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

FIELD: metallurgy.

SUBSTANCE: procedure consists in supply of metal scrap and liquid iron as metal charge into furnace, in melting, in oxidising, in melting steel in batches, in tapping melt and leaving part of metal in furnace, in adding solid slag forming mixture, deoxidisers and alloying agents into ladle during tapping and in heat finishing steel at ladle-furnace aggregate. Metal scrap at amount of 25-65% of charge weight and lime at amount of 2.8-4.3% of charge weight are charged on slag and part of metal left in the furnace after tapping. Liquid iron containing silicon not more, than 0.45% and phosphorus not more, than 0.09 % at amount of 35-75% of charge weight is supplied upon scrap melting at specific consumption of electric power 130-380 kWT·h/t of metal scrap. Oxidation is performed with gaseous oxygen at consumption rate 80-150 m³/h per ton of metal charge. Upon supply of liquid iron, lime by portions 50-200 kg at amount 0.4-1.4 % of metal charge weight is added to the furnace. Carbon containing dust is blown in at rate 35-120 kg/min. Also there is maintained FeO=13-30% contents in furnace slag, while ratio of CaO/FeO is maintained within the range 2.5-4.6.

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