多段深絞り加工による純チタン角筒容器の成形性

抄録

In press forming, pure titanium sheet has sufficient ductility. However, the seizure tends to occur during the deep drawing due to high reactivity with die materials. The authors reported that the heat oxided sheets were treated by oxide coating so as to get oxide surface layer effective for preventing the seizing. In the current study, the square titanium cups were formed by multistage deep drawing using oxided titanium sheets for preventing seizing. The sheets were employed and a flat sheet blank is formed into a square by a punch. Various cups were drawn by exchanging the punch and die. The die was a funnel shape without a blankholder in the subsequent stages. The effects of the oxide layer and die shape on the occurrence of seizure in multistage deep drawing were examined. The square cups were successfully drawn by oxide coating. As the number of drawn cups increases, the thickness strain increases at the corner of cups. However, the seizure did not cause even for cups of the 12th stage. It was found that the oxide titanium sheets have sufficient ability in preventing the seizure in multistage deep drawing processes.