Analysis of thin strip edge drop formation during cold rolling process

Abstract

ABSTRACT In order to produce a thin non-oriental silicon steel strip with high surface quality, the hot rolled strip needs to undertake a large reduction by cold tandem rolling process. As a result of thin strip rolling, the rolling pressure is concentrated on a small area of the work roll surface causing a large elastic deformation. Because of the transverse thickness distribution of strip is strongly dependent of roll’s shape, it is imperative to consider work roll’s non-circular shape. By relaxing the Hitchcock assumption, vertical displacement of work roll surface is calculated in both rolling and transverse direction. By assuming the thickness of strip does not increase when rolled, a Slab method is implemented to calculate roll pressure due to work roll’s shape. Combined with Influence Function Method for loads distribution between stacked rolls, the proposed model can predict thin strip transverse thickness profile with a good accuracy compared with industrial data under varied conditions. Five-pass cold reversal rolling process is investigated by the validated model. It is revealed that the transverse thickness deviation can be effectively reduced by decreasing the entry thickness of strip.