Metallurgical and Materials Transactions A

, Volume 36, Issue 8, pp 2107–2114 | Cite as

Effective grain size and charpy impact properties of high-toughness X70 pipeline steels

  • Byoungchul Hwang
  • Yang Gon Kim
  • Sunghak Lee
  • Young Min Kim
  • Nack J. Kim
  • Jang Yong Yoo


The correlation of microstructure and Charpy V-notch (CVN) impact properties of a high-toughness API X70 pipeline steel was investigated in this study. Six kinds of steel were fabricated by varying the hot-rolling conditions, and their microstructures, effective grain sizes, and CVN impact properties were analyzed. The CVN impact test results indicated that the steels rolled in the single-phase region had higher upper-shelf energies (USEs) and lower energy-transition temperatures (ETTs) than the steels rolled in the two-phase region because their microstructures were composed of acicular ferrite (AF) and fine polygonal ferrite (PF). The decreased ETT in the steels rolled in the single-phase region could be explained by the decrease in the overall effective grain size due to the presence of AF having a smaller effective grain size. On the other hand, the absorbed energy of the steels rolled in the two-phase region was considerably lower because a large amount of dislocations were generated inside PFs during rolling. It was further decreased when coarse martensite or cementite was formed during the cooling process.


Martensite Cementite Acicular Ferrite Pipeline Steel Polygonal Ferrite 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    R. Denys: Pipeline Technology, Elsevier, Amsterdam, 2000, vols. I–II.Google Scholar
  2. 2.
    D.P. Fairchild, M.L. Macia, S.D. Papka, C.W. Petersen, J.H. Stevens, S.T. Barbas, N.V. Bangaru, J.Y. Koo, and M.J. Luton: Proc. Int. Pipe Dreamer’s Conf., M. Toyoda and R. Denys, eds., Yokohama, Japan, 2002, pp. 307–21.Google Scholar
  3. 3.
    K.T. Corbett, R.R. Bowen, and C.W. Petersen: Int. J. Offshore Polar Eng., 2004, vol. 14, pp. 75–80.Google Scholar
  4. 4.
    M. Matsuda and H. Miura: Met. Mater. Int., 2003, vol. 9, pp. 537–42.Google Scholar
  5. 5.
    C.-S. Oh, H.N. Han, C.G. Lee, T.-H. Lee, and S.-J. Kim: Met. Mater. Int., 2004, vol. 10, pp. 399–406.CrossRefGoogle Scholar
  6. 6.
    Recommended Practice for Conducting Drop-Weight Tear Tests on Line Pipe, API Recommended Practice 5L3, American Petroleum Institute, 1996.Google Scholar
  7. 7.
    G. Mannucci and D. Harris: “Fracture Properties of API X100 Gas Pipeline Steels,” Final Report, European Commission, Brussels, Belgium, 2002.Google Scholar
  8. 8.
    D.J. Horsley: Eng. Fract. Mech., 2003, vol. 70, pp. 547–52.CrossRefGoogle Scholar
  9. 9.
    G.M. Wilkowski, W.A. Maxey, and R.J. Eiber: Can. Metall. Q., 1980, vol. 19, pp. 59–77.Google Scholar
  10. 10.
    I. Tamura, H. Sekine, T. Tanaka, and C. Ouchi: Thermomechanical Processing of High-Strength Low-Alloy Steels, Butterworth & Co., Ltd., London, 1988.Google Scholar
  11. 11.
    E. Heier: “Drop Weight Tear Testing of High Toughness Pipeline Steel,” Technical Report, DET NORSKE VERITAS, Norway, 2003.Google Scholar
  12. 12.
    B. Hwang, S. Lee, Y.M. Kim, N.J. Kim, J.Y. Yoo, and C.S. Woo: Mater. Sci. Eng. A, 2004, vol. A368, pp. 18–27.Google Scholar
  13. 13.
    H. Kashimura, M. Ogasawara, and H. Mimura: Met. Progr., 1976, Nov., pp. 58-62.Google Scholar
  14. 14.
