Cold rolling elasticoplastic deformation rolling force and forward slip prediction method based on mechanism-data

Abstract

The invention provides a cold rolling elasticoplastic deformation rolling force and forward slip prediction method based on mechanism-data, and relates to the technical field of metallurgical rolling, and the method comprises the following steps: S1, collecting actual production data of equipment, specifications and process parameters in cold continuous rolling production; s2, constructing a contact arc length mechanism model of each region of non-arc flattening of the roller; s3, a rolling pressure mechanism model of rolled piece elastoplastic deformation and roller non-arc flattening is constructed; s4, constructing a new forward sliding mechanism model based on the non-circular flattening curve of the roller; s5, correcting the medium-thickness ratio and the proportion of the front neutral region in the mechanism model through the industrial data in the step S1; and S6, the rolling force, forward sliding and the plate and strip outlet speed are calculated. According to the method, mechanism model parameters are continuously corrected by utilizing a cyclic traversal and iteration method through collected actual measurement data of technological parameters in the cold continuous rolling process, so that an accurate rolling pressure distribution curve is obtained, and the prediction precision of rolling force and forward slip is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical rolling, and in particular to a cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data. Background Art

[0002] As the production of cold-rolled plates and strips develops towards high strength and thinning, the problems of difficult rolling and difficult control become more prominent, leading to abnormal equipment operation status and degradation of product functional accuracy. The accuracy of the mathematical model in the control system of the cold rolling mill is the core factor to ensure the control of the rolling process, the setting of key parameters and the stable operation of the equipment. Among them, the rolling force and forward slip models are particularly critical. The calculation accuracy of the rolling force model directly affects the formulation of the rolling schedule, the adjustment of the reduction amount and the setting of the roll gap, which in turn affects the control accuracy of the plate thickness and plate shape; while the calculation accuracy of the forward slip model affects the speed and tension setting of each frame, which is related to the stability of the rolling process and the quality of the final product. Therefore, improving the calculation accuracy of the rolling force model and the forward slip model is crucial to the efficient and high-quality production of high-strength thin plates.

[0003] At present, the research methods of mathematical models for cold rolling mainly include mechanism prediction, data prediction and mechanism-data collaborative prediction. The mechanism prediction method usually simplifies the theoretical derivation process to a certain extent and introduces some assumptions, resulting in reduced model prediction accuracy. When the data is sufficient and of good quality, the data prediction method can improve the prediction accuracy, but this "black box" prediction process often lacks clear physical meaning and mathematical relationships, making it difficult to intuitively understand and explain the prediction results, resulting in limited application of the data prediction method in actual production. The mechanism-data collaborative prediction method uses industrial data to compensate and correct the mechanism prediction model, and can construct a prediction model that is both highly accurate and well interpretable.

[0004] Domestic researchers have done a lot of work on the rolling force and forward slip prediction model during the rolling process. The Chinese invention patent (publication number CN114722516A) discloses a mechanism prediction method for the rolling force and rolling torque in the cold rolling deformation zone. The rolling force model is established by considering the elastic-plastic deformation of the rolled piece. The rolling force and Hitchcock flattening radius are iteratively calculated to continuously optimize the calculation results until the iterative convergence accuracy is met. This method comprehensively considers the deformation behavior of the rolled piece and its influence on the rolling force. The Chinese invention patent (publication number CN112487700A) discloses a rolling force data prediction method based on neural network and genetic algorithm. With pre-processed production data as input, the fast non-dominated genetic sorting algorithm is used to optimize the neural network model parameters, and a rolling force network model is established, which improves the rolling force prediction accuracy during the specification change process. The Chinese invention patent (publication number CN117983661A) discloses a rolling force model update method driven by mechanism and data. This method takes into account the impact of the use of equipment such as rolling rollers on the rolling force, and by continuously comparing the deviation between the calculated rolling force and the actual rolling force, it self-learns and saves the new self-learning coefficients into the model. This method has both the accuracy of data-driven and the interpretability of mechanism analysis, which helps to improve the control accuracy and production efficiency of the rolling process. The Chinese invention patent (publication number CN112711867A) discloses a rolling force prediction method that combines a mechanism model with a data model. This method is based on the rolling force mechanism model, and the mechanism model is corrected and supplemented by the BP neural network data prediction model, thereby improving the prediction accuracy of the rolling force. In addition to data methods, methods based on mechanisms and mechanism-data collaboration have also been used in the study of forward slip models. A Chinese invention patent (publication number CN107433288B) discloses a rolling stability determination method based on forward slip, which modifies the Dresden forward slip formula and neutral angle, derives a new forward slip model that can calculate the "negative forward slip" phenomenon, and links forward slip with mill slip and vibration, establishes a mill stability determination relationship, and clarifies the quantitative relationship between forward slip and mill instability. A Chinese invention patent (publication number CN108655176A) discloses a mechanism-data driven forward slip calculation method, which introduces a forward slip compensation factor, obtains the adaptive coefficient of the current strip from the forward slip measured value and the model calculated value and uses it for subsequent steel coils, improving the setting accuracy of the roll speed of each stand.

