Wettability between various Ti-based oxide inclusions and Ti-containing steel

The wettability between inclusions and molten steel are critical factors influencing the formation of large inclusion clusters. In this study, Ti-based oxide inclusions in steel were analyzed through thermodynamic calculations, and steels equilibrated with these inclusions were prepared. Subsequently, various Ti-based oxide inclusions substrate were prepared using a three-step route consisting of pressing, vacuum sealing, and high-temperature sintering. Their interfacial behaviors with molten steel were investigated by a sessile drop method combined with vacuum sealing. The results indicate that Ti2O3 inclusion formed in Ti-deoxidized steel, whereas pseudobrookite-type Al-Ti-O inclusions with an Al/Ti ratio of about 1:2, corresponding to Al2O3·4/3Ti3O5 formed in Al-Ti complex deoxidized steel. Both the Ti2O3 and Al2O3·4/3Ti3O5 substrates exhibited non-wetting behavior with molten steels, yielding average contact angles of 131.4° and 108.32°. In contrast, the TiO2 substrate was wetted by the Ti-deoxidized molten steel with a contact angle of 85.57° and showed clear evidence of erosion. No intermediate reaction layers were observed at any of the substrate-steel interfaces. Furthermore, an evaluation of agglomeration behavior based on the measured interfacial properties demonstrates that the pseudobrookite phase possesses a smaller contact angle than both Ti2O3 and Al2O3, which results in a weaker agglomeration tendency. Therefore, controlling the steel composition to favor the formation of the pseudobrookite phase can effectively suppress the clustering of large inclusions and thereby alleviate nozzle clogging during the continuous casting process.