PROCEDURE FOR RAIL STEEL MELTING Russian patent published in 2010 - IPC C21C5/52 C21C7/06 

FIELD: metallurgy.

SUBSTANCE: procedure consists in charging furnace with metal charge corresponding to metal scrap and liquid iron, in melting, in oxidation, in melting steel in batches, in tapping melt leaving slag and part of metal in furnace, in adding solid slag forming mixture, deoxidisers and alloying elements into ladle during tapping and in finishing steel at aggregate ladle-furnace. Metal scrap at amount of 15-35 % of charge weight, composite semi-finished product at amount of 10-40 % and lime at amount of 2.8-4.2 % of charge weight are charged upon melt tapping on slag and on part of metal left in the furnace. Liquid iron with contents of silicon not more, than 0.45 % and phosphorus not over 0.09 % at amount of 25-75 % of charge weight is poured upon metal scrap melting at specific consumption of electric power 130-380 kWT·h/t of summary weight of metal scrap and semi-finished composite product. Oxidation is performed with gaseous oxygen at consumption 80-120 m³/h per ton of metal charge. Lime is added into furnace by portions of 50-200 kg at amount 0.4-1.2% per weight of metal charge upon liquid iron supply; carbon containing dust is blasted at consumption 35-120 kg/min.

EFFECT: upgraded quality of steel, reduced duration of melting, and reduced consumption of lime, electric power and ferroalloys.