Method for refining molten steel with RH vacuum degassing equipment

摘要

PPROBLEM TO BE SOLVED: To provide a refining method by which when an Al-less extra-low carbon steel is refined using an RH-vacuum degassing apparatus, the erosion of a refractory in the RH-vacuum degassing apparatus caused by slag and deoxidation product can be prevented, as a result, the productivity of the RH-vacuum degassing apparatus is improved and production cost can be remarkably reduced compared with the conventional method. PSOLUTION: The method for refining molten steel with the use of the RH-vacuum degassing apparatus is provide in which unoxidized molten steel 3 is vacuum-degassing-treated using the RH-vacuum degassing apparatus and thereafter, Si-source for deoxidation is added into the molten steel in a RH-vacuum vessel 5 and the molten steel is deoxidized, and the Al-less extra-low carbon steel having 0.001 mass% Al content is refined by the RH-vacuum degassing apparatus, wherein at any timing of before charging the Si-source for deoxidation at the end period of the vacuum decarburization treatment, at the same time of charging the Si-source for deoxidation or after charging the Si-source for deoxidation, a flux 16 containing MgO as the main component is added into the molten steel in the RH-vacuum vessel. PCOPYRIGHT: (C)2009,JPO&INPIT