Thermodynamic Properties of Inclusions Formed Aluminum-Titanium Deoxidation of Molten Steel

Titanium alloyed steel has been widely used as automobile sheet steels, thick plate steels, and also stainless steels to improve the mechanical and chemical properties of many grade steels. Since Ti has strong affinity with oxygen, Ti is normally alloyed after Al deoxidation to keep the high yield of Ti. Therefore, Al-Ti deoxidation is one of the common and important secondary refining processes. Although the chemical stability diagram for this system has been reported by many researchers, these diagrams are inconsistent significantly each other. In the present study, the stability region of Al2TiO5 oxide was measured by equilibrating Fe-Al-Ti alloy and Al2TiO5 pellet in Al2O3 crucible at 1873 K. However, inclusions in metal after equilibration were Ti-containing Al2O3 or Al-containing TiOx. The precise phase diagrams and related thermodynamic data for the Al2O3-TiOx-FeO system should be determined.