Joining two or more parts by forming is an economical method in manufacturing complex shaped products. In this study, we discuss a form joining process to provide high torsional strength for shaft products. Experiments to join a shaft of quenched steel and a thick flange of mild steel was carried out. Joining was achieved by forming the hole of flange with a serrated shaft. The Formed joint was compared with a mechanically fitted one having the same shape and joining area, which proved that the joint by forming had higher torsional strength than that by fitting. One of the reasons was work hardening of formed serrations, which was evaluated by finite element analysis.
