Metal flowing and hole pattern research method based on hinge section steel rolling process

Abstract

The invention relates to the technical field of metal processing, in particular to a metal flowing and hole pattern research method based on a hinge section steel rolling process, finished products manufactured by a hinge section steel rolling process are named according to K14, K3, K2 and K1 and are modeled one by one, and the method comprises the following steps: S1, entering ABAQUS, and creating a geometric model by using a part module; according to the metal flow and pass research method based on the hinge profile steel rolling process, the rotating speed of a motor is 600 r. Min <-1 >, the pass deflection angle is 1.61 degrees, the roller diameter is configured to keep the radius of a lower roller unchanged, the radius of an upper roller is increased by 11.2 mm, the parameters are substituted into a finite element model, and the pass filling degree obtained through calculation is 100.23%; in the rolling process of the new technology, metal flows more regularly, and deformation is more uniform.

Description

Technical Field

[0001] The present invention relates to the technical field of metal processing, and specifically to a research method for metal flow and pass during the rolling process of hinge-shaped steel. Background Art

[0002] The finished hinge-shaped steel is a load-bearing part used for automobile connection, and has high requirements for dimensional accuracy and surface quality. The dimensional accuracy of the rolled piece in the final pass directly affects the mechanical properties and service life of the product. Ensuring that the rolled piece is slightly overfilled in the final pass not only reduces the material consumption in the subsequent finishing process and improves production efficiency, but also reduces the problems of surface defects of the shaped steel and poor cross-sectional dimension stability caused by small pass filling degree, thereby improving the strength and service life of the rolled piece. Therefore, studying the metal flow and pass filling law during the forming process of hinge-shaped steel has important engineering value for controlling product quality.

[0003] During the forming process of the finished hinge-shaped steel, the most perfect state is, of course, that the rolled piece just fills the pass (i.e., the pass filling degree is exactly 100%). Such a rolled piece can save a lot of post-treatment processes. However, due to different rolling process parameters during the rolling process, problems such as large "ears" and unfilled passes may occur at the roll gap. When small ears appear on the rolled piece (i.e., the pass filling degree is 100% - 108%), the ears can be effectively removed by a special hinge-shaped steel ear planing machine, and then the next finishing process can be carried out. The metal consumption is less and the production efficiency is higher. When large ears appear on the rolled piece (i.e., the pass filling degree exceeds 108%), the metal consumption is large when correcting the size of the rolled piece, and microcracks or burrs are likely to remain at the root of the flash, becoming stress concentration points and reducing the fatigue life. And unfilled passes after rolling will cause local dimensional deviations of the rolled piece, unable to meet the requirements of precision assembly and unable to repair the rolled piece through subsequent processes, resulting in scrap and other problems. Therefore, it is necessary to study the influencing factors and laws of pass filling of hinge-shaped steel in the final pass. Summary of the Invention

[0004] The purpose of the present invention is to provide a research method for metal flow and pass during the rolling process of hinge-shaped steel, so as to solve the problems mentioned in the above background art that the metal consumption is large when correcting the size of the rolled piece, and microcracks or burrs are likely to remain at the root of the flash, becoming stress concentration points and reducing the fatigue life. And unfilled passes after rolling will cause local dimensional deviations of the rolled piece, unable to meet the requirements of precision assembly and unable to repair the rolled piece through subsequent processes, resulting in scrap. To achieve the above purpose, the present invention provides the following technical solution: A research method for metal flow and pass during the rolling process of hinge-shaped steel, naming the finished products made by the hinge-shaped steel rolling process as K14... K3, K2, K1 one by one, and modeling them one by one, including the following steps:

[0005] S1: Enter ABAQUS and use the part module to create a geometric model;

[0006] S3: Use the Property module to define material properties;

[0007] S6: Use the Assembly module to assemble the model;

[0008] S9: In the Interaction module, define contact and friction;

[0009] S12: In the mesh module, mesh the rolled piece;

[0010] S15: In the step module, create a Dynamic, Explicit analysis step and set the time length of the analysis step;

[0011] S18: In the Load module, define boundary conditions and loads;

[0012] S21: In the Job module, create a job and submit it;

[0013] S24: In the Visualization module, open the calculation result file to view the stress, strain distribution and deformation of the section steel.

