Advertisement

Journal of Materials Science

, Volume 32, Issue 21, pp 5603–5610 | Cite as

Fe-Zn phase formation in interstitial-free steels hot-dip galvanized at 450°C: Part II 0.20 wt% Al-Zn baths

  • C. E JORDAN
  • A. R MARDER
Article

Abstract

The effect of solute additions of titanium, titanium and niobium and phosphorus on interstitial-free steels on Fe-Zn phase formation after immersion in a 0.20 wt% Al-Zn bath was studied to determine the morphology and kinetics of the individual Fe-Zn phases formed. These results were contrasted to the previous study using a pure zinc (0.00 wt% Al) bath in Part I. It was found that in the 0.20 wt% Al-Zn bath, an iron-aluminide inhibition layer prevented uniform attack of the steel substrate. Instead, localized Fe-Zn phase growth occurred, termed outbursts, containing a two-phase layer morphology. Delta-phase formed first, followed by gamma-phase. Zeta-phase did not form in the 0.20 wt% Al-Zn bath, in contrast with zeta-phase formation in the pure zinc bath. As in the pure zinc bath, the growth kinetics of the total layer was controlled by the Fe-Zn phase in contact with the liquid zinc during galvanizing. For the 0.20 wt% Al-Zn bath, the Fe-Zn phase in contrast with the liquid zinc was the delta-phase, whereas the zeta-phase was in contact with liquid zinc in the pure zinc bath. The delta-phase followed t1/2 parabolic growth, while the gamma-phase showed essentially no growth after its initial formation. Titanium and titanium + niobium solute additions, which enhance grain-boundary reactivity, resulted in more rapid growth kinetics of the gamma- and delta-phases. Phosphorus additions, which decrease grain-boundary reactivity, generally increased the incubation time and retarded the growth rate of the gamma-phase. These results further confirm the concept that solute grain-boundary reactivity is primarily responsible for Fe-Zn phase growth during galvanizing in a liquid Zn-Al bath in which an iron aluminide inhibition layer forms prior to Fe-Zn phase formation.

Keywords

Substrate Steel Alloy Layer Solute Addition Interstitial Free Liquid Zinc 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    C. E. JORDAN and A. R. MARDER, J. Mater. Sci. 32 (1997) 56035610.CrossRefGoogle Scholar
  2. 2.
    J. S. KIRKALDY and M. UREDNICEK, Z. Metallkde 64 (1973) 899.Google Scholar
  3. 3.
    A. R. P. GHUMAN and J. I. GOLDSTEIN, Metall.Trans. 2A (1971) 2903.CrossRefGoogle Scholar
  4. 4.
    J. MACOWIAK and N. R. SHORT, Int. Metals Rev. 1 (1979) 1.Google Scholar
  5. 5.
    C. E. JORDAN and A. R. MARDER, "GALVATECH '95" edited by J.E. Hartmann (Iron and Steel Society, Warrendale, PA, 1995) p. 319.Google Scholar
  6. 6.
    N-Y. TANG, G. R. ADAMS and P. S. KOLISNYK, ibid., p. 777.Google Scholar
  7. 7.
    C. E. JORDAN, K. M. GOGGINS, A. O. BENSCOTER and A. R. MARDER, Mater. Charact. 31 (1993) 107.CrossRefGoogle Scholar
  8. 8.
    P. PERROT, J-C. TISSIER and J-Y. DAUPHIN, Z. Metallkde 83 (1992) 11.Google Scholar
  9. 9.
    T. FUKUZUKA, M. URAI and K. WAKAYAMA, Kobe Steel Engng. Rep. 30 (1980) 77.Google Scholar
  10. 10.
    K. OSINSKI, Doctoral Thesis, Eindhoven, The Netherlands (1983).Google Scholar
  11. 11.
    C. E. JORDAN, K. M. GOGGINS and A. R. MARDER, Metall. Mater. Trans. 25A (1994) 2101.CrossRefGoogle Scholar
  12. 12.
    L. ALLEGRA, R. G. HART and H. E. TOWNSEND, Metall. Trans. 14A (1983) 401.CrossRefGoogle Scholar
  13. 13.
    T. TOKI, K. OSHIMA, T. NAKAMORI, Y. SAITO, T. TSUDA and Y. HOBO, in “The Physical Metallurgy of Zinc Coated Steel”, edited by A. R. Marder (TMS, Warrendale, PA, 1994) p. 169.Google Scholar

Copyright information

© Chapman and Hall 1997

Authors and Affiliations

  • C. E JORDAN
    • 1
  • A. R MARDER
    • 1
  1. 1.Department of Materials Science and EngineeringLehigh UniversityBethlehemUSA

Personalised recommendations