METHOD FOR PRODUCING CLEAN STEEL BY LADLE-REFINING METHOD

摘要

PPROBLEM TO BE SOLVED: To provide a method for producing a clean steel, such as a bearing steel having 0.0030% Ti and 0.0010% T.O by using a ladle-refining facility having pressure-reducing function while using flux containing no fluorine as the refining agent. PSOLUTION: After tapping off the molten steel from a converter or an electric furnace, the molten steel and slag are stirred and refined by using Ar or NSB2/SBgas under reducing pressure in the ladle, and the flux containing the fluorine, is not used as refining agent, and the slag composition after ladle-refining, is made, by mass, to be 1.0% TiOSB2/SBand 0.05-1.00% as the total of NaSB2/SBO and KSB2/SBO under condition of 30-60% CaO, 3.0-15% MgO, 10-30% AlSB2/SBOSB3/SBand 2.0-10.0 (%CaO/%SiOSB2/SB). PCOPYRIGHT: (C)2010,JPO&INPIT