Design of mold flux for continuous casting of special steels

The melting behavior of mold powder during continuous casting is an important consideration with respect to caster performance, production rate and steel quality. Two important factors, powder composition and carbon addition, are critical to control the properties and melting behavior of the mold flux. In this study the effect of different carbonaceous materials on the melting characteristics of mold powders was evaluated. Correlations were established between the structural factors and chemical reactivity of carbon and melting behavior of mold flux. Two examples are given of the effect of flux composition on casting performance for specific steels. A flux with reasonable basicity and additives was designed for the casting of heat-resistant steel (Incoloy 800) to reduce surface cracks. Another flux was designed for the casting of non-magnetic steel containing high aluminum by partially replacing SiO2 with Al2O3 to limit aluminum oxidation by SiO2.