MEDIUM CARBON SULFUR FREE CUTTING STEEL HAVING EXCELLENT MACHINABILITY AND METHOD FOR REFINING THE MELTING IRON OF THE SAME

摘要

PURPOSE: A medium carbon sulfur free cutting steel with excellent machinability and a method for refining the melting iron of the same are provided to minimize surface fault such as scab generated by inclusion in a hot rolling process. CONSTITUTION: A method for refining the melting iron of medium carbon sulfur free cutting steel comprises following steps. Sulfur alloy steel is added on a vacant teeming ladle before tapping molten iron at a converter. The molten iron is tapped on the teeming ladle in which sulfur alloy steel is contained. The molten iron is deoxidized by adding molten iron deoxidizer at the end of a tapping process. The molten steel and the slag are controlled.