Width control systems with roll force automatic width control and finishing vertical mill automatic width control in hot strip mill

This paper proposes a new width control system composed of an RF (roll force) AWC (automatic width control) in the roughing mill and a FVM (finishing vertical mill) AWC in the finishing mill which aims at obtaining the desirable width margin in the hot strip mill. The RF AWC is designed by the control model on the basis of a gauge meter equation using the roll force of the vertical mill. The FVM AWC is designed using a neural network based width prediction model to minimize a width variation between the measured width and the target value. The RF AWC and the FVM AWC combined with the conventional FB (feedback) AWC satisfy a desirable width margin. It is shown through the field test of the Pohang no. 1 hot strip mill of POSCO that the performance of the width margin is considerably improved by the proposed control schemes.