Heat treatment simulation program, recording medium, and heat treatment simulation device

Abstract

To provide a heat treatment simulation program, a recording medium, and a heat treatment simulation device capable of further improving analysis accuracy.SOLUTION: A heat treatment simulation program of the present disclosure causes a computer to execute an acquisition step, an application step, and an analysis step. In the acquisition step, the computer acquires physical quantity data obtained by performing forming processing analysis on material data, and shape data generated based on a shape obtained by performing the forming processing analysis on the material data. In the application step, the computer applies the physical quantity data to the shape data. In the analysis step, the computer performs an induction heat treatment analysis on the shape data to which the physical quantity data is applied.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a heat treatment simulation program, a recording medium, and a heat treatment simulation apparatus. [Background technology]

[0002] When manufacturing automobile parts, construction parts, etc., heat treatments such as quenching are carried out after the forming process in order to improve fatigue resistance and wear resistance. Induction hardening is a surface hardening heat treatment method that allows for short-time heating and in-line treatment, and has the advantages of low deformation and excellent reproducibility of hardened quality.

[0003] In induction hardening, there are many factors that affect the quality of the heat treatment, such as the hardening range, hardness distribution, amount of deformation, etc. In order to achieve the desired hardening, it is important to set the various conditions during heat treatment appropriately and optimally.

[0004] To set these conditions, prototype testing using heat treatment equipment would require a huge amount of work time, which would increase the cost and lead time of heat treatment. Therefore, with the aim of reducing the number of prototype tests required for induction hardening, an induction hardening simulation device has been developed.

[0005] For example, Patent Document 1 discloses an induction hardening simulation device that analyzes induction hardening by numerical calculation such as the finite element method. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-230331 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the analysis results obtained using the induction hardening simulator described above may differ from the results of actual induction hardening. In particular, differences are often observed in the heat treatment deformation and residual stress after hardening, as these are significantly affected by the stress and strain applied to the interior of the part in the pre-heat treatment process. Therefore, in the past, in order to achieve the desired hardening, it was necessary to perform an analysis using the induction hardening simulator and then check the hardening quality through prototype testing each time.

[0008] Therefore, in order to further reduce the number of prototype tests, it is desirable to improve the analytical accuracy using induction hardening simulation equipment.

[0009] In view of the above, an object of the present invention is to provide a heat treatment simulation program, a recording medium, and a heat treatment simulation apparatus that can further improve the accuracy of analysis. [Means for solving the problem]

[0010] The heat treatment simulation program disclosed herein causes a computer to execute an acquisition step, an application step, and an analysis step. In the acquisition step, the computer acquires physical quantity data obtained by performing a forming processing analysis on material data and shape data generated based on a shape obtained by performing the forming processing analysis on the material data. In the application step, the computer applies the physical quantity data to the shape data. In the analysis step, the computer executes an induction heat treatment analysis on the shape data to which the physical quantity data has been applied. [Effects of the Invention]

[0011] According to the present invention, there are provided a heat treatment simulation program, a recording medium, and a heat treatment simulation device that can further improve the accuracy of analysis. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example of a manufacturing process for a product. [Figure 2] FIG. 2 is a diagram illustrating an example of an analysis range of the simulation system according to the embodiment of the present disclosure. [Figure 3] FIG. 3 is a block diagram illustrating an example configuration of a simulation system according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of the induction heat treatment analysis unit according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram schematically illustrating an outline of the processing of the high-frequency heat treatment analysis unit according to the embodiment of the present disclosure. [Figure 6] FIG. 6 is a flowchart showing an example of the flow of a simulation process according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a detailed example of the flow of the simulation process according to the embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram illustrating an example of a result of the conversion process performed by the conversion unit according to the embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram showing an example of an analysis result of the plastic processing simulation according to the embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram illustrating an example of an analysis result of a simulation of induction heat treatment and straightening according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram for explaining an example of a simulation result according to an embodiment of the present disclosure. [Figure 12] FIG. 12 is a diagram for explaining an example of a simulation result according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] <<1. Introduction>> Fig. 1 is a diagram showing an example of a manufacturing process for a product. As shown in Fig. 1, products such as automobile parts and construction parts are manufactured from materials through processes including molding and high-frequency heat treatment.

[0015] Specifically, first, a forming process is performed on a raw material. The raw material is a metal member such as carbon steel or chrome-molybdenum steel having a predetermined shape such as a round bar or a rectangular parallelepiped. The raw material is then subjected to forming processes such as casting, forging, and machining.

[0016] In the following, for the sake of simplicity, plastic processing will be used as an example of forming processing, but the forming processing is not limited to plastic processing. Examples of forming processing include the above-mentioned casting processing, forging processing, and cutting processing.

[0017] For example, parts formed by plastic working are then heat treated by induction hardening, which improves fatigue resistance and wear resistance. After hardening, the parts are then subjected to high-precision processing such as straightening, cutting, and polishing before being shipped as products.

[0018] Here, conventional induction hardening simulations analyze induction heat treatment among the manufacturing processes of a product, and do not take into consideration the processes before induction heat treatment.

[0019] Here, the inventors have found that because induction hardening involves short heating times, stress and strain inside the component that have occurred in processes prior to hardening (e.g., forming processes such as forging, casting, and machining) are released during heating, which has a significant effect on hardening deformation.

[0020] For example, in the forming process shown in Figure 1, stress and strain are generated inside the part when the material is subjected to forming processes such as casting, forging, and machining. In addition, work hardening occurs in the part depending on the type of forming process.

