Contact resistance between roll and titanium sheet during cold rolling

In metal forming processes, electrical contact resistance between the workpiece and a tool could give useful information on the contact state of the two surfaces. However, measurement during rolling is difficult because rolls rotate at high speed. In this study, two titanium sheets were cold-rolled in parallel. A closed circuit was composed of the two sheets, one roll and a power source. Difference in electrical potentials between the two sheets was measured to estimate the contact resistance. It is found that the contact resistance decreases with reduction in thickness and that it depends on lubrication and surface conditions of the rolls. (C) 2019 Published by Elsevier Ltd on behalf of CIRP.