The coefficient of friction during hot rolling of low carbon steel strips

Hot rolling tests were performed on low carbon steel strips with the objective of determining the coefficient of friction as a function of the process variables. The growth of the scale prior to rolling was controlled and the thickness of the layer of scale at the entry remained in the range of 20-100 mum, somewhat higher than in the finishing train of a hot strip mill. Roll separating forces, roll torques, the speed, the reduction and the entry temperature were monitored. The effective coefficient of friction it-as determined by using a one-dimensional model of the flat rolling process. The coefficient it-as chosen to allow matching the measured and calculated roll force and the roll torque. Air empirical relation, connecting the coefficient of friction to process variables was obtained by non-linear regression analysis.