[0021] If induction hardening is performed while stress and strain remain inside the part, the residual stress and strain will have a significant effect on the heat treatment deformation and residual stress after hardening, due to the short heating time.

[0022] However, conventional induction hardening simulations did not consider the stress and strain that occurred in processes prior to hardening, such as forming. As a result, although the analysis results of heat treatment deformation after hardening using conventional induction hardening simulations could reproduce the trends of actual parts, there were often discrepancies in the absolute values.

[0023] As described above, conventional induction hardening simulations have room for improvement in terms of analytical accuracy.

[0024] Therefore, the technology disclosed herein proposes a simulation system that combines a forming simulation and an induction hardening simulation.

[0025] 2 is a diagram illustrating an example of an analysis range of the simulation system according to an embodiment of the present disclosure. As shown in FIG. 2, the simulation system according to an embodiment of the present disclosure analyzes forming processing and induction hardening of a material.

[0026] That is, the simulation system according to this embodiment performs a simulation of forming, and then performs a simulation of induction hardening in consideration of the results of the simulation.

[0027] In this way, the simulation system according to this embodiment can improve the analysis accuracy of induction hardening by simulating induction hardening while taking into account the simulation results of forming.

[0028] More specifically, the simulation system according to this embodiment functions as a heat treatment simulation device by executing a heat treatment simulation program.

[0029] The heat treatment simulation program according to this embodiment includes an acquisition step, an application step, and an analysis step.

[0030] In the acquisition step, physical quantity data obtained by performing a forming process analysis on the material data and shape data generated based on the shape obtained by performing a forming process analysis on the material data are acquired.

[0031] In the application step, the physical quantity data is applied to an element model for induction hardening simulation that is fabricated based on the shape data. In the analysis step, an induction heat treatment analysis is performed on the element model to which the physical quantity data has been applied.

[0032] In this way, the heat treatment simulation program according to this embodiment executes an induction heat treatment analysis using physical quantity data obtained by performing a forming analysis on material data. As a result, the simulation system according to this embodiment can perform an induction hardening simulation taking into account the results of the forming simulation, thereby improving the analysis accuracy of the induction hardening.

[0033] <<2. Simulation system configuration example>> 3 is a block diagram showing an example configuration of a simulation system 100 according to an embodiment of the present disclosure. As shown in FIG. 3, the simulation system 100 includes an input / output unit 110, a calculation unit 120, and a storage unit 130.

[0034] (I / O section 110) The input / output unit 110 receives data input from the outside and outputs data to the outside. The input / output unit 110 can be a communication unit that communicates with an external device (not shown). The input / output unit 110 may be connected to a keyboard, a mouse, a display device, etc. and have the function of exchanging data with these devices.

[0035] (Storage unit 130) The storage unit 130 is configured with, for example, an SSD (Solid State Drive) or an HDD (Hard Disk Drive), etc. The storage unit 130 functions as a storage means of the simulation system 100.

[0036] The storage unit 130 stores various programs executed by the simulation system 100. Examples of these programs include a forming program, a conversion program, and a high-frequency heat treatment program. The high-frequency heat treatment program may include, for example, a magnetic field analysis program, a thermal analysis program, a structure analysis program, a stress / strain analysis program, a circuit analysis program, and a thermal fluid analysis program.

[0037] (Computation unit 120) The calculation unit 120 functions as a control unit that controls the entire simulation system 100. The calculation unit 120 includes, for example, a central processing unit (CPU). The calculation unit 120 may also include a graphics processing unit (GPU), a digital signal processor (DSP), a large scale integration (LSI), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc.

[0038] The calculation unit 120 functions as each unit described below by executing a program stored in the storage unit 130. The calculation unit 120 shown in FIG. 3 includes a processing analysis unit 121, a conversion unit 122, and an induction heat treatment analysis unit 123.

[0039] (Processing analysis department 121) The processing analysis unit 121 performs a forming processing analysis on the material data, and generates physical quantity data and post-forming shape data.

[0040] The material data is data relating to the components that are used to make the product, and may include, for example, material data relating to the material of the part, such as carbon steel or chrome molybdenum steel, and material shape data relating to the shape of the part before machining.

[0041] The material shape data includes shape designation data that specifies the shape of the material, such as a rectangular parallelepiped or a round bar (cylinder), and size data that specifies the length of the shape (for example, if the material shape is a round bar, the diameter and length, etc.).

[0042] The material shape data listed here is an example. The material shape data may be in any format as long as it can identify the shape of the material in the forming process analysis. For example, the material shape data may be three-dimensional CAD (Computer-Aided Design) data or three-dimensional element data. Examples of three-dimensional element data include three-dimensional mesh data.

[0043] The processing analysis unit 121 performs at least one analysis of, for example, a forging process, a casting process, a cutting process, a drawing process, a cold plastic working process, etc. In the following, for the sake of simplicity, the processing analysis unit 121 will be described as performing an analysis of a cold plastic working process.

[0044] The processing analysis unit 121 analyzes, for example, plastic processing and generates physical quantity data and after-forming shape data. The after-forming shape data is data related to the shape of an after-forming part (workpiece) produced by performing plastic processing on a material. The after-forming shape data is, for example, three-dimensional element data.

[0045] The physical quantity data is data relating to physical quantities imparted to the formed part by the plastic processing process, such as stress data relating to the stress inside the formed part (e.g., data relating to stress distribution) and strain data relating to the strain inside the formed part (e.g., data relating to plastic strain distribution).

