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.

由于当前汽车工业朝着轻量化设计的趋势发展，对汽车用空心阶梯齿轮轴及其径向锻造工艺进行了广泛的研究。利用有限元热力学耦合模型，模拟了汽车空心阶梯齿轮轴的径向锻造过程。还使用正交设计方法选择了三个工艺参数的最佳组合，包括初始温度，转速和径向还原率。为了检查锻件的应变不均匀性，引入了应变不均匀性因子。结果表明，空心阶梯齿轮轴的最大有效应变和最小有效应变分别出现在不同截面的最外层和最内层。