Method for manufacturing ultra low carbon steel having ultra low sulphur

摘要

PURPOSE: A method for manufacturing ultra-low carbon steel having 20 ppm or less of sulfur, that is, ultra-low sulfur by reducing content of sulfur contained slag charged into converter along with hot metal, thereby reducing resulfurization quantity in converter process is provided. CONSTITUTION: In a method for manufacturing ultra-low carbon steel containing 20 ppm or less of sulfur, the method comprises first slag off step of slagging off slag produced by injecting desulfurizer into hot metal tapped from blast furnace; second slag off step of slagging off slag produced by injecting desulfurizer into the first slag off treated hot metal; a step of performing injection operation by charging the second slag off treated hot metal into converter; and a step of decarburizing molten steel tapped from the converter in degassing facility, wherein the first slag off step comprises the steps of receiving the hot metal tapped from the blast furnace into torpedo car; injecting CaCO3 based desulfurizer into the hot metal received into the torpedo car; receiving the hot metal desulfurized in the torpedo car into charging ladle; and slagging off slag that is charged into the charging ladle along with the desulfurized hot metal.