[0005] Although the above patents have improved the calculation accuracy of the rolling force and forward slip models from multiple methods and angles, the non-circular flattening phenomenon of the roll caused by the elastic-plastic deformation of the rolled piece in cold rolling production and its influence on the rolling force and forward slip still need to be further studied. Moreover, with the development of newer materials, higher strength and thinner specifications of plate and strip products, the accuracy of the traditional rolling force model is low, and the forward slip correction model that can effectively predict "negative forward slip" has not yet been popularized, which seriously restricts the improvement of production efficiency and product quality. Therefore, based on the mechanism-data collaborative driving method, constructing a rolling force model and a forward slip model for the elastic-plastic deformation of the rolled piece and the non-circular flattening phenomenon of the roll is a new way to improve the model accuracy. Summary of the invention

[0006] The purpose of the present invention is to provide a cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data. On the basis of the rolling pressure and forward slip mechanism model of the elastic-plastic deformation of the rolled piece and the non-arc flattening of the roller, the measured data of the process parameters of the cold rolling process are collected, and the parameters of the mechanism model are continuously corrected by loop traversal and iteration methods to obtain an accurate rolling pressure distribution curve, thereby improving the prediction accuracy of the rolling force and forward slip.

[0007] Specifically, the present invention provides a cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data, which comprises the following steps:

[0008] S1. Collecting actual production data in cold rolling production;

[0009] S2, construct the contact arc length model of each zone of the non-circular arc flattening of the roller to calculate the distance x0 from the center line of the roller to the exit of the plastic zone before flattening, the distance x1 from the center line of the roller to the entrance of the plastic zone before flattening, the total contact arc length l of the plastic zone, the contact arc length Δx0 of the exit elastic recovery zone, and the contact arc length Δx1 of the entrance elastic compression zone;

[0010] S3. Construct a rolling pressure mechanism model of elastic-plastic deformation of rolled pieces and non-circular flattening of rollers. The rolling pressure mechanism model is as follows:

[0011]

[0012] Among them, P is the total rolling force, b is the width of the rolled piece, and p rx is the unit pressure of the inlet elastic compression zone, p hx is the unit pressure in the back sliding area, p hnx is the unit pressure in the post-neutral zone, p cx is the unit pressure of the outlet elastic recovery zone; p qnx is the unit pressure in the front neutral zone, p qx is the unit pressure in the front sliding zone, x n is the coordinate of the neutral point, l nis the arc length of the neutral zone, which includes the front neutral zone and the back neutral zone, k l is the ratio of the anterior neutral zone to the entire neutral zone;

[0013] S4. A new forward slip mechanism model is constructed based on the non-circular flattening curve of the roller. The forward slip mechanism model is as follows:

[0014]

[0015] Among them, h qn is the thickness of the rolled piece at the intersection of the neutral zone and the front sliding zone, y qn is the coordinate of the roller at the intersection of the neutral zone and the front sliding zone, h p is the thickness of the rolled product at the junction of the front sliding zone and the outlet elastic recovery zone, ε x is the elastic deformation of the rolled piece in the rolling direction, and R is the radius of the working roll of the roll;

[0016] S5, correcting the mid-thickness ratio and the proportion of the front neutral zone according to the actual production data in step S1, specifically including the following sub-steps:

[0017] S51, based on the current middle-thickness ratio a n And actual production data to determine the initial contact arc length;

[0018] Among them, l n / h y is the arc length of the neutral zone l n The average thickness of the rolled product h y The ratio of n ;

[0019] S52, at the current initial contact arc length and the proportion of the front neutral zone k l Next, the rolling force and contact arc length are iteratively calculated using the actual production data of step S1. From the second iteration step, it is determined whether the rolling force meets the convergence accuracy, and the rolling force, forward slip and roller non-circular coordinate points that meet the requirements are saved:

[0020]

[0021] Where kl = l n1 / l n , l n1 is the arc length of the anterior neutral zone, P j is the rolling force calculated in step j, ε is the convergence accuracy;

[0022] S53, loop through the thickness ratio a in sequence n and the proportion of the front neutral area k l , repeat steps S51-S52 in each layer cycle until the two-layer traversal is completed, minimize the relative error between the rolling force and the forward slip and the measured value, and obtain the corrected value of the mid-thickness ratio and the proportion of the front neutral zone;

[0023] S6. Substitute the mid-to-thickness ratio and the proportion of the front neutral zone obtained in step S53 into the models of step S3 and step S4 to calculate the rolling force, forward slip and plate and strip exit speed during the stable rolling process.

[0024] Preferably, in step S53, a weight coefficient is added during minimization, and the weight coefficient calculation formula is as follows:

[0025]

[0026] Among them, α1 is the weight coefficient of the relative error of rolling force, α2 is the weight coefficient of the relative error of forward slip; P cal(i,m) The calculated rolling force value returned under the current iteration parameters, P act is the actual value of rolling force, f slip,cal(i,m) The forward sliding calculation value returned under the current iteration parameter, f slip,act is the actual value of forward slip;

[0027] S21. After the arc of the roller before flattening undergoes elastic deformation, the coordinates of the roller profile curve are as follows:

[0028]

[0029] Where R is the radius of the working roll, x0 is the distance from the center line of the roll to the exit of the plastic zone before flattening, and v is the elastic displacement of the roll surface, which is calculated from the unit pressure in the deformation zone according to the elastic half-plane formula;

[0030] S22, x0 is obtained from the boundary condition of the lowest point of the contour curve after elastic flattening of the roller:

[0031]

[0032] in, is the displacement derivative of the roll surface, θ is a composite parameter variable, p(ξ) is the pressure of the workpiece on the roll, ξ is the horizontal coordinate of the rolling unit pressure diagram, x is the distance of the displacement point to be sought, and dξ is the infinitesimal element of the unit pressure horizontal coordinate ξ;

