METHOD OF SMELTING LOW-CARBON VANADIUM-CONTAINING STEEL OF INCREASED STRENGTH AND COLD RESISTANCE Russian patent published in 2002 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: method involves oxygen blowing of carbonaceous intermediate product in converter in two stages with intermediate skimming of slag and running off newly supplied slag with at least triple basicity; introducing vanadium slag in an amount of 4-6 kg/t of steel jointly with lime at the ratio of 1:1; transferring ladle with metal to furnace-ladle unit and introducing slag forming materials and liquefying material; reducing melt with aluminum; introducing vanadium slag in an amount of 8-12 kg/t of steel jointly with lime at the ratio of 1:0.8 and ferroalloys in an amount required for reducing vanadium and correcting steel chemical composition; vacuumizing steel in circulation vacuumizer while treating melt with aluminum and powder calcium silicon wire. Lime-aluminous slag is introduced as liquefying material into furnace-ladle unit in an amount of 4-7 kg/t of steel for running off liquid slag with at least double basicity. Method allows high-quality low-carbon vanadium-containing steel to be manufactured. Such steel contains vanadium 0.08-0.16 wt%, phosphor less than 0.01 wt% and sulfur less than 0.005 wt%. Vanadium-containing steel has good welding capacity and may be used for manufacture of critical welded structures in construction and mechanical engineering, including structures built in North regions. EFFECT: increased efficiency and improved quality of steel. 2 cl, 4 tbl, 1 ex