The Optimization Solution of the Vertical Rolling Force by Using Unified Yield Criterion

2021 ◽  
Author(s):  
Yufeng Zhang ◽  
Meiying Zhao ◽  
Li Xu ◽  
Hong Shuang Di ◽  
Xiaojuan Zhou ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Prediction Accuracy ◽  
Rolling Force ◽  
Yield Criterion ◽  
Reduction Rate ◽  
Total Power ◽  
Force Model ◽  
Dog Bone ◽  
Mill Equipment ◽  
Admissible Condition

Abstract Vertical rolling is an important technique to control the width of continuous casting slab in hot rolling field. Accurate prediction of vertical rolling force is a core point to maintain rolling mill equipment. Due to the limitation of the algorithm, the prediction accuracy of most vertical rolling force models based on the energy method can only reach more than 10%. Therefore, it is challenging to optimize the rolling force model to improve the prediction accuracy. This paper presents an innovative approach for optimizing the calculation of vertical rolling force with a unified yield criterion. Firstly, the maximal width of dog bone region is determined by the slip-line method and described the dog bone shape via sine function model. Furthermore, proposed velocity and corresponding strain rate fields satisfy kinematically admissible condition is used to calculate the total power. Finally, the analytical solution of the rolling force and dog bone shape model is obtained by repeatedly optimizing the weighted coefficient b of intermediate principal shear stress on the yield criterion. And the effectiveness of the proposed mechanical model is verified by measured data in strip hot rolling field and other models’ results. The results shows that the prediction accuracy of vertical rolling force model can be improved by optimizing the value of b. Then, the impacts of reduction rate, initial thickness and friction factor on dog-bone shape size and vertical rolling force are discussed.

Slab analysis based on stream function method in chamfer edge rolling of ultra-heavy plate

2016 ◽  
Vol 231 (7) ◽  
pp. 1237-1251
Author(s):  
JG Ding ◽  
HY Wang ◽  
DH Zhang ◽  
DW Zhao
Keyword(s):  
Velocity Field ◽  
Stream Function ◽  
Function Method ◽  
Rolling Force ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Total Power ◽  
Shape Coefficient ◽  
Heavy Plate ◽  
Dog Bone

In this paper, three-dimensional velocity field is proposed by means of stream function method with bisecting yield criterion in chamfer edge rolling of ultra-heavy plate. Parabolic dog-bone shape function is derived so as to obtain velocity field with fixed angle of chamfer edge by stream function method, dog-bone shape coefficient η can be derived from volume invariant condition, and then the plastic deformation power, shear power as well as friction power are obtained respectively with the bisecting yield criterion. Summing up the power contributions, total power functional is presented, from which minimum value can be obtained by searching method, and vertical rolling force and torque are also finally obtained. The predictions of roll force and torque are compared with different angles of chamfer edge as well as different plate thicknesses. The results are shown to be in a very good agreement with the analytical and experimental results.

Analysis of Vertical Rolling Force with GM Yield Criterion and Anti-Symmetric Parabola Dog-Bone Shapes

2015 ◽  
Vol 775 ◽  
pp. 34-38 ◽  
Author(s):  
Hong Yu Wang ◽  
De Wen Zhao ◽  
Dian Hua Zhang
Keyword(s):  
Plastic Deformation ◽  
Rolling Force ◽  
Yield Criterion ◽  
Deformation Characteristic ◽  
Analytical Form ◽  
Total Power ◽  
Average Error ◽  
Total Deformation ◽  
Dog Bone ◽  
Gm Yield Criterion

Vertical rolling is a vital method for width control in rolling, which has its own deformation characteristic. During the processing, plastic deformation does not go further into center of slab, only in edge where the deformation will be occurred. In this paper, an anti-symmetric parabola is creatively used to describe dog-bone shape and innovatively applied to establish a knematically admissible continuous velocity field for vertical rolling. Based on this field, an analytical form of total deformation power is obtained which is a function of reduction geometric parameters, and friction factor m, as well as parameter of A which is to be determined. With minimization of total power results in rolling forces and torque calculated by this new method is obtained. Copper and aluminum experiments conducted by S.-E.Lundberg are used to verified the results calculated by formula in present paper and compared with those by Lundberg and Duckjoongs’ models. The error is no more than 13%, (average error 7%).

scholarly journals Vibration Characteristics of Hot Rolling Mill Rolls Based on Elastoplastic Hysteretic Deformation

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 869
Author(s):  
Rongrong Peng ◽  
Xingzhong Zhang ◽  
Peiming Shi
Keyword(s):  
Hot Rolling ◽  
Internal Resonance ◽  
Rolling Mill ◽  
Rolling Force ◽  
Subharmonic Resonance ◽  
Force Model ◽  
Maximum Lyapunov Exponent ◽  
Vibration System ◽  
Hot Rolling Mill ◽  
Rolling Mill Vibration

