Effect of Nozzle Permeability on Clogging

Submerged entry nozzle (SEN) and tundish well nozzle clogging are common problems in the continuous casting of aluminum-killed steels. Often the accretion layer grows throughout a casting sequence until it forces a nozzle change or the cast to be aborted. In some cases when clogging is not severe enough to result in stopping of the strand, sections of the accretion layer break free and enter the steel stream causing operational and quality problems. This paper studies the effects of permeability on clogging behavior. Laboratory sized casting nozzles were fabricated from refractories of different levels of permeability using two standard nozzle materials, alumina graphite and magnesia. Laboratory casting experiments designed to simulate industrial conditions were conducted to investigate clogging behavior. In summary, nozzle clogging was not significantly affected by the permeability of the nozzle