METHOD FOR MAKING HIGH-GRADE STEEL IN ELECTRIC ARC FURNACE Russian patent published in 1995 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: charged on bath is composite mixture of melted cast iron and iron-rich pellets with apparent density of (4,5-5,8)·10^-3 kg/cm³ in amount of 20-35 mas. of liquid metal in furnace before tapping. Continuous charging of iron-rich pellets is carried out in two periods of operating conditions: in the first period with specific rate from 0.38 to 0.45 kg/MWs up to attaining metal temperature of 1550-1570 C; and in the second period, up to the end of charging iron-rich pellets, with specific from 0.45 to 0.50 kg/MWs with preservation of attained temperature. In so doing, carbon is oxidized in synchronous manner and oxidation is completed simultaneously with the end of continuous charging of iron-rich pellets. Duration of the second period and carbon oxidation are determined depending on input power, specific rate of pellet charging and gaseous oxygen supply flow rate. EFFECT: higher efficiency. 2 cl, 2 dwg, 1 tbl