Spheroidizing annealing billet drawing cracking prediction method and system based on abaqus

Abstract

This invention provides a method and system for predicting cracking during drawing of spheroidized annealed billets based on ABAQUS, belonging to the field of steel smelting and processing. The method first constructs a GTN model for drawing spheroidized annealed billets considering spheroidization rate. Tensile test data and metallographic data of billets with different spheroidization rates are collected to train the GTN model. The ABAQUS software's Property module is used to user-defined materials, and the GTN model parameters are set based on the trained parameters. A geometric model of the spheroidized annealed billet and a drawing die are established based on ABAQUS and assembled using the Assembly module. Then, the time step, state variable output, contact characteristics, applied boundary conditions and loads for drawing, and mesh generation are set. After calculation, the results are viewed to determine whether cracking has occurred. This invention improves the accuracy of predicting whether billet cracking will occur, saving development time and costs.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgical processing, and in particular to a method and system for predicting the drawing cracks of spheroidized annealed billets based on ABAQUS. Background Technology

[0002] With the increasingly widespread application of industrial robots in intelligent manufacturing, the demand for high-precision linear guides is also growing. The materials used in high-precision linear guides have evolved from high-carbon steel, represented by GGr15, to medium-carbon alloy steel. Representative medium-carbon alloy steels include 55 steel, 50CrMo, S55C, and G50Mn2Cr. These medium-carbon alloy steel bars first undergo spheroidizing annealing to obtain predetermined plasticity, and then are drawn to obtain the guide rail blank. However, if the drawing parameters are not suitable for the material properties, cracking is highly likely. Therefore, it is necessary to predict the drawing cracking of the spheroidized annealed blank material to obtain the optimal drawing parameters.

[0003] In existing technologies, researchers generally use the Gurson-Tvergaard-Needleman (GTN) model to predict pull-out cracks. However, the GTN model is based on hot-rolled pearlitic steel rather than spheroidized pearlitic steel, and cannot take into account the influence of spheroidization rate on the equivalent void volume fraction. This leads to discrepancies between the cracking conditions and the actual situation, resulting in inaccurate predictions. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method and system for predicting drawing cracks in spheroidized annealed billets based on ABAQUS. By constructing a GTN model for drawing spheroidized annealed billets that considers the spheroidization rate, and combining it with a geometric model of the spheroidized annealed billets and drawing dies constructed using ABAQUS, the spheroidization rate factor is introduced into the drawing process to accurately predict the drawing crack problem of spheroidized annealed billets.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0006] In a first aspect, embodiments of the present invention provide a method for predicting drawing cracks in spheroidized annealed billets based on ABAQUS, the method comprising the following steps:

[0007] A GTN model for drawing spheroidized annealed billets considering spheroidization rate was constructed; tensile test data and metallographic data of billets with different spheroidization rates in the range of 0~100% were collected, and the GTN model considering spheroidization rate was trained to obtain the parameters of the trained GTN model.

[0008] A geometric model of spheroidized annealed billet and a drawing die were established based on ABAQUS.

[0009] Using the Property module of ABAQUS software, user-defined materials are used to complete the parameter settings of the GTN model for drawing spheroidized annealed billets considering spheroidization rate, based on the trained GTN model parameters.

[0010] The assembly module of ABAQUS software was used to complete the assembly of the geometric model of the spheroidized annealed billet and the drawing die;

[0011] The time step for the spheroidizing annealed billet drawing simulation was set using the Step module of ABAQUS software, and the state variable output was set in the FieldOutput module.

[0012] The contact characteristics between the spheroidizing annealed billet geometry model and the drawing die were set using the Interaction module of ABAQUS software.

[0013] The ABAQUS software's Load module applies the pull-out boundary conditions and loads;

[0014] The mesh generation of the geometric model of the spheroidized annealed billet was completed using the Mesh module of ABAQUS software;

[0015] The calculation was submitted using the Job module of the ABAQUS software, and the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet were viewed using the Visualization module of the ABAQUS software to determine whether cracking had occurred.

[0016] As a preferred embodiment of the present invention, the process of constructing and training a GTN model for drawing spheroidized annealed billets considering spheroidization rate includes:

[0017] The spheroidization rate of billets with different spheroidization rates in the range of 0 to 100% was determined by metallographic observation; the true stress-strain curves of billets with different spheroidization rates in the range of 0 to 100% were obtained by uniaxial tensile test.

[0018] Based on the spheroidization rate and the corresponding real stress-strain curves, a billet sample dataset is constructed.

