9th ECCC European Continuous Casting Conference – ECCC 2017

High-Al steels attract wide attention in the automobile industry owing to their excellent combination of high strength and superior formability. The reaction between Al in the liquid steel and SiO2 in lime-silica-based mould fluxes during the continuous casting of these steels causes chemical compositional changes in the mould flux, subsequently affecting the surface quality of slabs. In order to solve the aforementioned problem, lime-alumina-based mould powders have been developed which can lead to an increase in the surface quality of cast slabs by inhibiting molten steel/mould powder interaction. However, the mould slag tends to crystallize easily, which results in mould lubrication deterioration. Therefore, knowledge of liquid steel-slag interaction is required to select the appropriate casting powder. Changes in physical properties such as crystallinity and melting behaviour of lime-alumina-based mould powders with increasing CaO/Al2O3 ratio have been observed through STA (Simultaneous Thermal Analysis), HSM (Hot Stage Microscopy) and XRD (X-ray Diffraction, and changes in slag chemistry over time have been analysed using XRF. This paper will present a summary of these results.