Analysis on and countermeasures against clogging problem of submerged entry nozzle in continuous caster

Submerged entry nozzle often incurs nodulation,even blockage,because of the attachment of alumina to the nozzle wall during the process of pouring molten steel,especially for the alumina-killed steel.It not only reduces the production efficiency and shortens the service life of the nozzle,but affects the quality of billets.This paper analyzes the clogging mechanism of the submerged entry nozzle from various aspects,such as the source,microstructure,distribution and formation of stemming.It also introduces new technologies of preventing submerged entry nozzle nodulation at home and abroad,and puts forward concreate measures to optimize nozzle structure,properly select nozzle material and improve the cleaness of steel.