[0019] A finite element inverse calibration method combining central composite design, response surface methodology, and multi-objective genetic algorithm was used to construct the GTN-NH damage constitutive equation considering sphericity as the GTN model.

[0020] The GTN model considering spheroidization was trained using a billet sample dataset. The spheroidization correction parameter and the void-related damage parameter were determined as the parameters of the trained GTN model. The user material subroutine VUMAT was written.

[0021] As a preferred embodiment of the present invention, the GTN model considering sphericity is as follows:

[0022] Yield function: (1)

[0023] Hole evolution: (2)

[0024] In equations (1) and (2), Represents the plastic potential function. For the sphericity correction parameter, and These are macroscopic equivalent stress and hydrostatic pressure, respectively. The yield stress of the material, This represents the equivalent void volume fraction. , and To correct the parameters, it is usually taken as follows: =1.5, =1.0, = =2.25; Where f is the porosity of the material, and f is the pore volume fraction; Indicates the plastic volumetric strain rate; This represents the shear damage weighting coefficient; Represents equivalent plastic strain. For equivalent plastic strain rate, Here, ω(θ) is the shear correction parameter, and ω(θ) is the Lode angle function. For macroscopic deviatoric stress tensor, This represents the plastic strain rate tensor.

[0025] In a preferred embodiment of the present invention, the void-related damage parameters include the initial void volume fraction f0 and the critical void volume fraction f1. c Failure void volume fraction f F and nucleation pore volume fraction f N .

[0026] As a preferred embodiment of the present invention, the parameter settings of the GTN model considering the spheroidization rate for drawing the spheroidized annealed billet include:

[0027] Using the Property module of ABAQUS software, materials are created, and the number of non-independent variables is set on the general page;

[0028] Set user-defined material parameters on the user materials page, including the spheroidization correction parameter k in the GTN model that considers spheroidization. q Initial void volume fraction f0, critical void volume fraction f c Failure void volume fraction f F and nucleation pore volume fraction fN Damage parameters.

[0029] As a preferred embodiment of the present invention, the step of setting the time step for the spheroidizing annealed billet drawing simulation and setting the state variable output in the FieldOutput module includes:

[0030] The time step for spheroidizing annealed billet drawing simulation was set using the Step module of ABAQUS software;

[0031] Using the Step module of ABAQUS software, set the state variable output on the FieldOutput page and select SDV output;

[0032] Using the Step module of ABAQUS software, ALE adaptive mesh control is created in the other settings page; and ALE adaptive mesh region settings are performed, selecting spheroidized annealed billet as the adaptive mesh region.

[0033] In a preferred embodiment of the present invention, the setting of the contact characteristics between the spheroidized annealed billet geometry model and the drawing die includes:

[0034] The contact characteristics between the spheroidizing annealed billet geometry model and the drawing die were set to Explicit surface-to-surface contact using the Interaction module of ABAQUS software.

[0035] Using the Interaction module of ABAQUS software, when editing contact properties, the mechanics page selects tangential behavior and uses a penalty function to set the friction coefficient.

[0036] In a preferred embodiment of the present invention, when applying the boundary conditions and load for drawing, the Load module of ABAQUS software is used to create a boundary condition page, apply a fully fixed constraint to the mold, and apply the drawing speed as the velocity boundary condition to the geometric model of the spheroidized annealed billet.

[0037] In a preferred embodiment of the present invention, when meshing the geometric model of the spheroidized annealed billet, the Mesh module of ABAQUS software is used, the C3D8R element type is selected, and the element deletion option is enabled to complete the meshing of the geometric model of the spheroidized annealed billet; the R3D4 discrete rigid body element type is selected to complete the meshing of the drawing die.

[0038] Secondly, embodiments of the present invention also provide an ABAQUS-based system for predicting drawing cracks in spheroidized annealed billets. The system includes: an experimental data acquisition module, a GTN model construction and training module considering spheroidization rate, an ABAQUS geometric model construction module, a GTN model parameter setting module considering spheroidization rate, an ABAQUS geometric model setting module, a calculation submission module, and a result analysis module; wherein...

[0039] The experimental data acquisition module is used to collect tensile test data and metallographic structure data of billets with different spheroidization rates in the range of 0~100%;

[0040] The GTN model construction and training module considering spheroidization rate is used to construct a GTN model for drawing spheroidized annealed billets considering spheroidization rate, and to train the GTN model considering spheroidization rate based on experimental data to obtain the parameters of the trained GTN model.

