Roll pressure distribution in strip rolling.

The determination of the pressure distribution generated along the arc of contact between the rolls and workpiece during the rolling process has been a subject of interest to researchers for many years. Existing rolling theories make assumptions and include simplifications which are not often substantiated by direct measurement techniques in which pressure transducers are located within the roll surfaces. Such techniques are effective but prohibitively expensive since they render the rolls useless for rolling. A technique has been developed in which the pressure distribution and roll separating load are determined from consideration of the elastic deformation of the rolls during operation. By interrupting a rolling pass before completion, the shapes of the deformed rolls are imparted to the workpiece surface. Accurate measurement of the imparted profiles at several sections across the width of the workpiece allows the extent of the elastic deformation of the roll to be determined. An analytical solution based on solid body contact theory was used to determine the pressure distribution responsible for the elastic deformation along each section. The solution incorporates experimentally determined parameters and functions relating to specific mill-stands and schedules.Initial experimental work was undertaken in which the proposed technique was applied to the quasi-static indentation of flat and inclinedstrip specimens. Having established the basic features of the method relating to these modes of deformation the technique was then applied to the cold rolling process in the form of interrupted rolling passes.Tests were undertaken using a two-high laboratory rolling mill reducing the thickness of mild steel strip workpieces. Comparisons between the predicted pressure profiles using the technique developed and those determined by others using pressure transducers show close similarities. A comparison between the predicted roll separating loads and those determined experimentally show a reasonable correlation.