PROCESS FOR REFINING MOLTEN STEEL

摘要

PURPOSE:To produce a steel contg. N2 at a lower rate at a good yield of a deoxidizing agent by putting the molten steel tapped from a converter without deoxidation into a ladle refining furnace and adding the deoxidizing agent such as Al to the molten steel after removing molten slag therefrom. CONSTITUTION:The pickup of N2 from the inside of the air increases if the content of O2 in the molten steel is low. The molten steel tapped from the converter is therefore tapped together with the molten slag into the ladle refining furnace without subjecting the same to the deoxidizing treatment. Al as the deoxidizing agent is added to the molten steel after the molten slag is removed in the ladle refining furnace. The Al is used for the deoxidation of the molten steel at a high yield without oxidation loss by the molten slag as molten slag does not exist in the molten steel. The pickup of N2 is eliminated as the molten steel is not deoxidized in the stage of tapping from the converter. The deoxidation with high yield of the Al which is the reducing agent is thus made possible and the low nitrogen steel is produced stably at a low cost.