| 摘要 |
PURPOSE:To improve the weldability of inside and outside shells and to reduce cost by charging a flux by a carrier of an inert gas during the time when the molten metal for an inside shell is cast and shielding the intrusion of air by the inert gas. CONSTITUTION:The flux 4 is charged by the inert gas 5 for preventing the oxidation of the inside surface of an outside shell layer 8 as a carrier after the molten metal for the outside shell is cast. A partition 7 is provided near the feed port for the flux 4 and said part is shielded by using the inert gas so as to prevent the intrusion of the air in the atmosphere. The high-temp. oxidation of the inside surface of the layer 8 by the air in the stage of charging the flux is prevented by the above-mentioned method. The abnormal phase is thus prevented on the outside surface of the layer 8 and since the flux 4 captures impurities, the weldability of the inside and outside layers is improved and the cost is reduced. |
