JPS57124513A - Sheet thickness controlling method for continuous rolling mill - Google Patents

Abstract

PURPOSE:To improve the controlling accuracy of sheet thickness in a continuous mill, by predicting the fluctuation quantity of the sheet thickness at the exit side on the downstream from the rolling conditions on the upper stream between optional stands, and controlling a rolling reduction on the downstream side, based on the predicted results. CONSTITUTION:In a range between 2 optional stands of a continuous rolling mill, the load fluctuation quantity DELTAP1 detected at the 1st stand, the changing quantity of rolling reductions DELTAS1, the thickness changing quantity DELTAH1 at the inlet, and the mill rigidity factor M1 from a rolling-schedule operator 3, etc. are read into an operator 2 to perform predictive compution of the sheet-thickness fluctuation at the exit side of the 2nd stand. The result is outputted to a register 4 to read a roll peripheral speed from a pulse generator 31, and the sheet- thickness fluctuation quantity is outputted to an operator 5 by synchronizing it with the time that a predicting position of the sheet- thickness fluctuating quantity reaches the 2nd stand. The operator 5 reads in a mill rigidity factor M2, etc. of the 2nd stand to compute a desired load changing quantity. The result is inputted to a comparator 6 to be compared with a load fluctuating quantity and to control a hydraulic screw-down device 9 by giving a command to a servovalve 8 thereby controlling the rolling reduction of the 2nd stand.