Mechanical Engineering, University of Tokyo
The size and length effects of an inclusion on multi-pass copper shaped-wire drawing were investigated. For this purpose, an experimental investigation on optimal die half-angle was conducted. Based on experimental data of optimal die half-angle, wire and inclusion deformations, drawing and hydrostatic stress of copper shaped-wires that contain an inclusion were calculated by two-dimensional finite element analysis. As a result, during drawing of a wire containing an inclusion, necking occurred. The effects of inclusion size and length on drawing stress and maximum hydrostatic tensile stress in front of inclusion during multi-pass copper shaped-wire drawing were carried out. The maximum hydrostatic tensile stress occurred on wire centerline in front of inclusion for single-pass drawing. When the wire was repeatedly drawn, the maximum hydrostatic tensile stress regions symmetrically separated out and were at both side of wire centerline in front of inclusion. Symmetrical double crack easily occurred in those regions.