[0014] Specifically for S1, a CAD-ABAQUS collaborative solution is adopted: First, edit the roll assembly drawing in CAD software, convert it to an ABAQUS-compatible format and import it into the sketch module. Then, obtain a three-dimensional roll model by rotation in the PART module. The modeling of the guide device adopts a simplified processing strategy, and its cross-sectional shape is consistent with the roll pass. Select a deformable body, and the part shape is selected as a shell. Couple it as a rigid body in the contact module. The diameter of the rolled piece is 140 mm, and a cylindrical structure is used to simplify the model. To ensure sufficient time for the stable rolling stage of the rolled piece and consider the calculation efficiency, the length of the rolled piece is set to 1000 mm, which is a deformable body. After completing the modeling of each part, assemble it according to the technical requirements of the factory roll assembly.

[0015] Specifically for S2, when setting the basic material parameters, establish a material model and unify the units. The modeling uses units of mm. Define the material as isotropic through ABAQUS, and only assign material properties to steel. The hinge steel selected is Q355D steel, and only establish the material properties of Q355D, and select the true stress-strain curve of Q355D.

[0016] Specifically, S4 is to set contacts in the ABAQUS interaction module. The surfaces of the hinge-shaped steel, the rolled piece, and the guide and guard device and the rolled piece are all in surface contact. In the ABAQUS interaction module, it is set as surface-to-surface contact. The rolled piece is selected as the slave surface, and the roll and the guide and guard device are selected as the master surface. The setting of the contact properties includes normal behavior and tangential behavior. The normal behavior is configured as hard contact, and the tangential behavior selects penalty contact. Coulomb friction is used to calculate the friction, and the value of the friction coefficient is a fixed value. The friction coefficient between the roll and the rolled piece during rough rolling is taken as 0.5, and 0.4 during finish rolling. The friction between the rolled piece and the guide and guard is not considered.

[0017] Specifically, S5 is to select linear reduced hexahedron elements. The elements of the hinge-shaped steel are C3D8RT, and they are divided to refine the local mesh.

[0018] Specifically, S6 is to divide the rolling process of each pass into a transfer stage and a rolling stage, and determine the time length of each analysis step by referring to the transfer speed and rolling speed in actual production. In the setting interface of the analysis step, configure the mass scaling parameter, and the maximum value of the mass scaling coefficient is set to 50.

[0019] The geometric model is established in passes. The ODB result data of the previous analysis process of the rolled piece is given to the new model as the initial state by the Initialstate command in the predefined field, so as to continue the subsequent analysis. The Initialstate command requires that the assembly instance is consistent with the original analysis step, and the material parameters and mesh size of the rolled piece remain unchanged.

[0020] Specifically, S7 is that during the rolling production process, the main motion of the roll is rotational motion, while the rolled piece moves through the transfer device until it is captured by the roll. The guide and guard plate remains stationary throughout the process. Since each component has six degrees of freedom, for the roll, only its rotation around its own central axis is allowed, and the rotation direction is determined according to the rolling direction, and the rotation speed calculated from the actual rolling speed is given to the corresponding rotational degree of freedom, and the remaining degrees of freedom are all restricted to zero. The position of the guide and guard plate is fixed, and the displacements in all directions are constrained to zero. The initial temperature of the rolled piece is set to 1200 °C, the ambient temperature is set to 30 °C, and the plastic work heat generation coefficient is set in the inelastic heat fraction in the material properties, taking 0.9.

