Two=step deoxidation of steel - by pptn. of oxide(s) followed by slag metal exchange

摘要

Method of deoxidising or metallic(steel) both after refining, for subsequent continuous casting, is claimed. Process comprises first precipitating oxides by addition of a deoxidant to the bath. Slag-metal exchange is then effected in the tundish of a continuous casting plant in the presence of a mixt. of products introduced in solid form, consisting of components of a metallurgical slag contg. in its oxidised form an energetic deoxidant. The activity of the oxide associated with the deoxidant used is as low as possible and in any case does not exceed during the course of treatment that which would be in equilibrium with a metallic bath, the O2 content of which corresponds to a killed state of the bath. By avoiding pptn. of Al2O3 and similar oxides in the tundish, the chance of blocking the exit orifice is made negligible, and loss of castability is avoided.