CORRECTION METHOD FOR OIL FILM THICKNESS ON BACKUP ROLL OF ROLLING MILL

摘要

PURPOSE:To easily correct the thickness of an oil film and to improve the plate thickness accuracy by detecting acceleration or deceleration of a rolling speed and adding a positive and a negative correction values to a film thickness in a bearing of a backup roll at each acceleration and deceleration of the rolling speed respectively at the time of setting a drafting position of a rolling mill drafting device. CONSTITUTION:An acceleration and deceleration detecting means 10 decides that a rolling mill 14 is in an acceleration or a deceleration condition. When the mill 14 is decided to be in an acceleration condition, a computing element 26 adds a constant fixed value rhoC to the preceding correction value rhoC to find a new correction value rhoC and outputs the new value to a limiter 28. If the new rhoC is smaller than a set value in the limiter 28, the new value is outputted; if the new value is larger than the set value, the preceding correction value is outputted. In a deceleration condition, the constant value rhoC is subtracted from the preceding correction value rhoC and a new correction value rhoC is outputted to the limiter 28. At that time, if the new value rhoC is smaller than a set value in the limiter 28, the former value rhoC is outputted; if the former value is larger than the set value, the preceding correction value rhoC is outputted. Thus, those addition and subtraction are repeated so that the correction value rhoC runs down to zero.