Investigation of model error on calculating strip profile in 4-high mills

Abstract

In 4-high mills the slit model is usually used to determine elastic roll stock deformation, in order to predict the strip profile. In this model, the roll axis deflections obtained by the simple beam theory are satisfactory, but the roll flattening obtained by the elasticity theory of the half-space or the half-plane is inaccurate. In the present paper 5 models are introduced to determine the roll flattening. Change of the roll flattening causes the change of internal pressure between work roll and back-up roll, in turn, the change of strip profile. Therefore influence of the flattening models on the strip crown was investigated. Strip crown difference between these flattening models can reach 60 μm in the present simulation. With the increase of the strip width or the roll force the strip crown difference increases, namely the model error increases. The bending jack force and roll crown have a small influence on the model error.