초록
A impeller hub is usually made through three forging processes : forward extrustion, upsetting and finishing. The finishing process is closed die forging in which the load increases abruptly at the final stage, resulting in underfilling in the finished product due to insufficient load capacity of the press. In this study, the rigid-plastic finite element analysis was applied to the impeller hub forging process in order to optimize process and to estimate required load. As a result, two kind of improvements for the process were suggested to reduce the load requirement in the finishing process.