Influence of radial forging process on strain inhomogeneity of hollow gear shaft using finite element method and orthogonal design

Abstract

Due to the current trend towards lightweight design in automotive industry, hollow stepped gear shafts for automobile and its radial forging process are widely investigated. Utilizing coupled finite element thermo-mechanical model, radial forging process of a hollow stepped gear shaft for automobile was simulated. The optimal combination of three process parameters including initial temperature, rotation rate and radial reduction was also selected using orthogonal design method. To examine the strain inhomogeneity of the forging workpiece, the strain inhomogeneity factor was introduced. The results reveal that the maximum effective strain and the minimum effective strain appeared in the outermost and innermost zones of different cross sections for the hollow stepped gear shaft, respectively. Optimal forging parameters are determined as a combination of initial temperature of 780 °C, rotation rate of 21°/stroke and radial reduction of 3 mm.