Abstract
A dieless drawing process without using any dies and tools is applied to magnesium alloy to fabricate fine tubes in this study. The extruded tube used in the experiment is made of AZ 31 magnesium alloy and has an outer diameter of 2mm, wall thickness of 0.5mm and average grain size of 5.2μm. A high-frequency induction heating apparatus with an air-cooling device is used for dieless drawing. The deformation behavior and microstructure during the dieless drawing process are investigated experimentally. A limiting reduction in area of 60% can be achieved in the experiment under a heating temperature of 400°C. In addition, it is confirmed that the ratio of inner to outer tube diameters remains a constant value during dieless drawing. In other words, the geometrical similarity with the minimization of dimensions is satisfied in this process for the AZ31 tube. Furthermore, grain growth occurs during process under a heating temperature of 400°C. Meanwhile, 4μm fine grains can be obtained after dieless drawing at a heating temperature of 300°C. Thus, it is concluded that the microstructure after dieless drawing can be controlled by adjusting the drawing conditions.
