Theoretical and experimental research on rolling force for rail hot rolling by universal mill

2010 ◽  
Vol 17 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Yong-gang Dong ◽  
Wen-zhi Zhang ◽  
Jian-feng Song
Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 869
Author(s):  
Rongrong Peng ◽  
Xingzhong Zhang ◽  
Peiming Shi

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.


2016 ◽  
Vol 88 (5-8) ◽  
pp. 2053-2059 ◽  
Author(s):  
Si Li ◽  
Zhigang Wang ◽  
Changming Liu ◽  
Jinhua Ruan ◽  
Zengbing Xu

2012 ◽  
Vol 602-604 ◽  
pp. 1864-1868 ◽  
Author(s):  
Lan Wei Hu ◽  
Xia Jin ◽  
Lei Shi ◽  
Sheng Zhi Li

A 3-D thermal-mechanical model was built to simulate the hot rolling process of medium plate, with the aid of nonlinear commercial FE code MSC.SuperForm on a company's actual process parameters. The hot rolling process of single-pass which slab thickness is 180mm was simulated, and the influence of pass reduction on metal flow, stress-strain field, contact stress and rolling force were researched. The study revealed that pass reduction should be at least 20% by increase depress in pass in addition to rolling efficiency. As that, rolling efficiency be increased, roll contact stress be brought down, and its service life be prolonged. And metal plastic strain enhanced, metal flow increased, but its strain field non-uniformly distributed, metal flow and plastic deformation would be strengthen by increase pass reduction, and the lateral broadening in the head is bigger than that in the tail.


2011 ◽  
Vol 16 ◽  
pp. 745-754 ◽  
Author(s):  
Huang Changqing ◽  
Deng Hua ◽  
Chen Jie ◽  
H.U Xinghua ◽  
Yang Shuangcheng

2011 ◽  
Vol 03 (03) ◽  
pp. 469-489 ◽  
Author(s):  
JINLING ZHANG ◽  
ZHENSHAN CUI

A mathematical model integrating analytical method with numerical method was established to simulate the multi-pass plate hot rolling process, predicting its strain, strain rate, stress and temperature. Firstly, a temperature analytical model was derived through series function solution, the coefficients in which for successive processes were smoothly transformed from the former process to the latter. Therefore, the continuous computation of temperature for multi-operation and multi-pass was accomplished. Secondly, kinematically-admissible velocity function was developed in Eulerian coordinate system according to the principle of volume constancy and characteristics of metal flow during rolling with undetermined coefficients — which were eventually solved by Markov variational principle. Thirdly, strain rate was calculated through geometric equations and the difference-equations for solving strain and a subsequent recurrent solution were established. Fourthly, rolling force was calculated on the base of Orowan equilibrium equation, considering the contribution to flow stress of strain, strain rate and temperature, rather than taking the flow stress as a constant. Consequently, the thermo-mechanics and deformation variables are iteratively solved. This model was employed in the simulation of an industrial seven-pass plate hot rolling schedule. The comparisons of calculated results with the measured ones and the FEM simulation results indicate that this mathematical model is able to reasonably represent the evolutions of various variables during hot rolling so it can be used in the analysis of practical rolling. Above all, the greatest advantage of the presented is the high efficiency. It costs only 12 seconds to simulate a seven-pass schedule, more efficient than any other numerical methods.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Guangxu Zhang ◽  
Jiahan Bao ◽  
Wenhao Li ◽  
Zhichong Wang ◽  
Xiangshuai Meng

It is important to study the vibration of rolling mills to improve the stability of rolling production. A dynamic rolling process model is established by considering the elastic recovery of the exit strip and the influence of multiroll equilibrium, and the accuracy of the model is verified by experimental data. On this basis, based on the distribution of friction force in the deformation zone, the rolling force and rolling torque are nonlinearized. In addition, a rolling mill structure model is established by considering the structure gap and a piecewise nonlinear horizontal-vertical-torsional vibration model of the rolling mill is established by combining the structure model and dynamic rolling process model. Finally, the amplitude-frequency characteristics of the work roll under different external excitation amplitude and the dynamic bifurcation characteristics of the work roll under different gaps are analyzed. The study indicates that, by reducing excitation amplitude and structure gap, the system vibration can be reduced. The research results can provide a theoretical reference for further exploration of the coupling vibration of hot rolling mills.


1995 ◽  
Vol 117 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Zone-Ching Lin ◽  
Y. C. Cheng

The paper is an investigation of strip curvature caused by the different speeds between the upper work roll and the lower work roll in the rolling process for an aluminum strip. At the same time, we analyzed the variations in the temperature field and strain field, and used a method of speeds variation of the upper and lower work rolls to calibrate the deformation curvature caused by the coolant condition in the hot rolling process. Based on the large deformation-large strain theory, and by means of the Updated Lagrangean Formulation (ULF) and increment theory, a coupled thermoelastic-plastic analysis model for hot rolling process is thus constructed. At the same time the finite difference method was also used to solve the transient heat transfer equation. Finally, the numerical analysis method developed in this study was employed to analyze the changes in the aluminum strip’s temperature and other changes during rolling. In addition, the average rolling force obtained from the simulation was compared with that from the experiments. It verified that the model in this study is reasonable.


1999 ◽  
Author(s):  
Yhu-Jen Hwu ◽  
Chang-Huei Wu

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.


2016 ◽  
Vol 15 ◽  
pp. 64-74
Author(s):  
Filippo Cianetti ◽  
Claudio Braccesi ◽  
Maria Cristina Valigi

In the design of the rolling mill plants, it is fundamental to study the behaviour of the deformation process to assess the main process variables (such as torque and rolling force) in all operating conditions.In this paper, a finite element model is developed and the numerical simulations of the plastic deformation process, in the hot rolling mill of AISI 304 stainless steel, are shown. In the proposed model a Multilinear Isotropic Hardening behaviour of material has been assumed and true stress-true strain curves have been found, taking into account temperature and strain rate. Numerical results are compared with experimental measures regarding an existing hot rolling mill plant.


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