Katelyn Kiser, a doctoral candidate in metallurgical engineering, will defend their dissertation titled “Influence of Chemistry on Solidification, Segregation, and Hot Tearing Susceptibility of Advanced High Strength Steels.” Their advisor, Dr. Ronald O’Malley, is a professor in the material science and engineering department. Their co-advisor, Dr. Laura Bartlett, is an associate professor in the materials science and engineering department. The dissertation abstract is provided below.

Understanding the solidification of steel grades is of immense importance when it comes to successfully continuously casting them with limited defects. Solidification conditions can affect micro and macro segregation, each leading to their own set of equally detrimental defects. This work set off to compare the solidification of traditionally continuously cast steels such as X70 and AISI52100 with the solidification of newer grades of steel such as AF9628 and FeMnAl steels which are not yet continuously cast.

Casting trials were conducted using controlled deformation upon solidification to determine what conditions were required for the formation of hot tearing. Additionally, postmortem analysis was performed to assess the impact of segregation and cast structure on the formation of the hot tears.

Solidification studies in the HT-LSCM were used to develop a more advanced understanding of the effect of process conditions on the solidification structure and how that might translate to castability at an industrial scale.

Overall, this research demonstrates that with proper control of the casting process, there is a potential future in the continuous casting of AF6928 and FeMnAl steels. It also shows that for any steel grade of interest, a combination of casting trials for the understanding of process force limitations and HT-LSCM for development of solidification behavior at different cooling rates, the continuous casting of any alloy can be optimized to reduce the likelihood of detrimental defects related to segregation.