Improvement of the Control Model of Longitudinal Thickness Variability of Cold-Rolled Annealed Strip on a Skin Rolling Mill

The basic control model of longitudinal thickness variability based on the graphic solution to the system of two equations is improved. The model allows regulating the longitudinal profile at skin rolling of a strip on a cold-rolling mill taking into account the most important technological parameters affecting the cold rolling force. Representation of this system as differential equations confirms the original correctness of the graphic solution, allows determining the stiffness modulus of the rolled strip, and choosing the control actions for the technological parameters of the skin rolling process. The reliability of this model is checked by comparing the profile diagrams of the calculated and measured mean values of the longitudinal thickness variability at cold rolling of strips on a skin rolling mill 2000 of Severstal Company. It is shown that an increase in the head and trail specific tensions on a skin rolling mill allows reducing the oscillations of the thickness over the entire area of the rolled strip to the required tolerance from the nominal thickness.