In Situ Method to Study the Dissolution of Ti(C,N) Inclusion in Molten Mold Flux

Mold fluxMold flux plays a critical role in absorbing the inclusions floating from the liquid steel. However, this dissolution process is hard to observe in situ because the moldMolds is a “black box”. This paper used the in-situ single hot thermocouple technique (SHTT) combined with high definition microscope to investigate the dissolution behavior of Ti(C,N) inclusionTi(C,N) inclusion in molten CaO–SiO2–B2O3-based mold fluxMold flux, as well as the dissolution mechanism was explored by scanning electron microscope (SEMScattering electron microscopy (SEM)) equipped with X-ray energy spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The results suggest that Ti(C,N) inclusionTi(C,N) inclusion was oxidized and then dissolved in molten slag as [TiO4] tetrahedra and [TiO6] octahedra, which is accompanied by the generation of N2 and CO2 gas. In addition, CaTiO3 crystals tend to precipitate and stabilize in the molten slag, leading to the final solid–liquid mixed state of the meltMelt. In addition, the precipitated CaTiO3 crystals are greater in number but smaller in size because the dissolution of Ti(C,N) releases more gases that can provide more nucleationNucleation sites, thereby increasing the nucleationNucleation of the crystal.