JPS56154212A - Controlling method for breadth of sheet - Google Patents

Abstract

PURPOSE: To make the breadth controllable even in case of an average breadth greatly different from an aimed breadth, by controlling with a vertical rolling mill the breadth deviation on the run- out side of a roughing mill group so as to be nil, and by controlling with another different vertical rolling mill the predicted average breadth so as to coincide with an aimed breadth.

CONSTITUTION: In a hot roughing mill group comprising alternately arranged vertical rolling mills E₁WE₆ and horizontal rolling mills R₁WR₆, a material 1 to be rolled is passed in the arrowed direction and receives a breadth control in each couple of vertical and horizontal rolling mills. The breadth size of the sheet 1 finished a rolling pass of the rolling mill R₃ is measured over all length of the sheet 1 by a breadth meter 2 installed on the run-out side of the rolling mill R₃; the data of this measurement are stored as the actually measured breadth W₃ in an electronic computer 3. The computer 3 computes thereupon the actually measured average breadth W₃A on the basis of the stored breadth W₃ and the difference (breadth deviation Δd) between the breadth W₃A and the breadth W₃ at every point along the longitude of the sheet 1. Thereupon, the set point of the roll gap of the rolling mill E₄ is controlled so as to eliminate this deviation Δd, and besides, the roll gap of the rolling mill E₅ sitting on the downstream side of the rolling mill E₄ is controlledly corrected so as to make the predicted average breadth w₆A on the run-out side of the rolling mill R₆ coincide with the aimed value therein.

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