A short stress rolling mill rolling force calculation method based on thermal coupling simulation

Abstract

The application discloses a short stress rolling mill rolling force calculation method based on thermal coupling simulation, and the method comprises the following steps: step 1, importing an existing short stress rolling mill model into engineering simulation software after simplification; step 2, performing dynamic analysis on a rolling process by using explicit dynamics of the engineering simulation software; step 3, adjusting a Sims hot rolling formula in combination with a rolling roll and a rolling piece contact area in a simulation result, and calculating rolling force load; and step 4, comparing an average value of the simulation obtained rolling force with the theoretically calculated rolling force, and verifying the accuracy of the simulation result. The Johnson-Cook constitutive model is used to simulate rolling piece stress and strain, so that the simulation result is more in line with the actual situation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rolling mill equipment, and in particular to a short stress rolling mill rolling force calculation method based on thermal coupling simulation. BACKGROUND

[0002] The basic situation of the related patent is as follows: application number CN202311074118.4; patent name: a high Mg aluminum alloy hot rolling damage prediction method; abstract: the patent discloses a high Mg aluminum alloy hot rolling damage prediction method, including the following steps: S1, based on thermal physical test and thermal simulation test, obtaining high Mg aluminum alloy thermal physical property parameters and mechanical property parameters; S2, constructing high temperature damage model and welding model; S3, establishing hot rolling coupling damage and welding hot rolling simulation model and simulation operation; S4, carrying out hot rolling process test and damage organization analysis. The patent creatively proposes a new damage mathematical model coupling temperature, strain rate, stress and strain, and a damage-welding composite simulation model, which can effectively predict high Mg aluminum alloy hot rolling damage and welding distribution, and has an important supporting role for guiding high Mg aluminum alloy hot rolling process parameter formulation and optimization.

[0003] The basic situation of the related patent is as follows: application number CN201510194490.8; patent name: rod wire pass low temperature control rolling motor power load distribution design method; abstract: a rod wire pass low temperature control rolling motor power load distribution design method belongs to the field of rolling engineering design and production technology. The method flow is as follows: design new production line product outline→use Gleeble thermal simulation to determine the deformation resistance of steel grade as input parameter→use DEFORM finite element software to simulate each pass rolling deformation under actual pass of rod wire→simulate and calculate the rolling force of each pass biting, rolling and steel throwing process→calculate the rolling moment→calculate the power of rolling mill. The advantage is that: the calculation of rolling force first fully considers the actual distribution difference of deformation temperature, strain amount and strain rate of different position points in each pass. It is the most accurate method for calculating the power of rod wire pass low temperature control rolling motor at present, thereby providing important and reliable basis for new production line rolling mill rated power distribution design and low temperature rolling process parameter formulation.

[0004] It can be seen that the existing technology uses theoretical derivation, numerical simulation and test observation to study the rolling force load variation law of hot rolling plate or cold rolling condition, and puts forward the rolling force calculation model suitable for the rolling condition respectively. However, the research on short stress rolling mill hot rolling rod is less, and the research on rolling force is more focused on calculating the rolling force through the thickness change of steel before and after rolling. SUMMARY

[0005] The purpose of this invention is to provide a method for calculating the rolling force of a short-stress rolling mill based on thermo-solid coupling simulation.

[0006] The technical solution adopted in this invention is:

[0007] A method for calculating the rolling force of a short-stress rolling mill based on thermo-mechanical coupling simulation includes the following steps:

[0008] Step 1: Simplify the existing short-stress rolling mill model and import it into the engineering simulation software to obtain the engineering model;

[0009] Step 2: Explicit dynamics analysis of the rolling process is performed using engineering simulation software; the stress-strain of the rolled piece is simulated using the Johnson-Cook constitutive model to calculate a new plastic deformation curve.

[0010] Step 3: Adjust the Sims hot rolling formula based on the contact area between the rolling roller and the workpiece in the simulation results, and calculate the rolling force load.

[0011] Step 4: Compare the average rolling force obtained from the simulation with the rolling force obtained from the theoretical calculation to verify the accuracy of the simulation results.

