Computational prediction of chevron cracking during multi-pass cold forward extrusion

Abstract

The cold forward extrusion is a manufacturing process that is widespread in automated production due to its economic benefits. The cross-section is reduced during this process, which is accompanied by large plastic deformations. It may lead to the chevron cracking, which has to be predicted for flawless production and maintaining economic advantage. Therefore, the multi-pass cold forward extrusion of cylinder made from AISI 1045 was numerically simulated. The central cracks were predicted by the recently proposed uncoupled ductile fracture criteria. These were calibrated using various experiments, including the small punch test with additional fractographic observation. The material model was implemented into Abaqus using the user subroutine so that defects were successfully predicted using an element deletion technique.