금속 와이어의 무구속 열간 인발 특성 -스테인레스강 와이어와 구리 와이어-

Micro-sized metal fibers are suitable for multi-functional and high performance industrial components, but the fiber manufacturing process relies heavily on wire drawing with dies, which can cause die-raw material friction. An alternative for the efficient production of the metal fibers is to use dieless wire drawing technology. This paper reports the characteristic differences of the dieless wire drawing process, which relies on forced necking. The hot working principle was applied to the most frequently used raw materials, stainless steel and copper, while a microwave furnace and susceptor were employed. The experimental trials showed that stainless steel wires could be more advantageous in dieless drawing than copper wires in that the necking of the stainless steel wire took place in a narrower zone than copper. Furthermore, a mathematical model was set up considering volume heating and wire cooling and combining the temperature effect of viscosity in Arrhenius form with the plastic deformation in Bingham form. The model showed good agreement with the experiments when the process was carried out in a steady state at various draw ratios and process speeds. These results suggest that the theoretical model can depict the real process quite well.