[0012] Furthermore, step 1 specifically includes the following steps:

[0013] Step 1-1: After simplifying the two-dimensional CAD drawings of the short-stress rolling mill roll system through modeling, perform geometric modeling in three-dimensional modeling software (Solidworks);

[0014] Steps 1-2 involve importing the acquired geometric model into engineering simulation software for assembly to obtain the engineering model.

[0015] Steps 1-3: Based on the Johnson-Cook constitutive model, set the parameters of the corresponding engineering model in the engineering simulation software.

[0016] Furthermore, in steps 1-2, components of the roll that did not participate in rolling contact in the original geometric modeling were deleted and replaced with two rigid plates bound to the shaft body. Components that do not participate in rolling contact include the journal and the shaft head.

[0017] Furthermore, Abaqus software was used for engineering simulation, and Solidworks software was used for 3D modeling.

[0018] Furthermore, in step 2, the formula for calculating the stress and strain of the material affected by temperature using the Johnson-Cook constitutive model is as follows:

[0019]

[0020] in, For equivalent flow stress, For the reference strain rate and the reference temperature, the yield stress is... The strain hardening modulus of the material. For strain rate strengthening parameters, For plastic strain, The heat softening index, For effective strain rate, The material hardening index. This refers to relative temperature.

[0021] Furthermore, step 2 specifically includes the following steps:

[0022] Step 2-1: Set the boundary conditions and loads for the rolling process according to the actual production situation of the factory;

[0023] Specifically, the rolling speed is set to 13 m / s, the rolling temperature is set to 1050℃, and the reduction is set to 35 mm; the rolls are constrained and fixed so that they can only rotate around the Z-axis; frictional contact is added between the rolls and the workpiece and the friction coefficient is set to 0.3, while heat exchange is established between the rolls and the workpiece, and between the workpiece and the air.

[0024] Step 2-2: The entire engineering model is meshed using hexahedral elements. The surface of the roll is then refined using a temperature-displacement coupling mesh type.

[0025] Furthermore, the formula for the rolling force in step 3 is as follows:

[0026] (1)

[0027] (2)

[0028] (3)

[0029] (4)

[0030] (5)

[0031] (6)

[0032] (7)

[0033] (8)

[0034] In the formula, This refers to the average contact area between the rolls and the workpiece during the rolling process. This is the external friction stress state coefficient; For deformation resistance; The flattening radius of the roll; , These are the rolling parameters; The Poisson's ratio of the rolls; Young's modulus of the roll; This is the amount of pressure applied; The reduction rate; , For compression ratio, T is the dimensionless deformation temperature parameter; ε is the true strain. For strain rate, The thickness at the entry point of the rolled piece. The thickness at the exit of the rolled piece. The radius of the roll is denoted as .

[0035] Further, in step 4, the difference value after comparison is compared with the preset allowable error. If it is less than the allowable error, it is determined that the simulation structure calculated in the current simulation is accurate; otherwise, step 2 is executed.

[0036] This invention employs the above technical solution, requiring only a model of the contact area between the roll and the workpiece, eliminating the need for overall roll simulation analysis. It utilizes the Johnson-Cook constitutive model to simulate the stress and strain of the workpiece, making the simulation results more consistent with reality. The simulated contact area between the roll and the workpiece replaces the workpiece width and contact arc length parameters in the original formula, making the formula equally applicable to the rolling force calculation of hot-rolled bars, while also reducing the computational workload of determining parameters. The simulation results present a dynamic load history. The results, visualized through simulation software, provide designers with a more intuitive view of the stress and deformation of the workpiece during the rolling process. This can provide excellent guidance for the design phase of other types of rolling mills, shortening the development cycle, saving costs, avoiding waste of human and material resources, and improving the market competitiveness of enterprises. Attached Figure Description

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments;

[0038] Figure 1 This is a flowchart illustrating a method for calculating rolling force in a short-stress rolling mill based on thermo-mechanical coupling simulation according to the present invention.

