METHOD FOR AVOIDANCE OF ABNORMAL DROP OF TENSION IN SKIN PASS ROLLING MILL

摘要

PURPOSE:To restrain increase of a slip and to prevent abnormal drop of tension by controlling a slip tension control signal by detecting a slip in case of generation of the slip between either of the mill inlet or outlet side bridle rolls and a strip. CONSTITUTION:A difference between both the numbers of pulses generated by pulse generators 18, 19 during a unit lapse time and a difference between both the numbers of pulses generated by pulse generators 20, 21 during a unit lapse time are detected as a slip speed Se between a mill inlet side bridle roll 5 and a strip 15 and a slip speed Sd between a mill outlet side bridle roll 6 and the strip 15, respectively. Further, a speed having a larger absolute value between both the speeds Se and Sd is always selected and is denoted by S. Then, level decision is performed to the speed S. When an S larger than a given absolute level Sa is detected, a decision of slip generation is performed and a strip tension control signal is kept. When the S is smaller than an specific absolute level Sb after the strip tension control signal is kept, keeping the signal is canceled and control is returned to a normal control; where, Sb is a smaller value than the Sa.