Speaker
Description
High nitrogen austenitic stainless steels (HNAUSS) exhibit excellent corrosion resistance in combination with outstanding mechanical properties that outperform those of conventional austenitic stainless steels $^1$. In HNAUSS, the deformation mechanism is primarily planar slip $^2$. HNAUSS can be produced by melting in a high-pressure N-containing atmosphere, but higher nitrogen contents can be dissolved directly into the solid-state by high-temperature solution nitriding (HTSN) $^3$. In the present work, it is shown that the chemical composition of conventional high C, low Cr martensitic steel grades can be tailored by HTSN to promote particularly high strain-hardening via the TRIP effect. The technological challenge with HTSN is grain growth resulting from the high processing temperature $^{3,4}$, which results in relatively large grains and premature failure by intergranular fracture $^2$. A method is presented to reduce the grain size after HTSN of the steel. This remedy is reminiscent of the eutectoid decomposition of austenite into pearlite in plain carbon steels. The combined effect of high C and N contents enables a combination of high strength and high ductility.
1 T. Nakanishi, T. Tsuchiyama, H. Mitsuyasu, Y. Iwamoto, and S. Takaki, Mater. Sci. Eng. A 460–461, 186 (2007).
2 T. Onomoto, Y. Terazawa, T. Tsuchiyama, and S. Takaki, ISIJ Int. 49, 1246 (2009).
3 H. Berns, J.W. Bouwman, U. Eul, J. Izagirre, R.L. Juse, H.J. Niederau, G. Tavernier, and R. Zieschang, Materwiss. Werksttech. 31, 152 (2000).
4 R. Mohammadzadeh and A. Akbari, Mater. Charact. 93, 119 (2014).
| Speaker Country | Denmark |
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| Register for the Tom Bell Young Author Award (TBYAA)? | Yes |