[0046] The processing analysis unit 121 outputs the after-forming shape data to the conversion unit 122 and outputs the physical quantity data to the high-frequency heat treatment analysis unit 123 .

[0047] The calculation unit 120 of the simulation system 100 functions as a processing analysis unit 121 by executing, for example, a forming processing program stored in the storage unit 130. In other words, the simulation system 100 functions as a simulation device for forming processing analysis (forming processing simulation device) by executing the forming processing program.

[0048] (Conversion unit 122) The conversion unit 122 converts the post-molding shape data generated by the processing analysis unit 121 into data (an example of shape data, hereinafter also referred to as second post-conversion shape data) for the high-frequency heat treatment analysis unit 123 to perform high-frequency heat treatment analysis.

[0049] For example, the conversion unit 122 converts the post-molding shape data, which is three-dimensional element data, into first post-conversion shape data, which is three-dimensional CAD model data. Then, the conversion unit 122 converts the first post-conversion shape data, which is three-dimensional CAD model data, into second post-conversion shape data, which is three-dimensional element data.

[0050] Specifically, the conversion unit 122 converts the after-molding shape data into first after-conversion shape data through a reverse engineering operation. For example, the conversion unit 122 converts the after-molding shape data into the first after-conversion shape data in accordance with an instruction from a user of the simulation system 100.

[0051] Next, the conversion unit 122 generates an analytical model of the high-frequency heat treatment. Specifically, the conversion unit 122 converts the first post-conversion shape data into second post-conversion shape data in accordance with, for example, an instruction from a user who uses the simulation system 100.

[0052] In this way, the conversion unit 122 generates the second post-conversion shape data based on the after-molding shape data. The conversion unit 122 outputs the generated second post-conversion shape data to the induction heat treatment analysis unit 123.

[0053] Here, the reason why the conversion unit 122 generates the second converted shape data based on the after-forming shape data will be described. As described above, the after-forming shape data is three-dimensional element data generated by the processing analysis unit 121 through analysis of the plastic processing process. Therefore, it can be said that the after-forming shape data is data suitable for plastic processing analysis, in other words, data that appropriately indicates the shape of the after-forming part.

[0054] For example, the after-molding shape data may be generated at a density according to the shape of the after-molding part. For example, if the shape of the after-molding part is flat, the elements of the after-molding shape data may be coarse, and if the shape of the after-molding part is complex, the elements of the after-molding shape data may be fine.

[0055] In this way, the after-molding shape data has an element structure suitable for representing the shape of the after-molding part (for example, for display on a display).

[0056] On the other hand, it is desirable that the data (an example of input data) used for the analysis by the high-frequency heat treatment analysis unit 123 is three-dimensional element data having an element structure suitable for analyzing high-frequency heat treatment.

[0057] As described above, the simulation system 100 performs both the forming analysis and the induction heat treatment analysis, but the element structure suitable for each analysis differs. Therefore, even if the simulation system 100 performs the induction heat treatment analysis using the after-forming shape data generated by the forming analysis as is, there is a high possibility that the desired analysis accuracy cannot be obtained.

[0058] Therefore, in this embodiment, the conversion unit 122 converts the post-molding shape data (three-dimensional element data) into first post-conversion shape data (three-dimensional CAD data), and then converts the first post-conversion shape data into second post-conversion shape data (three-dimensional element data).

[0059] In this way, the conversion unit 122 generates second post-conversion shape data (three-dimensional element data) suitable for analyzing the induction heat treatment based on the after-molding shape data. The simulation system 100 performs the induction heat treatment analysis using the second post-conversion shape data, thereby enabling the analysis of the induction heat treatment to be performed with higher accuracy.

[0060] Here, it is stated that the conversion unit 122 generates the second post-conversion shape data by converting the post-molding shape data into the first post-conversion shape data and then converting it into the second post-conversion shape data, but the method of generating the second post-conversion shape data is not limited to this.

[0061] For example, the conversion unit 122 may generate the second post-conversion shape data directly from the post-shaping shape data. In this case, the conversion unit 122 converts the post-shaping shape data (three-dimensional element data) into the second post-conversion shape data (three-dimensional element data).

[0062] Alternatively, the simulation system 100 may use the post-molding shape data as the second post-conversion shape data. In this case, the conversion unit 122 may be omitted.

[0063] The second converted shape data generated by the conversion unit 122 may be data suitable for a simulation by the high-frequency heat treatment analysis unit 123 (data that allows for highly accurate analysis), and the method for generating the data does not matter.

[0064] The calculation unit 120 of the simulation system 100 functions as a conversion unit 122 by executing, for example, a conversion program stored in the storage unit 130. In other words, the simulation system 100 functions as a conversion device by executing the conversion program.

[0065] (High Frequency Heat Treatment Analysis Department 123) The induction heat treatment analysis unit 123 performs induction hardening analysis using the second converted shape data. At this time, the induction heat treatment analysis unit 123 applies (maps) physical quantity data, which is the result of the plastic working analysis, to the second converted shape data. The induction heat treatment analysis unit 123 performs induction hardening analysis on the second converted shape data onto which the physical quantity data is mapped.

[0066] This allows the induction heat treatment analysis unit 123 to perform induction hardening analysis taking into consideration physical quantity data (for example, stress and strain) obtained from plastic processing analysis.

[0067] Fig. 4 is a block diagram showing an example of the configuration of the high-frequency heat treatment analysis unit 123 according to an embodiment of the present disclosure. The high-frequency heat treatment analysis unit 123 shown in Fig. 4 includes a control unit 123A, a magnetic field analysis unit 123B, a heat generation amount calculation unit 123C, a heat treatment analysis unit 123D, a physical property value update unit 123E, a circuit analysis unit 123F, and a thermal fluid analysis unit 123G.

