GB1326157A - Control of strip tension in rolling mills - Google Patents

Abstract

1326157 Rolling mills NIPPON KOKAN KK 25 Aug 1971 [26 Aug 1970] 39773/71 Heading B3M In a method of controlling a cold tandem strip mill having stands 1 and 2, the tensile stress acting on a rolled strip is kept constant despite changes in its width or thickness. The method is applicable to a mill in which lengths of strips having different widths or thickness are joined together before rolling, to provide one continuous strip. The thickness of the strip is measured by a counter 7, its width by a counter 8, and its tension by a meter 9. The thickness and width signals are fed to a multiplier 10, and to a calculator 11 which provides a signal corresponding to the desired total tension in the strip. This signal is compared with the actual tension from the meter 9, and any error signal is used to control the speeds of the stands or the screwdown of stand 2 so that the error signal is reduced. Instead of the thickness counter 7, a load cell and screwdown position indicator associated with stand 1 may be employed. To compensate for the different positions of the counters 7 and 8 and meter 9 relative to the strip, delay circuits which are sensitive to the strip speed, may be positioned between the counters and the multiplier 10.