STEEL-MAKING METHOD IN ARC ELECTRIC STEEL-SMELTING FURNACE Russian patent published in 2010 - IPC C21C5/52 

FIELD: metallurgy.

SUBSTANCE: method includes feeding into arc furnace of scrap metal and liquid cast iron, melting, oxidation period, tapping with keeping of slag and part of metal in furnace. After tapping it is implemented furnace charge on kept in furnace slag and part of metal to diffuse in amount 1-2 % and scrap metal in amount 70-80 % of mass of metallic stock, pouring of liquid cast iron in amount 20-30% from mass of metallic stock. Oxidisation of metal is carried out with gaseous oxygen at a rate of 3000-4000 nm³/h of carbon content in limits 0.03-0.07% and a temperature in the range 1620-1660°C. During melting of steel it is implemented blowing of metal by argon through bottom plugs with consumption 20-60 l/min, blowing of carbon-earing material with consumption 20-100 kg/min and additive of lime by portions of 250-300 kg in amount 1-2% of mass of metal stock. During tapping there are added ferrous alloys from the calculation of receiving of content of silicon and manganese, equal to bottom grade limit of content of these elements in smelted grade of steel and solid slag-forming mixture, containing lime, calcium fluoride and aluminium in ratio 3:1:0.5 in amount 5-10 kg/t with blowing of metal in ladle with argon.

EFFECT: reducing of melting duration, reduction of ferrous alloys consumption, reducing of power and electrodes consumption.