[0021] The raw material is round steel with a diameter of 140 mm. After being heated in a heating furnace to 1200°C ± 50°C, it is descaled by high-pressure water at 25 MPa and then enters the blooming mill for 7 passes of rolling. After preliminary deformation, the head and tail are cut by a hot saw, and then it enters the roughing mill for 3 passes of rolling. Subsequently, the rolled piece passes through the 1#, 2#, and 3# short-stress finishing mills in sequence, with one pass of rolling on each mill. After being descaled by high-pressure water again, it enters the 4# finishing mill. Finally, the finished product is made after 14 passes of rolling and is transferred to the air-cooling zone. The finished products made after 14 passes of rolling are named according to K14...K3, K2, K1.

[0022] The angular velocities of the rolling rolls for each pass are as follows:

[0023]

[0024] During the rolling process, the heat convection phenomenon of the rolled piece mainly manifests in two forms: natural convection in the air and forced convection under the condition of high-pressure water descaling. These heat convection phenomena can be described by Newton's cooling law, where the heat convection flux can be expressed as:

[0025] Q s =h(T s -T ∞ )

[0026] In the formula, Q s —— Heat convection flux

[0027] h—— Convective heat transfer coefficient. The natural convection coefficient of air is taken as 0.05 mW·mm-2·°C, and the forced convection coefficient of descaling water is taken as 1.3 mW·mm-2·°C.

[0028] The radiative heat transfer of the rolled piece is mainly the heat dissipation of the rolled piece at high temperature. The problem of heat radiation generally follows the s-p law. In the finite element software, it is necessary to define absolute zero to calculate heat radiation. The heat radiation flux can be expressed as:

[0029]

[0030] In the formula, Qt—— Heat radiation flux

[0031] T s —— Surface temperature of the rolled piece

[0032] ε—— Emissivity, generally taken as 0.6

[0033] δ—— Boltzmann constant, taken as 5.67×10-¹¹ mW·mm-2·K-4

[0034] T ∞ —— Ambient temperature, taken as 30°C

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] In the present invention, the optimal process parameter combination is calculated: the motor speed is 600 r·min-1, the hole deflection angle is 1.61°, the roller diameter is configured to keep the lower roller radius unchanged, and the upper roller radius is increased by 11.2 mm. Substituting the above parameters into the finite element model, the hole filling degree is calculated to be 100.23%. During the rolling process of the new process, the metal flow is more regular and the deformation is more uniform.

[0037] In the present invention, the calculation results of each process link can be independently verified and debugged. When a problem is found, only local model correction and recalculation are required, which saves time in adjusting the model. Secondly, the spatial position adjustment of the rolled piece is realized through the assembly coordinate system transformation technology, which restores the entire rolling process to the greatest extent. The data obtained is closer to actual production. When establishing the model, the model is established in stages. Each model only calculates one rolling process, and then a new roller model for the next stage is created. The rolled piece refers to the data after deformation of the previous stage to ensure data inheritance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Establish a basic flow chart for the model of the present invention;

[0039] Figure 2 (a) Grid division of the guide device; (b) Schematic diagram of grid division of the rolled product;

[0040] Figure 3 Schematic diagram of analysis steps and mass scaling of the present invention;

[0041] Figure 4 The contact arrangement between the guide and the rolled piece of the present invention;

[0042] Figure 5 A predefined field setting diagram for the present invention;

[0043] Figure 6 Schematic diagram of the roller motion boundary conditions of the present invention;

[0044] Figure 7 This is a schematic diagram of the cross-sectional dimensions of the finished product of the present invention;

[0045] Figure 8 This is the cross-sectional extraction diagram of the finished product of the present invention;

[0046] Figure 9 Extraction code diagram for part of the rolled piece cross section of the present invention;

[0047] Figure 10 This is a schematic cross-sectional view of a K3 pass rolled piece according to the present invention;

[0048] Figure 11 This is a schematic diagram of some hole fillings of the present invention;

[0049] Figure 12 Schematic diagram of (a) displacement of the rolled piece in the X direction and (b) displacement of the rolled piece in the Y direction according to the present invention;

[0050] Figure 13 Curve graph of (a) displacement of the characteristic point on the rolled piece in the X direction and (b) displacement of the characteristic point on the rolled piece in the Y direction according to the present invention;

