Journal of Powder Materials (한국분말재료학회지)

The Korean Powder Metallurgy & Materials Institute (한국분말재료학회 (*구 분말야금학회))
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Measurement Method of Prior Austenite Grain Size of Nb-added Fe-based Alloys

Nb 첨가 철계 합금의 Prior austenite 결정립크기 측정 방법

  • Ko, Kwang Kyu (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Bae, Hyo Ju (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Jung, Sin Woo (Materials Science & Engineerings, Dept. of Metallurgical and Materials Engineering, Gyeongsang National University (GNU)) ;
  • Sung, Hyo Kyung (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Kim, Jung Gi (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU)) ;
  • Seol, Jae Bok (Department of Materials Engineering and Convergence Technology, Gyeongsang National University (GNU))
  • 고광규 (경상국립대학교 나노신소재융합공학과) ;
  • 배효주 (경상국립대학교 나노신소재융합공학과) ;
  • 정신우 (경상국립대학교 나노신소재공학부 금속재료공학과) ;
  • 성효경 (경상국립대학교 나노신소재융합공학과) ;
  • 김정기 (경상국립대학교 나노신소재융합공학과) ;
  • 설재복 (경상국립대학교 나노신소재융합공학과)
  • Received : 2021.07.22
  • Accepted : 2021.08.21
  • Published : 2021.08.28
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Abstract

High-strength low-alloy (HSLA) steels show excellent toughness when trace amounts of transition elements are added. In steels, prior austenite grain size (PAGS), which is often determined by the number of added elements, is a critical factor in determining the mechanical properties of the material. In this study, we used two etching methods to measure and compare the PAGS of specimens with bainitic HSLA steels having different Nb contents These two methods were nital etching and picric acid etching. Both methods confirmed that the sample with high Nb content exhibited smaller PAGS than its low Nb counterpart because of Nb's ability to hinder austenite recrystallization at high temperatures. Although both etching approaches are beneficial to PAGS estimation, the picric acid etching method has the advantage of enabling observation of the interface containing Nb precipitate. By contrast, the nital etching method has the advantage of a very short etching time (5 s) in determining the PAGS, with the picric acid etching method being considerably longer (5 h).

Keywords

Acknowledgement

이 논문은 2021년도 정부(한국연구재단)의 재원으로 한국연구재단의 지원을 받아 수행된 연구임(No.2021R1A2C400262211).

References

  1. J. R. Davis: Alloying: Understanding the Basics, ASM International, USA, (2001).
  2. M. S. Rashid: Science, 208 (1980) 862. https://doi.org/10.1126/science.208.4446.862
  3. D. A. Skobir: Mater. Technol., 45 (2011) 295.
  4. W. B. Lee, K. B. Kang and C. G. Park: Korean J. Met. Mater., 34 (1996) 688.
  5. G. S. Park: Analysis of phase transformation theory in Nb alloyed HSLA steel by hot rolling deformation, M.S thesis. Hanyang Univ, Seoul, Republic of Korea (2016).
  6. M. Calcagnotto, D. Ponge, Y. Adachi and D. Raabe: In Proceedings of the 2nd International Symposium on Steel Science (ISSS 2009), Kyoto, Japan, (2009) 21.
  7. N. Hansen: Scr. Mater., 51 (2004) 801. https://doi.org/10.1016/j.scriptamat.2004.06.002
  8. M. Okatasu, K. Sato, M. Mizuno, D. Y. Hwang and D. H. Shin: Int. J. Fatigue, 30 (2008) 1358. https://doi.org/10.1016/j.ijfatigue.2007.10.011
  9. J. Komotori and M. Shimizu: ICF7 (1989) 1213.
  10. G. H. Kim, J. H Jang, S. H. Kim, B. J. Kim, K. Y. Sohn and D. G. Nam: Korean J. Met. Mater., 55 (2017) 559. https://doi.org/10.3365/KJMM.2017.55.8.559
  11. G. R. Wang, T. W. Lau, G. C. Weatherly and T. H. North: Metall. Trans. A, 20 (1989) 2093. https://doi.org/10.1007/BF02650295
  12. M. Islam and M. M. A. Bepari: J. Mater. Eng. Perform., 5 (1996) 593. https://doi.org/10.1007/BF02646087
  13. C. B. Park: The effect of austenite grain size on the γ/α transformation in Nb added microalloyed steel, M.S thesis. Hanyang Univ, Seoul, Republic of Korea (2010)
  14. B. Dutta, E. Valdes and C. M. Sellars: Acta Metall. Mater., 40 (1992) 653. https://doi.org/10.1016/0956-7151(92)90006-Z
  15. J. G. Speer and S. S. Hansen: Metall. Trans. A, 20 (1989) 25. https://doi.org/10.1007/BF02647491
  16. A. Matsuzaki and H. K. D. H. Bhadeshia: Mater. Sci. Technol., 15 (1999) 518. https://doi.org/10.1179/026708399101506210
  17. R. Thackray, E. J. Palmiere and O. Khalid: Materials, 13 (2020) 3296. https://doi.org/10.3390/ma13153296
  18. ASTM E407-07e1, Standard Practice for Microetching Metals and Alloys, ASTM International, West Conshohecken, PA (2007).
  19. J. O. Andersson, T. Helander, L. Hoglund, P. Shi and B. Sundman: Calphad, 26 (2002) 273. https://doi.org/10.1016/S0364-5916(02)00037-8
  20. ASTM E112-13, Standard Test Methods for Determining Average Grain Size, ASTM International, West Conshohocken, PA (2013).
  21. A. W. Brewer, K. A. Erven and G. Krauss: Mater. Charact., 27 (1991) 53. https://doi.org/10.1016/1044-5803(91)90079-J
  22. V. L. Viswanathan: Metallography, 10 (1977) 291. https://doi.org/10.1016/0026-0800(77)90032-5
  23. D. A. Porter and K. E. Easterling: Phase Transformation in Metals and Alloys(2nd Ed.) ITC, Korea (1992) 213.