Analysis of stress in cross wedge rolling with application to failure

In the present investigation, a previously developed three-dimensional fini te-element model for the cross-wedge rolling (CWR) process has been used to characterize the workpiece material stress and deformation behavior. Parti cular attention has been paid to the center and mid-radius points of the bi llet where internal defects (i.e, internal cracks and porous voids) often o ccur. Several failure criteria in the solid mechanics theory are summarized . The effect of three important CWR parameters, namely the forming angle, t he area reduction, and the friction coefficient, on the field variables has been investigated, including the first principal stresses, maximum shear s tresses, etc. A total of 14 rolling conditions are analyzed for the billet material aluminum alloy 1100, After initially verifying the numerical resul ts, several tendencies for the CWR process, as related to failure, are asce rtained and discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.