Advertisement

Metallurgical and Materials Transactions A

, Volume 49, Issue 12, pp 6290–6307 | Cite as

Microstructural Evolution and the Effect on Hardness and Impact Toughness of Sanicro 25 Welded Joints After Aging at 973 K

  • Renyuan Zhou
  • Lihui Zhu
  • Yitao Yang
  • Zhengran Lu
  • Liang Chen
Article

Abstract

Sanicro 25 tubes were welded using Alloy 617 mod. as the filler material, and the welded joints were aged at 973 K up to 10,000 hours. The hardness and impact toughness of welded joints were measured, and the microstructural evolution after aging was systematically investigated by means of OM, SEM, and TEM. After aging, the predominant precipitates in the base metal are secondary NbCrN, Cu-rich particles, and M23C6. The great increase in the hardness of base metal at the early stage of aging is attributed to the precipitation of secondary NbCrN, Cu-rich particles, and M23C6. The calculation of pinning force implies that secondary NbCrN possesses the strongest precipitation strengthening because it is extremely fine and stable. Also, Cu-rich particles are the key precipitates owing to the significant effect on the hardness change of base metal during aging. Aging results in the precipitation of needle-like M23C6 and spherical γ′ phase as well as large M23C6 particles at the grain boundaries in the weld metal. Hence, the hardness of weld metal increases. With the increasing aging time, the growths of M23C6 and γ′ phase decrease the hardness. Some cuboids of M23C6 are observed after long-term aging. The significant decrease in the impact toughness of the aged welded joints mainly results from the growth of M23C6 at the grain boundaries and the interdendritic regions. Needle-like and cuboids of M23C6 further decrease the impact toughness.

Notes

Acknowledgments

This study is supported by the National Key Research and Development Program of China (No. 2016YFC0801904). The authors are grateful for the help provided by the Instrumental Analysis & Research Center in the Shanghai University. The authors also would like to thank Shanghai Boiler Works, Ltd. for providing the specimens and properties data.

