The Behavior of Oxygen in Liquid Steel during the Continuous Casting

Abstract

In order to clarify the origin of macrcscopic oxide inclusions in continuously cast steel, it is necessary to understand quantitatively (1) the balance of oxygen in steel during casting and (2) the entrapment of floating oxide inclusions by solidified steel.
Accordingly, the behavior of cxygen in steel was investigated during casting of AISI 304 grade steel containing silicate inclusions, then the balance of oxygen and the entrapnent of oxide inclusions were analyzed.
It became clear that the behavior of oxygen in steel is remarkably different during casting between by open nozzle and by submerged nczzle. A characteristic of casting by open nczzle is that the oxygen content of liquid steel in mold is remarkably higher than that of poured steel. The oxygen content of solidified steel, however, does not always become higher than that of poured steel. This shows that the oxidation of liquid steel by the air is sufficiently compensated by the separation of scum. On the other hand, the oxygen content of poured steel, that of liquid steel in mold and that of solidified steel are equivalent during casting by submerged nozzle.