[0068] (Control unit 123A) The control unit 123A controls each unit of the high-frequency heat treatment analysis unit 123 (magnetic field analysis unit 123B, heat generation amount calculation unit 123C, heat treatment analysis unit 123D, physical property value update unit 123E, circuit analysis unit 123F, and thermal fluid analysis unit 123G).

[0069] The control unit 123A exchanges commands and data between the various units of the high-frequency heat treatment analysis unit 123, and exchanges data between the processing analysis unit 121, the conversion unit 122, the input / output unit 110, and the storage unit .

[0070] The control unit 123A also controls the number of repetitions and step time of the coupled analysis, monitors the temperature of a specified part, etc. Note that "coupled analysis" refers to performing a short-term analysis multiple times while taking into account the complex mutual influences of multiple physical phenomena.

[0071] Furthermore, the control unit 123A applies (maps) the physical quantity data, which is the result of the plastic working analysis, to the second converted shape data to generate second converted shape data (shape data related to the formed part) to be used in the induction hardening analysis. Each unit of the induction heat treatment analysis unit 123 executes each process described below using the mapped second converted shape data.

[0072] (Magnetic field analysis department 123B) The magnetic field analysis unit 123B performs magnetic field analysis using the finite element method based on Maxwell's electromagnetic equations. Specifically, the magnetic field analysis unit 123B uses the A method or A-φ method, which are finite element methods that allow frequency response analysis, to calculate the magnetic flux distribution generated around the heating coil and the eddy currents generated near the surface of the workpiece (formed part) due to changes in that distribution over time.

[0073] The magnetic field analysis unit 123B divides the workpiece, the heating coil, and the space around them into a plurality of elements. Therefore, the data input to the magnetic field analysis unit 123B is, for example, as follows:

[0074] One type of data (first type of data) is a magnetic field analysis FEM model (for example, the second converted shape data after mapping described above, or model data obtained from this second converted shape data) in which the workpiece, heating coil, and the space around them are divided into multiple elements at each node. This magnetic field analysis FEM model includes node information indicated by coordinates and a combination of node information constituting each element (hereinafter simply referred to as "element information").

[0075] One type of data (second type of data) is material property information about the materials of the workpiece and heating coil. This material property information includes the electrical conductivity and magnetization curve (information that represents magnetization characteristics, a curve of magnetic field strength H and magnetic flux density B) for each metal structure. Both of these have temperature dependency.

[0076] One type of data (third type of data) includes information about analysis conditions, such as the frequency of the high-frequency induction heating power supply and the heating coil current or voltage.

[0077] One of the types of data (fourth type of data) is temperature information at each node in the FEM model for magnetic field analysis. Note that the initial value of this temperature information is, for example, room temperature, and is successively rewritten by the control unit 123A.

[0078] The magnetic field analysis unit 123B sets the current or voltage flow plane on the cross section of the heating coil using an FEM model for magnetic field analysis. The magnetic field analysis unit 123B calculates the magnetic flux distribution based on this setting. The magnetic field analysis unit 123B calculates the eddy current distribution based on the magnetic flux distribution and calculates the Joule loss (heat density) for each element of the FEM model.

[0079] That is, the magnetic field analysis unit 123B calculates the amount of Joule loss for each element in the FEM model for magnetic field analysis. Then, the magnetic field analysis unit 123B outputs data indicating the amount of Joule loss for each element to the heat generation amount calculation unit 123C. The magnetic field analysis unit 123B may output the magnetic flux distribution and eddy current distribution obtained by the magnetic field analysis to the input / output unit 110 (for example, a display) via the control unit 123A.

[0080] (heat generation amount calculation unit 123C) The heat generation amount calculation unit 123C calculates the heat generation amount of each element from the Joule loss amount of each element input from the magnetic field analysis unit 123B, and outputs the calculated amount to the heat treatment analysis unit 123D.

[0081] The information input to the heat generation amount calculation unit 123C includes node information and element information. The node information and element information are defined by coordinates set on the workpiece. Both the node information and element information are defined for each FEM model for magnetic field analysis and each FEM model for heat treatment analysis (for example, the second converted shape data after the above-mentioned mapping, or model data obtained from this second converted shape data).

[0082] The heat generation amount calculation unit 123C performs a mapping process between the node information and element information in the FEM model for magnetic field analysis and the node information and element information in the FEM model for heat treatment analysis. The heat generation amount calculation unit 123C calculates the heat generation amount of each element in the FEM model for heat treatment analysis. The heat generation amount calculation unit 123C outputs the calculated heat generation amount to the heat treatment analysis unit 123D directly or via the control unit 123A.

[0083] (Heat Treatment Analysis Unit 123D) FIG. 5 is a diagram schematically illustrating an outline of the processing of the high-frequency heat treatment analysis unit 123 according to the embodiment of the present disclosure.

[0084] As shown in Fig. 5, the temperature, structure, and stress of each part of the workpiece are interrelated. For this reason, the heat treatment analysis unit 123D performs a coupled analysis of these interrelationships to predict the temperature and strain of each node set in the FEM model for heat treatment analysis, the stress for each element, the metal structure, and the like.

