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Quantitative analysis of retained austenite in Nb added Fe-based alloy

  • Kwang Kyu Ko (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Jin Ho Jang (Department of Metallurgical and Materials Engineering, Gyeongsang National University (GNU)) ;
  • Saurabh Tiwari (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Hyo Ju Bae (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Hyo Kyung Sung (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Jung Gi Kim (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Jae Bok Seol (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU))
  • Received : 2022.02.18
  • Accepted : 2022.05.04
  • Published : 2022.12.31

Abstract

The use of Pipelines for long-distance transportation of crude oil, natural gas and similar applications is increasing and has pivotal importance in recent times. High specific strength plays a crucial role in improving transport efficiency through increased pressure and improved laying efficiency through reduced diameter and weight of line pipes. TRIP-based high-strength and high-ductility alloys comprise a mixture of ferrite, bainite, and retained austenite that provide excellent mechanical properties such as dimensional stability, fatigue strength, and impact toughness. This study performs microstructure analysis using both Nital etching and LePera etching methods. At the time of Nital etching, it is difficult to distinctly observe second phase. However, using LePera etching conditions it is possible to distinctly measure the M/A phase and ferrite matrix. The fraction measurement was done using OM and SEM images which give similar results for the average volume fraction of the phases. Although it is possible to distinguish the M/A phase from the SEM image of the sample subjected to LePera etching. However, using Nital etching is nearly impossible. Nital etching is good at specific phase analysis than LePera etching when using SEM images.

Keywords

Acknowledgement

This work was financially supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1A2C4002622) and Fundamental Research Program of the Korean Institute of Materials Science (No. PNK8730).

References

  1. A.K. De, J.G. Speer, D.K. Matlock, Adv. Steels Processing 161, 27-30 (2003)
  2. C.A. Dube, H.I. Aaronson, R.F. Mehl, Rev. Met. Paris 55, 201-210 (1958)
  3. F.S. LePera, Metallography. 12, 263-268 (1979)
  4. G. Krauss, Mater. Sci. Eng. A 273-275, 40-57 (1999)
  5. H. Daniel Herring. "A Discussion of Retained Austenite" The Heat Treat Doctor.(2005) http://www.heat-treatdoctor.com/documents/retainedaustenite.pdf.
  6. H.C. Chen, H. Era, M. Shimizu, Metall. Trans. A. 20, 437-445 (1989)
  7. J. Chipman, Metall. Mater. Trans. B Process Metall. Mater. Process. Sci. 3, 55-64 (1972)
  8. J.M. Rigsbee, P.S. VanderArend, in Formable HSLA and Dual-Phase Steels, ed. by A. T. Davenport. (TMS-AIME, New York, 1979), p. 58
  9. J.Y. Yoo, S.S. Ahn, D.H. Seo, W.H. Song, K.B. Kang, Mater. Manuf. Process. 26, 154-160 (2011)
  10. M.J. Santofimia, L. Zhao, R. Petrov, J. Sietsma, Mater. Charact. 59, 1758-1764 (2008)
  11. M.J. Santofimia, T. Nguyen-Minh, L. Zhao, R. Petrov, I. Sabirov, J. Sietsma, Mater. Sci. Eng. A 527, 6429-6439 (2010)
  12. O. Matsumura, Y. Sakuma, H. Takechi, Trans., ISIJ 27, 570-579 (1987)
  13. P. Tsipouridis, Mechanical properties of Dual-Phase steelsPh.D. Thesis (Technische Universitat Munchen, Munchen, 2006)
  14. S. Hayami, T. Frukawa, Microalloying 75 (Union Carbide Corp, New York, 1975), p. 87
  15. S.H. Hashemi, Mater. Sci. Eng. A 528, 1648-1655 (2011)
  16. V.F. Zackay, E.R. Parker, D. Fahr, R. Bush, ASM Trans Quart 60, 252-259 (1967)
  17. Y. Gong, J. Uusitalo, M. Hua, Y. Wu, A.J. DeArdo, J. Mater. Sci. 54, 7211-7230 (2019)
  18. Z. Nishiyama, Martensitic Transformation, vol 263 (Academic, New York, 1978)