Application of CAE in cold forging and heat treatment processes for manufacturing of precision helical gear part

In this study, numerical simulations, using the general-purpose process simulation software DEFORM-3D/HT, were carried out for the design of the cold forged precision helical gear used for the automotive steering part. The helical gear forging was carried out using the designed die set. From the simulation results, forming load, normal pressure, effective strain distributions on the workpiece, and stress distributions on forging dies were investigated. The predicted workpiece geometry showed good agreement with experimental result. Also, the heat treatment processes of the forged helical gear parts were simulated and compared with the experimental results. Highly accurate heat transfer coefficients considering the complex boundary heat transfer were applied in the current simulations to improve the simulation accuracy. The inverse calculation technique was used to find out the accurate heat transfer coefficients to minimize the difference between simulation and experiment. From the simulation result, the microstructure distribution and geometrical change of teeth were investigated for various quenching media, such as oil, water, and polymer.