A study was made on the problem of tundish nozzle constriction in continuous casting of titanium bearing stainless steel slabs. The constriction becomes more severe as the percentage of alumina in the molten steel in the tundish, and subsequently the ratio of alumina to titanium nitride increases. The main origin of titanium nitride and alumina particles in the buildup are denitrification and deoxidation products in the molten steel. Alumina from the nozzle refractory and the reaction between aluminum in the steel and silica in the refractory, in addition to the deoxidation product, plays a significant part in buildup process at the initial stage. The buildup process is assumed to be a phenomenon involving not only deposition of the nonmetalics and freezing of the steel but also subsequent removal of the buildup.