[0041] The ABAQUS geometric model building module is used to build a geometric model of spheroidized annealed billet and a drawing die based on ABAQUS.

[0042] The GTN model parameter setting module that considers spheroidization rate is used to set the GTN model parameters for drawing spheroidized annealed billets by using user-defined materials in the Property module of ABAQUS software and based on the trained GTN model parameters.

[0043] The ABAQUS geometry model setting module is used to assemble the spheroidizing annealed billet geometry model with the drawing die using the Assembly module of the ABAQUS software, set the time step of the spheroidizing annealed billet drawing simulation using the Step module, set the state variable output using the FieldOutput module, set the contact characteristics between the spheroidizing annealed billet geometry model and the drawing die using the Interaction module, apply the boundary conditions and loads for drawing using the Load module, and complete the mesh generation of the spheroidizing annealed billet geometry model using the Mesh module.

[0044] The calculation submission module is used to submit calculations using the Job module of the ABAQUS software;

[0045] The result analysis module is used to view the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet using the Visualization module of ABAQUS software, and to determine whether cracking has occurred.

[0046] The solutions of the embodiments of the present invention have the following beneficial effects:

[0047] The ABAQUS-based method and system for predicting drawing cracks in spheroidized annealed billets provided in this invention constructs a GTN model for drawing spheroidized annealed billets considering spheroidization rate. Tensile test data and metallographic data of billets with different spheroidization rates within the range of 0-100% are collected to train the GTN model considering spheroidization rate, obtaining the trained GTN model parameters. A geometric model of the spheroidized annealed billet and a drawing die are established based on ABAQUS. The Property module of ABAQUS software is used to define user-defined materials, and the GTN model parameters for drawing spheroidized annealed billets are set based on the trained GTN model parameters. The Assembly module of ABAQUS software is used to complete the spheroidization rate prediction. The assembly of the spheroidized annealed billet geometric model and the drawing die involves using the Step module to set the time step for the spheroidized annealed billet drawing simulation, setting the state variable output in the FieldOutput module, using the Interaction module to set the contact characteristics between the spheroidized annealed billet geometric model and the drawing die, using the Load module to apply the drawing boundary conditions and loads, and using the Mesh module to complete the mesh generation of the spheroidized annealed billet geometric model. Finally, the Job module of ABAQUS software is used to submit the calculation, and the Visualization module of ABAQUS software is used to view the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet to determine whether cracking has occurred. This invention, based on secondary development of ABAQUS, provides a crack prediction model for spheroidized annealed billet drawing considering the spheroidization rate. It accurately identifies the dangerous cracking area during the spheroidized annealed billet drawing process and accurately predicts whether the billet will crack. This provides an efficient analysis tool for drawing die and process design, saving new process development time and reducing new process development costs.

[0048] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart of the ABAQUS-based method for predicting drawing cracks in spheroidized annealed billets, as described in an embodiment of the present invention.

[0051] Figure 2 This is a SEM image of a spheroidized annealed billet with a spheroidization rate of 60% in an application example of this invention;

[0052] Figure 3This is a SEM image of a spheroidized annealed billet with a spheroidization rate of 80% in an application example of this invention;

[0053] Figure 4 These are the actual stress-strain curves of materials with different spheroidization rates in application examples of this invention;

[0054] Figure 5 This is an equivalent void volume fraction distribution diagram of the geometric model of the spheroidized annealed billet after drawing in an application example of the present invention;

[0055] Figure 6 This is a diagram showing the cracked area of ​​the geometric model of the spheroidized annealed billet after drawing in an application example of the present invention. Detailed Implementation

[0056] After discovering the aforementioned problems, the inventors of this application conducted a detailed study on existing methods for predicting drawing cracks in spheroidized annealed billets, particularly medium-carbon alloy steel used in high-precision guide rail materials. The study found that for medium-carbon alloy steel used in guide rails and other applications requiring drawing, spheroidization annealing with different parameters is performed first, depending on the requirements. Different spheroidization annealing rates cause changes in localized stress concentration within the material, thus affecting its plasticity; different plasticities in steel necessitate different drawing parameters; and using the same drawing process for bars with different spheroidization rates increases the likelihood of cracking. Therefore, if the influence of spheroidization rate is not considered when building the GTN calculation model, the prediction conditions will deviate from reality, resulting in inaccurate prediction results. Therefore, the influence of spheroidization rate needs to be considered in the prediction calculation of drawing cracks in spheroidized annealed billets.

