PROCEDURE FOR RAIL STEEL MELTING Russian patent published in 2010 - IPC C21C5/52 C21C7/76 

FIELD: metallurgy.

SUBSTANCE: procedure consists in charging arc electric furnace with metal charge corresponding to metal scrap and liquid iron, in melting, in oxidation, in melting steel in series, 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. Upon melt tapping metal scrap at amount 25-70% of charge weight and lime at amount of 1.5-3.0% of charge weight are charged onto part of metal and slag left in the furnace. When metal scrap has been melted with specific consumption of electric power 125-300 kWt-h/per t of metal scrap, there is cast liquid iron with contents of silicon not over 0.45% and phosphorus not over 0.09% at amount of 30-75% of weight of charge together with ladle slag of FeO contents below 3.0 % and ratio CaO/SiO₂ 2.0-4.4 at amount 0.5-6.0% of charge weight. Oxidation is performed with gaseous oxygen at consumption 50-140 m³/h per ton of metal charge. Lime is added into furnace by portions of 50-200 kg at amount 0.3-1.0% per weight of metal charge upon liquid iron casting; carbon containing dust is blasted at consumption 40-80 kg/min.

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