Control Equations of Multistand Cold Rolling Mills

Abstract

For the practical assessment of the operating behaviour of a multistand cold rolling mill, it is necessary to know how gauge, speed and interstand tensions are affected by screw and speed-setting changes. This paper sets out the control equations governing the response of each stand to any combination of the external disturbances, that is, how the interstand thicknesses, tensions and final output change due to changes of ingoing gauge, coiler tensions, roll gap settings and roll speeds. The partial derivatives of the roll force, roll torque and forward slip, which enter as factors in the governing equations, are evaluated mathematically, and then expressed in nomographic form. Examples of the use of the nomographs are given.