Experiments and numerical analyses on splitting fracture of wire under multi-pass drawing

Abstract

The splitting phenomenon during drawing will cause the quality decline of wire. A clear understanding of formation mechanism of splitting can help to promote the development of engineering drawing. Therefore, the splitting fracture and microstructure are analyzed by SEM. The experimental results indicate that the main crack run through the core and surface of both sides of wire. Furthermore, multi-pass drawing of different material properties and die angles is simulated by using FEM with the developed damage modeling. The results show that after each drawing pass, the damage and section stress are formed near the center and surface of wire, respectively. Meanwhile, the damage will be enhanced with the increase of die angle, drawing strain and material properties. Among these influencing factors, the die angle has little effect on the section stress, but the increase of the other two factors will lead to the gradual increase of section stress. Moreover, wire core becomes the source of crack due to its larger damage, and then crack propagates to the surface of wire under the action of stress, thus forming splitting fracture.