METHOD FOR CONTROLLING SHEET THICKNESS DURING PASSING THROUGH CONTINUOUS HOT ROLLING MILL

摘要

PURPOSE:To execute surely screw-down correction with fast response by detecting the deviation of rolling load and the deviation of screw-down position at the point of the time when the corresponding stand bites the front end of a material to be rolled, determining the screw-down correction rate of the succeeding stage according to the detected deviations and correcting the screw-down before the stand bites the front end. CONSTITUTION:The deviation DELTAPi of the rolling load and the deviation DELTASi of the screw-down position indicating the deviation from a preliminarily given target value are detected by the load cell 14i of the corresponding i-th stand and a screw-down position detector provided to a screw-down position control device 16i right after the rolls 12i of the corresponding i-th stand bites the front end 10A of the material 10 to be rolled. The prescribed calculation is made in a computer 20, etc. by the detected values thereof and the rolling reduction DELTASi+1* of the succeeding (i+1)-th stand is calculated. The screw-down position of the roll 12i+1 is changed by the screw-down position control device 16i+1 of the (i+1)-th stand before said stand bites the front end. As a result the safe control is executed even if there is a detection error in the rolling load and the screw-down position. The titled control of the sheet thickness by which the target sheet thickness is surely obtd. from the front end of the coil is thus executed.