IMMERSION NOZZLE

摘要

Disclosed is an immersion nozzle which includes a vertically tubular straight barrel portion and a pair of right-and-left symmetric discharge holes. The barrel portion allows molten steel to pass therethrough in the vertical direction downward from a molten steel inlet portion provided on the upper end. The pair of discharge holes is provided at a lower portion of the straight barrel portion to discharge the molten steel sideward from the side of the straight barrel portion. To allow the molten steel to be discharged through the discharge holes of the immersion nozzle in a uniform and laminar flow and to prevent inclusion of mold powder in the vicinity of the immersion nozzle, the immersion nozzle is constructed such that the discharge holes have the following inner shape in the longitudinal cross section of the immersion nozzle passing through the center of the immersion nozzle and the center of the discharge holes. That is, the inner shape is gradually reduced in diameter in a curve from the starting point to the end portion of the discharge hole. Furthermore, within at least part or the entirety of the discharge hole, the curve representing the gradual reduction in diameter has an inner shape of the discharge hole expressed by a diameter in the longitudinal cross section of the immersion nozzle.