METHOD OF MAKING RAIL STEEL Russian patent published in 2005 - IPC

FIELD: ferrous metallurgy; making rail steel.

SUBSTANCE: proposed method includes charging scrap and lime into electric steel-making furnace. After melting of scrap liquid cast iron is poured from above at power requirement of 180-300 kW·h/t and temperature of 1280-1400°C in the amount of 30-60% of mass of charge containing the following components, mass-%:C, 2.0-3.5; Si lesser than 0.01;P, lesser than 0.015 and S, lesser than 0.025. Carbon is oxidized by gaseous oxygen at temperature in furnace not higher than 1700°C. At tapping the steel, furnace slag is separated and molten metal in the amount of 10-15% of total mass is left in furnace. Slag-forming mixture containing lime and fluorspar at ratio of (0.8-1.2) : (0.2-0.5) at flow rate of steel of 10-17 kg/t is fed to ladle during tapping.

EFFECT: reduced melting time; reduced power requirements; enhanced assimilation of alloys and ferroalloys; reduced level of contamination of steel by non-metallic inclusions.

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