Abstract
The phase changes of Fe−20Mn−13Cr−3Co/1.2Ti alloys have been studied during solution nitriding at 1150 °C in a nitrogen gas atmosphere. Investigations have focused on the phase change, the variation of nitrogen content, the hardness change, and the corrosion resistance. Fe−20Mn−13Cr−3Co alloy displayed austenite single phase by solution nitriding at the surface layer, while the interior region, where the nitrogen did not permeate, exhibited a mixture of austenite, ferrite, and ε-martensite. For the alloy of Fe−20Mn−13Cr−1.2Ti, titanium nitrides of square type at the outmost surface and of rod type at the next surface were detected in the austenite matrix, while ferrite and austenite appeared in the interior region. From observation of the microstructure of two austenites of Fe−20Mn−13Cr−1.2Ti alloy, it was found that few stacking faults existed in the austenite of the surface layer, likely due to a high SFE caused by high nitrogen content. In contrast, many stacking faults were observed in the nitrogen-free austenite of the interior region, possibly due to a low SFE. The nitrogen content of Fe−20Mn−13Cr−3Co alloy decreased gradually with increasing depth below the surface after showing a maximum of 1.30% at the outmost surface, which was in line with the trend of the hardness decrease. For the Fe−20Mn−13Cr−1.2Ti alloy, Ti diffused from the interior to the surface when the nitrogen permeated from the surface into the interior owing to strong affinity between Ti and N, which resulted in a maximum Ti content at the outmost surface. Solution nitriding remarkably improved the corrosion resistance in Fe−20Mn−13Cr−3Co alloy, while the precipitation of titanium nitride deteriorated the corrosion resistance in Fe−20Mn−13Cr−1.2Ti alloy.
Similar content being viewed by others
References
H. Berns and S. Siebert,9th Int. Cong. on Heat Treat and Surf. Eng., p. 175, Nice, France (1994).
H. Berns and S. Siebert,ISIJ Int. 36, 927 (1996).
Valentin G. Gavriljuk,ISIJ Int. 36, 738 (1996).
G. Paul, H. Chapman-Kpodo, and Alan Hendry,ISIJ Int. 36, 867 (1996).
T. H. Lee, C. S. Oh, C. G. Lee, S. J. Kim, and S. Takaki,Met. Mater.-Int. 10, 231 (2004).
V. G. Gavriljuk and H. Berns,High Nitrogen Steels, p. 205, Springer, Germany (1999).
J. Charles,Forth International Conference Duplex Stainless Steels, paperKI TWI, Scotland (1994).
S. W. Jun, K. K. Jee, S. H. Baik, C. S. Choi, and M. C. Shin,J. Kor. Inst. Met. & Mater. 37, 749 (1999).
C. S. Choi,Bull. Kor. Inst. Met. & Mater. 12, 186 (1999).
K. Miyahara,J. Alloys Comp. 355, 17 (2003).
J. H. Jun, D. K. Kong, and C. S. Choi,Mater. Res. Bull. 33, 1419 (1998).
S. H. Baik, J. C. Kim, K. K. Jee, M. C. Shin, and C. S. Choi,J. of Korean Society for Heat Treatment 9, 53 (1996).
J. H. Jun, Y. K. Lee, and C. S. Choi,J. Kor. Inst. Met. & Mater. 33, 1600 (1995).
S. I. Shim, Y. S. Park, S. T. Kim, and C. B. SongMet. Mater.-Int. 8, 301 (2002).
J. H. Yoo, J. H. Jun, Y. K. Lee, and C. S. Choi,J. Kor. Inst. Met. & Mater. 33, 1544 (1995).
V. G. Gavriljuk and H. Berns,High Nitrogen Steels, p. 61 Springer, Germany (1999).
Y. K. Lee,J. Mater. Sci. Lett. 21, 1149 (2002).
Z. Nishiyama,Mariensitic Transformation (eds. M. E. Fine, M. Meshii, C. M. Wayman), p. 40, Academic Press, London (1978).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sung, J.H., Joo, D.W., Kim, I.S. et al. Phase changes of Fe−20Mn−13Cr−3Co/1.2Ti alloys during solution nitriding. Met. Mater. Int. 11, 157–163 (2005). https://doi.org/10.1007/BF03027460
Issue Date:
DOI: https://doi.org/10.1007/BF03027460