A Universal Continuous Caster-Hot Strip Mill Direct Rolling Process by Effective Utilization of the Unique Schedule Free Rolling Operation System

Abstract

A new 66-in. Yawata hot strip mill put into operation in Apr. 1982 and the total production amounted to 17 million tons at the end of June 1987. In this mill, up-to-date equipments, such as the 6Hi mill, work-roll shift device, etc. and large scale computer control system were introduced. This SFR operation has been established by a lot of developments about the unique softwares, such as the work-roll shift system, automatic crown and flatness control system, the resistance to deformation model employing the dislocation theory, forward slip measuring system, specialized operation of the reheating furnaces, etc. As a result, the coupled and synchronized operation between continuous caster and hot strip mill has been carried out successfully, so-called hot charged rolling (HCR), which has brought not only to the cost reduction but also to the market need without production shortage. This epoch-making SFR operation has surely changed the image of hot strip mill operation. And, an advanced and lay-out free direct rolling (CC-HDR) operation started-up in June 1987.