PURPOSE: To facilitate the rapid exchange of a plug for injecting refining gas or the like into molten steel, by constituting the plug with a refeactory nozzle having a through hole and a metal pipe inserted into the through hole, and providing an annular slit having specified width between them.
CONSTITUTION: As a porous plug for injecting refining gas such as oxygen gas, inert gas or the like into molten steel, a small pipe 5 of stainless steel having an inner diameter below 6mm is inserted into the through hole of a refractory nozzle 4, and a difference of 0.5W1.0mm is made between the through hole and the outer diameter of the small pipe 5 of stainless steel to provide a narrow annular slit (g) between the through hole and the small pipe 5 of stainless steel. As long as the slit is held at such degree, there is not the fear that the molten steel leaks through the slit during the injection of gas. In addition, the exchange of the porous plug after the completion of blowing works is easily finished by exchanging only the small pipe of stainless steel for a new one.
IWANAGA YUUSUKE
ANZAI SHIGEO
MORIMOTO MASAOKI
USHIGOME SUSUMU
WATANABE YOSHIAKI
MIYAGAWA NOBUO
TOKYO YOGYO KK