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Metallurgical and Materials Transactions A

, Volume 26, Issue 7, pp 1847–1858 | Cite as

Influence of microstructural variations in the weldment on the high-temperature corrosion of 2.25Cr-1Mo steel

  • R. K. Singh Raman
Welding and Joining

Abstract

In order to study the influence of microstructural variation on the oxidation of the weldment of 2.25Cr-1Mo steel, regions with different microstructures were identified by optical microscopy. The weld metal, the base metal, and the heat-affected zone (HAZ), as well as the subzones within the HAZ, i.e., the intercritical (ICR), the fine-grain bainite (FGB), and the coarse-grain bainite (CGB) regions were separated from the weldment by precise steps of metallography. Transmission electron microscopic examinations for the identification of the secondary phases in microstructurally different regions and subzones have suggested that M23C6 and M7C3 pre-cipitates form predominantly in the subzones of HAZ, whereas the Mo2C type of carbide forms exclusively in the weld-metal and base-metal regions of the weldment. However, population and distribution of the secondary phases were different in the three subzones of the HAZ. In order to understand the influence of these microstructural variations on the oxidation behavior, the various regions and subzones were oxidized at 773 and 873 K. The HAZ and its constituents were found to oxidize at much higher rates than the weld metal and the base metal. Relative compositions and morphologies of the scales were compared by scanning electron microscopy with energy-dispersive analyses of X-rays (SEM/EDX), and secondary ion mass spectrometry (SIMS). Scale formed over the weld metal shows a greater tendency for spallation, as suggested by tests monitoring acoustic emission. X-ray diffraction (XRD) patterns of the scales over these specimens were taken. Results of the SEM/EDX, SIMS, and XRD investigations suggest for-mation of inner scales with less Cr(i.e., less protective) over the HAZ than over the weld-metal and the base-metal regions. Variation in the Cr contents of the scales formed over the various regions is proposed to arise from the difference in microstructural features in different regions of the weldments.