[0057] It should be noted that the defects in the above-mentioned prior art solutions are all the result of the inventors' practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of the present invention in the following text should be the inventors' contributions to the present invention.

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0059] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of the embodiments of the present invention, the terms "first," "second," "third," "fourth," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, sometimes a subscript such as W1 may be written in a non-subscript form such as W1, and their meanings are consistent unless the distinction is emphasized.

[0060] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0061] Following the above in-depth analysis, this invention provides a method and system for predicting drawing cracks in spheroidized annealed billets based on ABAQUS. The method involves determining a GTN model considering spheroidization rate; completing geometric modeling of the spheroidized annealed billet drawing process using ABAQUS or other 3D software; further completing preprocessing settings in ABAQUS, requiring user-defined materials in the material property definition module, calling the VUMAT subroutine, and defining corresponding material parameters and the number of state variables; applying boundary conditions and loads for drawing; calculating the spheroidized annealed billet drawing process; and obtaining the equivalent void volume fraction of the drawn spheroidized annealed billet to predict drawing cracks. This invention, based on secondary development of ABAQUS, provides a method and system for predicting drawing cracks in spheroidized annealed billets considering spheroidization rate. It can accurately identify the dangerous areas for cracking during the drawing process of spheroidized annealed billets and accurately predict whether cracking will occur, providing an efficient analysis tool for drawing die and process design.

[0062] The ABAQUS-based method for predicting cracking during the drawing of spheroidized annealed billets obtains the stress and strain values ​​at different nodes during the drawing process, as well as the curves showing the equivalent void volume fraction over time, thereby predicting whether cracking will occur. Using finite element software, considering drawing process parameters including drawing ratio, drawing speed, and friction coefficient, a three-dimensional stress field model is established to predict the drawing cracking of spheroidized annealed billets. Figure 1 As shown, the method specifically includes the following steps:

[0063] Step S1: Construct a GTN model for drawing spheroidized annealed billets considering spheroidization rate; collect tensile test data and metallographic data of billets with different spheroidization rates in the range of 0~100%, train the GTN model considering spheroidization rate, and obtain the parameters of the trained GTN model.

[0064] This step specifically includes:

[0065] Step S11: Determine the spheroidization rate of billets with different spheroidization rates within the range of 0 to 100% by observing the metallographic structure; obtain the true stress-strain curves of billets with different spheroidization rates within the range of 0 to 100% by uniaxial tensile test;

[0066] Step S12: Based on the spheroidization rate and the corresponding real stress-strain curve, construct a billet sample dataset;

[0067] Step S13: The GTN-NH damage constitutive equation considering the sphericity is constructed as the GTN model by using the finite element reverse calibration method that combines central composite design, response surface method and multi-objective genetic algorithm.

[0068] Step S14: Train the GTN model considering spheroidization using the billet sample dataset, determine the spheroidization correction parameter and the pore-related damage parameter as the parameters of the trained GTN model, and write the user material subroutine VUMAT.

[0069] This step involves constructing a GTN model that considers spheroidization rate based on the GTN-Nahshon-Hutchuinson (GTN-NH) model. The GTN model considering spheroidization rate, i.e., the GTN-NH damage constitutive equation considering spheroidization rate, is as follows:

[0070] Yield function: (1)

[0071] Hole evolution: (2)

[0072] In equations (1) and (2), Represents the plastic potential function. For the sphericity correction parameter, and These are macroscopic equivalent stress and hydrostatic pressure, respectively. The yield stress of the material, This represents the equivalent void volume fraction. , and To correct the parameters, it is usually taken as follows: =1.5, =1.0, = =2.25; Where f is the porosity of the material, and f is the pore volume fraction; Indicates the plastic volumetric strain rate; This represents the shear damage weighting coefficient; Represents equivalent plastic strain. For equivalent plastic strain rate, Here, ω(θ) is the shear correction parameter, and ω(θ) is the Lode angle function. For macroscopic deviatoric stress tensor, This represents the plastic strain rate tensor.

[0073] By fitting the actual stress-strain curve of uniaxial tension and the corresponding spheroidization rate using finite element method, the model was trained to obtain the spheroidization rate correction parameter in the GTN-NH damage constitutive equation considering the spheroidization rate. Initial void volume fraction f0, critical void volume fraction f c Failure void volume fraction f F and nucleation pore volume fraction f N There are a total of 4 damage parameters. Write the user material subroutine VUMAT.

[0074] Step S2: Establish the geometric model of the spheroidized annealed billet and the drawing die based on ABAQUS.

