Stress and Strain Analysis in Temper Rolling for Thin Steel Sheet by Elastic–Plastic Finite Element Method

Abstract

The temper rolling is applied to eliminate the stretcher strain, to improve the flatness and to control the surface roughness of rolled-sheet as the finishing process in cold rolling. However, there are some problems remain in analysis of the temper rolling. The classical rolling theory based on the rigid plastic theory, can not deal with non-uniform elastic–plastic deformation in the thickness direction, because the deformation is partly concentrated on the surface layer of the sheet. This paper presents an elastic–plastic finite element analysis of stress and strain behaviors in plane strain temper rolling for as-annealed mild steel sheet. In the analysis, the upper yield stress, the lower yield stress and yield point elongation are taken into account for the stress–strain relation of material rolled. For the contact boundary between roll and deforming material, both slipping and sticking are considered, and the Coulomb friction law is employed to represent the slipping friction. Furthermore, calculated rolling force by the EP-FEM is compared with that by the classical rolling theory as Karman's equation and that obtained by a laboratory scale rolling experiment with bright rolls or dull rolls. As the results, in the case of small friction between roll and deforming material, the rolling force obtained by Karman's equation coincide with that by EP-FEM and that by experiment.