METHOD OF STEEL MAKING IN ELECTRIC ARC FURNACE Russian patent published in 2001 - IPC

FIELD: ferrous metallurgy, particularly, methods of making steel with preset content of nitrogen in electric arc furnace. SUBSTANCE: method includes charging of burden, its melting, formation of slag melt, conduction of oxidation by introduction of oxygen-containing gas. After oxidation period and before metal tapping, introduced into furnace is limestone and oxygen-containing gas. The latter is introduced continuously onto surface of slag melt with specific consumption of α = (20-100)[S.h/M], where S is surface area of slag melt on slag-gas phase interface, sq.m; h is thickness of slag melt, m; M is mass of metal melt, t. Limestone with specific total consumption of 35-48 kg/t of steel is supplied continuously since the moment of beginning of formation of slag melt and before beginning of metal tapping. In the course of introduction of oxygen-containing gas, melt is blown with neutral gas in bubbles with its specific consumption of 0.15-0.19 cu.m/t of steel. EFFECT: reduced nitrogen solubility in slag melt on slag-gas phase interface due to increase of partial pressure of oxygen, to decrease content of nitrogen in steel with preserved state low oxidation. 1 tbl, 4 ex