[0039] Figure 2 This is a schematic diagram of the short-stress rolling mill structure of the present invention;

[0040] Figure 3 A simplified structural diagram of the rolling mill roll system;

[0041] Figure 4 A schematic diagram showing the setting of rolling load;

[0042] Figure 5 Set up a schematic diagram for boundary conditions;

[0043] Figure 6 This is a schematic diagram of the mesh refinement on the surface of the roll;

[0044] Figure 7 A schematic diagram of the overall grid division of the rolling mill roll system;

[0045] Figure 8 A cloud map showing the temperature changes at the nodes;

[0046] Figure 9 This is a diagram showing the rolling force history.

[0047] Figure 10 This is a schematic diagram illustrating the process of the contact area between the workpiece and the roll. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0049] This invention primarily focuses on the calculation of rolling force during short-stress rolling mill operations. The main objective is to fill the market gap in calculating rolling force for hot-rolled bars using short-stress rolling mills. Secondly, current rolling force calculations present challenges in dynamic modeling and solution due to the complexity of the model structure and the numerous material property parameters involved. This invention introduces the Johnson-Cook constitutive model to simulate the plastic deformation of materials during hot rolling. Thirdly, referencing the Sims hot rolling formula and combining it with the contact area between the workpiece and rolls calculated using simulation software, the rolling force is calculated after certain modifications to the formula.

[0050] like Figures 1 to 10 As shown in one example, this invention discloses a method for calculating the rolling force of a short-stress rolling mill based on thermo-solid coupling simulation, which includes the following steps:

[0051] Step 1: Simplify the existing short-stress rolling mill model and import it into the engineering simulation software to obtain the engineering model;

[0052] Furthermore, step 1 specifically includes the following steps:

[0053] Step 1-1: After simplifying the two-dimensional CAD drawings of the short-stress rolling mill roll system through modeling, perform geometric modeling in the three-dimensional modeling software (Solidworks);

[0054] Steps 1-2: Import the acquired geometric model into engineering simulation software for assembly to obtain the engineering model;

[0055] Steps 1-3: Based on the Johnson-Cook constitutive model, set the parameters of the corresponding engineering model in the engineering simulation software.

[0056] Furthermore, the engineering simulation software used is Abaqus.

[0057] Step 2: Explicit dynamic analysis of the rolling process is performed using engineering simulation software (Abaqus / explicit); the stress-strain of the rolled piece is simulated using the Johnson-Cook constitutive model to calculate a new plastic deformation curve.

[0058] Furthermore, step 2 specifically includes the following steps:

[0059] Step 2-1: Set the boundary conditions and loads for the rolling process according to the actual production situation of the factory;

[0060] Step 2-2: The entire engineering model is meshed using hexahedral elements. The surface of the roll is then refined using a temperature-displacement coupling mesh type.

[0061] Step 3: Adjust the Sims hot rolling formula based on the contact area between the rolling roller and the workpiece in the simulation results, and calculate the rolling force load.

[0062] Step 4: Compare the average rolling force obtained from the simulation with the rolling force obtained from the theoretical calculation to verify the accuracy of the simulation results.

[0063] The specific principles of this invention will be explained in detail below:

[0064] like Figure 2 As shown, a short-stress rolling mill is a large-scale piece of equipment specifically designed for metal rolling, consisting of a mill support 1, a mill roll system 2, and a mill roll gap adjustment device 3. Due to its high rigidity, high precision, and ability to quickly adjust the roll gap, it is now widely used in industries such as construction, automobile manufacturing, and machinery manufacturing. Rolling force is the most important mechanical property parameter in the hot-rolled steel production process. Accurately obtaining the rolling force of the mill is crucial for improving the dimensional accuracy of the rolled product, reducing form and position errors, optimizing load distribution, and ensuring equipment safety. This invention is based on explicit dynamics and uses Abaqus numerical simulation software to calculate the rolling process of a short-stress rolling mill.

[0065] This invention provides a method for calculating the rolling force of a short-stress rolling mill based on thermo-mechanical coupling simulation. The specific operation steps are as follows:

[0066] Step 1, as follows Figure 3As shown, based on the two-dimensional CAD drawings of the short-stress rolling mill roll system, the model was simplified and then geometrically modeled in the three-dimensional modeling software Solidworks. The geometric model was then imported into Abaqus for assembly. In the original model, components that do not participate in rolling contact, such as the journal and head of the roll, were deleted and replaced with two rigid plates that were bound to the shaft body.

