Treatment for improving the castability of aluminum killed continuously cast steel
AssigneeUsinor
InventorsFlorence Bertrand, Jean Lehmann, Laurent Sosin
Life of this patent
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Abstract
According to this treatment, calcium is added to ultra low molten steel or low carbon which is aluminum killed (or in the course of being killed) in order to form non-metallic deoxidation inclusions that have a melting point which is below the casting temperature; the molten metal is maintained in the chain of treatment ranging from the ladle refining installation to the copper mold with a low minimum low magnesium content of approximately 2 ppm. The inventive method increases the scope of fusibility of the inclusionary population of steels, thereby improving the castability of high aluminum-killed ultra low carbon grades without the need for argon bubbling.
Claims9
A process for the metallurgical treatment of a molten ultralow- or low-carbon steel to be continuously cast, comprising:
- killing the molten ultralow- or low carbon steel with aluminum in order to achieve a given oxygen content, so as to form deoxidation inclusions having a melting point below the temperature at which the steel is cast in the mold;
- adding magnesium after the steel has been killed with aluminum;
- wherein the molten metal is maintained during a treatment sequence going from a ladle to a casting mold, with a dissolved magnesium content of between a minimum value of approximately 2 ppm and a maximum value of 10 ppm.
Dependencies are inferred from the claim text.