OUT-OF-FURNACE STEEL REFINING METHOD Russian patent published in 2003 - IPC

FIELD: metallurgy. SUBSTANCE: method involves discharging metal melt into ladle; introducing aluminum and calcium into ladle in two portions; blasting melt with inert gas. Amount of first portion of aluminum is set on the basis of dependence: Q₁ = (5-2400)•10^-7 t/c, where Q₁ is amount of aluminum in first portion, kg/t of melt; t is melt temperature before introduction of first portion of aluminum, C; c is content of carbon in melt before introduction of first portion of aluminum, %; (5-2400)•10^-7 is empirical coefficient, kg%/T C. Second portion of aluminum is introduced into melt 5-60 min after introduction of first portion and before introduction of calcium or simultaneously therewith, an amount of calcium being set on the basis of dependence: q = (0,25-0,9)•ΔS/S; where q is amount of calcium, kg/t of melt; ΔS is required value for reducing sulfur content in melt, %; S is sulfur content in melt before introducing second portion of aluminum and calcium, %; (0.25-0.9) is empirical coefficient, kg/t of melt. Amount of second portion of aluminum is set on the basis of dependence: Q₂ = (5-20)ΔA1 +(0.1-0.7)q, where Q₂ is amount of aluminum in second portion, kg/t of melt; ΔA1 is required value of increase of aluminum content in melt, %; (5-20) is empirical coefficient, kg/t; (0.1-0.7) is empirical coefficient. First portion of aluminum is introduced in the form of bars, cuttings, lumps for 0.1-3.0 min and second portion of aluminum is introduced in the form of wire for 3.5-20.0 min. Method is used for complex processing and finishing of steel in ladle after melting in converter and before continuous pouring process. EFFECT: increased efficiency in out-of-furnace refining process and improved quality of ingots. 2 cl, 1 tbl, 1 ex