References

  1. 1.
    M.H. Jang, J.Y. Kang, J.H. Jang, T.H. Lee, and C. Lee: Mater. Sci. Eng. A, 2017, vol. 696, pp. 70-79.CrossRefGoogle Scholar
  2. 2.
    K.H. Lee, S.M. Hong, J.H. Shim, J.Y. Suh, and J.Y. Huh: Mater. Charact., 2015, vol. 102, pp. 79-84.CrossRefGoogle Scholar
  3. 3.
    Y. Ding, T. Hussain, and D.G. Mccartney: J. Mater. Sci., 2015, vol. 50, pp. 6808-6821.CrossRefGoogle Scholar
  4. 4.
    D.H. Bechetti, J.N. Dupont, J.J.D. Barbadillo, B.A. Baker, and M. Watanabe: Metall. Mater. Trans. A, 2014, vol. 46, pp. 739-755.Google Scholar
  5. 5.
    C.Y. Chi, H.Y. Yu, and X.S. Xie: World Iron Steel, 2013, vol. 13, pp. 42-60.Google Scholar
  6. 6.
    R. Viswanathan, K. Coleman, and U. Rao: Int. J. Pressure Vessels Piping, 2006, vol. 83, pp. 778-783.CrossRefGoogle Scholar
  7. 7.
    F. Masuyama: ISIJ Int., 2001, vol. 41, pp. 612-625.CrossRefGoogle Scholar
  8. 8.
    M. Evans: J. Mater. Sci., 2014, vol. 49, pp. 329-339.CrossRefGoogle Scholar
  9. 9.
  10. 10.
    G.C. Chai, M. Boström, M. Olaison, and U. Forsberg: Procedia Engineering, 2013, vol. 55, pp. 232-239.CrossRefGoogle Scholar
  11. 11.
    X. Zhang: Power Equip, 2015, vol. 29, pp. 439-442.Google Scholar
  12. 12.
    Jamrozik P, Sozańska M: Solid State Phenom., 2014, vol. 212, pp. 71-74.CrossRefGoogle Scholar
  13. 13.
    R. Rautio, S. Bruce: 4th International Conference on Advances in Materials Technology for Fossil Power Plants 2005, pp. 274–90.Google Scholar
  14. 14.
    B. Rutkowski, A. Gil, and A. Czyrska-Filemonowicz: Corros. Sci., 2016, vol. 102, pp. 373-383.CrossRefGoogle Scholar
  15. 15.
    B. Zhao, H. Bao, Z. Liu, and L. Li: Mater. Rev., 2012, vol. 26, pp. 174-179.Google Scholar
  16. 16.
    G. Chai, P. Kjellström, M. Boström (2013) 13th ICF, 3, 2489-2497.Google Scholar
  17. 17.
    J. Högberg, G.C. Chai, P. Kjellström, M. Boström, U. Forsberg, and R. Sandström: ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference, 2010, vol. 6, pp. 421–28.Google Scholar
  18. 18.
    R. Rautio, and S. Bruce: Adv. Mater. Processes, 2008, vol. 166, pp. 35-37.Google Scholar
  19. 19.
    J. Zurek, S-M. Yang, D-Y. Lin, T. Huttel, L. Singheiser, and W.J. Quadakkers: Mater. Corros., 2015, vol. 66, pp. 315-327.CrossRefGoogle Scholar
  20. 20.
    R. Zhou, L. Zhu, Y. Liu, Z. Lu, and L. Chen: J. Mater. Sci. 52, 6161-6172 (2017)CrossRefGoogle Scholar
  21. 21.
    H. Tanaka, M. Murata, F. Abe, and H. Irie: Mater. Sci. Eng. A, 2011, vol. 319-321, pp. 788-791.Google Scholar
  22. 22.
    Y.Y. Fang, J. Zhao, and X.N. Li: Acta. Metall. Sin., 2010, vol. 46, pp. 844-849.CrossRefGoogle Scholar
  23. 23.
    T. Sourmail, H.K.D.H. Bhadeshia: Metall. Mater. Trans. A, 2005, vol. 36, pp. 23-34.CrossRefGoogle Scholar
  24. 24.
    Yong QL (2006) Second Phases in Structural Steels. Metallurgical Industry Press, Beijing.Google Scholar
  25. 25.
    Y. Zhang, L. Zhu, A. Qi, and Z. Lu: Trans. ISIJ, 2010, vol. 50, pp. 596-600.CrossRefGoogle Scholar
  26. 26.
    Q. Wu, H. Song, R.W. Swindeman, J.P. Shingledecker, and V.K. Vasudevan: Metall. Mater. Trans. A, 2008, vol. 39, pp. 2569-2585.CrossRefGoogle Scholar
  27. 27.
    S. Schlegel, S. Hopkins, E. Young, C. Cole, T. Lillo, and M. Frary: Metall. Mater. Trans. A, 2009, vol. 40, pp. 2812-2823.CrossRefGoogle Scholar
  28. 28.
    H.U. Hong, B.S. Rho and S.W. Nam: Mater. Sci. Eng. A, 2001, vol. 318, pp. 285-292.CrossRefGoogle Scholar
  29. 29.
    Y. Guo, B.H. Wang and S.F. Hou: Acta. Metall. Sin, 2013, vol. 26, pp. 307-312.CrossRefGoogle Scholar
  30. 30.
    D. Tytko, P.P. Choi, J. Klöwer, A. Kostka, G. Inden and D. Raabe: Acta. Mater, 2012, vol. 60, pp. 1731-1740.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2018

Authors and Affiliations

  • Renyuan Zhou
    • 1
  • Lihui Zhu
    • 1
  • Yitao Yang
    • 1
  • Zhengran Lu
    • 2
  • Liang Chen
    • 2
  1. 1.State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and EngineeringShanghai UniversityShanghaiP.R. China
  2. 2.Shanghai Boiler Works, Ltd.ShanghaiP.R. China

Personalised recommendations