[0075] In this step, when creating the geometric model of the spheroidizing annealed billet and the drawing die, you can use the Part module of ABAQUS to create the geometric model of the spheroidizing annealed billet and the drawing die, or draw the geometric model of the spheroidizing annealed billet and the drawing die through other 3D drawing software and import it into ABAQUS software in STEP format.

[0076] Step S3: Using the Property module of ABAQUS software, user-defined materials are used to complete the parameter settings of the GTN model for drawing spheroidized annealed billets considering spheroidization rate, based on the trained GTN model parameters.

[0077] This step specifically includes:

[0078] Step S31: Using the Property module of ABAQUS software, create materials and set the number of non-independent variables on the general page;

[0079] Step S32: Set user-defined material parameters on the user material page, including the sphericity correction parameter k in the GTN model that considers sphericity. q Initial void volume fraction f0, critical void volume fraction f c Failure void volume fraction f F and nucleation pore volume fraction f N Damage parameters, etc.

[0080] Step S4: Use the Assembly module of ABAQUS software to assemble the geometric model of the spheroidized annealed billet with the drawing die.

[0081] Step S5: Use the Step module of ABAQUS software to set the time step for the spheroidizing annealed billet drawing simulation, and set the state variable output in the FieldOutput module.

[0082] This step specifically includes:

[0083] Step S51: Use the Step module of ABAQUS software to set the time step for the spheroidizing annealed billet drawing simulation;

[0084] Step S52: Using the Step module of the ABAQUS software, set the state variable output on the FieldOutput page and select SDV output;

[0085] Step S53: Using the Step module of ABAQUS software, create ALE adaptive mesh control on the other settings page; and set the ALE adaptive mesh region, selecting the spheroidized annealed billet as the adaptive mesh region.

[0086] Step S6: Use the Interaction module of ABAQUS software to set the contact characteristics between the spheroidizing annealed billet geometry model and the drawing die.

[0087] This step specifically includes:

[0088] Step S61: Using the Interaction module of ABAQUS software, set the contact characteristics between the spheroidizing annealed billet geometry model and the drawing die to surface-to-surface contact (Explicit).

[0089] In step S62, using the Interaction module of the ABAQUS software, when editing contact properties, select tangential behavior on the mechanics page and set the friction coefficient using the penalty function.

[0090] Step S7: Apply the pull-out boundary conditions and loads using the Load module of the ABAQUS software.

[0091] In this step, when applying the boundary conditions and loads for drawing, the Load module of ABAQUS software is used to create a boundary condition page, apply a fully fixed constraint to the die, and then create another boundary condition page to apply the drawing speed as the velocity boundary condition to the spheroidized annealed billet geometry model. When the spheroidized annealed billet geometry model and the drawing die are calculated using a symmetrical model, the Load module of ABAQUS software needs to be used to create a boundary condition page and apply symmetrical boundary conditions to the spheroidized annealed billet.

[0092] Step S8: Use the Mesh module of ABAQUS software to complete the mesh generation of the geometric model of the spheroidized annealed billet.

[0093] In this step, when meshing the geometric model of the spheroidized annealed billet, preferably, the Mesh module of ABAQUS software is used, the C3D8R element type is selected, and the "element deletion" option is turned on to complete the meshing of the geometric model of the spheroidized annealed billet; the R3D4 discrete rigid body element type is selected to complete the meshing of the drawing die.

[0094] Step S9: Submit the calculation using the Job module of ABAQUS software, and use the Visualization module of ABAQUS software to view the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet to determine whether cracking has occurred.

[0095] In this step, the Job module of ABAQUS software is used. On the general page, the location of the user subroutine VUMAT is set, and the calculation is submitted. To view the calculation results, the Visualization module of ABAQUS software is used. Selecting "Draw contour plot on deformation diagram" allows you to view the stress (S) distribution, strain (LE) distribution, and equivalent void volume fraction (SDV5) distribution of the spheroidized annealed billet. If the equivalent void volume fraction exceeds the critical void volume fraction, the mesh at that location will be deleted, which can be used to determine whether cracking has occurred.

[0096] Based on the same idea, this invention also provides an ABAQUS-based system for predicting drawing cracks in spheroidized annealed billets. The system includes: an experimental data acquisition module, a GTN model construction and training module considering spheroidization rate, an ABAQUS geometric model construction module, a GTN model parameter setting module considering spheroidization rate, an ABAQUS geometric model setting module, a calculation submission module, and a result analysis module.

