Metallurgical and Materials Transactions A

, Volume 45, Issue 11, pp 4960–4971 | Cite as

Microstructural Features Controlling Mechanical Properties in Nb-Mo Microalloyed Steels. Part I: Yield Strength

  • Nerea Isasti
  • Denis Jorge-Badiola
  • Mitra L. Taheri
  • Pello Uranga
Article

Abstract

Low carbon Nb-Mo microalloyed steels show interesting synergies between the “micro”-alloying elements when high strength–high toughness properties are required. Strain accumulation in austenite is enhanced, and therefore grain sizes are refined in the final microstructures. The presence of Mo facilitates the presence of non-polygonal phases, and this constituent modification induces an increment in strength through a substructure formation as well as through an increase in the dislocation density. Regarding fine precipitation and its strengthening effect, the mean size of NbC is reduced in the presence of Mo and their fraction increased, thus enhancing their contribution to yield strength. In this paper, a detailed characterization of the microstructural features of a series of microalloyed steels is described using the electron-backscattered diffraction technique. Mean crystallographic unit sizes, a grain boundary misorientation analysis, and dislocation density measurements are performed. Transmission electron microscopy is carried out to analyze the chemical composition of the precipitates and to estimate their volume fraction. In this first part, the contribution of different strengthening mechanisms to yield strength is evaluated and the calculated value is compared to tensile test results for different coiling temperatures and compositions.

