METHOD OF DEOXIDATION AND ALLOYING OF STEEL Russian patent published in 2003 - IPC

FIELD: ferrous metallurgy; methods of deoxidation and alloying of steel in the course of tapping steel from converter to steel-teeming ladle. SUBSTANCE: proposed method includes making steel in converter, tapping steel from converter to steel-teeming ladle, supplying deoxidants and alloying materials in form of ferroalloys and aluminum in three portions. First portion of silicon-containing ferroalloys and carburizer at weight ratio of 1: (0.1-10.0) is introduced at the beginning of tapping under jet of steel till filling the ladle to 0.2-0.3 of height of its working cavity. Weight flow rate of silicon-containing ferroalloys in first portion M₁ in kg/t of steel is set according to the following relationship: M₁ = K₁•(C₂-C₁)•t/C₁, where C₁ is content of carbon in steel before tapping from converter, mass-%; C₂ is required content of carbon in steel after tapping from converter, mass-%; t is temperature of steel in converter before tapping, C; K₁ is coefficient equal to (8,2-17,0)•10^-5, kg/t. C. Second portion of manganesecontaining and/or silicon-containing materials at weight flow rate between 1.0 and 30.0 kg/t of steel is introduced till filling the ladle to 0.25-0.6 of height of its working cavity. Third portion which consists of aluminum is introduced at filling the ladle to 0.4-0.8 of height of its working cavity. Weight flow rate of aluminum M₂ in kg/t of steel is set according to the following relationship: M₂ = K₂•Al., T/a, Al is required content of aluminum in steel after tapping from converter, mass-%; T is mass of steel, t; a is magnitude of assimilation of aluminum by steel equal to 15- 30%; K₂ is coefficient equal to 2.5-10.0. Ferrosilicine or silicocalcium may be used as silicon-containing ferroalloy. Ferromanganese or silicomanganese may be used as manganese-containing ferroalloy. Ratio of weight amounts of silicon-containing and manganese-containing ferroalloys is set within 1: (1-10). Proposed method enhances modes of making additives and alloying materials in ferroalloy ladle and assimilation of carbon, manganese and aluminum. EFFECT: enhanced efficiency. 7 cl, 1 tbl, 1 ex