| 摘要 |
PURPOSE:To draw efficiently a specifically composed NiTi alloy to a wire rod by forming an oxide film of an adequate thickness so as to exist on the surface of the wire rod of said alloy and drawing the wire rod thereby decreasing the seizure of a die, extending the life of the die and preventing disconnection. CONSTITUTION:An NiTi alloy contg. 50-60wt% Ni and consisting of the balance Ti or an NiTi alloy in which a part of said Ni or Ti is substd. with >=1 kind of elements such as Fe, Co, Cu, Al, Zr, V, etc. within a 10% range is drawn to a wire. An oxide film is formed to exist at 0.03-3mum thickness on the surface of the wire rod prior to drawing of such alloy by a die thereby reducing seizure of the die, extending the life of the die, preventing a disconnection accident and reducing the roughened surface of the wire rod during drawing. Said oxide film is formed to the adequate thickness by controlling the oxidative effect of the atmosphere in a stress relief annealing stage before the drawing stage. |
