| 摘要 |
PURPOSE:To stably obtain steel melt having S content below 0.005wt%, by adding misch metal to the steel melt in a ladle, and agitating the steel melt. CONSTITUTION:After 0.1-0.4wt% misch metal, i.e. the mixture (alloy) of rare earth metals, is added to steel melt in a ladle, the steel melt is agiated by the injection of inert gas. Hence said amount of misch metal may be added to the steel melt being agitated by the injection of inert gas. Since the rare earth metals are hardly evaporated at the temp. of the steel melt, their yield in the steel melt is excellent. Since they hardly form sulfides in the steel melt, excellent desulfurization is performed. The sulfides, even if being formed, are not sufficiently separated from the steel melt by flotation but left in the steel melt. In this regard, lances are inserted into the steel melt, and inert gas is injected through them to agitate the steel melt. Consequently, the sulfides can be transferred from the steel melt to slag and separated from the steel melt. |