[0067] Considering the influence of temperature on the plasticity of the rolled piece during hot rolling in a short-stress mill, the Johnson-Cook constitutive model is introduced, with parameters shown in Table 1, to calculate a new plastic deformation curve. These parameters are then input into the Abaqus software.

[0068] Table 1. Q235 Johnson-Cook Constitutive Model

[0069]

[0070] Step 2: Set the analysis step type to display dynamics, temperature-displacement coupled unit, and time length to 0.35.

[0071] Furthermore, in step 2, the formula for calculating the stress and strain of the material affected by temperature using the Johnson-Cook constitutive model is as follows:

[0072]

[0073] in, For equivalent flow stress, For the reference strain rate and the reference temperature, the yield stress is... The strain hardening modulus of the material. For strain rate strengthening parameters, For plastic strain, The thermal softening index, For effective strain rate, The material hardening index. This refers to relative temperature.

[0074] like Figure 4 and 5 As shown, the boundary conditions and load settings are based on the actual production conditions of the factory. The rolling speed is set to 13 m / s, the rolling temperature to 1050℃, and the reduction to 35 mm. The rolls need to be constrained, fixing them so that they can only rotate around the Z-axis. Frictional contact needs to be added between the rolls and the workpiece, with the friction coefficient set to 0.3. Simultaneously, heat exchange between the rolls and the workpiece, and between the workpiece and the air, needs to be established.

[0075] like Figure 6 and 7As shown, mesh generation was performed. Hot rolling simulation involves the plastic deformation of materials at high temperatures, as well as heat conduction between the workpiece and the rolls, and between the workpiece and the air. With numerous parameters and complex calculations, hexahedral elements were used for the entire model, and the surface of the rolls was further refined. Temperature-displacement coupling was selected as the mesh type. After meshing, the total number of nodes was 98,144, and the total number of elements was 81,178.

[0076] Step 3: Calculate the theoretically required rolling force. The rolling force formula used in this invention is shown below.

[0077] (1)

[0078] (2)

[0079] (3)

[0080] (4)

[0081] (5)

[0082] (6)

[0083] (7)

[0084] (8)

[0085] In the formula, This refers to the average contact area between the rolls and the workpiece during the rolling process. This is the external friction stress state coefficient; For deformation resistance; The flattening radius of the roll; , These are the rolling parameters; The Poisson's ratio of the rolls; Young's modulus of the roll; This is the amount of pressure applied; The reduction rate; , For compression ratio, T is the dimensionless deformation temperature parameter; ε is the true strain. For strain rate, The thickness at the entry point of the rolled piece. The thickness at the exit of the rolled piece. The radius of the roll is denoted as .

[0086] Step 4: The theoretically calculated rolling force of 1181519.947 N has an error of only 1.83% compared to the average rolling force of 1159793 N calculated by simulation, verifying the accuracy of the simulation result. Table 2 shows some of the rolling force results obtained from the simulation.

[0087] Table 2 Partial Rolling Force Data

[0088] Time / s Rolling force / N 0.017507602 1427669 0.035002131 1474514.25 0.066510186 1075857.375 0.105000235 975934.0625 0.152263701 1260101.875 0.182000071 1169766.875 0.210010365 1135170.125 0.239759877 1125657.375 0.262511104 816402.5625 0.294006497 1395835.875 0.301007092 890674

[0089] The hot rolling process was simulated to obtain the temperature change contour maps of the workpiece and rolls, the rolling force change history map over time, and the change in the contact area between the workpiece and rolls during the rolling process, as shown below. Figure 8 , Figure 9 and Figure 10 As shown.