[0033] S23, x1 is obtained from the thickness difference of the rolled product at the entrance and exit of the plastic zone:

[0034]

[0035] Among them, Δh′ is the thickness difference of the rolled product between the entrance and exit of the plastic zone, x1 is the distance from the center line of the roll to the entrance of the plastic zone before flattening, and Δv is the displacement difference of the roll surface at the entrance and exit of the plastic zone;

[0036] S24. The total contact arc length l in the plastic zone is:

[0037] l=x0+x1;

[0038] S25. Δx0 is obtained from the thickness difference of the rolled product in the outlet elastic recovery zone:

[0039]

[0040] Among them, Δr1 is the elastic deformation of the outlet elastic recovery zone, and Δv′ is the roller surface displacement difference at the outlet and the outlet of the outlet elastic recovery zone;

[0041] S26, Δx1 is obtained from the thickness difference of the rolled product in the elastic compression zone at the entrance:

[0042]

[0043] Among them, Δr0 is the elastic deformation of the inlet elastic compression zone, and Δv″ is the roller surface displacement difference between the inlet and outlet of the inlet elastic compression zone.

[0044] Preferably, step S3 specifically includes the following sub-steps:

[0045] S31, dividing the rolling deformation zone and establishing a coordinate system, from the rolling entrance to the exit, it is sequentially divided into an entrance elastic compression zone, a rear sliding zone, a neutral zone, a front sliding zone and an exit elastic recovery zone;

[0046] S32. The unit pressure distribution curves of the elastic recovery zone at the outlet and the elastic compression zone at the inlet of the rolled piece are established respectively by using the geometric equation, physical equation and equilibrium equation of the rolled piece:

[0047]

[0048] Among them, p rx is the unit pressure of the inlet elastic compression zone, p0 is the unit pressure at the junction of the inlet elastic compression zone and the back sliding zone, Δx1 is the contact arc length of the inlet elastic compression zone, l is the contact arc length of the plastic zone, B0 is the composite parameter variable of the inlet elastic compression zone, p cx is the unit pressure of the outlet elastic recovery zone, p1 is the unit pressure at the junction of the front sliding zone and the outlet elastic recovery zone, Δx0 is the contact arc length of the outlet elastic recovery zone, and B is the composite parameter variable of the outlet elastic recovery zone;

[0049] S33. The unit pressure distribution curves of the rear sliding zone, rear neutral zone, front neutral zone and front sliding zone of the rolled piece are established respectively based on the equilibrium equation, plastic deformation condition and friction model:

[0050]

[0051] Among them, p hx is the unit pressure in the rear sliding area, μ is the friction coefficient, h y is the average thickness of the rolled piece, x is the horizontal coordinate of any point in the deformation zone, p hnxis the unit pressure in the post-neutral zone, p c ′ is the unit pressure at the junction of the rear sliding zone and the rear neutral zone, l n is the neutral zone length, k l is the proportion of the front neutral zone, x n is the neutral point position, p c ″ is the unit pressure at the junction of the front neutral zone and the front sliding zone;

[0052] S34. According to the unit pressure distribution, the unit pressure of each part is integrated along the contact arc length to obtain the rolling pressure mechanism model.

[0053] Preferably, step S4 specifically includes the following sub-steps:

[0054] S41, bringing the unit pressure distribution curve and the contact arc length of each zone into the coordinates of the roller profile curve to obtain the coordinates of the roller at the boundary points of each zone;

[0055] S42. Assuming that the speed of the rolled piece in the outlet elastic recovery zone satisfies a linear relationship, the speed relationship between the two end points of the outlet elastic recovery zone is:

[0056] v d =(1+2ε x )v p

[0057] Among them, v d is the exit speed of rolled product, v p is the speed of the rolled piece at the junction of the front sliding zone and the outlet elastic recovery zone, ε x The elastic deformation of the rolled piece in the rolling direction is calculated according to Hooke's law;

[0058] S43. Based on the definition of forward slip, the metal second flow equation and the velocity relationship between the two end points of the outlet elastic recovery zone, a forward slip mechanism model of elastic-plastic deformation of the rolled piece and non-circular flattening of the roller is constructed.

[0059] Preferably, step S1 collects actual production data in cold rolling production, including equipment parameters, specification parameters and process parameters:

[0060] Among them, the equipment parameter is the roller working radius R;

[0061] The specification parameters are the width of the rolled piece b, the thickness of the rolled piece at the entrance h0, the thickness of the rolled piece at the exit h1, the Poisson's ratio ν and the elastic modulus E;

[0062] The process parameters are inlet deformation resistance kf0, outlet deformation resistance kf1, front tension σ1, rear tension σ0, friction coefficient μ, actual rolling force P act And the actual forward slip value f slip,act .

[0063] Preferably, the friction model in step S33 is:

[0064]

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) The present invention provides a method for predicting the rolling force and forward slip of the cold rolling process based on mechanism-data collaborative driving. The mechanism model of this method simultaneously considers the elastic-plastic deformation of the rolled piece and the non-arc flattening of the roller, and refines the friction state in the neutral zone. Compared with the existing rolling force and forward slip prediction methods, the physical factors considered are more comprehensive, ensuring that the method has higher prediction accuracy and wider applicability.

