Evolution of Inclusions after Cerium and Titanium Addition in Aluminum Deoxidized Fe-17Cr-9Ni Austenitic Stainless Steel

In this study, the effects of the addition of Ce and Ti on the evolution of inclusions in Al deoxidized Fe-17Cr-9Ni austenitic stainless steel were investigated. When the Ce was added before Ti, Al2O3 can be effectively modified into Ce-containing oxides by Ce. With the increase of Ce content, the oxides evolutionary process is as follows: Al2O3 → CeAl11O18 → CeAlO3 → Ce2O3. After the addition of Ti, TiN appeared on the surface of oxides except Ce2O3. When Ti was added before Ce, due to the simultaneous effects of Ti on the modification of smaller size Al2O3 and precipitation of TiN, spherical Al2O3–TiOx inclusion that was completely wrapped by TiN formed. On the other hand, the larger size Al2O3 was not significantly modified by Ti, and cannot completely be wrapped by TiN. After Ce was added, the oxides which were not completely wrapped by TiN were modified to Ce-containing oxides. However, Ce could not modify the oxides that were completely wrapped by TiN.