Incidence of die spacing in the evolution of damage in two-pass wire drawing processes

Abstract

Multipass wire drawing can be made by passing the wire through consecutive dies (tandemconfiguration) or through dies apart from each other (sequential configuration). In this work,both configurations are simulated with the purpose of determining the effect of die spacing on thedevelopment of fractures in two-pass drawn wires subjected to different area reductions. Toachieve this, an uncoupled ductile fracture criterion that considers the evolution of damage underconditions of increasing effective plastic deformation and triaxiality occurring in the material isapplied and assessed in its ability to predict the beginning of fracture under the two analyzedconfigurations.The comparison between tandem and sequential configurations allows the extension of thefracture model used in previous work in order to account for the evolution of damage not onlyunder positive triaxiality values but also and simultaneously for positive triaxiality rates duringthe entire drawing sequence. This new model reproduces in a good way the differences in thedamage evolution between both configurations and also allows to explain the reason why thetandem configuration is more unsafe than the sequential one.