Analysis and optimization of die geometry for forging dies in railway wheel manufacturing

Forging is an essential step in the multi-stage forming process of railway wheels. Maintaining dimensional accuracy of forging output is crucial for any railway wheel manufacturing industry to attain desired productivity. The present work aims to analyze the influence of various die geometry parameters in railway wheel forging. It is perceived that an insight into the effects of various die design parameters will be beneficial to designers to infer the significance of each parameter on metal flow during forging, thereby attaining quality forging output. With this aim, the present work focused on developing a 3D-FE model using DEFORM 3D to simulate the forging process of a railway wheel. This model was further utilized as an experimental setup for DOE techniques to optimize die geometry parameters. In the optimization process, considering the various process variations commonly observed in the manufacturing industry, the present work developed a robust design of the forging die using Taguchi methods. The significant die geometry parameters were obtained using ANOVA analysis, and optimized levels for each parameter were finalized. It was seen that factor X "inside boss angle of forming die" and factor Z "groove height of preform die" have the maximum significance. The optimized results were further validated with output from industrial-scale production of forged railway wheels. Comparing the forging dimensions and the forging load predicted by the developed simulation model with the actual output of industrial forging of railway wheels, it was suggested that the accuracy of the FEM model is reasonably satisfactory when considered in conjunction with already published literature. The present work provides insight into the effects of various parameters of die geometry in railway wheel forging and helps develop a robust die design suited for industrial application.