A General Method of Analysis for Predicting Profile and Flatness

A “first principles” approach is developed to calculate the difference in longitudinal stress in hot and cold rolling as the profile is changed. This knowlege is important in the control of profile and flatness. This approach eliminates the empirical constants that need to be tuned from experimental rolling trials. The program has the speed and accuracy necessary to be used on-line. The model is based on a viscoelastic internal variable analysis in which the influence of stress relaxation and changes in microstructure on the difference in longitudinal stress and profile are determined. The model works for steel, aluminum, and other nonferrous metals, hot and cold rolling, reversing mills, plate mills, and tandem finishing mills. Discussion of the factors that influence the difference in longitudinal stress and profile for a carbon steel, AISI 1020, and commercially pure aluminum, and recommendations for future work are also included.