Investigation of the cogging process by three-dimensional thermo-viscoplastic finite element analysis

Abstract

The purpose of cogging in open-die press forging is to maximize the internal deformation for better structural homogeneity and centre-line consolidation in the core of the ingot. A three-dimensional thermo-viscoplastic finite element analysis is carried out for the non-isothermal cogging process in order to study the distribution of hydrostatic stresses, effective strains and temperature of the ingot and the die during the process. In the simulation, V-die and flat-die are employed for computation. A circular ingot of body weight 160 ton is subjected to cogging simulation and the effects of cogging parameters, such as die configuration, die width, temperature gradient, height reduction and draft design, are compared between two types of dies. Thus favourable working conditions are suggested for better and more desirable product quality.