[0067] (2) The method of the present invention is based on the characteristics of elastic-plastic deformation of the rolled piece and non-circular flattening of the rolling roller, and simultaneously constructs a rolling force and forward slip prediction method, which can not only accurately display the rolling pressure distribution in the deformation zone, but also provide theoretical support for the "negative forward slip" phenomenon that frequently occurs in cold rolling production, and can better solve these problems.

[0068] (3) The method of the present invention corrects the parameters of the mechanism model by introducing industrial data from actual production, thereby improving the stability and reliability of the model prediction and laying a technical foundation for achieving stable and efficient rolling. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic diagram of the overall process of the cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data of the present invention;

[0070] Figure 2a and Figure 2b It is a schematic diagram of the friction shear stress and flattening curve of the deformation zone of the present invention, wherein: Figure 2a This is a schematic diagram of the friction shear stress in the deformation zone of the present invention, Figure 2b It is a schematic diagram of a flattening curve of the present invention;

[0071] Figure 3 It is the rolling force calculation error diagram of each stand of the present invention;

[0072] Figure 4a-4e They are respectively schematic diagrams of the compression stress in the deformation zone, the friction shear stress, the roll flattening curve and the exit speed corresponding to the rolling force prediction results on the five stands in the embodiment of the present invention, wherein: Figure 4a Schematic diagram of compressive stress, friction shear stress, roller flattening curve and exit speed in S1 deformation zone. Figure 4b Schematic diagram of compressive stress, friction shear stress, roller flattening curve and exit speed in the S2 deformation zone. Figure 4c Schematic diagram of compressive stress, friction shear stress, roller flattening curve and exit speed in S3 deformation zone. Figure 4d Schematic diagram of compressive stress, friction shear stress, roller flattening curve and exit speed in S4 deformation zone. Figure 4e Schematic diagram of compressive stress, friction shear stress, roller flattening curve and exit speed in S5 deformation zone;

[0073] Figure 5a-5c The calculated values ​​and actual values ​​of the embodiments of the present invention in the S1 stable rolling process and the results of different rolling force prediction methods are compared, wherein: Figure 5a are the calculated and actual values ​​of rolling force, forward slip and strip exit speed during S1 stable rolling of this method, Figure 5b and Figure 5c are the calculated values ​​and calculation errors of this method and the classical rolling force prediction method in the S1 stable rolling process;

[0074] Figure 6a-6c They are respectively the comparison diagrams of the calculated value and the actual value of the method in the stable rolling process of the S2 deformation zone and the results of different rolling force prediction methods, where: Figure 6a are the calculated and actual values ​​of rolling force, forward slip and strip exit speed during the stable rolling process in the S2 deformation zone by this method, and Figures 6b and 6c are the calculated values ​​and calculation errors of this method and the classical rolling force prediction method during the stable rolling process in the S2 deformation zone, respectively;

[0075] Figure 7a-7c They are the calculated and actual values ​​of this method in the stable rolling process of S3 deformation zone and the comparison of the results of different rolling force prediction methods, among which, Figure 7a are the calculated and actual values ​​of rolling force, forward slip and strip exit speed in the stable rolling process of the S3 deformation zone according to this method, Figure 7b and Figure 7c are the calculated values ​​and calculation errors of this method and the classical rolling force prediction method in the stable rolling process of S3 deformation zone;

[0076] Figure 8a-8c They are the calculated and actual values ​​of the method in the stable rolling process of S4 deformation zone and the comparison of the results of different rolling force prediction methods, among which, Figure 8a are the calculated and actual values ​​of rolling force, forward slip and strip exit speed in the stable rolling process of the S4 deformation zone according to this method, Figure 8b and 8c are the calculated values ​​and calculation errors of this method and the classical rolling force prediction method in the stable rolling process of S4 deformation zone;

[0077] Figure 9a-9c They are the comparison between the calculated value and the actual value of the method in the stable rolling process of the S5 deformation zone and the results of different rolling force prediction methods, among which, Figure 9aare the calculated and actual values ​​of rolling force, forward slip and exit speed in the stable rolling process of S5 deformation zone according to this method, Figure 9b and Fig.9c They are the calculated values ​​and calculation errors of this method and the classical rolling force prediction method in the stable rolling process of S5 deformation zone, respectively. DETAILED DESCRIPTION

[0078] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0079] The present invention provides a cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data, such as Figure 1 As shown, it includes the following steps:

[0080] S1. Collect actual production data of equipment, specifications and process parameters in cold rolling production, including the following parameters:

[0081] Equipment parameters: R roller working radius; Specification parameters: b width of rolled piece, h0 thickness of rolled piece at entry, h1 thickness of rolled piece at exit, ν Poisson's ratio, E elastic modulus; Process parameters: kf0 deformation resistance at entry, kf1 deformation resistance at exit, σ1 front tension, σ0 rear tension, μ friction coefficient, P act Actual rolling force, f slip,act Actual forward slip value.

[0082] S2, constructing the contact arc length model of each zone of the non-arc flattening of the roller, specifically including the following sub-steps:

[0083] S21. After the arc of the roller before flattening undergoes elastic deformation, the coordinates of the contour curve of the roller after elastic flattening are:

[0084]

[0085] Among them, R is the radius of the working roll of the roll, x0 is the distance from the center line of the roll to the exit of the plastic zone before flattening, and v is the elastic displacement of the roll surface, which is calculated by the unit pressure in the deformation zone according to the elastic half-plane formula.

