METHOD OF TREATMENT OF STEEL IN LADLE Russian patent published in 2002 - IPC

FIELD: metallurgy; off-furnace treatment of steel in ladle. SUBSTANCE: method includes procedure of tapping steel from steel-making unit to ladle. After tapping steel (0.01 to 1.0 min), mixture of deoxidizer and slag-forming material is fed to ladle; slag-forming material contains calcium and magnesium oxides; consumption of this mixture is set according to dependence: P = K•τ•T/F•M;, where P is consumption of oxidizer and slag-forming material mixture, kg per of steel; τ is steel tapping time, min; T is steel tapping temperature, C; F is area of metal surface in ladle, sq. m; M is mass of steel in ladle, t; K is empirical coefficient equal to 0.15-2.3; kg. sq. m/min.C. Content of oxidizer in mixture is set within 5 and 35 mas.% and content of slag-forming material is set within 5 and 60 at fraction of 5-60 mm. In the course of off-furnace treatment, steel in ladle is blown with argon through dip tuyere at flow of 0.001 to 0.007 cu/m/min per ton of steel and is alloyed with aluminum in form of wire rod at consumption of 0.1-3.0 kg per ton of steel and manganese-containing material at consumption of 0.1-5.0 kg per ton of steel. It is good practice to deoxidize slag in ladle to content of common iron of 5-15 mas.%. Content of magnesium oxides in slag-forming material ranges from 1-50 mas.%, calcium oxides, the balance. Aluminum granules at fraction of 5-30 mm may be used as deoxidizer. Silicon-containing material of fraction of 5-30 mm may be also used as deoxidizer. Provision is also made for use of mixture of granules of aluminum and silicon-containing material at ratio of 1:(1-10). EFFECT: possibility of ensuring schedules deoxidization of slag in ladle; reduced losses of aluminum and manganese-containing at off-furnace treatment of steel. 6 cl, 1 tbl