[0085] For example, when the temperature changes in any part of a workpiece, a phase transformation occurs. Conversely, when a phase transformation occurs, latent heat is generated and absorbed. When a phase transformation occurs unevenly within a workpiece, the volume changes locally, causing deformation and stress. Conversely, when stress occurs, it affects the occurrence of a phase transformation. When a workpiece deforms, the deformed part generates or absorbs heat. When a temperature difference occurs inside a workpiece, deformation and stress occur.

[0086] Here, conventional high-frequency heat treatment analysis takes into account the heat treatment stress / strain caused by the high-frequency heat treatment, but does not take into account the stress and strain caused by the forming process. In other words, conventional high-frequency heat treatment analysis is performed assuming that the stress and strain before the heat treatment are zero.

[0087] Stress and strain are generated during both forming and induction hardening, and are calculated using elastic-plastic analysis.

[0088] The stress and strain generated during the forming process are released during heating by induction heating, which affects heat treatment deformation (deformation of the workpiece after induction hardening).

[0089] Therefore, in this embodiment, the induction heat treatment analysis is performed using the second converted shape data in which the physical quantity data (data related to stress and strain) is mapped, which allows the induction heat treatment analysis unit 123 to perform the induction hardening analysis taking the stress and strain into consideration, thereby enabling the induction hardening analysis to be performed with higher accuracy.

[0090] The heat treatment analysis unit 123D uses the finite element method to divide the workpiece into multiple elements to analyze the above interrelationships, and performs an analysis for each element by interrelating the temperature, elastic-plastic structure, and phase transformation.

[0091] The heat treatment analysis unit 123D performs analysis using a heat conduction equation or the like based on the heat generation amount for each element input from the heat generation amount calculation unit 123C, and calculates the temperature of each node in the heat treatment analysis FEM model, the amount of deformation, the stress / strain of each element, and the metal structure (metal structure volume fraction). At this time, the stress and strain of each element calculated by the heat treatment analysis unit 123D are stress and strain that take into account the stress and residual strain that occurred in the previous processing step.

[0092] The metallographic volume fraction represents the ratio of the steel structure, for example, ferrite, pearlite, austenite, martensite, bainite, etc. The stress and strain data may be converted for each node instead of for each element.

[0093] The data input to the heat treatment analysis unit 123D are, for example, as follows:

[0094] One of the types of data (first type of data) is a heat treatment analysis FEM model related to the shape and dimensions of the workpiece (for example, the second converted shape data after the mapping described above, or model data obtained from this second converted shape data). The heat treatment analysis FEM model includes nodal information indicated by coordinates and combinations of nodes that make up each element (element information).

[0095] One type of data (second type of data) is physical property information of the steel that constitutes the workpiece. Examples of the physical property information include phase transformation characteristic information and stress / strain physical property information.

[0096] Examples of phase transformation characteristic information include an isothermal transformation diagram (TTT: Time-Temperature-Transformation diagram), a continuous cooling transformation curve (CCT: Continuous-Cooling-Transformation diagram), austenite transformation temperature information (TTA: Time-Temperature-Austenization diagram), and martensite transformation temperature.

[0097] The phase transformation characteristic information includes, for example, information on thermal conductivity, specific heat, density, latent heat, etc. The stress / strain physical property information includes, for example, Young's modulus, Poisson's ratio, linear expansion coefficient, yield point, work hardening coefficient, transformation expansion coefficient, and transformation plasticity coefficient.

[0098] One type of data (third type of data) is information for estimating the cooling process of the workpiece. As information for estimating the cooling process of the workpiece, the value of the heat transfer coefficient h is defined as a thermal boundary condition on the cooling surface of the workpiece. These have temperature dependency.

[0099] One of the types of data (fourth type of data) is information on the amount of heat generated at each node defined in the heat treatment analysis FEM model, which is input from the heat generation amount calculation unit 123C.

[0100] One type of data (the fifth type of data) is information about analysis conditions, such as heating time, cooling time, and the number of coupling runs.

[0101] The heat treatment analysis unit 123D outputs data indicating the temperature of each node and the metallographic volume fraction of each element in the heat treatment analysis FEM model to the physical property value update unit 123E directly or via the control unit 123A. The heat treatment analysis unit 123D also outputs data indicating the deformation of the workpiece to the thermal fluid analysis unit 123G directly or via the control unit 123A.

[0102] (Physical property update unit 123E) The physical property value update unit 123E acquires data indicating the temperature of each node and the metallographic volume fraction of each element in the FEM model for heat treatment analysis from the heat treatment analysis unit 123D. Based on this data acquired from the heat treatment analysis unit 123D, the physical property value update unit 123E calculates the electrical conductivity and magnetization curve of each element from the temperature of each node in the FEM model for magnetic field analysis.

[0103] The physical property update unit 123E outputs the calculated electrical conductivity and magnetization curve of each element to the magnetic field analysis unit 123B directly or via the control unit 123A. The temperature of each node and the electrical conductivity and relative permeability of each element affect the penetration depth.

[0104] (Circuit analysis department 123F) The circuit analysis unit 123F performs, for example, a circuit simulation by performing calculations using circuit equations regarding the electrical circuit of the high frequency induction heating power supply, matching box, high frequency transformer, and heating coil to determine the coil current or coil voltage.

[0105] The circuit analysis unit 123F outputs the results to the magnetic field analysis unit 123B directly or via the control unit 123A. This allows the high-frequency heat treatment analysis unit 123 to evaluate the temporal fluctuation of the induction heating phenomenon between the heating coil and the workpiece.

[0106] In induction hardening equipment, an LCR resonant circuit is used to apply power of a fixed frequency to a heating coil to heat the workpiece by high-frequency induction. However, changes in the temperature distribution of the workpiece cause the circuit load to constantly fluctuate, which in turn causes fluctuations in the coil current, coil voltage, and resonant frequency.

