Improvement of roll-gap set-up accuracy using a modified mill stiffness from gaugemeter diagrams

Abstract

Mill-stiffness modification was performed to achieve a more precise roll-gap set-up in the finishing stands of a hot-strip mill. The exit strip-thickness error was assumed to be caused by incorrect mill stiffness. A modification equation which can eliminate thickness set-up error as well as roll-force prediction error was derived from the gaugemeter diagram on the assumption of constant strip stiffness. Measured mill-stiffness values were replaced successively by modified mill-stiffness values. The replacement of the mill stiffness was repeated until saturated mill-stiffness values were obtained at each stand. After mill-stiffness modification, the exit thickness accuracy was markedly increased and the operational stability also improved.