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Practical failure analysis

, Volume 2, Issue 2, pp 51–57 | Cite as

Failure analysis of gas turbine last stage bucket made of udimet 500 superalloy

  • Z. Mazur
  • J. Kubiak
  • C. Mariño-Lopez
Peer Reviewed Articles
  • 116 Downloads

Abstract

This article presents a failure analysis of 37.5 mW gas turbine third stage buckets made of Udimet 500 superalloy. The buckets experienced repetitive integral tip shroud fractures assisted by a low temperature (type II) hot corrosion. A detailed analysis was carried out on elements thought to have influenced the failure process:
  1. a)

    the stress increase from the loss of a load bearing cross-sectional area of the bucket tip shroud by the conversion of metal to the corrosion product (scale),

     
  2. b)

    influence of the tip shroud microstructure (e.g., a presence of equiaxed and columnar grains, their distribution and orientation),

     
  3. c)

    evidence of the transgranular initiation, and

     
  4. d)

    intergranular creep mechanism propagation.

     

The most probable cause of the bucket damage was the combination of increased stresses due to corrosion-induced thinning of the tip shroud and unfavorable microstructures in the tip shroud region.

Keywords

hot corrosion creep fatigue equiaxed grains columnar grains gas turbine buckets 

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References

  1. 1.
    M. McLean:Directionally Solidified Materials for High Temperature Service, The Metals Society, London, 1983, pp. 209–13.Google Scholar
  2. 2.
    Z. Mazur, C. Mariño-Lopez, and J. Kubiak:Rev. Metal. Madrid (in Spanish), 1999,35(1), pp. 39–46.CrossRefGoogle Scholar
  3. 3.
    G.W. Goward:Turbomach. Int., May–June 1985, pp. 24–8.Google Scholar
  4. 4.
    J.C. Galsworthy:The Effects of Seasalt on the High Temperature Creep Properties of a Nickel Base Gas Turbine Blade Alloy, Corrosion and Mechanical Stress at High Temperature, Petten, the Netherlands, 1980, pp. 197–206.Google Scholar
  5. 5.
    H. Lewis and R.A. Smith:1st Int. Congress on Metallic Corrosion, London, 1962, pp. 202–12.Google Scholar
  6. 6.
    D.J. Wortmann, R.E. Fryxell, and J.J. Bessen:3rd Conf. Congress on Gas Turbine Materials in Marine Environment, Bath, England, 1976, pp. 1–11.Google Scholar
  7. 7.
    Anon.: inMetals Handbook, 9th ed., Vol. 13, Corrosion, ASM International, 1987, p. 1001.Google Scholar
  8. 8.
    Anon.: in Inspection and Acceptance Requirements Investment Cast W501B/B6 Turbine Blades,TIS 1004, Tusco Corporation, 1994, p. 2.Google Scholar
  9. 9.
    C.T. Sims, N.S. Stoloff, and W.C. Hagel:Superalloys II, High-Temperature Materials for Aerospace and Industrial Power, 1987, pp. 423-4, 433.Google Scholar
  10. 10.
    G.R. Leverant:Parameters Controlling the Thermal Fatigue Properties of Conventionally-Cast and Directionally-Solidified Turbine Alloys, Materials Engineering and Research Laboratorires, Pratt & Whitney, East Hartford, CT.Google Scholar
  11. 11.
    P.W. Schilke, A.M. Beltran, A.D. Foster, and J.J. Pepe:Advanced Gas Turbine Materials and Coatings, G.E. Industrial & Power Systems, Schenectady, NY, 1992.Google Scholar

Copyright information

© ASM International - The Materials Information Society 2002

Authors and Affiliations

  • Z. Mazur
    • 1
  • J. Kubiak
    • 1
  • C. Mariño-Lopez
    • 1
  1. 1.Instituto de Investigaciones EléctricasTemixco, MorelosMéxico

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