[0107] The high frequency power supply control method includes a method of controlling any one of the coil current, coil voltage, and input power to a constant value. In this embodiment, the analysis results of the magnetic field analysis unit 123B are input to the circuit analysis unit 123F. The analysis results of the circuit analysis unit 123F are also input to the magnetic field analysis unit 123B. This allows the magnetic field analysis and circuit analysis to be linked, and the high frequency heat treatment analysis unit 123 can improve the accuracy of the high frequency hardening simulation.

[0108] (Thermal Fluid Analysis Department 123G) The thermal fluid analysis unit 123G performs a thermal fluid simulation using computational fluid dynamics based on a structural model that represents the configuration of the cooling device. The structural model includes information such as the shape of the cooling jacket, the shape of the workpiece, the positional relationship between the coolant nozzle in the cooling jacket and the workpiece, and the direction in which the coolant is sprayed from the cooling jacket.

[0109] Data indicating the physical properties and flow rate of the coolant is input to the thermal fluid analysis unit 123G via the input / output unit 110. In addition, temperature data including the workpiece surface temperature and data indicating the amount of deformation of the workpiece are input from the heat treatment analysis unit 123D.

[0110] The thermal fluid analysis unit 123G performs a thermal fluid simulation based on the input data to analyze the flow of the coolant and calculate the flow rate of the coolant on the surface of the workpiece. Note that the thermal fluid analysis unit 123G may also calculate the temperature and pressure of the coolant in addition to the flow rate of the coolant on the surface of the workpiece.

[0111] The control unit 123A acquires the flow velocity of the coolant on the surface of the workpiece from the thermal fluid analysis unit 123G. The control unit 123A acquires the heat transfer coefficient h by referring to the relationship (Tvh relationship) between the workpiece surface temperature Ts, the coolant flow velocity v, and the heat transfer coefficient h stored in the memory unit 130, and outputs the heat transfer coefficient h to the heat treatment analysis unit 123D.

[0112] The calculation unit 120 of the simulation system 100 functions as an induction heat treatment analysis unit 123 by executing, for example, an induction heat treatment program stored in the storage unit 130, and executes the processing of each unit. In other words, the simulation system 100 functions as a simulation device for induction heat treatment analysis (induction heat treatment simulation device) by executing the induction heat treatment program.

[0113] The simulation system 100 may be realized as a single device or may be realized by combining multiple devices. For example, the simulation system 100 may include a forming simulation device, a conversion device, and an induction heat treatment simulation device.

[0114] At least some of the functions executed by the simulation system 100 may be realized as a cloud on a network. For example, at least some of the forming process analysis by the process analysis unit 121, the conversion process by the conversion unit 122, and the high-frequency heat treatment analysis by the high-frequency heat treatment analysis unit 123 may be implemented as one function of a cloud server device.

[0115] <<3. Example of Simulation System Operation>> 6 is a flowchart showing an example of the flow of a simulation process according to an embodiment of the present disclosure. The simulation process of FIG. 6 is executed by the simulation system 100 in accordance with, for example, an instruction from a user.

[0116] 6, the simulation system 100 executes a forming analysis (step S101). The simulation system 100 executes a forming analysis (e.g., a plastic forming analysis) based on, for example, material data related to a material, and generates after-forming shape data and physical quantity data related to residual stress / residual strain.

[0117] Next, the simulation system 100 generates second post-conversion shape data from the after-molding shape data (step S102). For example, the simulation system 100 converts the after-molding shape data, which is three-dimensional element data, into first post-conversion data, which is three-dimensional CAD data. Thereafter, the simulation system 100 converts the first post-conversion data into second post-conversion shape data, which is three-dimensional element data.

[0118] The simulation system 100 maps the physical quantity data onto the second converted shape data (step S103). The simulation system 100 executes a high-frequency heat treatment analysis using the second converted shape data onto which the physical quantity data has been mapped (step S104).

[0119] In this way, the simulation system 100 executes the high-frequency heat treatment analysis using the shape data (second converted shape data) to which the physical quantity data, which is the forming analysis result, is applied (mapped). This allows the simulation system 100 to execute the high-frequency heat treatment analysis taking the forming result into consideration, thereby improving the accuracy of the high-frequency heat treatment analysis.

[0120] FIG. 7 is a diagram illustrating a detailed example of the flow of the simulation process according to the embodiment of the present disclosure.

[0121] 7, the simulation system 100 performs plastic processing analysis on a material, more specifically, material data (step S201), and outputs after-forming shape data. This after-forming shape data is a three-dimensional (3D) element model (a 3D mesh model in FIG. 7).

[0122] The process including step S201 (step S11) is executed by the processing analysis unit 121 of the simulation system 100. Step S201 corresponds to, for example, step S101 in FIG.

[0123] 7, the simulation system 100 performs a reverse engineering operation (step S202) to generate first post-conversion shape data. The reverse engineering operation is an operation of converting element data into three-dimensional (3D) CAD data (element (mesh in FIG. 7) → 3D CAD conversion). The first post-conversion shape data is a 3D CAD model.

[0124] The simulation system 100 creates an induction heat treatment analysis model (step S203) and outputs second converted shape data. The creation of the induction heat treatment analysis model is a process of converting three-dimensional (3D) CAD data into element data (3D CAD → element (mesh in FIG. 7) model). The second converted shape data is a three-dimensional element model (3D mesh model in FIG. 7).

