METHOD OF STEEL MELTING IN OPEN-HEARTH FURNACE Russian patent published in 2001 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: method includes charging of iron charge, its heating and melting, finishing of liquid metal to attain required characteristics, and its blowing with neutral or inert gas by means of multinozzle blowing devices located in porous refractory layer of hearth. Liquid metal is blown by zones which are distributed along furnace longitudinal axis. Neutral or inert gas is supplied to each zone from blowing devices provided with at least 30 nozzles with diameter from 1.0 to 3.0 mm and gas pressure of 1-6 atm. Neutral or inert gas is passed with its distribution over zone surface through layer of porous refractory material with 2-10 mm fraction and thickness equalling 0.5-0.8 of total thickness of hearth to ensure specific density of blowing in each zone within range of 2.0-11.5 cu. m/h per 1 sq.m of its surface. Total intensity of blowing of liquid metal with neutral or inert gas is maintained within ranges ensuring efficient heat-mass transfer of liquid metal layers. Consumption of neutral or inert gas is varied from 0.09 to 0.45 cu.m per unit of thermal capacity of fuel flame as heat duty in furnace rises. EFFECT: higher productivity of steel melting process with provision of high quality parameters of steel, higher operating reliability of blowing devices. 5 cl, 3 dwg, 1 ex