| 摘要 |
PURPOSE:To obtain an ingot or a billet contg. <=20ppm oxygen by refining molten steel in the presence of highly basic slag in a vessel lined with a CaO-base lining material while keeping the concn. of O2 in the atmosphere at a specified value or below, adding Ca to the refined molten steel, and casting the steel at once. CONSTITUTION:Molten steel is refined in the presence of highly basic slag in a refining vessel lined with a CaO-base lining material while keeping the concn. of O2 in the atmosphere at <=1% to obtain molten steel having <=20ppm oxygen content. To the molten steel is added >=10ppm Ca, and the steel is cast within 15min to obtain an ingot or a billet having <=20ppm oxygen content. Slag contg. <=10% SiO2+MnO2+Cr2O3+FeO is used as the high basicity slag. |
