Immersion nozzle for continuous casting of steel and method for continuous steel casting of steel using the immersion nozzle

摘要

Disclosed is a nozzle for continuous casting of clean steel, capable of preventing adhesion of Al₂O₃-based inclusions to a wall surface of the inner hole of the nozzle while fully achieving an effect of a swirl vane provided as a means to prevent occurrence of drift in molten steel passing through the inner hole. The swirl vane is disposed in the inner hole having the wall surface at least partly formed as a tubular-shaped refractory layer prepared by controlling a weight ratio of CaO/MgO and an apparent porosity to have a thickness of 3 to 20 mm, so as to prevent adhesion of Al₂O₃-based inclusions to the wall surface and the swirl vane while effectively maintaining the anti-drift effect for long hours. Further, inert gas is injected into a molten steel flow between an upper nozzle and the swirl vane to facilitate surfacing of Al₂O₃-based inclusions in a mold and reduce Al₂O₃-based inclusions in molten steel so as to achieve stable casting operation and high-quality steel with high cleanness.