Stress and deformation analysis of the metal extrusion process

Abstract

A complete stress analysis of a metal-forming process is necessary in order to assess the onset of metal-forming defects such as the initiation of internal or surface cracks or the generation of residual stresses. This demands elasticplastic analysis. A program to evaluate complete stress distributions has been developed and applied to the extrusion process. Such solutions have not previously been obtained for general two- and three-dimensional problems encompassing the technologically important steady state processes, although these solutions are essential for the rational assessment of limits on process variables which will ensure a satisfactory metal-forming procedure. The stress fields obtained for the extrusion process exhibit features which are consistent with the known development of extrusion defects, such as the appearance of surface cracks.