| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a heating-refining method for sufficiently heating additional refining agent and obtaining the high desulfurizing efficiency even in the case of using a desulfurizing agent containing no CaF<SB>2</SB>, wherein the preheating of a vacuum vessel and the melting of metal, the temperature-raising of the molten steel, the decarburizing treatment of the molten steel, etc., can be performed. <P>SOLUTION: In the heating-refining method in a vacuum-degassing apparatus, in which at the center part of the tip-end of a lance, a nozzle for injecting independently respective three kinds of oxygen gas, inert gas and powdery refining agent is arranged and at the circumference of the nozzle, a compound lance 13 where combustion burners for injecting the fuel and gas for burning are arranged at two or more positions is inserted into the vacuum vessel 5. The method includes performing at least one of (A) the preheating of the vacuum vessel before degassing-treatment, (B) the heating-raising of temperature of the molten metal 3 during degassing-treatment, (C) the decarburizing treatment of the metal during degassing treatment, (D) the refining such as the desulfurizing treatment of the molten metal during degassing-treatment and (E) the heating-melting removal of the stuck material on the inner wall of the vacuum vessel during degassing treatment or after degassing treatment. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