[0097] The experimental data acquisition module is used to collect tensile test data and metallographic structure data of billets with different spheroidization rates in the range of 0~100%;

[0098] The GTN model construction and training module considering spheroidization rate is used to construct a GTN model for drawing spheroidized annealed billets considering spheroidization rate, and to train the GTN model considering spheroidization rate based on experimental data to obtain the parameters of the trained GTN model.

[0099] The ABAQUS geometric model building module is used to build a geometric model of spheroidized annealed billet and a drawing die based on ABAQUS.

[0100] The GTN model parameter setting module that considers spheroidization rate is used to set the GTN model parameters for drawing spheroidized annealed billets by using user-defined materials in the Property module of ABAQUS software and based on the trained GTN model parameters.

[0101] The ABAQUS geometry model setting module is used to assemble the spheroidizing annealed billet geometry model with the drawing die using the Assembly module of the ABAQUS software, set the time step of the spheroidizing annealed billet drawing simulation using the Step module, set the state variable output using the FieldOutput module, set the contact characteristics between the spheroidizing annealed billet geometry model and the drawing die using the Interaction module, apply the boundary conditions and loads for drawing using the Load module, and complete the mesh generation of the spheroidizing annealed billet geometry model using the Mesh module.

[0102] The calculation submission module is used to submit calculations using the Job module of the ABAQUS software;

[0103] The result analysis module is used to view the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet using the Visualization module of ABAQUS software, and to determine whether cracking has occurred.

[0104] The system or device for executing the method in this embodiment of the invention can be a terminal or a server. The system includes a processor, a memory, and / or a transceiver, etc., and is connected via a communication bus. Each module can be implemented by a processor, a memory, and / or a transceiver, etc. The processor can be, but is not limited to, one or more microprocessors (MPUs), central processing units (CPUs), network processors (NPs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components, etc., or can be configured to implement one or more integrated circuits of this invention. The processor can perform various functions by running or executing software programs in the memory and calling data in the memory. The memory includes Random Access Memory (RAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Compact Disc Read-Only Memory (CD-ROM), and / or Non-Volatile Memory (NVM), etc. The transceiver is used to communicate with network devices or terminal devices, and includes a receiver and a transmitter. The memory and transceiver can be integrated with the processor or exist independently.

[0105] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0106] It should also be noted that the ABAQUS-based spheroidizing annealed billet drawing crack prediction system described in this embodiment corresponds to the ABAQUS-based spheroidizing annealed billet drawing crack prediction method. The description and limitations of the method also apply to the system, and will not be repeated here.

[0107] The method and system for predicting drawing cracks of spheroidized annealed billets based on ABAQUS, as described in the embodiments of the present invention, are applied to the prediction of drawing cracks of spheroidized annealed billet bars of 50Mn2Cr, wherein the spheroidized annealed billet is used to prepare high-precision guide rails.

[0108] First, the spheroidization rate of billets with different spheroidization rates is determined through metallographic observation, such as... Figure 2 and Figure 3 As shown, the spheroidization rates of the spheroidized annealed billets were 60% and 80%, respectively; the true stress-strain curves of materials with different spheroidization rates were obtained through uniaxial tensile tests, as shown in the figure. Figure 4 As shown in the figure, the lower the spheroidization rate, the higher the yield strength and tensile strength of the material, the lower the elongation and the worse the plasticity. Based on equations (1) and (2), the GTN-NH damage constitutive equation considering the spheroidization rate is constructed, and the spheroidization rate correction parameter and the pore-related damage parameter are solved. The user material subroutine VUMAT is written.

[0109] The geometric model of the spheroidized annealed billet / bar was created using the Part module of ABAQUS. A 3D model of the drawing die was drawn using the Creo 3D modeling software and imported into ABAQUS in STEP format. The material was created using the Property module of ABAQUS. On the General page, the number of non-independent variables was set to 18, and on the User Material page, 27 user-defined material mechanical parameters were set, including a spheroidization correction parameter. Damage parameters related to the four holes were determined; the geometric model of the spheroidized annealed billet and the drawing die were assembled using the Assembly module of ABAQUS software.

