PROCESS FOR PRODUCING HIGH CLEANLINESS STEEL

摘要

A steel of high cleanliness is produced through satisfactory elimination of nonmetallic inclusions. There is disclosed a process for producing a high cleanliness steel, comprising the step of subjecting a molten steel outputted from a converter (1) to ladle refining and thereafter vacuum degassing refining with the use of a reflux vacuum degassing unit to thereby obtain a high cleanliness steel, wherein refining is performed so that the Al content value after the ladle refining falls within the range of 0.030 to 0.070% and wherein FeO, MnO, CaO, SiO2, MgO, Al2O3 and TiO2 constituting the slag after the ladle refining are optimized. Further, at the time of the vacuum degassing refining, the agitation period and molten steel reflux rate are optimized.