Study of process parameters towards improving efficiency of closed die hot forging process

Abstract

Closed die hot forging process is one of the most adopted methods for forming complex shaped parts with satisfactory geometrical accuracy. Over sixty percent of the forgings are processed through this route. Forged parts, though required in many engineering sectors, play a vital role in the automotive sector. The majority of the crucial load bearing structural components as well as safety critical items are processed via the forging route. This is mainly due to the inherent strength to weight ratio and dimensional accuracy that can be combined into the components. Faster production of complex shapes with least wastage of material are some of the other benefits. The metal flow analysis of the process is complex due to the involvement of a large number of parameters. A number of experimental testings and production-trials are being done in the industry in order to develop a robust manufacturing process. Such practices however involve huge investments in tooling and raw materials, including a great deal of development time and effort. In recent years, finite element method has emerged as a suitable tool for virtual process trials and simulation based design. This would lead to an improvement in overall efficiency of the process at a lower cost. Through the present study, an attempt has been made to gain an insight into the process parameters influencing the closed die hot forging and their interaction. As a sample case, a real life automotive driveline component, a flange yoke, is taken for investigation. A simulation-driven approach using a commercial package (DEFORM), based on finite element method, was adopted. Trials were conducted using an industrial press, data generated were validated against those predicted. The correlation was found to be satisfactory.