PURPOSE: To control a flow rate of gas extending over a wide range, and to efficiently execute refining, by providing plural nozzles consisting of a nonporous refractory material on which a through-hole having a specific diameter has been formed, under the steel bath surface of the furnace bottom of a converter, and blowing in gas from the nozzles by specific pressure.
CONSTITUTION: A nozzle is constituted of a one body substance of a nonporous refractory material 1 whose section is trapezoidal, and is covered with an iron plate 2 except its upper surface. On the refractory material 1, plural through- holes 3 are provided in the longitudinal direction, a space 4 is formed on the bottom part of the nozzle, and the lower end part of each through-hole 3 is opened. Also, a gas lead-in pipe 5 is provided to the space 4, and gas is lead equally into each through-hole 3 by the space 4 and is blown into the furnace. In case when the through-hole 3 is round, its diameter is regulated to 0.1W5mm, and in case when it is square, its short side is regulated to 0.1W5mm. Also, bottom blow gaseous pressure is regulated to molten steel + slag static pressure or higher, and a flow rate of gas is regulated to 0W0.5Nm3/min.T.
HANMIYOU MASAYUKI
TERADA OSAMU
HASEGAWA TERUYUKI
NIMURA YOUICHI
HIRAGA NORIYUKI
