Inclusion Formation and Interfacial Reactions between FeTi Alloys and Liquid Steel at an Early Stage

Abstract

Titanium is usually added to the liquid steel in the form of ferroalloys with varying Ti concentrations. These titanium sources also contain Al, Ca and O as the main impurities. In the present work, three different titanium sources, namely, pure Ti and two commercially produced Ti alloys i.e. FeTi70 and FeTi35 are studied. The Ti or FeTi was brought in contact with the liquid iron using the suction method, for a predetermined time and quenched. The reaction zone between the liquid Fe and the titanium source was subjected to microstructural investigation. The high Ti concentration region obtained in a pure Ti–Fe reaction couple, the inclusion formation in liquid iron after coming in contact with FeTi70 and the evolution of existing inclusions in FeTi35 after coming in contact with liquid iron have been studied. The present study has helped in understanding the influence of impurities from the Ti source on the dissolution behavior and the inclusion formation. On the basis of this study, it can be concluded that the Ti rich regions formed after the introduction of pure Ti could modify the existing alumina inclusions in liquid steel, the impurities in FeTi70 contribute to the inclusion formation depending upon the availability of O while FeTi35 introduces inclusions to the liquid steel.