JPS56126015A - Controlling method for breadth of strip in hot strip mill - Google Patents

Abstract

PURPOSE: To prevent a fluctuation of the height of looper and the thickness of the strip, by correcting the roll gap and the revolution number of the roll adjoining to the looper correspondingly to the quantity of computed correction value for the roll gap.

CONSTITUTION: The breadth deviation operator 22 operates the breadth deviation ΔW_i from the strip breadth W_i detected by breadth-meter 20 and the aimed breadth W₀ inputted from outside; the rate of breadth variation ΔW_i/W_i is operated by the rate-of-breadth-variation operator 24. The function generator 26 produces a signal ΔU_t for the variation of the corresponding unit tension; depending on this signal ΔT_t, the looper torque variation operator 28 operates the variation ΔT of the torque, which is then inputted to the controller 18; thereby, the controller 18 changes the torque of the looper 16. On the other hand, the revolution number correction operator 30 operates the revolution number correction operator 30 operates the revolution number correction value ΔN_i-1 for the roll of the upstream side rolling stand 10_i-1; this correction value ΔN_i-1 is inputted to the roll's revolution number controller 13 which thereby corrects the revolution number of said roll. Meanwhile, the roll gap correction operator 34 operates the roll gap correction value ΔS_i for the roll of downstream side rolling stand 10_i, and inputs it to the roll gap controller 14 which thereby corrects the roll gap of the downstream side rolling stand 10_i.

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