Research of Multi-Stage Cold Deep Drawing Technique of Long Pure Titanium Cups

采用多道次冷拉深成形技术，以彩色钛板为材料，制备了长形纯钛髋臼杯。钛板具有足够的延展性和高的r值用于深冲压，然而由于与模具材料的高反应性，在深冲压期间易于发生咬合。对着色纯钛板进行电化学涂层处理，以获得有效防止咬边的表面氧化层。采用商品化的彩色钢板，可避免钣金成形企业对涂层设备的投资，并可控制氧化层的质量。研究了氧化层厚度、模具材料和润滑剂对多道次拉深时咬死发生的影响。结果表明，彩色纯钛板在多道次拉深过程中具有足够的抗咬合能力。

Long pure titanium cups were formed by multi-stage cold deep drawing using commercial colored titanium sheets for preventing seizure. The titanium sheets have sufficient ductility and high r-value for the deep drawing, whereas the seizure tends to occur during the deep drawing due to high reactivity with die materials. The colored pure titanium sheets were treated by electrochemical coating so as to get oxide surface layer effective for preventing the seizing. By the use of commercial colored sheets, the investment of coating machines can be avoided in sheet metal forming makers and the quality of the oxide layer can be controlled. The effects of the thickness of the oxide layer, die materials and lubricants on the occurrence of seizure in multi-stage deep drawing were examined. It was found that the coloured pure titanium sheets have sufficient ability in preventing the seizure in multi-stage deep drawing processes.