[0125] The process including steps S202 and S203 (step S12) is executed by the conversion unit 122 of the simulation system 100. Step S12 corresponds to, for example, step S102 in FIG.

[0126] Here, Fig. 8 is a diagram showing an example of a result of the conversion process by the conversion unit 122 according to an embodiment of the present disclosure. Fig. 8(a) shows an example of post-forming shape data. Fig. 8(b) shows first post-conversion shape data. Fig. 8(c) shows second post-conversion shape data. In Fig. 8, the shape of the workpiece after plastic processing is assumed to be a round bar (cylinder).

[0127] For example, when the conversion unit 122 acquires post-molding shape data of the three-dimensional element model shown in FIG. 8(a), it generates first post-conversion shape data of the three-dimensional CAD model shown in FIG. 8(b) by reverse engineering.

[0128] Next, the conversion unit 122 converts the first post-conversion shape data shown in FIG. 8(b) to generate second post-conversion shape data of the three-dimensional element model shown in FIG. 8(c).

[0129] Returning to FIG. 7, the simulation system 100 maps the physical quantity data, which is the result of the plastic working analysis, onto the second converted shape data (step S204). Next, the simulation system 100 executes a high-frequency heat treatment analysis (step S205). This high-frequency heat treatment analysis takes into account the stress and strain imparted by the plastic working. The simulation system 100 outputs an analytical evaluation result of the high-frequency heat treatment analysis.

[0130] The process (step S13) including steps S204 and S205 is executed by the induction heat treatment analysis unit 123 of the simulation system 100. Step S204 corresponds to step S103 in FIG. 6, and step S205 corresponds to step S104 in FIG.

[0131] The simulation system 100 performs reverse engineering to convert the after-molding shape data, which is three-dimensional element data, into 3D CAD data, and then generates second after-conversion shape data to be used in the high-frequency heat treatment analysis. This allows the simulation system 100 to more easily generate three-dimensional element data (second after-conversion shape data) suitable for the high-frequency heat treatment analysis.

[0132] Furthermore, the simulation system 100 maps the plastic working analysis result onto the second converted shape data and executes the high-frequency heat treatment analysis, thereby enabling the simulation system 100 to execute the high-frequency heat treatment analysis taking into account the physical quantities (stress and strain) imparted by the plastic working.

[0133] <<4. Simulation example using the simulation system>> Next, an example of a simulation performed using the simulation system 100 according to this embodiment will be described with reference to FIGS.

[0134] Here, a case will be described in which the simulation system 100 simulates a manufacturing process for manufacturing a rack bar using a hollow round bar as a material.

[0135] The simulation system 100 performs a plastic processing simulation on a material (hollow round bar), and then performs a simulation of induction hardening.

[0136] 9A and 9B are diagrams showing an example of analysis results from a plastic processing simulation according to an embodiment of the present disclosure. FIG. 9A is a diagram showing a material for plastic processing. FIG. 9B is a diagram showing a workpiece after flattening processing has been performed on the material. FIG. 9C is a diagram showing a workpiece after tooth forming processing has been performed. The legend in FIG. 9 indicates the depth from the surface of the workpiece.

[0137] The simulation system 100 performs flattening processing on a hollow round bar material shown in Fig. 9(a) by pressing a punch 201 into the material as shown in Fig. 9(b). Next, the simulation system 100 performs tooth forming processing by sandwiching the area where the flattening processing was performed by pressing the punch 201 between a tooth mold 202 and a mandrel 203 to form teeth.

[0138] 10A and 10B are diagrams showing an example of analysis results of induction hardening simulation according to an embodiment of the present disclosure. Fig. 10A is a diagram showing the temperature distribution of the workpiece at the end of heating by induction hardening. Fig. 10B is a diagram showing the distribution of martensite after induction hardening.

[0139] As shown in Figure 10(a), induction hardening is performed on the formed area of ​​the workpiece, and as shown in Figure 10(b), martensite is generated in the formed area of ​​the workpiece by induction hardening.

[0140] 11 and 12 are diagrams for explaining an example of a simulation result according to an embodiment of the present disclosure. Fig. 11 shows the amount of deformation in the height direction of the workpiece (the vertical direction in Fig. 12). The vertical axis of Fig. 11 shows the amount of deformation in the height direction (the vertical direction in Fig. 12), and the horizontal axis shows the distance from the tip of the workpiece (the distance in the horizontal direction in Fig. 12).

[0141] 11, the analysis results (analysis values) obtained by the simulation according to this embodiment are shown by a straight line. That is, when both plastic working and induction hardening are taken into consideration, in other words, the analysis results of induction hardening taking into consideration the stress and strain caused by plastic working are shown by a straight line.

[0142] The dashed-dotted line in Fig. 11 shows the analysis results (analytical values) when a conventional induction heat treatment simulation is performed. That is, the dashed-dotted line shows the analysis results for induction hardening alone, in other words, induction hardening without taking into account the stress and strain caused by plastic processing.

[0143] The dotted line in FIG. 11 indicates the actual measured value of the amount of deformation when a workpiece is actually manufactured.

[0144] As shown in Fig. 11, the actual measured values ​​and the analytical values ​​when both plastic working and induction hardening are considered show that the deformation in the height direction is larger in the positive direction (upward in Fig. 12) toward the tip of the workpiece. On the other hand, the analytical values ​​when only induction heat treatment is performed show that the deformation in the height direction is larger in the negative direction (downward in Fig. 12) toward the tip of the workpiece.