[0051] Figure 14 Pass filling diagram according to the present invention. Detailed implementation manners

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0053] Tools and samples used in the specific implementation

[0054] The hinge-shaped steel samples are from the products actually rolled in the factory;

[0055] The temperature measuring device is an IT-8H2 high-precision infrared thermometer. The test range of this instrument is 300 - 1500 °C, and the measurement accuracy is ±1% FS. The specific parameters are as follows:

[0056]

[0057] Example 1

[0058] During factory production, an IT-8H2 high-precision infrared thermometer is used to measure the surface temperature of the rolled piece at the outlet of each pass of the hinge-shaped steel rolling mill. The measured data is compared with the finite element simulation results: during box pass rolling, the temperature measuring point is located at the middle position of the upper surface of the rolled piece; during special-shaped pass rolling, the temperature measuring point is selected at the center position of the upper surface of the thicker area of the rolled piece. As shown in the following table, the relative error range is 0.51% - 2.04%. The results show that the setting of the thermal boundary conditions has high accuracy and is relatively in line with the actual situation.

[0059] Comparison table of the measured results and simulation results of the surface temperature of the rolled piece at the outlet of each pass of the rolling mill

[0060]

[0061]

[0062] To verify the accuracy of the finite element model in simulating the deformation process of hinge-shaped steel, a series of characteristic points were selected on the cross-section of the finished product obtained from the experiment. The selected points were all in the area on the contour that was not restricted by the pass. The selection of the characteristic points and the measurement method of the geometric dimensions of the cross-section of the finished product are as follows Figure 7 shown. Characteristic points 1, 2, 3, and 4 in this area were selected, and two reference line segments were formed by connecting 1 and 4, and 2 and 3 respectively. The lengths of line segments 14 and 23 were measured, and the widths of the left edge line A at characteristic points 1, 2, 3, and 4 were obtained and compared with the measured values. In addition, the contour map of the cross-section of the finished product was extracted through the post-processing module of the finite element simulation ( Figure 8 ), and the characteristic points corresponding to the experimental measurement were located in the figure to ensure that the height parameters from the characteristic points to the bottom edge line B were consistent in the two sets of data, and a systematic comparison was made with the experimental measurement results. The following table details the absolute error and relative error of each parameter. The analysis results show that the relative error is between 0.7% and 4.4%. The numerical simulation results are in good agreement with the experimental measurement data, verifying the reliability of the established model.

[0063] Table of relative errors between the measured and simulated results of the finished product dimensions

[0064]

[0065] The surface temperature of the rolled piece was measured using a high-precision infrared thermometer and compared with the simulated temperature. The error between the calculated result and the simulated result was between 0.51% and 2.04%. The cross-section dimensions of the rolled piece in the simulation were measured and compared with the actual dimensions, and the error was between 0.7% and 4.4%. This verified the accuracy and reliability of the rolling finite element model.

[0066] Example 2

[0067] To study the metal flow of the finished hinge-shaped steel, it is necessary to extract the cross-sectional shape of the finished rolled piece. However, since the hinge-shaped steel will produce bending deformation during the rolling process, the cross-sectional shape of the rolled piece has both concave and convex contours at the same time. Therefore, it is impossible to directly extract the cross-sectional shape of the rolled piece after rolling in the ABAQUS post-processing module. It is necessary to first extract the coordinates corresponding to the cross-sectional elements through the post-processing function, and then obtain the set of contours by writing a convex hull detection program. However, the convex hull check cannot identify concave and convex polygons at the same time, so it is also necessary to write code for identifying the minimum closed area to ensure that the cross-sectional contours of the rolled piece with complex shapes can also be extracted. Part of the data extraction code is as follows Figure 9 shown.

[0068] After extracting the cross-sectional contour of the rolled piece, the data was imported into AUTOCAD to draw the cross-sectional diagram. Figure 10 The cross-sectional diagram obtained after the rolling of the rolled piece in the K3 pass was completed.

