METHOD OF MAKING RAIL STEEL Russian patent published in 2003 - IPC

FIELD: making rail steels in electric arc steel melting furnaces. SUBSTANCE: proposed method includes charging scrap, molten iron and lime in the amount of 4 to 8% of mass of charge into electric arc steel melting furnace, melting metal charge, oxidation of carbon by gaseous oxygen at rate of 15 to 30 cu nm/ht of steel, dephosphorization by addition of iron ore followed by tapping steel into ladle; during tapping of mixture which includes lime, feldspar, calcium-silicon alloy and ferrovanadium is added to ladle. Iron ore in the amount of 4 to 5% of mass of charge is additionally added to charge. Molten iron is poured to furnace at the top after deep fusion of scrap in the amount of 30 to 35% of mass of charge at rate of 6 to 12 t/min at power requirement of 220 to 320 kWh/t. Iron ore and lime are added for dephosphorization at consumption of steel of 70 to 120 kg/t at ratio of (1-2) : (2.5-3.5) respectively followed by drainage of oxidizing slag through pores of working port. Consumption of mixture added to ladle during tapping is maintained between 18 and 27 kg/t of steel at ratio of lime, feldspar, SiCa and FeV of (1-1.50) : (0.30-0.40) : (0.50-0.65) : (0.07 0.015), respectively. Proposed method ensures reduction of melting time and power requirements, contamination of steel with nonmetallic inclusions. EFFECT: improved mechanical properties and impact elasticity of rail steel. 2 tbl