JPS57130710A - Automatic controlling method for sheet breadth in hot roughing mill - Google Patents

Abstract

PURPOSE:To reduce the fluctuation of a strip breadth and an interstrip breadth and to reduce the difference between the breadths, by utilizing a phenomenon that the spreading quantity of the breadth after the next horizontal rolling changes responding to the breadth-reduction quantity for a vertical roll of controlling object, in rolling the strip with plural rolls. CONSTITUTION:A control-interference is obtained by computing the max. controlling breadth- reduction of a controlling-object vertical-roll 7 basing on the respective limiting equations for power consumption, rolling load, buckling, and biting. The strip-breadth, prior to controlling, is determined from said interference and a desired strip-breadth at the exit side of a roughing mill basing on the predetermined equation of a breadth-spreading. Then a roll gap of a vertical rool on the upper stream side is set so as to obtain the strip-breadth prior to controlling, thereby measuring the breadth and temp. of the strip with a breadth meter 1 and a thermometer 2 at the inlet side of the mill. The roll gap is then computed and controlled continuously by using the measured results and the equation of breadth-spreading. At the same time, the rolling load is measured by a load meter 3, and a load, equivalent to a mill spring of the roll 7, is corrected by a mill-spring correcting device 19. Thus, the breadth fluctuation within a same hot strip is reduced and breadths of whole strips approach the aimed one, and the difference between the actual breadth and ordered one is reduced.