References

  1. 1.
    S.G. Jansto: New Developments on Metallurgy and Applications of High Strength Steels Conf., Buenos Aires, 2008, TMS, Warrendale, PA, pp. 1313–26.Google Scholar
  2. 2.
    D. Bhattacharya: 6th Int. Conf. on High Strength Low Alloy Steels, HSLA 2011, Beijing, China, 2011, CD-Rom.Google Scholar
  3. 3.
    M. Gómez, L. Rancel, and S.F. Medina: Met. Mater. Int.., 2009, vol. 15, pp. 689–99.CrossRefGoogle Scholar
  4. 4.
    R. Bengoechea, B. López, and I. Gutiérrez: ISIJ Int., 1999, vol. 39, pp. 583–91.CrossRefGoogle Scholar
  5. 5.
    N. Isasti, D. Jorge-Badiola, M.L. Taheri, B. López and P. Uranga: Metall. Mater. Trans. A, 2011, vol. 42A, pp. 3729–42.CrossRefGoogle Scholar
  6. 6.
    N. Isasti, D. Jorge-Badiola, M.L. Taheri, and P. Uranga: Metall. Mater. Trans. A, 2013, vol. 44A, pp. 3552–63.CrossRefGoogle Scholar
  7. 7.
    A. Iza-Mendia, and I. Gutiérrez: Mater. Sci. Eng. A, 2013, vol. 561, pp. 40–51.CrossRefGoogle Scholar
  8. 8.
    M. Calcagnotto, D. Ponge, E. Demir, and D. Raabe: Mater. Sci. Eng. A, 2010, vol. 527, pp. 2738–46.CrossRefGoogle Scholar
  9. 9.
    S. Patra, Sk.Md. Hasan, N. Narasaiah, and D. Chakrabarti: Mater. Sci. Eng. A, 2012, vol. 538, pp. 145–55.CrossRefGoogle Scholar
  10. 10.
    R.L. Higginson and C.M. Sellars: Worked Examples in Quantitative Metallography, The Institute of Materials, Minerals and Mining, London, 2003, pp. 1–116.Google Scholar
  11. 11.
    F.S. LePera: Metallography, 1979, vol. 12, pp. 263–68.CrossRefGoogle Scholar
  12. 12.
    W. He, W. Ma, and W. Pantleon: Mater. Sci. Eng. A, 2008, vol. 494, pp. 21–27.CrossRefGoogle Scholar
  13. 13.
    M. Olasolo, P. Uranga, J.M. Rodriguez-Ibabe, and B. López: Mater. Sci. Eng. A, 2011, vol. 528, pp. 2559–69.CrossRefGoogle Scholar
  14. 14.
    S. Zajac, V. Schwinn, and K.H. Tacke: Mater. Sci. Forum, 2005, vols. 500–501, pp. 387–94.CrossRefGoogle Scholar
  15. 15.
    S.Y. Han, S.Y. Shin, S. Lee, N.J. Kim, J. Bae, and K. Kim: Metall. Mater. Trans. A, 2009, vol. 41A, pp. 3029–39.Google Scholar
  16. 16.
    S.K. Kim, Y.M. Kim, Y.J. Lim, and N.J. Kim: in Proc. of 15th Conference On Mechanical Behaviors of Materials, Korea Institute of Metals and Materials, Seoul, Korea, 2001, pp. 177–86.Google Scholar
  17. 17.
    F.B. Pickering: Physical Metallurgy and the Design of Steels, Applied Science Publishers Ltd., London, 1978, pp. 10-35.Google Scholar
  18. 18.
    E.O. Hall: Proc. Phys. Soc., 1951, vol. 64B, pp. 747–53.CrossRefGoogle Scholar
  19. 19.
    N.J. Petch: J. Iron Steel Inst., 1953, vol. 173, pp. 25–7.Google Scholar
  20. 20.
    T. Gladman, I.D. McIvor, and F.B. Pickering: J. Iron Steel Inst., 1972, vol. 210, pp. 916–30.Google Scholar
  21. 21.
    S. Wolf: JOM, 1967, vol. 19, pp. 22–28.Google Scholar
  22. 22.
    E. Nembach: Acta Metall. Mater., 1992, vol. 40, pp. 3325–30.CrossRefGoogle Scholar
  23. 23.
    M. Charleux, W.J. Poole, M. Militzer, and A. Descamps: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 1635–47.CrossRefGoogle Scholar
  24. 24.
    I.A. Yakubtsov, J.D. Boyd, W.J. Liu, and E. Essadiqui: 42nd Mechanical Working and Steel Processing Conference, Iron and Steel Society/AIME, Toronto, ON, 2000, pp. 429–39.Google Scholar
  25. 25.
    O. Bouaziz, G. Herman, M. Piette, T. Iung, and Ch. Perdrix: Proc. Thermomechanical Processing of Steels, IOM Comm., London, 2000, 342–51.Google Scholar
  26. 26.
    F.B. Pickering, and T. Gladman: Metallurgical Developments in Carbon Steels, Iron and Steel Inst., London, 1963, Special Report No. 81.Google Scholar
  27. 27.
    J. Lu, O. Omotoso, J.B. Wiskel, D.G. Ivey, and H. Henein: Metall. Mater. Trans. A, 2012, vol. 43A, pp. 3043–61.CrossRefGoogle Scholar
  28. 28.
    G. Langford, and M. Cohen: Trans. ASM, 1969, vol. 62, pp. 623–38.Google Scholar
  29. 29.
    L.A. Norstrom: Scand. J. Metall., 1976, vol. 5, pp. 159–65.Google Scholar
  30. 30.
    J.P. Naylor: Metall. Trans. A, 1979, vol. 10A, pp. 861–73.CrossRefGoogle Scholar
