Effect of inner cone punch on metal flow in extrusion process

Using numerical simulation and experiment, the mechanical mechanisms of metal flow behavior were investigated in the extrusion process with inner cone punch. The characteristic variables, second invariant of the stress deviator J ₂ and the Lode’s coefficient μ were employed to partition the deformation region. It is shown that no metal flow interface occurred at the container bottom in the extrusion with inner cone punch and the dead zone disappeared completely. The strain types of the material in the plastic deformation area decreased from three types into a single type of tension and the homogeneity of metal deformation as well as metal flow was greatly improved. It was also indicated that inner cone punch was beneficial to the extrusion process and the promotion of product quality.