A Novel Technology on Unfilled Corner Occurred in Gear Two-Step Warm Forging Process

Abstract

Based on the geometric feature of back gear with double bosses, a new two-step warm forging process before cold precision forging was developed to reduce the number of process and the overall cost of manufacture. However, after the new process being conducted, unfilled corners were found at the bottom profile of all teeth. Two different methods were adopted to solve the issue but the results were unsatisfied. In order to solve the issue, a rigid plastic FE model was established to simulate the process. The velocity, stress and strain fields were investigated. In the mean time the metal flow rules were discussed along with experimental results. Through expanding the radial wave shape by means of a groove established in die and a qualified forge piece was achieved finally.