Wetting and Reaction Behavior of TiN and TiO₂ with Different Mold Fluxes for High Ti-Bearing Stainless Steel

The wettability and reaction behavior of mold flux with different basicity on TiN and TiO₂ substrates were investigated at up to 1400 °C by the sessile drop method, which can provide a theoretical basis for optimizing the composition of the mold flux for high Ti-bearing steel. As the basicity increased, the mold flux exhibited better wettability and a stronger interfacial reaction with TiN. Thus, it was easier to absorb the TiN inclusion in the order of CaO–SiO₂-based flux (CS) > CaO–SiO₂–Al₂O₃-based flux (CSA) > CaO–Al₂O₃-based flux (CA). Scanning electron microscopy coupled with energy-dispersive spectroscopy showed that the interfacial reaction was also related to basicity. There was a visible and regular interfacial reaction layer between TiN and CS and the CSA flux, which was produced by the redox reaction between the SiO₂ in the slag and the TiN substrate, whereas there was no interfacial reaction layer between TiN and the CA flux. As the basicity decreased, the mold flux exhibited better wettability and a stronger interfacial reaction with TiO₂; thus, it was easier to absorb the TiO₂ inclusion in the order of CA > CSA > CS. There was also a visible and regular interfacial reaction layer between TiN and the three fluxes, which was produced by the dissolution of TiO₂ and then reacted with CaO to generate CaTiO₃.