Wetting Behavior of CaO–SiO₂- and CaO–Al₂O₃-Based Mold Slags on High-Ti Steel

Wetting behavior of mold slag on steel affects the surface qualify of steel products. In this study, the rheological behavior of the two types of mold slags (CaO–SiO₂- and CaO–Al₂O₃-based mold slags), the reactivity, and wettability behavior between the slags and high-Ti steel were investigated. The results indicated that the aluminate-based slag showed the lower reactivity comparing with the silicate-based slag, and the rheological behavior of the aluminate-based slag was better than that of the silicate-based slag. The contact angle between the CaO–Al₂O₃-based slag and steel substrate was 30.61 deg, which was 17.17 deg lower than that for the CaO–SiO₂-based slag due to the high CaF₂ content. Moreover, the adhesion energy of the two types of slags exhibited the same trend from the contact angles. The micro-morphology and element distribution at the steel–slag interface revealed that more steel droplets dispersing in the silicate-based slag and the wider transition zones of [Si] and [Fe] at the interface between the CaO–SiO₂-based slag and steel, indicating the interface reaction and mass transfer were more drastic between the CaO–SiO₂-based slag and steel than that for the CaO–Al₂O₃-based slag. The study indicates that aluminate-based slag has industrial application potential in the continuous casting of high-Ti steel.