[0090] This invention employs the above technical solution, requiring only a model of the contact area between the roll and the workpiece, eliminating the need for overall roll simulation analysis. It utilizes the Johnson-Cook constitutive model to simulate the stress and strain of the workpiece, making the simulation results more consistent with reality. The simulated contact area between the roll and the workpiece replaces the workpiece width and contact arc length parameters in the original formula, making the formula equally applicable to the rolling force calculation of hot-rolled bars, while also reducing the computational workload of determining parameters. The simulation results present a dynamic load history. The results, visualized through simulation software, provide designers with a more intuitive view of the stress and deformation of the workpiece during the rolling process. This can provide excellent guidance for the design phase of other types of rolling mills, shortening the development cycle, saving costs, avoiding waste of human and material resources, and improving the market competitiveness of enterprises.

[0091] Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Without conflict, the embodiments and features in the embodiments of this application can be combined with each other. The components of the embodiments of this application described and illustrated herein can generally be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for calculating rolling force of a short stress rolling mill based on thermal-elastic coupling simulation, characterized in that: It comprises the following steps: Step 1, the existing short stress rolling mill model is simplified and introduced into engineering simulation software to obtain an engineering model; step 1 specifically comprises the following steps: Step 1-1, after the two-dimensional CAD drawing of the short stress rolling mill roll system is simplified, geometric modeling is carried out in three-dimensional modeling software; Step 1-2, the obtained geometric modeling is imported into the engineering simulation software for assembly to obtain an engineering model; the components in the original geometric modeling that do not participate in the rolling contact are deleted, and two rigid sheets are used to replace the shaft body for binding connection; the components that do not participate in the rolling contact include the shaft neck and the shaft head part; Step 1-3, based on the Johnson-Cook constitutive model, the parameters of the corresponding engineering model are set in the engineering simulation software; Step 2, dynamic analysis of the rolling process is carried out by using the explicit dynamics of the engineering simulation software to obtain simulation results; the Johnson-Cook constitutive model is used to simulate the stress and strain of the rolled piece to calculate a new plastic deformation curve; Step 3, the Sims hot rolling formula is adjusted in combination with the contact area between the rolling ring and the rolled piece in the simulation results to calculate the rolling force load; in step 3, the rolling force formula is as follows: (1) (2) (3) (4) (5) (6) (7) (8) wherein is the average contact area between the roll and the rolled piece during rolling; is the coefficient of the external friction stress state; is the deformation resistance; is the flattening radius of the roll; , is the rolling parameter; is the Poisson's ratio of the roll; is the Young's modulus of the roll; is the reduction; is the reduction rate; , is the reduction rate related parameter; T is the dimensionless deformation temperature parameter; e is the true strain; is the strain rate, is the thickness of the rolled piece at the inlet, is the thickness of the rolled piece at the outlet, is the radius of the roll; Step 4, the average rolling force obtained by simulation is compared with the rolling force obtained by theoretical calculation to verify the accuracy of the simulation results.

2. The short stress mill rolling force calculation method based on thermal coupling simulation according to claim 1, characterized in that: The engineering simulation software uses Abaqus software; the three-dimensional modeling software uses Solidworks software.

3. The short stress mill rolling force calculation method based on thermal coupling simulation according to claim 1, characterized in that: In step 2, the stress and strain of the material affected by temperature are calculated by using the Johnson-Cook constitutive model, and the calculation formula is as follows: wherein, is the equivalent flow stress, is the yield stress at the reference strain rate and reference temperature, is the material strain hardening modulus, is the strain rate hardening parameter, is the plastic strain, is the thermal softening index, is the effective strain rate, is the material hardening index, is the relative temperature.

4. The short stress mill rolling force calculation method based on thermal coupling simulation according to claim 1, characterized in that: Step 2 comprises the following steps: Step 2-1, according to the actual production situation of the factory, the boundary conditions and load of the rolling process are set; Step 2-2, hexahedral elements are used for meshing for the entire engineering model, and the surface of the roll is subjected to mesh refinement treatment, and the temperature displacement coupling is selected for the mesh type.

5. The method for calculating rolling force of a short stress rolling mill based on thermal coupling simulation according to claim 1, characterized in that: In step 4, the difference value after comparison is compared with the pre-set allowable error, when it is less than the allowable error, it is judged that the simulation structure of the current simulation calculation is accurate; otherwise, step 2 is executed.

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