JPS56144813A - Controlling method for thickness of tail end of strip - Google Patents

Abstract

PURPOSE: To previously decrease the interstand tension for diminishing the influence of disappearance of tension of the next stand, to be caused by the dropout of tail end of the strip, and to reduce the amount of off-gauge strip, by increasing the roll gap of the next stand just before the tail end of strip drops out of the preceding stand.

CONSTITUTION: When the tail end of strip S passes over the detector 4, the timer 11 generates and inputs a signal to the screw position controller 12 after a prescribed time. The screw position controller 12 thereupon computes the correction value for the roll gap of the stand 2, and sends out a signal to the screw down device 9 which then increases the roll gap of the stand 2 so as to decrease the strip tension between the stands 1, 2 to ≤50% of the strip tension working just before increasing the roll gap. Thereby, the fluctuation of strip thickness in the stand 2, to be caused by disappearance of tension as a result of dropout of the tail end of strip S from the stand 1, is decreased. When the tail end of strip S passes over the load cell 5, the screw down device 10 increases the roll gap through the timer 11 and the screw position controller 12 similarly to above; hereby, the strip tension between the stands 2, 3 is decreased and the correcting operation is repeated so as to decrease the fluctuation of thickness in the stand 3.

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