2016 Volume 56 Issue 4 Pages 584-593
In the current study, steel samples in continuous casting tundish were taken at every 5–10 minutes to investigate the reoxidation behavior and inclusions in Si-killed stainless steel in the tundish during a casting sequence with three heats. Contours were employed to clearly illustrate the distribution of number density, diameter and area fraction of inclusions in composition ternary diagrams. After reoxidation of Si-killed stainless steel, [Al] and [Ca] in the steel were oxidized and decreased to extremely low levels in the reoxidized region of the molten steel. A large number of MnO-riched small inclusions as transitional products were generated by the oxidation of high [Mn], and gradually decreased. The population density function (PDF) of inclusions tended to a power law type function (f(r)=4.54×10−5·r−3.66). Moreover, thermodynamic calculation illustrated that, the increase rate of MnO and SiO2 content in liquid inclusions are much faster than that of Al2O3 and CaO during reoxidation of Si-killed stainless steel, while solid inclusions become predominant and transfer from CaAl4O7 to CaAl12O19 to Al2O3 in Al-killed stainless steel.