METHOD FOR SMELTING STEEL IN OXYGEN CONVERTERS Russian patent published in 1997 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: in a process of smelting steel in oxygen converters including loading scrap as cooler, pouring in liquid cast iron, blowing fusion with gas oxygen, introducing slag-forming materials and solid oxidants, the latter are introduced in the form of stock consisting of iron-carbon alloy and oxide material, stock being introduced in amount 5.5-30% based on metal charge weight. Method is distinguished with following operations. Stock is added in two portions: the first one, in amount 20-75% of its total intake, being added before pouring in liquid cast iron, and remaining portion being introduced during blowing operation with rate 0.25-6.0 t/min. Possible is also portion-wise introduction of stock during the blowing with rate 0.25-6.0 t/min with 0.5-5 min intervals between portion additions. In stock added in the charging stage, ratio of iron-carbon alloy to oxide material is (65-85):(35-15), and in that added during the blowing, (85-95): (15-5). Temperature of added stock ranges from 100 to 800 C. Before pouring in cast iron, stock is utilized with excess oxygen over its stoichiometrically required quantity. When content of carbon in fusion attains 0.1-0.8%, stock is used in which oxygen content is below its stoichiometric quantity with regard to sum C+Mn+Si+P+V+Ti+Cr contained in iron-carbon alloy. EFFECT: improved quality of steel and increased productivity of installation. 7 cl, 4 tbl