Agglomeration behaviors of various oxide inclusions in Fe–Al–Ti–O melts
摘要
The formation of large-sized inclusions cluster severely impacts the continuous casting process and product quality of titanium-containing steel. Thermodynamic calculations were initially conducted to predict the formation of various complex oxide inclusions, namely Al2O3, TiOx and Al–Ti–O. Based on that, laboratory-scale experiments were designed to prepare samples with a single type of inclusions. Then, the scanning electron microscope–energy dispersive spectrometer was used for quantitative characterization. Subsequently, the agglomeration behavior of inclusions in Fe–Al–Ti–O melt was observed in situ by high-temperature confocal laser scanning microscopy. Furthermore, a quantitative analysis of the agglomeration characteristics of the various inclusions was conducted based on the attractive forces in accordance with Newton's second law and the capillary forces as described by the Kralchevsky–Paunov model. The results indicate that the size of Al2O3 inclusions is larger than that of TiOx and Al–Ti–O, but the number density of TiOx is the highest. Based on the in situ observation and the theoretical calculation, Al2O3, TiOx and Al–Ti–O inclusions can all agglomerate into large-sized clusters without segregation, but the agglomeration tendency of Al2O3 and TiOx is stronger than that of Al–Ti–O. The attractive force between Al2O3 inclusions’ pair is the largest, ranging from 2.26 × 10–15 to 6.12 × 10–14 N, followed by TiOx (7.13 × 10–16 to 3.56 × 10–14 N) and Al–Ti–O (1.16 × 10–17 to 3.77 × 10–16 N).