2014 Volume 100 Issue 4 Pages 548-555
Non-metallic inclusions in steel considerably affect various properties of products and thus it is important to understand the formation and evolution behaviors of inclusions in steel. Much attention is paid to steel grades containing Ti because of its excellent mechanical properties and it is well known that such functions are mainly created by Ti-based inclusions. In the present study, the effect of Ti addition and cooling patterns on the inclusion properties such as size and composition was observed to understand fundamental behaviors of inclusions in steel containing Ti and N.
Ti addition had following effects: (1) decrease of average size of inclusions, (2) increase of the fraction of TiN and other Ti-containing inclusions, (3) promotion of the transition of MnS single phase inclusion into Mn-Ti based inclusions. Slower cooling rate promoted TiN formation and growth. Inclusions with several phases were observed and its formation mechanism was discussed by considering the morphology and composition of oxide phases at center of multi-phase inclusions.
