Inclusion characteristics and microstructure properties under different cooling conditions in steel with nanoparticles addition

ABSTRACT

In the present study, the experimental steel containing nanoparticles was manufactured and then cooled to room temperature under different cooling rates. The differences on the inclusion characteristics and microstructure morphologies between the original steel and experimental steel were compared. The results revealed that the majority of reaction products in the experimental steel were Al₂O₃–MgO-bearing hybrid inclusions. These inclusions under brine quenching, and water quenching had large potential for inducing intra-granular acicular ferrites (IAF). Hence the microstructure in the experimental steel mainly consisted of fine IAF. For the original steel, SiO₂–MnO–MnS-based inclusions could hardly induce IAF, and the microstructure consisted of relatively larger intra-granular banded ferrites, and intra-granular polygonal ferrites. The differences on microstructure morphologies between the two steels had a correlation with the inclusion composition, and size. These were the primary factors to determine whether a particular type of inclusion could induce IAF effectively or not.

KEYWORDS:

• Nanoparticles
• cooling rates
• intra-granular acicular ferrites
• microstructure

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The Chinese Scholarship Council (CSC) is acknowledged for financial support of Xiangzhou Gao’s studies at University of Toronto. This research is supported by National Natural Science Foundation of China (Nos. 51674023 and 51474076).