[0110] Using the Step module of ABAQUS software, the time step for the spheroidizing annealed billet drawing simulation was set. On the FieldOutput page, the state variable output was set, selecting SDV output. On the other settings page of the Step module, ALE adaptive mesh control was created, and the ALE adaptive mesh region was set, selecting the spheroidizing annealed billet as the adaptive mesh region. Then, using the Interaction module of ABAQUS software, the contact characteristics between the spheroidizing annealed billet geometry model and the drawing die were set to surface-to-surface contact (Explicit). When editing the contact properties, the mechanics page selected tangential behavior, and the friction coefficient was set to 0.08 using a penalty function. Finally, using the Load module of ABAQUS software, the drawing boundary conditions and loads were applied. On the boundary conditions page, a fully fixed constraint was applied to the die; on the boundary conditions page, a velocity boundary condition of 600 mm / s was applied to the spheroidizing annealed billet. Using the Mesh module of ABAQUS software, select the C3D8R element type and enable the element deletion option to complete the mesh generation of the spheroidized annealed billet. Select the R3D4 discrete rigid body element type to complete the mesh generation of the drawing die.

[0111] After completing the above settings, in the general page of the Job module in the ABAQUS software, set the location of the user subroutine VUMAT and submit the calculation; using the Visualization module of the ABAQUS software, select to draw a contour plot on the deformation diagram to view the stress (S) distribution, strain (LE) distribution, and equivalent void volume fraction (SDV5) distribution of the highly spheroidized annealed billet. Figure 5 As shown, the equivalent void volume fraction after drawing is highly unevenly distributed across the cross-section, with the maximum value appearing on the outer surface of the corner of the drawn billet; as Figure 6 As shown, the billet cracks at the corner after being drawn. The unit at the cracked part is deleted, making it easy to determine whether a crack has occurred and to confirm the location of the crack.

[0112] As can be seen from the above technical solutions, the ABAQUS-based method and system for predicting cracking in spheroidized annealed billets provided in this invention has developed a spheroidized annealed billet drawing crack prediction model that considers the spheroidization rate based on ABAQUS. It accurately identifies the dangerous area for cracking during the drawing process of spheroidized annealed billets and accurately predicts whether the billet will crack, providing an efficient analysis tool for drawing die and process design.

[0113] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0114] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the scope of the claimed invention, but merely to illustrate preferred embodiments of the invention. Those skilled in the art should understand that the scope of the invention is not limited to the specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for predicting drawing cracks in spheroidized annealed billets based on ABAQUS, characterized in that, The method includes the following steps: A GTN model for drawing spheroidized annealed billets considering spheroidization rate was constructed; tensile test data and metallographic data of billets with different spheroidization rates in the range of 0~100% were collected, and the GTN model considering spheroidization rate was trained to obtain the parameters of the trained GTN model. A geometric model of spheroidized annealed billet and a drawing die were established based on ABAQUS. Using the Property module of ABAQUS software, user-defined materials are used to complete the parameter settings of the GTN model for drawing spheroidized annealed billets considering spheroidization rate, based on the trained GTN model parameters. The assembly module of ABAQUS software was used to complete the assembly of the geometric model of the spheroidized annealed billet and the drawing die; The time step for the spheroidizing annealed billet drawing simulation was set using the Step module of ABAQUS software, and the state variable output was set in the FieldOutput module. The contact characteristics between the spheroidizing annealed billet geometry model and the drawing die were set using the Interaction module of ABAQUS software. The ABAQUS software's Load module applies the pull-out boundary conditions and loads; The mesh generation of the geometric model of the spheroidized annealed billet was completed using the Mesh module of ABAQUS software; The calculation was submitted using the Job module of the ABAQUS software, and the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet were viewed using the Visualization module of the ABAQUS software to determine whether cracking had occurred.

2. The method according to claim 1, characterized in that, The process of constructing and training a GTN model for drawing spheroidized annealed billets considering spheroidization rate includes: The spheroidization rate of billets with different spheroidization rates in the range of 0 to 100% was determined by metallographic observation; the true stress-strain curves of billets with different spheroidization rates in the range of 0 to 100% were obtained by uniaxial tensile test. Based on the spheroidization rate and the corresponding real stress-strain curves, a billet sample dataset is constructed. A finite element reverse calibration method combining central composite design, response surface methodology, and multi-objective genetic algorithm was used to construct the GTN-NH damage constitutive equation considering sphericity as the GTN model. The GTN model considering spheroidization was trained using a billet sample dataset. The spheroidization correction parameter and the void-related damage parameter were determined as the parameters of the trained GTN model. The user material subroutine VUMAT was written.