    T. Ishihara, J. Kondo, T. Kitada, and T. Akiyama: Trans. Iron Steel Inst. Jpn., 1987, vol. 27, pp. 219–21.Google Scholar
  15. 15.
    J.C. Newman, Jr., M.A. James, and U. Zerbst: Eng. Fract. Mech., 2003, vol. 70, pp. 371–85.CrossRefGoogle Scholar
  16. 16.
    B. Hwang, S. Lee, Y.M. Kim, N.J. Kim, and S.S. Ahn: Metall. Mater. Trans. A, 2005, vol. 36A, pp. 725–39.CrossRefGoogle Scholar
  17. 17.
    A.K. De, J.G. Speer, and D.K. Matlock: Adv. Steels Processing, 2003, vol. 161, pp. 27–30.Google Scholar
  18. 18.
    ASTM Standard E23-02, ASTM, Philadelphia, PA, 2002.Google Scholar
  19. 19.
    W. Oldfield: ASTM Standardizations News, 1975, pp. 24–29.Google Scholar
  20. 20.
    M. Diaz-Fuentes, A. Iza-Mendia, and I. Gutierrez: Metall. Mater. Trans. A, 2003, vol. 34A, pp. 2505–16.CrossRefGoogle Scholar
  21. 21.
    J.Y. Koo, M.J. Luton, N.V. Bangaru, R.A. Petkovic, D.P. Fairchild, C.W. Petersen, H. Asahi, T. Hara, Y. Terada, M. Sugiyama, H. Tamehiro, Y. Komizo, S. Okaguchi, M. Hamada, A. Yamamoto, and I. Takeuchi: Int. J. Offshore Polar Eng., 2004, vol. 14, pp. 2–10.Google Scholar
  22. 22.
    F.B. Pickering: Mater. Sci. Technol., 1993, vol. 7, pp. 45–94.Google Scholar
  23. 23.
    A.F. Gourgues, H.M. Flower, and T.C. Lindley: Mater. Sci. Technol., 2000, vol. 16, pp. 26–40.CrossRefGoogle Scholar
  24. 24.
    F.B. Pickering: Proc. Symp. on Transformation and Hardenability in Steels, Climax Molybdenum Co. and The University of Michigan, Ann Arbor, MI, 1967, pp. 109–29.Google Scholar
  25. 25.
    P. Brozzo, G. Buzzichelli, A. Mascanzoni, and M. Mirabile: Met. Sci., 1977, pp. 123-29.Google Scholar
  26. 26.
    Y. Ohomori, H. Ohtani, and T. Kunitake: Met. Sci., 1974, vol. 8, pp. 357–66.CrossRefGoogle Scholar
  27. 27.
    J.P. Naylor and P.R. Krahe: Metall. Trans., 1974, vol. 5, pp. 1699–1701.Google Scholar
  28. 28.
    H.N. Han, C.-S. Oh, D.W. Suh, C.G. Lee, T.-H. Lee, and S.-J. Kim: Met. Mater. Int., 2004, vol. 10, pp. 221–29.Google Scholar
  29. 29.
    T.-H. Lee, C.-S. Oh, C.G. Lee, S.-J. Kim, and S. Takaki: Met. Mater. Int., 2004, vol. 10, pp. 231–36.Google Scholar
  30. 30.
    N.J. Kim: J. Met., 1983, vol. 35, pp. 21–27.Google Scholar
  31. 31.
    J.Y. Yoo and J.S. Woo: Proc. Int. Pipe Dreamer’s Conf., M. Toyota and R. Denys, eds., Scientific Surveys, Ltd., Yokohama, Japan, 2002, pp. 441–56.Google Scholar
  32. 32.
    D. Bhattacharjee, J.F. Knott, and C.L. Davis: Metall. Mater. Trans. A, 2004, vol. 35A, pp. 121–30.CrossRefGoogle Scholar
  33. 33.
    J.Y. Yang and H.K.D.H. Bhadeshia: Mater. Sci. Technol., 1989, vol. 5, pp. 93–97.Google Scholar
  34. 34.
    F.J. Barbaro, P. Kraulis, and K.E. Easterling: Mater. Sci. Technol., 1989, vol. 5, pp. 1057–68.Google Scholar
  35. 35.
    I. Madariaga, I. Gutierrez, and H.K.D.H. Bhadeshia: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 2187–97.CrossRefGoogle Scholar
  36. 36.
    E. Sarah Kumar-Menon and H.I. Aaronson: Acta Metall., 1987, vol. 35, pp. 549–63.CrossRefGoogle Scholar

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2005

Authors and Affiliations

  • Byoungchul Hwang
    • 1
  • Yang Gon Kim
    • 1
  • Sunghak Lee
    • 1
  • Young Min Kim
    • 1
  • Nack J. Kim
    • 1
  • Jang Yong Yoo
    • 2
  1. 1.Center for Advanced Aerospace SteelsPohang University of Science and TechnologyPohangKorea
  2. 2.Plate Research Group, Technical Research LaboratoriesPOSCOPohangKorea

Personalised recommendations