Advertisement

Journal of Materials Science

, Volume 28, Issue 19, pp 5169–5175 | Cite as

The effect of alloying elements on the structure and mechanical properties of ultra low carbon bainitic steels

  • Shyi -Chin Wang
  • Po -We Kao
Papers

Abstract

Microalloying with Nb and B leads to a granular bainite microstructure which is composed of a bainitic ferrite matrix and a uniformly distributed martensite/austenite-constituent in the as-rolled condition. Due to this transformation strengthening mechanism, high strength and toughness could be achieved even though the C content was extremely low. It was found that both dissolved Nb in austenite and free B are prerequisites for granular bainite formation. Furthermore, there is a critical B content to achieve the complete bainitic transformation strengthening effect. The critical B content increases with C content. C thus diminishes the effect of B in promoting bainite transformation, due to the formation of boron carbides or the depletion of dissolved Nb in austenite. The effect of Mn, Mo and Ni on the decomposition of austenite is similar. A parameter“Mneq” which relates the effect of these alloying elements on the Bs temperature was derived. It was confirmed that the strength of bainitic steels is inversely proportional to theBs temperature.

Keywords

Ferrite Austenite Boron Bainite Boron Carbide 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    H. W. Paxton, in “Alloys for the Eighties” (Climax Molybdenum Company, 1980) p. 185.Google Scholar
  2. 2.
    H. Gondoh, H. Nakasugi, H. Matsuda, H. Tamehiro andH. Chino,Nippon Steel Tech. Rep. 14 (1979) 55.Google Scholar
  3. 3.
    H. N. Lander, J. W. Morrow andA. P. Coldren, in “Steels for Linepipe and Pipeline Fittings” (The Institute of Metals, London, 1981) p. 136.Google Scholar
  4. 4.
    C. M. Brown andD. B. McCutcheon,ibid.“, p.156.Google Scholar
  5. 5.
    T. Sawamura, T. Hashimoto, Y. Komizo andY. Yamaguchi,Sumitomo Met. 37 (1985) 57.Google Scholar
  6. 6.
    M. Pontremoli, P. Bufalini, A. Aprile andC. Jannone,Metals Technol. 11 (1984) 504.CrossRefGoogle Scholar
  7. 7.
    C. I. Garcia andA. J. Deardo, in “Microalloyed HSLA Steels” (ASM, Chicago, 1988) p. 291.Google Scholar
  8. 8.
    R. M. Davison andD. R. Dendel, “Mechanical Working and Steel Processing XII” (The Institute of Metals, London, 1974) p. 91.Google Scholar
  9. 9.
    A. P. Coldren, Y. E. Smith andR. L. Cryderman, in Proceedings of the AIME Symposium on Processing and Properties of Low Carbon Steels, Cleveland, 1972, p. 163.Google Scholar
  10. 10.
    H. K. D. H. Bhadeshia andD. V. Edmonds,Acta Metall. 28 (1980) 1265.CrossRefGoogle Scholar
  11. 11.
    L. J. Habraken andM. Economopoulos, in, “Transformation and Hardenability in Steels” (Climax Molybdenum Company, Ann Arbor, MI, 1967) p. 69.Google Scholar
  12. 12.
    Y. Ohmori, H. Ohtani andT. Kunitake,Trans. ISIJ 11 (1971) 250.Google Scholar
  13. 13.
    Y. Ohmori,Trans. ISIJ 11 (1971) 339.Google Scholar
  14. 14.
    I. Weiss andJ. J. Jonas,Met. Trans. 10A (1979) 831.CrossRefGoogle Scholar
  15. 15.
    H. Tamehiro, M. Murata, R. Habu andM. Nagumo,Tetsu-to-Hagane,72 (1986) 458.CrossRefGoogle Scholar
  16. 16.
    H. Nakasugi, H. Matsuda andH. Tamehiro, in “Steels for Linepipe and Pipeline Fittings” (The Institute of Metals, London, 1981) p. 98.Google Scholar
  17. 17.
    H. Ohtani, T. Hashimoto andT. Kyogoku, “HSLA Steel Technology and Applications”, (ASM, Philadelphia, PA, 1983) p. 843.Google Scholar
  18. 18.
    A. P. Coldren, R. L. Cryderman andM. Semchyshen, in “Steel Strengthening Mechanisms” (Climax Molybdenum Company, Ann Arbour, MI, 1969) p. 17.Google Scholar
  19. 19.
    H. Tamehiro, M. Murata, R. Habu andM. Nagumo,Tetsu-to-Hagane 72 (1986) 466.CrossRefGoogle Scholar
  20. 20.
    M. Nikura, S. Yamamoto, C. Ouchi andI. Kozasu,ibid. 70 (1984) 1429.CrossRefGoogle Scholar

Copyright information

© Chapman & Hall 1993

Authors and Affiliations

  • Shyi -Chin Wang
    • 1
  • Po -We Kao
    • 1
  1. 1.Institute of Materials Science and EngineeringNational Sun Yat-Sen UniversityKaohsiungTaiwan

Personalised recommendations