Slag and oxide inclusions during continuous casting of steel

Abstract

In this paper, a report is given on slag and oxide inclusions when casting strands with small cross-sections and on possibilities for their reduction. In order to avoid the disturbing effect of slag in continuous-casting moulds and to reduce the quantity of oxide inclusions in and on the surface of cast material, deoxidation methods must be adjusted to suit the oxygen content of the bath and the continuouscasting conditions. With poor deoxidation and/or large temperature gradients between tapping and casting, further quantities of slag may arise owing to secondary deoxidation reactions. Reactions between casting stream and atmospheric oxygen may also lead to renewed slag formation. It is particularly difficult to protect the casting stream from atmospheric oxidation during casting of strands with small cross-sections, but casting with liquefied inert gas shielding has given good results.