Long Term Experiences of the Hybrid Tension Control of Hot Strip Finishing Mill

Abstract

The fine tension control for the steel material in the hot strip finishing mill is quite important to achieve the operational stability of the rolling mill and the high level property of the products. To realize this drastically in mechanics and instruments of looper tension control system, authors developed the hybrid tension control system. This system realized the looperless rolling for the heavy gauge strip to redesign loopers scaling down into 1/4 in its GD2 only for the light gauge strip use. The system aimed 2 points: Achieving the direct improvement of the control ability by making the actuator and process simple without applying sophisticated feedback control techniques. Realizing non-overloaded tension meters with high resolution. This system has been applied for almost 20 years in the hot strip finishing mill of Keihin, JFE Steel Corp. No operational troubles due to the system have been since ever and this has been supporting the development of the new grades of materials.