Consideration of Circumferential Work Roll Surface Displacements in a Non-Circular Arc Temper Rolling Model

In the course of the production of cold rolled flat products, temper and skin-pass rolling represents the final rolling operation. Thereby a slight thickness reduction resulting in an elongation of app. 0.2-2% is applied to the cold rolled and annealed strip. Usual mathematical models for cold rolling of strip cannot be used in temper rolling conditions, as high work roll flattening, high macroscopic friction between work roll and strip due to textured work rolls, significant elasto-plastic strip behavior, relatively large no-slip zones and the potential appearing of "contained plastic flow" make the situation much more complicated. A new temper rolling model is presented applying a non-circular arc theory for the calculation of the elastic work roll flattening. In addition to the radial displacements of the work roll surface, also its circumferential displacements, generated mainly by the shear stresses acting between work roll and strip, are taken into account. The underlying rate-dependent elasto-plastic model of the strip allows for the appearance of several subsequent elastic and plastic zones. The consequence is that the case of "contained plastic flow" will appear automatically without additional simplifying assumptions. Excellent agreement between measured and predicted rolling forces and rolling torques was achieved.