  31. 31.
    D.J. Abson, and J.J. Jonas: Met. Sci. J., 1970, vol. 4, pp. 24–28.CrossRefGoogle Scholar
  32. 32.
    D. Kuhlmann-Wilsdorf: Mater. Sci. Eng. A, 1989, vol. 113, pp. 1–41.CrossRefGoogle Scholar
  33. 33.
    N. Isasti, B. Pereda, B. López, J.M. Rodriguez-Ibabe, and P. Uranga: in Nb and Mo Metallurgy for More Sustainable Steels, H. Mohrbacher, ed., TMS, 2014.Google Scholar
  34. 34.
    R.D.K. Misra, H. Nathani, J.E. Hartmann, and F. Siciliano: Mater. Sci. Eng. A, 2005, vol. 394, pp. 339–52.CrossRefGoogle Scholar
  35. 35.
    A.S. Keh and S. Weissmann: in Electron Microscopy and the Strength of Crystals, G. Thomas and J. Washburn, eds., Interscience, New York, 1963, pp. 231–300.Google Scholar
  36. 36.
    S.S. Campos, E.V. Morales, and H.J. Kestenbach: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 1245–48.CrossRefGoogle Scholar
  37. 37.
    H.K.D.H. Bhadeshia: Bainite in Steels, Transformations, Microstructure and Properties, 2nd ed., The Institute of Materials, London, 2001, pp. 277–79.Google Scholar
  38. 38.
    L.P. Kubin, and A. Mortensen: Scripta Mater., 2003, vol. 48, pp. 119–25.CrossRefGoogle Scholar
  39. 39.
    N. Hansen, X. Huang, and G. Winther: Mater. Sci. Eng. A, 2008, vol. 494, pp. 61–7.CrossRefGoogle Scholar
  40. 40.
    D. Jorge-Badiola, A. Iza-Mendia, and I. Gutiérrez: J. Microsc., 2009, vol. 235, pp. 36–49.CrossRefGoogle Scholar
  41. 41.
    M. Takahashi, and H.K.D.H. Bhadeshia: Mater. Sci. Technol., 1990, vol. 6, pp. 592–603.CrossRefGoogle Scholar
  42. 42.
    C. Garcia-Mateo, F.G. Caballero, C. Capdevila, and C. Garcia de Andrés: Scripta Mater., 2009, vol. 61, pp. 855–8.CrossRefGoogle Scholar
  43. 43.
    M.J. Roberts: Metall. Trans., 1970, vol. 1, pp. 3287-94.Google Scholar
  44. 44.
    R.Z. Wang, C.I. Garcia, M. Hua, K. Cho, H.T. Zhang, and A.J. Deardo: ISIJ Int., 2006, vol. 46, pp. 1345–53.CrossRefGoogle Scholar
  45. 45.
    T. Gladman: Mater. Sci. Technol., 1999, vol. 15, pp. 30–36.CrossRefGoogle Scholar
  46. 46.
    H.J. Kestenbach: Mater. Sci. Technol., 1997, vol. 13, pp. 731–39.CrossRefGoogle Scholar
  47. 47.
    N. Isasti: PhD Thesis, Tecnun (University of Navarra), San Sebastian, 2013.Google Scholar
  48. 48.
    W.B. Lee, S.G. Hong, C.G. Park, and S.H. Park: Metall. Mater. Trans. A, 2002, vol. 33A, pp. 1689–98.CrossRefGoogle Scholar
  49. 49.
    A.J. Lapointe, and T.N. Baker: Met. Sci., 1982, vol. 16, pp. 207–16.CrossRefGoogle Scholar
  50. 50.
    J. Lu, D. Ivey, and H. Henein: Iron Steel Technol., 2013, vol. 10, pp. 232–44.Google Scholar
  51. 51.
    N. Isasti, D. Jorge-Badiola, M.L. Taheri, and P. Uranga: Met. Mater. Int., 2014 (in press).Google Scholar
  52. 52.
    M.F. Ashby, and R. Ebeling: AIME Met. Soc. Trans., 1966, vol. 236, pp. 1396–1404.Google Scholar
  53. 53.
    K. Poorhaydari, and D.G. Ivey: Can. Metall. Q., 2009, vol. 48, pp. 115–22.CrossRefGoogle Scholar
  54. 54.
    K. Poorhaydari, B.M. Patchett, and D.G. Ivey: in Conference of Metallurgists, The International Symposium on Pipelines for the 21st Century, W. Chen, ed., The Metall. Soc. CIM, Calgary, 2005, pp. 231–34.Google Scholar
  55. 55.
    H. Wada, and R.D. Pehlke: Metall. Trans., 1985, vol. 16, pp. 815–22.CrossRefGoogle Scholar
  56. 56.
    M.G. Akben, B. Bacroix, and J.J. Jonas: Acta Met., 1983, vol. 31, pp. 161–74.CrossRefGoogle Scholar
  57. 57.
    J. Hua, L.-X. Dua, and J. J. Wang: Mater. Sci. Eng. A, 2012, vol. 554, pp. 79–85.CrossRefGoogle Scholar
  58. 58.
    M.E. Bush and P.M. Kelly: Acta Metall., 1971, vol. 19, vol. 1363–72.Google Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2014

Authors and Affiliations

  • Nerea Isasti
    • 1
  • Denis Jorge-Badiola
    • 1
  • Mitra L. Taheri
    • 2
  • Pello Uranga
    • 1
  1. 1.CEIT and TECNUN (University of Navarra)Donostia-San SebastiánSpain
  2. 2.Department of Materials ScienceDrexel UniversityPhiladelphiaUSA

Personalised recommendations