Formation of deposits inside the submerged entry nozzles used in continuous casting ofespecially low-silicon Al-killed mild steels may often cause nozzle clogging and castingdisorder. Technological experience has shown that the application of Ca-treatment beforecasting usually eliminates this phenomenon. In order to understand deposit formation andthe way it can be avoided, we have carried out detailed mineralogical analyses of thedeposits formed on the inner and outer surfaces of the nozzles by different techniques.Results obtained from deposits formed during the casting of only Al-killed andsubsequently Ca-treated steels show that the results obtained from deposits formed duringthe casting of only Al-killed and subsequently Ca-treated steels show that the aluminainclusions carried to the wall of the nozzle form the matrix of the dangerous deposits.Application of Ca-treatment resulted in mostly liquid aluminates compounds and almostnegligible deposit formation. The outer surface of the nozzles however showed similardeposit formation because of possible reoxidation of dissolved aluminium.
