A model for evaluating thermo-mechanical stresses within work-rolls in hot-strip rolling

A mathematical model is proposed for the determination of the thermo-mechanical stresses in work-rolls during hot-strip rolling. The model describes the evolution of the temperature fields in the work-roll and in the work-piece, and in the latter the plastic heat generation is taken into account. The frictional heat generated on the contact surface is also included. The problem is treated in two steps. First, a numerical method is developed for the analysis of the coupled thermal problem of the temperature distributions within the work-roll and metal being rolled, while an admissible velocity field is employed to estimate the heat of deformation. In the second step, the finite-element method is employed to determine the resulting thermo-mechanical stresses within the work-rolls. A slab method is used to obtain the mechanical boundary conditions in the contact region between the work-piece and the work-roll. The model takes into account the effects of different process parameters such as the initial temperature of the strip, reduction, and the rolling speed on the thermo-mechanical stresses and their distributions. The numerical predictions are compared with experimental results.