Numerical Simulation Of Friction On Width Spread Of Wide And Heavy Plate During Hot Rolling Process

Wide and heavy plate which is an important part of steel industry of a country, is widely used in military, industry, agriculture and other fields of national economy construction. In plate hot rolling process, the mass cutting caused by poor size control restrict the increase of plate yield. The thickness size is ascertained in laying down the rolling rules, and the width size and length size interact with each other during plate rolling. Reasonable control of width spread in plate rolling is significant to guarantee the plate size. Because the width spread in wide and heavy plate hot rolling is free spread, friction has a major impact on workpiece deformation process. Therefore, study on the effect of friction on width spread can provide the basis for the control of width spread. In this paper, the width spread during wide and heavy plate hot rolling was the objective of study. Then, the research of the effect of friction on width spread during plate rolling was studied by numerical simulation.Firstly, the influence factors of width spread and the effect of friction on workpiece deformation in rolling process were analyzed. The research progress of friction in rolling and the widely used spread formulas were summarized. A three dimensional thermal mechanical coupled finite element model of rolling process for wide and heavy plate was developed by using the finite element software MSC.Marc. In order to verify the reliability of the finite element model, it was used to simulate the rolling process of wide and heavy plate. The width spread results obtained by the model were in good agreement with the measured ones under the same condition and the feasibility of the FE model was verified. This work lay the foundation for the research of friction coefficient on width spread.Secondly, a large number of rolling processes under different reduction and friction coefficient condition of four common size workpieces were simulated by using the finite element model. It is obtained that longitudinal friction force mainly distributed in the width central region and the lateral friction force centralized at the edge of the workpiece. The value of the friction force increases with the increase of friction coefficient. The effect of friction coefficient on transverse flow of surface metal is more obvious than other layers. The width spread on the surface decreases and the width spread on symmetry plane in height direction increases with the increase of friction coefficient. The average width spread decreases with the increase of friction coefficient. The decreasing trend of average width spread is more obvious with the decrease of width of plate and the increase of reduction.Based on above width spread rule and the simulated spread data, the Shibahara formula was modified by friction coefficient. The spread results for the modified Shibahara formula are in good agreement with the simulation ones. The modified Shibahara formula may provide a reference for the accurate control of width spread during wide and heavy plate rolling.