Pressure Distribution, Roll Force and Torque in Cold Ring Rolling

Abstract

Normal pressure distribution, roll force and torque are measured accurately when rolling plain and profiled rings by using the pin-type pressure-transducer technique. A simple theoretical model, based on the plane strain slip-line field solution for the indentation of a block by opposed flat indenters, is developed to provide an estimate of roll force and torque for profiled rings. The driving torque is also predicted by deriving the resultant force and the lever arm. Examination of the results indicates that, in contrast to conventional strip rolling, the normal pressure distribution in ring rolling shows an early peak soon after the entry plane and that conventional friction-hill theory appears inapplicable. Recognizing the appreciable differences in geometry in the roll gap and elsewhere, flat rolling analysis seems generally inappropriate to ring rolling.