Forming of Long Pure Titanium Cups by Cold Multi-Stage Deep Drawing

摘要

Long pure titanium cups were formed by preventing seizing in cold multi-stage deep drawing processes by the use of commercial oxide and nitride coating. The colored pure titanium sheet was used as an oxide coating sheet. These coatings are effective in preventing the occurrence of seizure and galling, because the fresh and clean titanium is not in direct contact with the die during the forming due to the existence of the oxide and nitride layers. By the use of the commercial sheets, the investment in coating machines can be avoided in sheet metal forming makers. The effects of the coating conditions, die materials and lubricants on the occurrence of seizure in multi-stage deep drawing were examined. It was found that the coating titanium sheets have sufficient ability in preventing the seizure in multi-stage deep drawing processes. Long pure titanium cups with the height which is 6 times larger than the diameter were successfully formed by a multi-stage deep drawing operation without intermediate annealing.