Secondary Refining of Molten Steel

Secondary refining of molten steel, also called secondary steelmaking or ladle metallurgy, is a technique in which molten liquid that has been primarily refined in a steelmaking furnace (converter and electric furnaces) is moved to another container for refining. The primary smelting of the steelmaking furnace is to melt the charge, decarburize, remove inclusions (sulfur and phosphorus), heat up, and master alloying (molten iron and scrap) in an oxidizing atmosphere (blown into pure oxygen). Refining is to complete the metallurgical operations including decarburization, deoxidation, desulfurization, degassing and inclusion removal, inclusion morphology control, alloying and composition trimming, heating, and temperature homogenization of the primary molten steel in the vacuum, inert gas, or reducing atmosphere of the container. The two-step steelmaking can improve steel quality, increase varieties, shorten smelting time, improve productivity, adjust the production rhythm of...