FE Analysis On Strain Field For TWIP Steel Strip In Hot Asymmetrical Rolling Process

TWIP steel is also called twinning induced plasticity steel.Microstructure and performance of hot rolled and annealed TWIP steel is closely related to the refined and twinned grains,even the γ-texture density.Compared with the symmetrical rolling,the asymmetrical one is more easier to roll distorted permeation,obtain the finer twinned grains and higher γ-texture density to the realization of equivalent strain and the higher shear deformation.However,the distribution gradient of microstructure still exists in the thickness direction of the asymmetrically hot rolled strip.Therefore,it is of tremendous significance to deeply analyze the influence of process technology on the strain field as well as the disparity consisting in the thickness direction.In this paper,the rigid plastic finite element method(FEM)is used to simulate the hot asymmetrical rolling process of TWIP steel.Influence of such thermodynamic parameters as the velocity ratio,the initial temperature,the reduction rate,the work roll diameter and the friction coefficient on the center strain and the strain difference along the vertical direction of the hot rolled strip has been analyzed,even the related mathematical model has been constructed.The specific contents are as follows:(1)The thermophysical parameters and the true stress-strain curves of the TWIP steel will be obtained by the thermophysical tests and the uniaxial compressive experiments.The deformation resistance model of this steel is regressed by MATLAB software.(2)A FE model for the strain field analysis of the hot asymmetrical rolled strip is established using 2D rigid plastic FEM.The mesh size sensitivity has been analyzed by the analysis on the changed shear strain in the strip center with the number of units and verified by comparison of the maximal rolling force between the simulated and tested values.(3)According to the numerical simulated results,influence of the thermodynamic parameters on the shear strain,the compressive strain and the equivalent strain of the strip center and the strain distributed difference along the thickness direction of the hot rolled strip has been analyzed,and the related mathematical models will be constructed.