Cold Drawing of Magnesium Alloy Tubes for Medical

Magnesium alloy is the lightest in practical metals, and it is used for housing small home appliance products and automobile parts. It is also expected to be a new material for stents, because of its possibility of systemic absorption. Fineness, thinness, adequate strength and high-quality surface are required for the medical tube. It is known that cold-plastic working of magnesium alloy is very difficult. In this study, fabrication of a magnesium-alloys medical fine tube by cold fluid-mandrel drawing was attempted. Fineness, thinness, adequate strength and high-quality surface are required for the medical tube. Firstly, plug drawing was carried out, because it was thought to be one of the methods for satisfying the requirements. After all it was found to be impossible to apply this method, because magnesium alloy is too brittle for plug drawing. Secondly, soft-metal mandrel drawing was tried. Drawing was possible, but it was difficult to extract the mandrel, because there is a possibility that the tube might break due to its high drawing stress. So newly-processed fluid-mandrel drawing was carried out. As a result, it was found that the fabrication of medical tubes by fluid-mandrel drawing was possible. It is easy to extract mandrel after drawing, as the mandrel is fluid. And it is possible to prevent tube break during drawing, because drawing stress is lower than that of soft-metal mandrel drawing.