[0086] S22. Based on the analysis of step S21, the boundary condition of the lowest point of the contour curve after elastic flattening by the roller can be obtained as x0:

[0087]

[0088] in, is the surface displacement derivative of the roll, θ is a composite parameter variable, p(ξ) is the pressure of the workpiece on the roll, ξ is the horizontal coordinate of the rolling unit pressure diagram, and x is the distance of the desired displacement point.

[0089] S23. Based on the analysis of step S21, x1 can be obtained from the thickness difference of the rolled piece at the entrance and exit of the plastic zone:

[0090]

[0091] Among them, Δh′ is the thickness difference of the rolled product between the two points at the entrance and exit of the plastic zone, x1 is the distance from the center line of the roll to the entrance of the plastic zone before flattening, and Δv is the displacement difference of the roll surface at the entrance and exit of the plastic zone.

[0092] S24. Based on the contact arc lengths of steps S32 and S33, the total contact arc length l of the plastic zone is:

[0093] l=x0+x1.

[0094] S25. Based on the analysis of step S21, Δx0 can be obtained from the thickness difference of the rolled piece in the outlet elastic recovery zone:

[0095]

[0096] Among them, Δr1 is the elastic deformation of the outlet elastic recovery zone, and Δv′ is the roller surface displacement difference at the inlet and outlet of the outlet elastic recovery zone.

[0097] S26. Based on the analysis of step S21, Δx1 can be obtained from the thickness difference of the rolled piece in the inlet elastic compression zone:

[0098]

[0099] Among them, Δr0 is the elastic deformation of the inlet elastic compression zone, and Δv″ is the roller surface displacement difference between the inlet and outlet of the inlet elastic compression zone.

[0100] S3, constructing a rolling pressure mechanism model of elastic-plastic deformation of rolled pieces and non-circular flattening of rollers, which specifically includes the following sub-steps:

[0101] S31. Divide the rolling deformation zone and establish a coordinate system, which is divided into the inlet elastic compression zone, the plastic zone (rear sliding zone, neutral zone, front sliding zone) and the outlet elastic recovery zone from the rolling entrance to the exit.

[0102] S32, according to the analysis of step S21, the unit pressure distribution curves of the elastic recovery zone at the outlet and the elastic compression zone at the inlet of the rolled piece are respectively established by the geometric equation, physical equation and equilibrium equation of the rolled piece:

[0103]

[0104] Among them, p rx is the unit pressure of the inlet elastic compression zone, p0 is the unit pressure at the junction of the inlet elastic compression zone and the back sliding zone, Δx1 is the contact arc length of the inlet elastic compression zone, l is the contact arc length of the plastic zone, B0 is the composite parameter variable of the inlet elastic compression zone, p cxis the unit pressure of the outlet elastic recovery zone, p1 is the unit pressure at the junction of the front sliding zone and the outlet elastic recovery zone, Δx0 is the contact arc length of the outlet elastic recovery zone, and B is the composite parameter variable of the outlet elastic recovery zone.

[0105] S33, according to the analysis of step S21, the unit pressure distribution curves of the rear sliding zone, rear neutral zone, front neutral zone and front sliding zone of the rolled piece are respectively established by the equilibrium equation, plastic deformation condition and friction model:

[0106]

[0107] Among them, p hx is the unit pressure in the rear sliding area, μ is the friction coefficient, h y is the average thickness of the rolled piece, x is the horizontal coordinate of any point in the deformation zone, p hnx is the unit pressure in the post-neutral zone, p c ′ is the unit pressure at the junction of the rear sliding zone and the rear neutral zone, l n is the neutral zone length, k l is the proportion of the front neutral zone, x n is the neutral point position, p c ″ is the unit pressure at the junction of the front neutral zone and the front sliding zone.

[0108] Wherein, the friction model of step S33 is:

[0109]

[0110] S34, according to the unit pressure distribution of steps S22 and S23, the total rolling force in the rolling deformation zone is obtained by integrating the unit pressure of each part along the contact arc length, that is, the rolling pressure mechanism model is:

[0111]

[0112] Among them, P is the total rolling force and b is the width of the rolled piece.

[0113] S4. Constructing a new forward slip mechanism model based on the non-circular flattening curve of the roller, which specifically includes the following sub-steps:

[0114] S41, substituting the unit pressure distribution curve of step S2 and the contact arc length of each zone obtained in steps S32-S36 into the coordinates of the roller profile curve of step S31 to obtain the coordinates of the roller at the boundary points of each zone.

[0115] S42. Since the rolled piece does not satisfy the metal flow rate equation in the outlet elastic recovery zone, assuming that the speed of the rolled piece in the outlet elastic recovery zone satisfies a linear relationship, the speed relationship between the two end points of the outlet elastic recovery zone is:

[0116] v d =(1+2ε x)v p

[0117] Among them, v d is the exit speed of rolled product, v p is the speed of the rolled piece at the junction of the front sliding zone and the outlet elastic recovery zone, ε x The elastic deformation of the rolled piece in the rolling direction is calculated according to Hooke's law in practical applications.

[0118] S43, according to the definition of forward slip, the metal flow rate equation and the speed relationship of step S42, the forward slip mechanism model considering the elastic-plastic deformation of the rolled piece and the non-circular flattening of the roller is:

[0119]

[0120] Among them, h qn is the thickness of the rolled piece at the intersection of the neutral zone and the front sliding zone, y qn is the coordinate of the roller at the intersection of the neutral zone and the front sliding zone, h p It is the thickness of the rolled piece at the junction of the front sliding zone and the exit elastic recovery zone.

