NOZZLE FOR CONTINUOUS CASTING OF ALUMINUM KILLED STEEL AND CONTINUOUS CASTING METHOD

摘要

The present invention provides a technique of applying a CaO-containing material to a nozzle unit for casting of aluminum-killed steel, in such a manner that the amount of large-size alumina inclusions in slabs can be reduced irrespective of nozzle type, such as single-part type or multi-part type. The amount of large-size alumina inclusions in slabs obtained using a single-part type or multi-part type nozzle unit, which has an inner hole to be used for pouring molten steel from a tundish to a mold therethrough and CaO-containing refractories applied to a surface of the inner hole, has a strong correlation with the entire surface area of the inner hole of the nozzle unit and the amount of CaO contained in the employed refractories. According to the present invention, 50% or more of the entire surface area of the inner hole of the nozzle unit is formed of refractories containing 20 mass % or more of CaO to allow the amount of large-size alumina inclusions to be reduced.