Vyksa Steel Works (Vyksa, Russia):

D. V. Morov, Head of the Casting and rolling complex
S. A. Botnikov, Technologist of steelmaking production, e-mail: botnikov_sa@vsw.ru
V. N. Lavrov, Head specialist of the dept. of metallurgical processes and technologies of the scientific-technical center

One of the main contaminants of the steel with oxide nonmetallic inclusions is the secondary oxidation of the steel when moving from the casting ladle to the mold of continuous casting machine (CCM). The secondary oxidation includes the interaction of liquid steel with the oxygen in the air, the interaction with the slag of tundish and refractories. The secondary oxidation in the tundish can also be intensified by the processes like turbulent flows of steel in the tundish at the opening of the shroud over the slag level, by the particularities of the inner structure of the tundish, by the fluctuations of steel level in the tundish, excessive argon purging in the tundish, chemical composition of the refractories etc. In practice, it is difficult to separately evaluate the impact of the secondary oxidation processes on the formation of oxide non-metallic inclusions in the tundish due to the presence of other essential processes, which also have a significant impact on the steel contamination. For example, refractory wear, covering slag capturing in the melt, ladle slag entering in the tundish etc. In the present article indirect and direct methods for the evaluation of the secondary oxidation of the steel in the tundish during the casting at the CCM are considered. The methods described are good studied in the main and are in use for a quite long time. The authors have tried to generalize and analyze advantages and disadvantages of each method and to defi ne the conditions for applying each of them. The first part of the article shows the main practical examples of the estimation of the secondary oxidation of metal in the continuous casting machine.

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