[0121] S5, modifying the mid-to-thickness ratio and the proportion of the front neutral zone in the mechanism model by using the industrial data in step S1, specifically including the following sub-steps:

[0122] S51, at the current thickness ratio a n And the industrial data of step S1, determine the initial contact arc length.

[0123] Among them, the thickness ratio a n = l n / h y .

[0124] S52, at the current initial contact arc length and the proportion of the front neutral zone k l Next, the industrial data of step S1 is used to iteratively calculate the rolling force of steps S22-S24 and the contact arc length of each zone of steps S32-S36. From the second iteration step, it is determined whether the rolling force meets the convergence accuracy, and the rolling force, forward slip and roller non-circular coordinate points that meet the requirements are saved:

[0125]

[0126] Among them, k l = l n1 / l n , l n1 is the arc length of the anterior neutral zone, P j is the rolling force calculated in the jth step, and ε is the convergence accuracy.

[0127] S53, loop through the middle-thickness ratio an and the front neutral area proportion k in sequence l, repeat steps S51-S52 in each layer cycle until the two layers are traversed, minimize the relative errors between the rolling force and the front slip and the measured values, and obtain the corrected values ​​of the middle-thickness ratio and the front neutral zone ratio. Among them, due to the different magnitudes of rolling force and front slip, the weight coefficient is considered when minimizing:

[0128]

[0129] Among them, α1 is the weight coefficient of the relative error of rolling force, and α2 is the weight coefficient of the relative error of forward slip.

[0130] S6. Use the correction value of step S53 to calculate the rolling force, forward slip and strip exit speed during the stable rolling process of the coil.

[0131] The following is a further description of a specific implementation method. In this embodiment, a cold rolling equipment of a certain factory is taken as an example, and the above method is used to traverse and iteratively optimize the rolling force and the contact arc length in turn to obtain the middle thickness ratio a n and the proportion of the front neutral area k l The correction value is calculated and the correction result is used to predict the stable rolling process of the coil.

[0132] The cold rolling process elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data collaborative drive of the present invention is as follows: Figure 1 As shown, it includes the following steps:

[0133] S1. Collect process parameters in actual production and obtain actual production data of equipment, specifications and process parameters.

[0134] S2, by Figure 2a and Figure 2b The friction shear stress in the deformation zone and the roller flattening curve are shown, and the rolling pressure expressions of the elastic-plastic deformation of the rolled piece and the non-circular flattening of the roller are constructed. Figure 2a In the figure, a represents the inlet elastic compression zone, b represents the rear sliding zone, c represents the neutral zone, d represents the front sliding zone, e represents the outlet elastic recovery zone, f represents the rear neutral zone, and g represents the front neutral zone. Figure 2b In the figure, m represents the curve after roller flattening, and n represents the curve before roller flattening.

[0135] S3. Based on the roller flattening curve and corresponding boundary conditions shown in FIG2 , a contact arc length model of each zone of the roller non-arc flattening is constructed.

[0136] S4. Construct a new forward slip mechanism model based on the non-arc flattening curve of the roller.

[0137] S5. Use actual production data to correct the mid-to-thickness ratio and the proportion of the front neutral zone in the mechanism model to obtain the corresponding model parameter correction values ​​under this working condition.

[0138] S6. The correction value is used to calculate the rolling force, forward slip and strip exit speed during the stable rolling process of the coil.

[0139] In this embodiment, a certain oriented silicon steel coil is selected. Figure 1 Based on the prediction method shown in Figure 1, the correction values ​​of the model parameters on different stands were obtained respectively, and the rolling force, compressive stress, friction shear stress, roll flattening curve and outlet speed distribution in the deformation zone of the method on different stands were calculated. Then, the calculation ability of the method was compared with that of the classical rolling force prediction method. The results are shown in Table 1. The calculation error comparison results of each method and the actual value of rolling force are shown in Table 1. Figure 3 As shown in the figure; the compressive stress, friction shear stress, roller flattening curve and outlet speed distribution of each frame deformation zone are shown in the figure. Figure 4a-4e Table 1 shows the comparison of different rolling force models; Figure 3 The calculation error of rolling force on each stand for different prediction methods; Figure 4a The compressive stress, friction shear stress, roller flattening curve and outlet velocity distribution in the S1 deformation zone; Figure 4b The compressive stress, friction shear stress, roller flattening curve and outlet velocity distribution in the S2 deformation zone; Figure 4c The compressive stress, friction shear stress, roller flattening curve and outlet velocity distribution in the S3 deformation zone; Figure 4d The compressive stress, friction shear stress, roller flattening curve and outlet velocity distribution in the S4 deformation zone; Figure 4e The compressive stress, friction shear stress, roller flattening curve and outlet velocity distribution in the S5 deformation zone. Figure 3 It can be seen that compared with the classic rolling force mechanism model, the elastic-plastic rolling force model based on mechanism-data collaborative drive proposed in the present invention has calculated values ​​on each stand that are closer to the measured values ​​of the rolling force, showing a better prediction effect; Figure 4a-4e As shown, the precise distribution of key parameters in the deformation zone is displayed, which also provides a basis for explaining the “negative forward slip” phenomenon.

