MANUFACTURE OF ALUMINUM DEOXIDIZED KILLED STEEL TO PREVENT RISE OF SI CONTENT OF MOLTEN STEEL

摘要

PURPOSE:To reduce the amount of Si contained as much as possible by a procedure in which primary deoxidization is made by aluminum in a refining furnace, the steel so treated is discharged to a ladle lined with a refractory material containing less amounts of SiO2, and then the steel is further deoxidized secondarily by a aluminum. CONSTITUTION:In the manufacture of a low-silicon aluminum killed steel containing 0.010% or less Si, e.g., galvanized steel plate, etc., the primary deoxidization is first made by adding aluminum in a theoretical amount enough to deoxidize oxygen dissolved in the molten steel in a steel-making furnace, and then the molten steel is discharged to a ladle lined with a refractory material containing a very small amount of SiO2. In this case, the intermixture of molten slag into the molten steel is suppressed to a great extent. Because the molten steel in the ladle is secondarily oxidized when discharged, the molten steel is further mixed with a small amount of aluminum with sufficient stirring for deoxidization. Thus, a low-silicon aluminum killed steel containing 0.010% or less Si can be economically manufactured with less amounts of aluminum for deoxidization and without reducing SiO2 by excessive alumimum.