REDUCING METHOD FOR NONMETALLIC INCLUSION IN CONTINUOUS CASTING

摘要

PURPOSE:To float and capture nonmetallic inclusions and to clean steel by giving upward rotating flow to the molten steel in a casting mold by using a specific immersion nozzle. CONSTITUTION:An immersion nozzle is closed in a bottom part 1a, and has at least three discharge holes 40 on the nozzle side wall. Part of the inside wall of the holes 40 is made coincident with the tangent of the inside surface of the immersion nozzle. The nozzle 1 is set in such a way that the angle theta that the directions in the horizontal directions of the respective holes 40 and the perpendicular direction of the wall surfaces of a casting mold 2 facing each other assume attains at least 5 deg.. The angles at which the holes 40 face upward and the immersion depth of the nozzle are so adjusted that discharge flow 5 directs the boundary between the molten steel and a flux 3, and the molten steel is cast while the rotating flow 6 centering at the nozzle 1 is given in the mold.