REMOVAL OF INCLUSION IN MOLTEN STEEL

摘要

PURPOSE:To float and remove the inclusions in a molten steel by providing a refractory cylindrical body having an inflow port for the molten steel to the upper part of the nozzle aperture in the bottom of a tundish, supplying an inert gas to the inside of the cylindrical body and stirring the molten steel by a rotor. CONSTITUTION:The refractory cylindrical body 3 is installed above the aperture of the immersion nozzle 6 provided in the bottom of the tundish 2. The molten steel 14 poured from a ladle 1 into the tundish flows through the inflow port 12 provided to the body 3 into the body 3 in the direction tangential to the inside surface thereof and rotates the rotor 5 provided in the central part in the direction opposite from the inflow direction of the molten steel. The inert gas such as Ar is at the same time supplied in the state of foam 15 to the molten steel in the body 3 through a nozzle 7. The large inclusions in the molten steel are gathered to the central part by the centrifugal force generated by the rotation of the rotor 5 and are floated on a molten slag surface 13. The small inclusions are adsorbed to the inert gaseous foam fined by the rotor 5 in the mid-way of descending together with the downward flow of the molten steel 14 by which said inclusions are floated together with the foam 15 on the surface 13 and are thereby removed.