[0140] The correction values ​​obtained on each stand are used to calculate the rolling force, forward slip and strip exit speed at other sampling points in the stable rolling process, and compared with the results calculated by the classical rolling force prediction method. The results are shown in Figures 5 to 9. Figure 5a , Figure 6a , Figure 7a , Figure 8a and Figure 9a The calculated values ​​and measured values ​​of the rolling force, forward slip and strip exit speed of the five stands in this embodiment are shown in sequence; Figure 5b-Figure 5c , Figure 6b-6c , Figure 7b-7c , Figure 8b-Figure 8c and Figure 9b-9cThe results of the method in this embodiment and the classical rolling force prediction method are shown in turn; it can be seen from Figures 5 to 9 that compared with the classical rolling force prediction method, the rolling force prediction error of the stable rolling process obtained by the method of the present invention is the smallest, and the plate and strip outlet speed calculated by the forward slip result is highly consistent with the actual speed of the plate and strip. This method can predict the "negative forward slip" phenomenon that occurs in the rolling process.

[0141] Table 1 Comparison of different rolling force models (MN)

[0142]

[0143]

[0144] It can be seen from the above embodiments that the method of the present invention is based on the correction of the mechanism model based on data, takes into account the elastic-plastic deformation of the rolled piece and the non-circular flattening of the roller, and constructs a rolling force and forward slip prediction method. The rolling force calculated in the stable rolling process is more accurate than the classical rolling force method, and the forward slip model can reflect the "negative forward slip" phenomenon in actual production, providing more accurate support for setting rolling procedures and stabilizing the rolling process.

[0145] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data, characterized by: It includes the following steps: S1. Collect actual production data in cold rolling production; S2, construct the contact arc length model of each zone of the non-circular arc flattening of the roller to calculate the distance x0 from the center line of the roller to the exit of the plastic zone before flattening, the distance x1 from the center line of the roller to the entrance of the plastic zone before flattening, the total contact arc length l of the plastic zone, the contact arc length Δx0 of the exit elastic recovery zone, and the contact arc length Δx1 of the entrance elastic compression zone; S3. Construct a rolling pressure mechanism model of elastic-plastic deformation of rolled pieces and non-circular flattening of rollers. The rolling pressure mechanism model is as follows: Among them, P is the total rolling force, b is the width of the rolled piece, and p rx is the unit pressure of the inlet elastic compression zone, p hx is the unit pressure in the back sliding area, p hnx is the unit pressure in the post-neutral zone, p cx is the unit pressure of the outlet elastic recovery zone, p qnx is the unit pressure in the front neutral zone, p qx is the unit pressure in the front sliding area, x n is the coordinate of the neutral point, l n is the arc length of the neutral zone, which includes the front neutral zone and the back neutral zone, k l is the ratio of the anterior neutral zone to the entire neutral zone; S4. Based on the non-circular flattening curve of the roller, a forward slip mechanism model is constructed. The forward slip mechanism model is as follows: Among them, f slip For forward sliding, h qn is the thickness of the rolled piece at the intersection of the neutral zone and the front sliding zone, y qn is the coordinate of the roller at the intersection of the neutral zone and the front sliding zone, h p is the thickness of the rolled product at the junction of the front sliding zone and the outlet elastic recovery zone, ε x is the elastic deformation of the rolled piece in the rolling direction, and R is the radius of the working roll of the roll; S5, correcting the mid-thickness ratio and the proportion of the front neutral zone according to the actual production data in step S1, specifically including the following sub-steps: S51, based on the current middle-thickness ratio a n and actual production data to determine the arc length of the neutral zone; The calculation formula of the mid-thickness ratio is as follows: n = l n / h y ; l n / h y is the arc length of the neutral zone l n The average thickness of the rolled product h y The ratio of n ; S52, at the current initial contact arc length and the proportion of the front neutral zone k l In this case, the rolling force and contact arc length are iteratively calculated using actual production data. From the second iteration, it is determined whether the rolling force meets the convergence accuracy, and the rolling force, forward slip and roller non-circular coordinate points that meet the requirements are saved: Among them, k l = l n1 / l n , l n1 is the arc length of the anterior neutral zone, P j is the rolling force calculated in step j, ε is the convergence accuracy; k l is the ratio of the anterior neutral zone to the neutral zone; S53, loop through the thickness ratio a in sequence n and the proportion of the front neutral area k l , repeat steps S51-S52 in each layer cycle until the two-layer traversal is completed, minimize the relative error between the rolling force and the forward slip and the measured value, and obtain the corrected value of the mid-thickness ratio and the proportion of the front neutral zone; S6. Substitute the mid-to-thickness ratio and the front neutral zone ratio obtained in step S53 into the models of step S3 and step S4 to calculate the rolling force, forward slip and plate and strip exit speed during the stable rolling process.

2. The cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data according to claim 1, characterized in that: In step S53, a weight coefficient is added during minimization, and the weight coefficient calculation formula is as follows: Among them, α1 is the weight coefficient of the relative error of rolling force, α2 is the weight coefficient of the relative error of forward slip; P cal(i,m) The calculated rolling force value returned under the current iteration parameters, P act is the actual value of rolling force, f slip,cal(i,m) The forward sliding calculation value returned under the current iteration parameter, f slip,act is the actual value of the forward slide.