Based on the analysis of the influence of roll vibration on the elastoplastic deformation state of a workpiece in a rolling process, a dynamic rolling force model with the hysteresis effect is established. Taking the rolling parameters of a 1780 mm hot rolling mill as an example, we analyzed the hysteresis between the dynamic rolling force and the roll vibration displacement by varying the rolling speed, roll radius, entry thickness, front tension, back tension, and strip width. Under the effect of the dynamic rolling force and considering the nonlinear effect between the backup and work rolls as well as the structural constraints on the rolling mill, a hysteretic nonlinear vertical vibration model of a four-high hot rolling mill was established. The amplitude-frequency equations corresponding to 1/2 subharmonic resonance and 1:1 internal resonance of the rolling mill rolls were obtained using a multi-scale approximation method. The amplitude-frequency characteristics of the rolling mill vibration system with different parameters were studied through a numerical simulation. The parametric stiffness and nonlinear stiffness corresponding to the dynamic rolling force were found to have a significant influence on the amplitude of the subharmonic resonance system, the bending degree of the vibration curve, and the size of the resonance region. Moreover, with the change in the parametric stiffness, the internal resonance exhibited an evident jump phenomenon. Finally, the chaotic characteristics of the rolling mill vibration system were studied, and the dynamic behavior of the vibration system was analyzed and verified using a bifurcation diagram, maximum Lyapunov exponent, phase trajectory, and Poincare section. Our research provides a theoretical reference for eliminating and suppressing the chatter in rolling mills subjected to an elastoplastic hysteresis deformation.

scholarly journals Research on rolling force model in hot-rolling process of aluminum alloys

2011 ◽  
Vol 16 ◽  
pp. 745-754 ◽  
Author(s):  
Huang Changqing ◽  
Deng Hua ◽  
Chen Jie ◽  
H.U Xinghua ◽  
Yang Shuangcheng
Keyword(s):  
Aluminum Alloys ◽  
Hot Rolling ◽  
Rolling Force ◽  
Rolling Process ◽  
Force Model ◽  
Hot Rolling Process

scholarly journals Modeling of Rolling Force for Thick Plate of Multicomponent Alloys and Its Application on Thickness Prediction

2021 ◽  
Vol 8 ◽  
Author(s):  
Shun Hu Zhang ◽  
Jia Lin Xin ◽  
Li Zhi Che
Keyword(s):  
Thick Plate ◽  
Rolling Force ◽  
Yield Criterion ◽  
Metal Flow ◽  
Rolling Process ◽  
Logistic Function ◽  
Force Model ◽  
Multicomponent Alloys ◽  
Thickness Prediction ◽  
Predicted Values

During the rolling process of thick plate, the nonlinear specific plastic power that derived from the non-linear Mises yield criterion is difficult to be integrated, which has restricted the establishment of a rolling force model. To solve this problem, a new yield criterion is firstly established, and then used to derive a linear specific plastic power. Meanwhile, a kinematically admissible velocity field whose horizontal velocity component obeys the Logistic function is proposed to describe the metal flow of the deformed plate. On these bases, the rolling energy items including the internal deformation power of the deformed body, friction power on the contact surface, and shear power on the entry and exit sections are integrated successively, and the rolling force model is established. It is proved that the model can predict the rolling force well when compared with the actual data of multicomponent alloys. Besides, the formula for predicting the outlet thickness is ultimately given upon this derived model, and a good agreement is also found between the predicted values and the actual ones, since the absolute errors between them are within 0.50 mm.

Modeling the Temperature/Force Phenomena of an Extra-Low Carbon Steel in Two-Phase Hot Rolling

1999 ◽  
Author(s):  
Yhu-Jen Hwu ◽  
Chang-Huei Wu
Keyword(s):  
Carbon Steel ◽  
Hot Rolling ◽  
Rolling Force ◽  
Low Carbon Steel ◽  
Phase Transformation Temperature ◽  
Force Model ◽  
Low Carbon ◽  
Two Phase ◽  
Finishing Mill ◽  
Temperature Force

Abstract Extra-low carbon steel had been rolled in conventional hot rolling mill. For improving its mechanical and metallurgical properties, its high phase transformation temperature typically encountered in the finishing mill section that results in abrupt change of flow stress and consequently the rolling force. A simple temperature/force model is proposed to predict the strip temperature and mill loading force to achieve better understanding of complicated phenomena encountered in the field and also for future initial rolling condition setup. Preliminary results based on the model are satisfactorily close to the on-line rolling data from the seven-stand mill of China Steel Corporation.

scholarly journals Analysis of Rolling Force for Extra-Thick Plate with CA Criterion

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Shun Hu Zhang ◽  
Lei Deng ◽  
Peng Li
Keyword(s):  
Temperature Rise ◽  
Power Dissipation ◽  
Thick Plate ◽  
Control Method ◽  
Rolling Force ◽  
Yield Criterion ◽  
Inner Product ◽  
Relative Reduction ◽  
Force Model ◽  
Theoretical Results

