Elsevier

Scripta Materialia

Volume 215, 1 July 2022, 114685
Scripta Materialia

Improved hot ductility of an as-cast high Mn TWIP steel by direct implementation of an MnS-containing master alloy

https://doi.org/10.1016/j.scriptamat.2022.114685Get rights and content

Abstract

Transverse cracking is the main issue during continuous casting of TWIP steels due to degraded hot ductility at 700–950 °C. In this study, we improve the hot ductility of an 18.1Mn-0.68C-1.5Al (wt.%) TWIP steel by refining the as-cast structure via inoculation. Inoculation was implemented by direct addition of MnS-containing master alloy to the melt. Since MnS did not dissolve in the melt, they acted as heterogeneous nucleation sites for austenite nucleation. Consequently, MnS-inoculated steel shows finer grain sizes than reference steel. Additionally, MnS particles are found to have a polygonal shape, randomly distribute, and share a cube-on-cube orientation relationship with austenite; both habit planes are parallel to {111}. A periodic array of b= 1/6<112> edge dislocations at every fourth {222} planes of MnS is necessary to accommodate the large lattice misfit of the cube-cube relationship. The MnS-inoculated TWIP steel shows significantly improved hot ductility compared to previously reported TWIP steels.

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Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This work was supported by POSCO (Project. No. 4.0020945).

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