the S32760 two-phase constitutive model considering the viscosity effect is as follows: Austenite: Ferrite: Where σ is the yield stress; σ1 is the constant of the non-thermal stress term of the austenite phase; σ2 is the constant of the non-thermal stress term of the ferrite phase; is the ferrite hardening coefficient; ε is the equivalent plastic strain; n1 is the austenite strain sensitivity index; n2 is the ferrite strain sensitivity index; is the austenite hardening coefficient; is the reference value of the ferrite saturation threshold stress at T = 0K; β is a constant determined by the reference thermal activation energy and the Boltzmann constant; T is the temperature; is the equivalent plastic strain rate; is the reference strain rate; p and q are constants; α is a constant determined by the Burgers vector and shear modulus; is the reference saturation strain rate; μ1 is the viscosity effect coefficient of austenite; μ2 is the viscosity effect coefficient of ferrite.

2. The method for numerical simulation of duplex stainless steel cutting process according to claim 1, characterized in that: The step S2 comprises the following specific steps: 2.

1. Based on the EBSD image data of S32760 duplex stainless steel, the microstructure of the duplex stainless steel matrix was obtained using EBSD technology; 2.

2. Identify the microstructure of the material, extract the microstructure information of the EBSD image data of S32760 duplex stainless steel through digital image processing technology, and establish a geometric model based on the material microstructure; 2.

3. Further process the established model, create materials in the material library and name them aus, fe, and tool, and make corresponding material assignments to provide a basis for assigning material properties to subsequent subroutines.

3. The method for numerical simulation of duplex stainless steel cutting process according to claim 2, characterized in that: The step S3 performs secondary development on the S32760 two-phase constitutive model considering the viscosity effect established in step S1, and uses the FORTRAN language to write it into ABAQUS in the form of a VUHARD subroutine for finite element simulation, including the following specific steps: 3.

1. Write the program interface in the subroutine; 3.

2. Define three variables: equivalent plastic strain ε, equivalent plastic strain rate Temperature T, store it in the corresponding array; 3.

3. Derivative the two-phase constitutive equation with respect to different variables, including calculating the derivative of the constitutive equation with respect to the equivalent plastic strain, the derivative of the constitutive equation with respect to the equivalent plastic strain rate, and the derivative of the constitutive equation with respect to the temperature, and then store the results in the corresponding array; The specific equations and storage locations are as follows: Austenite phase constitutive equation, obtain the yield stress and store it in the yield stress array yield: The derivative of the austenite yield function with respect to the equivalent plastic strain ε is stored in the first column of the array of yield function derivatives with respect to the equivalent plastic strain dieldDeqps: Austenite yield function versus equivalent plastic strain rate The derivative of the yield function is stored in the second column of the array dyeldDeqps of the yield function derivative of the equivalent plastic strain: The derivative of the austenite yield function with respect to temperature T: The results are stored in the array of yield function derivatives with respect to temperature dieldDtemp: The result data obtained by the above four equations and the corresponding strains, a total of five arrays, are converted into units and then summarized and saved in the new state variable array stateNew; Similarly, the constitutive equation of ferrite phase is: The derivative of the ferrite yield function with respect to the equivalent plastic strain ε is: Ferrite yield function versus equivalent plastic strain rate The derivative of : The derivative of the ferrite yield function with respect to temperature T is: 3.

4. Select the constitutive model of the corresponding phase according to the material name, calculate and store the corresponding calculation results in a specific array, and assign material properties to the two-phase materials and simulate them; 3.

5. When running the simulation, select the VUHARD subroutine to implement the finite element calculation solution for distinguishing the two-phase material; 3.

6. After the solution is completed, the cutting force is obtained.

4. The method for numerical simulation of duplex stainless steel cutting process according to claim 3, characterized in that: In step S4, a piezoelectric dynamometer is used to measure the force. After the cutting force is collected, the collected cutting force needs to be filtered.

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