In order to solve the nonlinear integral difficulty of the Mises yield criterion, a linear yield criterion, called the collaborative approximation (CA) yield criterion, is proposed by the collaborative control method. According to the approximation method, the mathematical expression of the CA yield criterion is derived as a linear function of the three principal stresses. The theoretical results based on the yield criterion in the form of the Lode parameter are verified with the classical test data, and a good agreement is found. Meanwhile, for the purpose of proving the effectiveness of the yield criterion, its specific plastic power is derived and applied to establish the rolling force model of an extra-thick plate. In the modeling, the internal power of plastic deformation is obtained by using the derived specific plastic power, while the shear power dissipation and the frictional power dissipation are obtained by using the methods of strain vector inner product and average velocity integration. Then, the analytical solution of the rolling force is obtained and then extended to the one accounting for the temperature rise. The maximum errors of the predicted rolling torque and rolling force without considering the temperature rise are 12.72% and 11.78%, respectively, while those considering the temperature rise decrease to 3.54% and 5.23%, respectively. Moreover, the influence of relative reduction, friction factor, surface temperature, and the temperature rise of the workpiece on the theoretical results is discussed.

scholarly journals Modelling of Deformation Resistance with Big Data and Its Application in the Prediction of Rolling Force of Thick Plate

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shun Hu Zhang ◽  
Li Zhi Che ◽  
Xin Ying Liu
Keyword(s):  
Neural Network ◽  
Network Model ◽  
Neural Network Model ◽  
Bp Neural Network ◽  
Prediction Accuracy ◽  
Rolling Force ◽  
Deformation Resistance ◽  
Force Model ◽  
The Neural Network ◽  
Bp Neural Network Model

The precision of traditional deformation resistance model is limited, which leads to the inaccuracy of the existing rolling force model. In this paper, the back propagation (BP) neural network model was established according to the industrial big data to accurately predict the deformation resistance. Then, a new rolling force model was established by using the BP neural network model. During the establishment of the neural network model, the data set of deformation resistance was established, which was calculated back from the actual rolling force data. Based on the data set after normalization, the BP neural network model of deformation resistance was established through the optimization of algorithm and network structure. It is shown that both the prediction accuracy of the neural network model on the training set and the test set are high, indicating that the generalization ability of the model is strong. The neural network model of the deformation resistance is compared with the theoretical one, and the maximum error is only 3.96%. Furthermore, by comparison with the traditional rolling force model, it is found that the prediction accuracy of the rolling force model imbedding with the present neural network model is improved obviously. The maximum error of the present rolling force model is just 3.86%. The research in this paper provides a new way to improve the prediction accuracy of rolling force model.

Research on Finishing Rolling Force Model for Hot Rolling Wide and Heavy Stainless Steel Clad Sheets

2014 ◽  
Vol 488-489 ◽  
pp. 213-216 ◽  
Author(s):  
Jin He Rong ◽  
Xiao Hong ◽  
Geng Yong Xiang ◽  
Jiang Jin Shui
Keyword(s):  
Stainless Steel ◽  
Relative Error ◽  
Hot Rolling ◽  
Rolling Force ◽  
Rolling Stock ◽  
Force Model ◽  
Mechanical Coupling ◽  
Hot Rolled ◽  
Force Calculation ◽  
Unit Pressure

In order to effectively improve the calculation accuracy of finishing rolling force model for hot rolling wide and heavy stainless steel clad sheets, based on the E.Orowan unit pressure equilibrium differential equations and R.B.Sims unit pressure formulas, this paper divides hot-rolled composite deformation area into I, II two zones according to rolling stock jamming experiment, and then derives the finishing rolling force calculation formulas. Finally, by ANSYS/LS-DYNA thermal mechanical coupling simulation and experiment, the results show that compared with measured values, the relative error of simulated values is about 20%, the relative error of calculated values is less than 10%. Therefore, the rolling force model can accurately predict the size of rolling force and effectively improve the calculation accuracy of rolling force.

scholarly journals Analysis of 3D Plastic Deformation in Vertical Rolling Based on Global Weighted Velocity Field

2022 ◽  
Author(s):  
Boxin Yang ◽  
Haojie Xu ◽  
Qi An
Keyword(s):  
Velocity Field ◽  
Rolling Force ◽  
Minimum Energy ◽  
Reduction Rate ◽  
Rolling Process ◽  
Slab Thickness ◽  
Analysis Model ◽  
Dog Bone ◽  
Plastic Forming ◽  
Width Reduction

Abstract Energy method is an essential theoretical approach to analyze plastic forming, which is widely used in rolling. An analysis model for vertical rolling process is established according to energy theory. By using global weighted method firstly, the 3D continuous velocity field, strain rate field and the corresponding power functional are proposed. The unknown variables are solved numerically based on the principle of minimum energy. Then, deformation parameters and rolling force are determined. The analysis on specific examples with the width reduction rate of 0.03~0.05 shows that the theoretical prediction value of weighted model is in good agreement with experimental results. Moreover, the effects of several shape and rolling parameters on rolling force, rolling power and edge deformation are studied. Both the width reduction rate and initial slab thickness have significant influences on dog-bone size and rolling force. A wider slab slightly increases the nonuniformity of dog-bone deformation. An increase of vertical roller radius can weaken the edge deformation.

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