JPS56122608A - Loop controller for hot strip continuous rolling mill - Google Patents

Abstract

PURPOSE:To reduce the fluctuation of tension, and to improve the control performance, by including a tension control system in the loop controlling system for controlling the loop, and by controlling the tension between the rolling stands. CONSTITUTION:The amount of loop between the rolling stands fluctuates for every unit time according to the speed difference between the speed Vn of the rolled material 3 running out of the upstream stand 1a and the feeding speed Vn+1 of the material 3 into the downstream stand 1b; hereupon, the tension T also fluctuates. As a result, the looper angle theta fluctuates for every unit time. The amount of loop Sl is detected through the looper angle theta; this value Sl is compared with the reference loop Sl'; by thus obtained deviation of the amount of loop, the rolling speed Vn of the upstream stand 1a is corrected so as to control the amount of loop between the stands 1a and 1b. On the other hand, the fluctuation of amount of the loop causes the fluctuation of the tension, so that the tension controller 13 and the tension detector 12 are installed in order to reduce the fluctuation of the tension T. Hereby, under the steady condition, the tension becomes equal to the tension T corresponding to the torque Tl generated by the looper motor 6, so that the tension control system controls the tension T so as to be equal to the reference tension signal T.