A COMPARISON OF FRICTION COEFFICIENTS IN COLD-ROLLING

A sensor which uses strain gauges mounted on a conical cantilever sens ing element, has been designed to measure the three forces of interest at the roll/strip interface, namely the normal force, the friction fo rce in the rolling direction and the friction force in the direction t ransverse to rolling. Successful experiments have been conducted with the sensor using 1100 aluminium, with a low aspect ratio, as the rolle d product. An analysis of the experimental results reveals a 'rotating friction vector' which is not parallel to either axis of symmetry. Th is vector can be found when the transverse friction force, which is or thogonal to the rolling direction, is added vectorially to the frictio n in the rolling direction. When the rotating friction vector is consi dered in terms of 'Coulomb' friction, mu, a constant, direction depend ent mu occurs. The mu arrived at in this manner is compared to an 'old ' model by Ford and is found to be in agreement for this specific roll ing situation. Experimental results are presented for a 24.2% reductio n. (C) 1998 Elsevier Science S.A. All rights reserved.