[0069] Pass filling degree table for each pass

[0070]

[0071]

[0072] As Figure 11 shown, it shows the typical pass filling deformation diagram during the rolling process. Combining the content in the pass filling degree table for each pass, among the first 7 passes of rough rolling in the box pass, the pass with the lowest filling degree is pass K14, with a filling degree of about 85.91%. This is because pass K14 is the first pass of rolling. At this time, the round steel just enters the box pass for rolling, and the reduction amount of the rolled piece gradually decreases from the middle to both sides along the width direction, and the overall reduction amount is smaller. Therefore, the pass filling degree is lower. And the reduction amount of pass K8 is the largest among the rough rolling passes, so the pass filling degree is also the highest, reaching 98.89%. When rough rolling and finish rolling are carried out in the special-shaped pass, the relative filling degree of pass K7 is relatively low, only 85.59%. This phenomenon is due to the fact that the rolled piece just enters the special-shaped pass from the box pass for rolling at this time, and the uneven deformation generated is relatively large, resulting in a flow velocity difference between metals. The areas with slow metal flow velocity and the areas with fast flow velocity pull each other, resulting in insufficient elongation of the rolled piece in the width direction and insufficient pass filling. The uneven deformation of pass K7 is larger than that of the subsequent special-shaped pass rolling passes. Therefore, the pass filling degrees of the subsequent passes are relatively high, all above 90%. To ensure that the geometric dimensions of the finished section of the section steel meet the size requirements and accuracy requirements after finishing and post-treatment, it is necessary for the rolled piece to be slightly overfilled in the finishing pass, with a pass filling degree of 102.15%. Generally speaking, the pass filling situation is good, which can ensure the smooth completion of rolling production.

[0073] Example 3

[0074] Figure 13 Clearly shows the displacement vector during the rolling of the finishing pass of the hinge section steel. The thickness and length of the arrow represent the displacement magnitude. As can be seen from Figure 12 (a), in the X direction, the metal displacement direction in the left area B of the rolled piece cross-section is downward, and the metal displacement direction in the right area A is opposite to that in area B, and the downward displacement amount is less than the upward displacement amount; as can be seen from Figure 12 (b), in the Y direction, the metal in the lower half area D of the rolled piece cross-section generally flows to the right, and the metal in the upper half area C of the rolled piece cross-section flows to the left, and the rightward displacement amount is less than the leftward displacement amount. This is affected by the thickness of the rolled piece. The thicker the rolled piece, the more difficult it is for the temperature to be transferred to the surface, the lower the surface temperature, the lower the deformation resistance of the metal, and the easier it is for the material to deform. As Figure 14As shown in the figure, in order to more clearly analyze the flow law of the steel metal in each key position in the finished pass, 6 feature points are selected in the cross section of the finished pass, and the displacement of the key points in the X direction and Y direction are extracted respectively. Figure 14 It can be seen that at point P1, the center of the workpiece, metal flows almost non-existently, or in other words, there is very little displacement. The displacement curve at point P2 shows that the workpiece's displacement at the fillet is minimal along the X-axis, while displacement along the Y-axis increases significantly. This phenomenon is consistent with the theory of non-uniform deformation. Metal flow in the X-axis is restricted, while flow in the Y-axis is accelerated. Under the action of the rollers, the thickness of the workpiece begins to decrease on both sides, and excess metal begins to flow in the rolling direction and at the fillet, ultimately causing the sides of the workpiece to overflow the die, affecting die filling.

[0075] During rolling, the pass deformation was well filled, with most passes exceeding 90%. The finished pass exhibited slight overfill, reaching a pass fill of 102%. This helped ensure that the cross-sectional geometry met precision requirements after finishing. Metal flow patterns were primarily related to the deformation and stress of the workpiece. During the finishing phase, the workpiece showed minimal change. The thickness of the finished pass on both sides of the roll began to decrease, and excess metal began to flow toward the rolling direction and fillets, ultimately affecting the pass fill.