Keywords

Material Transaction Base Metal Acoustic Emission Bainite Weld Metal 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    K. Easterling:Introduction to Physical Metallurgy of Welding, Butterworth and Co., London, 1983.Google Scholar
  2. 2.
    B. Chew and P. Harris:Met. Constr., 1979, May, p. 11.Google Scholar
  3. 3.
    K. Laha, K.B.S. Rao, and S.L. Mannan:Mater. Sci. Eng. A, 1990, vol. 129, p. 183.CrossRefGoogle Scholar
  4. 4.
    I.J. Chilton, A.T. Price, and B. Wilshire:Met. Technol., 1986, vol. 11, p. 383.Google Scholar
  5. 5.
    P. Roy and T. Lauritzen:Welding J., Res. Suppl., 1986, vol. 65, p. 45s.Google Scholar
  6. 6.
    E. Smith, B.E. Blanchard, and R.L. Apps:Proc. Conf. on Welding of Creep Resistant Steels, The Welding Institute, Cambridge, United Kingdom, 1970, p. 79.Google Scholar
  7. 7.
    C.D. Lundin, S.C. Kelly, R. Menon, and B.J. Kruse:Stress Rupture Behaviour of Post Weld Heat Treated 2.25Cr-1Mo Steel Weld Metal, Welding Research Council Bulletin No. 315, 1984, pp. 1–66.Google Scholar
  8. 8.
    R.K. Singh Raman and J.B. Gnanamoorthy:J. Mater. Sci., 1992, vol. 27, p. 3435.CrossRefGoogle Scholar
  9. 9.
    R.K. Singh Raman, A.S. Khanna, and J.B. Gnanamoorthy:Proc. 1st. Int. Conf. on Microscopy of Oxidation, M.J. Bennet and G.W. Lorimer, eds., Cambridge, United Kingdom, 1990, pp. 54–64.Google Scholar
  10. 10.
    R.K. Singh Raman, J.B. Gnanamoorthy, and S.K. Roy:Oxid. Met., 1993, vol. 40, p. 1.CrossRefGoogle Scholar
  11. 11.
    R.L. Klueh and J.F. King:Welding J., Res. Suppl., 1982, vol. 61, p. 302s.Google Scholar
  12. 12.
    ASME Boiler and Pressure Vessel Code, Code Case N-47, 1986.Google Scholar
  13. 13.
    W. Arnswald, R. Blum, B. Neubauer, and K.E. Poulson:Proc. Int. Conf. Creep, Tokyo, Japan, April 1986, pp. 367–72.Google Scholar
  14. 14.
    P. Hancock:Vacancies ’76, R.E. Smallman and J.E. Harris, eds., The Metals Society, London, 1977, p. 215.Google Scholar
  15. 15.
    R.L. Hecht and J.R. Weertman:Metall. Trans. A, 1993, vol. 24A, pp. 327–33.Google Scholar
  16. 16.
    J. Pilling and N. Ridley:Metall. Trans. A, 1982, vol. 13A, pp. 557–63.Google Scholar
  17. 17.
    N. Gope, A. Chattergee, T. Mukherjee, and D.S. Sharma:Metall. Trans. A, 1993, vol. 24A, pp. 315–26.Google Scholar
  18. 18.
    R.G. Baker and J. Nutting:J. Iron Steel Inst., 1959, vol. 192, p. 275.Google Scholar
  19. 19.
    P.J. Alberry and W.K.C. Jones:Met. Technol., 1977, vol.4, p. 360.Google Scholar
  20. 20.
    E.F. Nippes:Welding J., Res. Suppl., 1959, vol. 38, p. Is.Google Scholar
  21. 21.
    CD. Lundin: inAdvances in Welding Science and Technology, Conf. Proceedings, S.A. David, ed., ASM INTERNATIONAL, Metals Park, OH, 1988.Google Scholar
  22. 22.
    O.V. Serrano, G.R. Edwards, and R.H. Frost: ASTM STP 775, 1982, p. 275.Google Scholar
  23. 23.
    R.L. Klueh:J. Nucl. Mater., 1974, vol. 54, p. 55.CrossRefGoogle Scholar
  24. 24.
    C.A. Hippsley:Met. Sci., 1981, vol. 10, p. 137.Google Scholar
  25. 25.
    J.H. Woodhead and A.G. Quarrel:J. Iron Steel Inst., 1965, vol. 203, p. 605.Google Scholar
  26. 26.
    M. Murphy and G. Branch:J. Iron Steel Inst., 1971, vol. 209, p. 546.Google Scholar
  27. 27.
    T. Wada and G.T. Eldis: ASTM STP 755, 1982, p. 343.Google Scholar
  28. 28.
    J. Leitnaker, R.L. Klueh, and W.R. Laing:Metall. Trans. A, 1975, vol. 6A, pp. 1949–55.Google Scholar
  29. 29.
    J. Orr, F.R. Beckitt, and G.D. Fawkes:Proc. BNES Int. Conf. on Ferritic Steels for Fast Reactor Steam Generators, London, 1978, S.F. Pugh and E.A. Little, eds., p. 91.Google Scholar
  30. 30.
    R.K. Singh Raman, A.S. Khanna, B.K. Choudhary, and J.B. Gnanamoorthy:Mater. Sci. Eng. A, 1991, vol. 148, p. 299.CrossRefGoogle Scholar
  31. 31.
    Y. Shida, N. Ohtsuka, J. Murayama, N. Fujino, and H. Fujikawa:Proc. JIMIS-3: High Temperature Corrosion, Trans. Jpn. Inst. Met., 1983, vol. 63.Google Scholar
  32. 32.
    S. Leistikow, I. Wolf, and H.J. Grabke:Werkst. Korros., 1987, vol. 38, p. 556.CrossRefGoogle Scholar
  33. 33.
    D.L. Douglass:Oxid. Met., 1969, vol. 1, p. 127.CrossRefGoogle Scholar
  34. 34.
    B. Borie, C.J. Sparks, and J.V. Cathcart:Acta Metall., 1962, vol. 10, p. 691.CrossRefGoogle Scholar
  35. 35.
    R.K. Singh Raman, A.S. Khanna, R.K. Tiwari, and J.B. Gnanamoorthy:Oxid. Met., 1992, vol. 37, p. 1.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Material Society 1995

Authors and Affiliations

  • R. K. Singh Raman
    • 1
  1. 1.School of Materials Science and EngineeringUniversity of New South WalesSydneyAustralia

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