JPS6447809A - Method for raising temperature of molten metal in ladle - Google Patents

Abstract

PURPOSE:To restrain loss of valued component without increasing heating cost by submerging a top-blowing lance composing of triplex pipes into molten steel, letting out a metal wire for raising temp. from the inner pipe at the specific velocity and blowing oxygen gas and inert gas respectively from the middle pipe and the outer pipe. CONSTITUTION:The top-blowing lance 3 having the triplex pipes composing of the inner pipe 3-1, middle pipe 3-2 and outer pipe 3-3 is submerged into the molten steel 2 in a ladle 1. Then metal wire 4 for raising temp. (Al, etc.) is let out from the inner pipe 3-1 at supplying velocity calculated from the equation, and the oxygen gas G1 from the middle pipe 3-2 and the inert gas G2 from the outer pipe 3-3 are blown, respectively. Then, in the equation, they use (v) for supplying velocity (m/min) of the metal wire for raising temp., WM for metal wt. (kg/Nm<3>) for raising temp., which is stoichimometrically equal to 1Nm<3> of oxygen, Qo2 for oxygen supplying velocity (Nm<3>/min), rho for the metal density (kg/m<3>) for raising temp. and (s) for cross sectional area (m<2>) of the metal wire for raising temp. By this method, at the time of raising the temp., low grade oxide in the slag is reduced and the cleanliness is improved.