3. The method according to claim 2, characterized in that, The GTN model considering sphericity is as follows: Yield function: (1) Hole evolution: (2) In equations (1) and (2), Represents the plastic potential function. For the sphericity correction parameter, and These are macroscopic equivalent stress and hydrostatic pressure, respectively. The yield stress of the material, This represents the equivalent void volume fraction. , and To correct the parameters; Where f is the porosity of the material, and f is the pore volume fraction; Indicates the plastic volumetric strain rate; This represents the shear damage weighting coefficient; Represents equivalent plastic strain. For equivalent plastic strain rate, Here, ω(θ) is the shear correction parameter, and ω(θ) is the Lode angle function. For macroscopic deviatoric stress tensor, This represents the plastic strain rate tensor.

4. The method according to claim 2, characterized in that, Pore-related damage parameters include the initial pore volume fraction f0 and the critical pore volume fraction f c Failure void volume fraction f F and nucleation pore volume fraction f N .

5. The method according to claim 1, characterized in that, The parameter settings for the GTN model considering the spheroidization rate for the completed spheroidized annealed billet drawing include: Using the Property module of ABAQUS software, materials are created, and the number of non-independent variables is set on the general page; Set user-defined material parameters on the user materials page, including the spheroidization correction parameter k in the GTN model that considers spheroidization. q Initial void volume fraction f0, critical void volume fraction f c Failure void volume fraction f F and nucleation pore volume fraction f N Damage parameters.

6. The method according to claim 1, characterized in that, The step of setting the time step for the spheroidizing annealed billet drawing simulation and setting the state variable output in the FieldOutput module includes: The time step for spheroidizing annealed billet drawing simulation was set using the Step module of ABAQUS software; Using the Step module of ABAQUS software, set the state variable output on the FieldOutput page and select SDV output; Using the Step module of ABAQUS software, ALE adaptive mesh control is created in the other settings page; and ALE adaptive mesh region settings are performed, selecting spheroidized annealed billet as the adaptive mesh region.

7. The method according to claim 1, characterized in that, The contact characteristics of the spheroidized annealed billet geometry model and the drawing die include: The contact characteristics between the spheroidizing annealed billet geometry model and the drawing die were set to Explicit surface-to-surface contact using the Interaction module of ABAQUS software. Using the Interaction module of ABAQUS software, when editing contact properties, the mechanics page selects tangential behavior and uses a penalty function to set the friction coefficient.

8. The method according to claim 1, characterized in that, When applying the boundary conditions and loads for drawing, the Load module of ABAQUS software is used to create a boundary condition page, apply a fully fixed constraint to the die, and apply the drawing speed as the velocity boundary condition to the geometric model of the spheroidized annealed billet.

9. The method according to claim 1, characterized in that, When meshing the geometric model of the spheroidized annealed billet, the Mesh module of ABAQUS software was used, the C3D8R element type was selected, and the element deletion option was enabled to complete the meshing of the geometric model of the spheroidized annealed billet; the R3D4 discrete rigid body element type was selected to complete the meshing of the drawing die.

10. A ABAQUS-based system for predicting drawing cracks in spheroidized annealed billets, characterized in that, The system includes: an experimental data acquisition module, a GTN model construction and training module considering sphericity, an ABAQUS geometric model construction module, a GTN model parameter setting module considering sphericity, an ABAQUS geometric model setting module, a calculation submission module, and a result analysis module; wherein, The experimental data acquisition module is used to collect tensile test data and metallographic structure data of billets with different spheroidization rates in the range of 0~100%; The GTN model construction and training module considering spheroidization rate is used to construct a GTN model for drawing spheroidized annealed billets considering spheroidization rate, and to train the GTN model considering spheroidization rate based on experimental data to obtain the parameters of the trained GTN model. The ABAQUS geometric model building module is used to build a geometric model of spheroidized annealed billet and a drawing die based on ABAQUS. The GTN model parameter setting module that considers spheroidization rate is used to set the GTN model parameters for drawing spheroidized annealed billets by using user-defined materials in the Property module of ABAQUS software and based on the trained GTN model parameters. The ABAQUS geometry model setting module is used to assemble the spheroidizing annealed billet geometry model with the drawing die using the Assembly module of the ABAQUS software, set the time step of the spheroidizing annealed billet drawing simulation using the Step module, set the state variable output using the FieldOutput module, set the contact characteristics between the spheroidizing annealed billet geometry model and the drawing die using the Interaction module, apply the boundary conditions and loads for drawing using the Load module, and complete the mesh generation of the spheroidizing annealed billet geometry model using the Mesh module. The calculation submission module is used to submit calculations using the Job module of the ABAQUS software; The result analysis module is used to view the stress-strain distribution and equivalent void volume fraction distribution of the spheroidized annealed billet using the Visualization module of ABAQUS software, and to determine whether cracking has occurred.

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