[0076] Example 4

[0077] In order to obtain the combination of rolling process parameters that effectively controls the pass filling of hinge steel, that is, controls the pass filling degree to 100%, a regression equation can be established between the significant influencing factors and the pass filling degree of the finished steel. Considering the interaction between rolling parameters, a binary quadratic polynomial regression model is established. The regression model is as follows:

[0078] Y=β0+β1X1+β2X2+β3X3+β 12 X1X2+β 13 X1X3+β 23 X2X3

[0079] +β 11 X1 2 +β 22 X2 2 +β 33 X3 2 +ε

[0080] Where: β0——constant;

[0081] β i ——various regression coefficients;

[0082] β ii ——The constant term of the interaction between two factors;

[0083] Y——Porosity filling degree (%)

[0084] X i ——Coefficient of linear term (1 represents motor speed, 2 represents pass deflection angle, 3 represents roll diameter configuration);

[0085] X i X i ——Coefficient of two-factor interaction term;

[0086] ε——Random error term

[0087] Not all terms corresponding to variables in a regression model have a significant impact. Normalize the independent variables within the range of 0 to 1, and use SPSS data analysis software for stepwise regression analysis to eliminate the terms with insignificant effects. Input variables X i and X i X i variables and the independent variable Y for analysis, and obtain the following regression analysis table:

[0088] Linear regression results

[0089]

[0090]

[0091] The relationship between different rolling parameters and the porosity filling degree Y can be obtained, and the regression equation is shown as follows:

[0092] Y = 90.234 + 15.362X1 + 2.127X1X2 - 0.672X1X3 + 0.782X2X3 + 0.003X1 2 - 0.335X2 2 + 2.150X3 2

[0093] In the linear regression result table, R2 is 0.952, indicating X1 2 、X2 2 、X3 2, X1X2, X1X3, X2X3, and X2X3 can explain 95.2% of the reasons for the change in the filling of the finished pass of hinge-shaped steel. The DW value is used to diagnose the independence of the error term in the regression model. A value close to 2 indicates that the residuals are independent of the independent variables. Use Excel to perform a Solver operation on the regression equation. With the independent variables ranging from 0 to 1, find the values of X1, X2, and X3 when the pass filling degree is closest to 100. The solution is X1 = 0.5, X2 = 0.23, and X3 = 0.8. That is, when the motor speed is 600 r.min-1, the pass deflection angle is 1.61°, and the roll diameter configuration is to keep the radius of the lower roll unchanged and increase the radius of the upper roll by 11.2 mm, the metal flow of the rolled piece can be effectively controlled to ensure that the pass is filled. Conduct another simulation experiment according to the optimal rolling process parameter combination. Figure 14 Figure 254 shows the pass filling diagram during the rolling process under the optimal rolling process combination. After calculation, its pass filling degree is 100.23%. The cross-sectional shape and dimensions all meet the production requirements. On this basis, adjust according to the influence of the above pass filling degree and the three process parameters to produce finished section steel rolled pieces with a pass filling degree exceeding 100%. Since the metal will undergo elastic recovery after unloading, resulting in a slight reduction in the size of the rolled piece, such rolled pieces can pre-compensate for this springback to ensure that the final product dimensions precisely meet the design requirements. The hinge-shaped steel product is an automotive parts product and is suitable for high-precision products such as automotive parts and aerospace structural parts to ensure dimensional stability during subsequent processing and use.

[0094] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A research method for metal flow and pass during the rolling process of hinge-shaped steel, characterized in that, Name the finished products made by the hinge-shaped steel rolling process as K14……K3, K2, K1, and model them one by one, including the following steps: S1: Enter ABAQUS and use the part module to create a geometric model; S2: Define material properties using the Property module; S3: Assemble the model using the Assembly module; S4: Define contact and friction in the Interaction module; S5: In the mesh module, mesh the rolled piece; S6: In the step module, create a Dynamic, Explicit analysis step and set the time length of the analysis step; S7: In the Load module, define boundary conditions and loads; S8: In the Job module, create a job and submit it; S9: In the Visualization module, open the calculation result file to view the stress, strain distribution and deformation of the section steel.

