Patent ID: 8973419
Filing Date: 2015-03-10
Classification: B21B

Abstract:
1. A rolling mill which has at least one upper and lower pair of a work roll and a backup roll, the rolling mill comprising: rolling devices positioned at a work side and a drive side, configured to close the upper and lower pair of backup rolls in a gap direction, load detecting devices for measuring rolling direction forces in a kiss roll state acting on roll chocks at the work side of the work roll and on roll chocks at the drive side of the work roll, rolling load detecting devices for measuring backup roll reaction forces at the work side and the drive side in a kiss roll state, a rolling direction force difference calculating device for calculating a difference of the rolling direction forces acting on the roll chocks at the work side and the roll chocks at the drive side measured by the load detecting devices, a left-right asymmetric roll gap control quantity calculating device for using the calculated value of the rolling direction force difference calculating device to calculate left-right asymmetric roll gap control quantities at the work side and the drive side of the rolling mill, and a left-right asymmetric roll gap control device for controlling the rolling devices at the work side and the drive side of the rolling mill based on the calculated values of the left-right asymmetric roll gap control quantity calculating device, the left-right asymmetric roll gap control quantity calculating device configured to calculate the left-right asymmetric roll gap control quantities at the work side and the drive side of the rolling mill so that a sum of detected backup roll reaction forces at the work side and the drive side in the kiss roll state becomes a value of within ±2% of a predetermined value and that the difference of the rolling direction forces acting on the roll chocks of the work side of the work rolls and the roll chocks of the drive side becomes a value of ±5% of the average of the rolling direction forces of the work side and the drive side.