[0145] As described above, it has been difficult to accurately analyze the deformation of a workpiece after heat treatment with conventional induction hardening simulations. On the other hand, the simulation system 100 according to this embodiment can obtain analysis results of induction hardening that are closer to actual measurements by taking into account the analysis results of plastic processing. In this way, the simulation system 100 according to this embodiment can perform induction heat treatment analysis with higher accuracy.

[0146] <<5. Summary>> The above-described embodiments are examples of realizing the present invention, and the present invention is not limited to these embodiments. For example, the present invention also includes embodiments in which some components are added, deleted, or modified in the above-described embodiments.

[0147] The present invention includes the following aspects. (1) an acquisition step of acquiring physical quantity data obtained by performing a forming processing analysis on material data, and shape data generated based on the shape obtained by performing the forming processing analysis on the material data; an applying step of applying the physical quantity data to the shape data; an analysis step of performing a high-frequency heat treatment analysis on the shape data to which the physical quantity data has been applied; A heat treatment simulation program that runs on a computer. (2) The heat treatment simulation program according to (1), wherein the physical quantity data includes at least one of data on stress distribution and data on strain distribution calculated by the forming processing analysis. (3) The heat treatment simulation program according to (1) or (2), wherein the shape data is data obtained by converting the shape obtained by performing the forming processing analysis into three-dimensional element data in order to perform the high-frequency heat treatment analysis. (4) the shape data is generated based on post-molding shape data relating to a shape obtained by performing the molding process analysis, The heat treatment simulation program according to any one of (1) to (3), wherein the post-forming shape data is three-dimensional element data. (5) The shape data is obtained by converting the after-molding shape data into three-dimensional CAD data, and then converting the three-dimensional CAD data into three-dimensional element data. (4) A heat treatment simulation program according to the present invention. (6) The heat treatment simulation program according to any one of (1) to (5), wherein the forming processing analysis includes analysis of at least one of cold forming processing, hot forming processing, forging processing, casting processing, and plastic processing. (7) On the computer, an acquisition step of acquiring physical quantity data obtained by performing a forming processing analysis on material data, and shape data generated based on the shape obtained by performing the forming processing analysis on the material data; an application step of applying the physical quantity data to the shape data; an analysis procedure for performing a high-frequency heat treatment analysis on the shape data to which the physical quantity data is applied; A computer-readable recording medium on which a program for executing the above is recorded. (8) acquiring physical quantity data obtained by performing a forming processing analysis on the material data, and shape data generated based on the shape obtained by performing the forming processing analysis on the material data; applying the physical quantity data to the shape data; a calculation unit that performs a high-frequency heat treatment analysis on the shape data to which the physical quantity data is applied; A heat treatment analysis device comprising: (9) a processing analysis device that performs a forming processing analysis on the material data and generates physical quantity data as the analysis result; acquiring shape data generated based on a shape obtained by performing the forming processing analysis on the physical quantity data and the material data; applying the physical quantity data to the shape data; performing a high-frequency heat treatment analysis on the shape data to which the physical quantity data has been applied; a heat treatment analysis device; An analysis system comprising: [Explanation of symbols]

[0148] 100 Simulation Systems 110 Input / output section 120 Arithmetic section 121 Processing analysis department 122 Conversion unit 123 High-Frequency Heat Treatment Analysis Department 123A Control Unit 123B Magnetic field analysis section 123C calorific value calculation section 123D Heat Treatment Analysis Department 123E Physical property update unit 123F Circuit analysis section 123G Thermofluid Analysis Department 130 Storage section

Claims

1. an acquisition step of acquiring physical quantity data obtained by performing a forming processing analysis on material data, and shape data generated based on the shape obtained by performing the forming processing analysis on the material data; an applying step of applying the physical quantity data to the shape data; an analysis step of performing a high-frequency heat treatment analysis on the shape data to which the physical quantity data has been applied; A heat treatment simulation program that runs on a computer.

2. The heat treatment simulation program according to claim 1 , wherein the physical quantity data includes at least one of data on stress distribution and data on strain distribution calculated by the forming processing analysis.

3. 2. The heat treatment simulation program according to claim 1, wherein the shape data is data obtained by converting the shape obtained by performing the forming processing analysis into three-dimensional element data for performing the high-frequency heat treatment analysis.

4. the shape data is generated based on post-molding shape data relating to a shape obtained by performing the molding process analysis, 2. The heat treatment simulation program according to claim 1, wherein the post-forming shape data is three-dimensional element data.

5. The shape data is obtained by converting the after-molding shape data into three-dimensional CAD data, and then converting the three-dimensional CAD data into three-dimensional element data. The heat treatment simulation program according to claim 4 .

6. The heat treatment simulation program according to claim 1 , wherein the forming analysis includes an analysis of at least one of a cold forming process, a hot forming process, a forging process, a casting process, and a plastic working process.

7. On the computer, an acquisition step of acquiring physical quantity data obtained by performing a forming processing analysis on material data, and shape data generated based on the shape obtained by performing the forming processing analysis on the material data; an application step of applying the physical quantity data to the shape data; an analysis procedure for performing a high-frequency heat treatment analysis on the shape data to which the physical quantity data is applied; A computer-readable recording medium on which a program for executing the above is recorded.

8. acquiring physical quantity data obtained by performing a forming processing analysis on the material data, and shape data generated based on the shape obtained by performing the forming processing analysis on the material data; applying the physical quantity data to the shape data; a calculation unit that performs a high-frequency heat treatment analysis on the shape data to which the physical quantity data is applied; A heat treatment simulation device comprising:

Images