A morphological comparison between inclusions in aluminium killed steels and deposits in submerged entry nozzle

A study was carried out to compare the inclusions present in low carbon aluminium killed (LCAK) steel with oxide particles in a clogging deposit formed during casting of LCAK steel. Steel pin samples were taken in the ladle and in the tundish. It was observed that oxide particles in the clogging deposit are mainly coral-shaped clusters, dendritic clusters and irregular plates. From the comparison with inclusions in LCAK steel, it is concluded that the particles in the clogging deposits are formed during reoxidation of the steel, at least after the ladle metallurgy process and most probably in the submerged entry nozzle. They are not the result of sintering of small pre-existing inclusions.