METHOD FOR CONTROLLING SHEET THICKNESS

摘要

PURPOSE:To improve the controlling accuracy of sheet thickness by changing an estimation value for the controlling calculation of a natural mill stiffness factor basing on the measured value of a rolling load. CONSTITUTION:A load sensor 12 such as a load cell is attached to a hydraulic cylinder 10 used for controlling the roll draft position of a rolling mill. Rolling loads measured at every moment by the sensor 12 are fetched into a setter of an estimation value for controlling calculation of a controller, to determine first a natural mill stiffness factor corresponding to each rolling load value basing on said measured values of rolling load and a curve of natural mill stiffness factor. A mill stiffness factor for controlling calculation is successively set so as to make it follow up said natural mill stiffness factor. A controlling calculation is performed by the controller basing on the newly set mill stiffness factor for controlling calculation, and the cylinder 10 is actuated in correspondence with the calculation to change the draft position of a roll 16 so as to control the exit sheet thickness to be constant.