2. The research method for metal flow and pass design based on the hinge-shaped steel rolling process according to claim 1, wherein: Specifically, S1 adopts the CAD-ABAQUS collaborative scheme: First, edit the roll assembly drawing in CAD software, convert it to the ABAQUS-compatible format and import it into the sketch module. Then, obtain the three-dimensional roll model by rotation in the PART module. The modeling of the guide device adopts a simplified processing strategy, and its cross-sectional shape is consistent with the roll pass. Select the deformable body, and the part shape is selected as the shell. Couple it as a rigid body in the contact module. The diameter of the rolled piece is 140 mm, and a cylindrical structure is adopted to simplify the model. To ensure sufficient time for the stable rolling stage of the rolled piece while considering the calculation efficiency, the length of the rolled piece is set to 1000 mm, which is a deformable body. After completing the modeling of each part, assemble it according to the technical requirements of the factory roll assembly.

3. The research method for metal flow and pass design based on the hinge-shaped steel rolling process according to claim 1, characterized in that: Specifically, S2 is to establish a material model when setting the basic material parameters and unify the units. The modeling uses units of mm. Define the material as isotropic through ABAQUS, and only assign material properties to steel. The hinge steel selected is Q355D steel, and only establish the material properties of Q355D, and select the true stress-strain curve of Q355D.

4. The method for studying metal flow and pass design based on the hinge-shaped steel rolling process according to claim 1, wherein: Specifically, S4 is to set contact in the ABAQUS Interaction module. The surfaces of the hinge-shaped steel and the rolled piece, and the guide and the rolled piece are all in surface contact. Set it as surface-to-surface contact in the ABAQUS Interaction module. Select the rolled piece as the slave surface, and the roll and the guide device as the master surface. The setting of the contact properties includes normal behavior and tangential behavior. The normal behavior is configured as hard contact, and the tangential behavior selects penalty contact. Coulomb friction is used for friction calculation, and the value of the friction coefficient is a fixed value. The friction coefficient between the roll and the rolled piece during rough rolling is taken as 0.5, and 0.4 during finish rolling. The friction between the rolled piece and the guide is not considered.

5. The research method for metal flow and pass during the hinge-shaped steel rolling process according to claim 1, characterized in that: Specifically, S5 is to select the linear reduced hexahedron element. The element of the hinge-shaped steel is C3D8RT, and it is divided to refine the local mesh.

6. The research method for metal flow and pass during the hinge-shaped steel rolling process according to claim 1, wherein: Specifically, S6 divides the rolling process of each pass into a transfer stage and a rolling stage, determines the time length of each analysis step by referring to the transfer speed and rolling speed in actual production, and configures the mass scaling parameter in the analysis step setting interface, with the maximum mass scaling coefficient set to 50.

7. The research method for metal flow and pass design based on the hinge-shaped steel rolling process according to claim 1, wherein: The geometric model is established by pass. The ODB result data of the previous analysis process of the rolled piece is given to the new model as the initial state by the Initialstate command in the predefined field, so as to continue the subsequent analysis. The Initialstate command requires that the assembly instance be consistent with the original analysis step, and the material parameters and mesh size of the rolled piece remain unchanged.

8. The method for studying metal flow and pass during the hinge-shaped steel rolling process according to claim 1, characterized in that: Specifically, S7 is as follows: during the rolling production process, the main motion of the rolling mill roll is rotational motion, while the rolled piece moves through the transfer device until it is captured by the roll. The guide plate remains stationary throughout the process. Since each component has six degrees of freedom, for the roll, only rotation around its own central axis is allowed, and the rotation direction is determined according to the rolling direction, and the rotation speed calculated from the actual rolling speed is given to the corresponding rotational degree of freedom, and the remaining degrees of freedom are all restricted to zero. The position of the guide plate is fixed, and the displacements in all directions are constrained to zero. The initial temperature of the rolled piece is set to 1200 °C, the ambient temperature is set to 30 °C, and the plastic work heat generation coefficient is set in the inelastic heat fraction in the material properties, taking 0.9.

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