A finite element thermal model for axisymmetric cold and hot extrusion using upper bound technique

Abstract

In this paper, a combined rigid plastic finite element (RPFE) model for steady state axisymmetric extrusion process is proposed using a kinematically admissible velocity field obtained from the upper bound model earlier proposed by Kumar, et al. Optimal power and temperature distribution in cold as well as hot extrusion processes are determined with RPFE method using the deformation field obtained from upper bound method. Effects of various process parameters, such, as, ram velocity, reduction, friction between die billet interface, die length and temperatures (initial billet, die and container and surrounding) has been analysed using the proposed combined UB-RPFE method. The result obtained agrees well with the experiment and analysis. The proposed model can further be extended for generalized solid shaped extrusion for both hot and cold cases.