3. The cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data according to claim 1, characterized in that: Step S2 specifically includes the following sub-steps: S21. After the arc of the roller before flattening undergoes elastic deformation, the coordinates of the roller profile curve are as follows: Where R is the radius of the working roll, x0 is the distance from the center line of the roll to the exit of the plastic zone before flattening, and v is the elastic displacement of the roll surface, which is calculated from the unit pressure in the deformation zone according to the elastic half-plane formula; S22, x0 is obtained from the boundary condition of the lowest point of the contour curve after elastic flattening of the roller: in, is the displacement derivative of the roll surface, θ is a composite parameter variable, p(ξ) is the pressure of the workpiece on the roll, ξ is the horizontal coordinate of the rolling unit pressure diagram, x is the distance of the displacement point to be sought, and dξ is the infinitesimal element of the unit pressure horizontal coordinate ξ; S23, x1 is obtained from the thickness difference of the rolled product at the entrance and exit of the plastic zone: Among them, Δh′ is the thickness difference of the rolled product between the entrance and exit of the plastic zone, x1 is the distance from the center line of the roll to the entrance of the plastic zone before flattening, and Δv is the displacement difference of the roll surface at the entrance and exit of the plastic zone; S24. The total contact arc length l in the plastic zone is: l=x0+x1; S25, Δx0 is obtained from the thickness difference of the rolled product in the outlet elastic recovery zone: Among them, Δr1 is the elastic deformation of the outlet elastic recovery zone, and Δv′ is the roller surface displacement difference at the outlet and the outlet of the outlet elastic recovery zone; S26, Δx1 is obtained from the thickness difference of the rolled product in the elastic compression zone at the entrance: Among them, Δr0 is the elastic deformation of the inlet elastic compression zone, and Δv″ is the roller surface displacement difference between the inlet and outlet of the inlet elastic compression zone.

4. The cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data according to claim 3, characterized in that: Step S3 specifically includes the following sub-steps: S31, dividing the rolling deformation zone and establishing a coordinate system, from the rolling entrance to the exit, it is the entrance elastic compression zone, the rear sliding zone, the neutral zone, the front sliding zone and the exit elastic recovery zone; S32. The unit pressure distribution curves of the elastic recovery zone at the outlet and the elastic compression zone at the inlet of the rolled piece are established respectively by using the geometric equation, physical equation and equilibrium equation of the rolled piece: Among them, p rx is the unit pressure of the inlet elastic compression zone, p0 is the unit pressure at the junction of the inlet elastic compression zone and the back sliding zone, Δx1 is the contact arc length of the inlet elastic compression zone, l is the contact arc length of the plastic zone, B0 is the composite parameter variable of the inlet elastic compression zone, p cx is the unit pressure of the outlet elastic recovery zone, p1 is the unit pressure at the junction of the front sliding zone and the outlet elastic recovery zone, Δx0 is the contact arc length of the outlet elastic recovery zone, and B is the composite parameter variable of the outlet elastic recovery zone; S33. The unit pressure distribution curves of the rear sliding zone, rear neutral zone, front neutral zone and front sliding zone of the rolled piece are established respectively based on the equilibrium equation, plastic deformation condition and friction model: Among them, p hx is the unit pressure in the rear sliding area, μ is the friction coefficient, h y is the average thickness of the rolled piece, x is the horizontal coordinate of any point in the deformation zone, p hnx is the unit pressure in the post-neutral zone, p c ′ is the unit pressure at the junction of the rear sliding zone and the rear neutral zone, l n is the neutral zone length, k l is the proportion of the front neutral zone, x n is the neutral point position, p c ″ is the unit pressure at the junction of the front neutral zone and the front sliding zone; S34. According to the unit pressure distribution, the unit pressure of each part is integrated along the contact arc length to obtain the rolling pressure mechanism model.

5. The cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data according to claim 4, characterized in that: Step S4 specifically includes the following sub-steps: S41, bringing the unit pressure distribution curve and the contact arc length of each zone into the coordinates of the roller profile curve to obtain the coordinates of the roller at the boundary points of each zone; S42. Assuming that the speed of the rolled piece in the outlet elastic recovery zone satisfies a linear relationship, the speed relationship between the two end points of the outlet elastic recovery zone is: v d =(1+2ε x )v p Among them, v d is the exit speed of rolled product, v p is the speed of the rolled piece at the junction of the front sliding zone and the outlet elastic recovery zone, ε x The elastic deformation of the rolled piece in the rolling direction is calculated according to Hooke's law; S43. According to the definition of forward slip, the metal flow rate equation and the velocity relationship between the two end points of the outlet elastic recovery zone, a forward slip mechanism model of elastic-plastic deformation of the rolled piece and non-circular flattening of the roller is constructed.

6. The cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data according to claim 1, characterized in that: Step S1 collects actual production data in cold rolling production, including equipment parameters, specification parameters and process parameters: Among them, the equipment parameter is the roller working radius R; The specification parameters are the width of the rolled piece b, the thickness of the rolled piece at the entrance h0, the thickness of the rolled piece at the exit h1, the Poisson's ratio ν and the elastic modulus E; The process parameters are inlet deformation resistance kf0, outlet deformation resistance kf1, front tension σ1, rear tension σ0, friction coefficient μ, actual rolling force P act And the actual forward slip value f slip,act .

7. The cold rolling elastic-plastic deformation rolling force and forward slip prediction method based on mechanism-data according to claim 1, characterized in that: The friction model in step S33 is:

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