Method for controlling rolling mill

TL;DR: In this paper, the authors proposed to suppress thickness variation of a rolled stock on the outlet side of a rolling mill even when difference is present between right and left rigidities of the rolling mill by adjusting a matrix of coefficients.

Abstract: PURPOSE: To suppress thickness variation of a rolled stock on the outlet side of a rolling mill even when difference is present between right and left rigidities of the rolling mill by changing the apparent rigidity of the rolling mill by adjusting a matrix of coefficients. CONSTITUTION: By expressing displacement of thickness on the inlet sides in the vicinity of one end and in the vicinity of the other end in the width direction of an object material of rolling by Δhd and Δhw, displacement of screw down positions on one end and the other end sides in the axial direction of roll by ΔSD, ΔSW, deviations of rolling load respectively by ΔPD and ΔPW, coefficients by K1-K8, deformation model of rolling mill expressed by the equation I and, by expressing the displacement of thicknesses on the outlet sides in the vicinity of one end and in the vicinity of the other end in the axial direction respectively by ΔHD and ΔHW and influence coefficient to the rolling load P of the thickness (h) on the outlet side by αp/αh, the model of the rolled stock expressed by the equation II are utilized. Deviations ΔPD and ΔPW of rolling load are inputted, screw down position displacing command value ΔSDref on the one end side and screw down position displacing command value ΔSWref in the axial direction are calculated based on the equation III and the screw down device of the rolling mill is controlled in accordance with the ΔSDref and ΔSWref.