| 摘要 |
<p>PURPOSE:To prevent water in the atmosphere from being adsorbed and easily obtain low oxygen metal and low alloy from rare earth metal by supplying hot water or vapor into a can structure and a cooling water piping installed in a heating coil when a furnace is opened. CONSTITUTION:A door 12 of a furnace is opened to the atmosphere, and a crucible 1 is set, including stock activated metal in an internal induction heating coil 2. Hot water is conducted from a changeover supply installation 6 to a direct copper part 10 of the furnace and a door 12 of the same, and to cooling water pipings for the heating coil 2 to heat the inner wall, coil, and heat insulating material, etc., of a vacuum furnace for prevention of water absorption. After the crucible 1 is set in the coil 2, the door 12 is closed and the vacuum furnace is drawn into a vacuum by a diffusion pump 5. After the predetermined degree of the vacuum is attained, hot water is changed over to cooling water for heating operation. Thereupon, although the cooling water to the coil is immediately changed over, higher quality low oxygen metal is yielded by conducting the hot water for an interval as long as possible.</p> |
