Optimization of hot free forging condition for the uniformity of forged shape by three dimensional rigid-plastic finite element analysis

Focusing on the rough forging stage of the hot free forging process, the in fluence of the operational conditions on the occurrence of concave defects was first numerically analyzed using a three dimensional rigid-plastic fini te element method. The validity of the analysis was examined by laboratory experiments using lead billets and the analytical results are in good agree ment with experimental results. As a result, the mechanism through which th e concave defects appear was clarified, and it. was revealed that by applyi ng only a small curvature to a plane surface of an anvil, the concave defec ts is enormously improved. Moreover, it was found that the new anvil geomet ry makes it possible to increase the productivity.