A study on the transient inclusion evolution during reoxidation of a Fe-Al-Ti-O melt

Abstract

The effect of a simulated reoxidizing environment on the chemical and morphological evolution of nonmetallic oxide inclusions was studied. Additions of 545 ppm and 274 ppm of soluble oxygen were introduced to an Al killed melt containing approximately 600 ppm of Ti and 600 ppm of Al. It was found that inclusion chemistry evolved from Al2O3, Al 2TiO5 and eventually to Ti3O5 for the higher oxygen addition case and to Al-Ti complex oxides for the lower oxygen addition one. Morphologically, it was observed that irregular inclusions gradually were replaced by spherical ones during the reoxidation process. These changes are discussed through the coupling of thermodynamic prediction and experimental conditions, and considerations on the local variations of O and metallic element activities. © 2011 ISIJ.