A Fast Computational Model for the Local Stress Distribution and Mechanical and Thermal Work Roll Deformations with Effects on Strip Profile and Flatness During Hot Rolling of Strip in Four-High Mills

Abstract

A fast model is presented for the three-dimensional stress distribution in the roll gap. This local data is used to calculate the 3D deformation of the work roll barrel by flattening and deflection using a combined analytical and finite element procedure. Detailed information about the work roll deformation can therefore be obtained because the model does not rely on a constant roll force. The local strip and work roll temperatures are calculated by a numerical solution of the heat equation and the evolution of thermal roll crown is calculated for a given rolling campaign. The strip shape is found by the intersection of the deformed roll with the initial strip shape. An upper-bound technique is applied for the resulting strip flatness. Typical methods of profile and flatness adjustment are discussed with effects on strip profile and flatness. These are static roll crowns as well as work roll bending, zonal roll cooling, and axially shiftable S-shaped grinded rolls (CVC—continuous variable crown).