Journal of Failure Analysis and Prevention

, Volume 14, Issue 2, pp 148–151 | Cite as

Spring Fatigue Fractures Due to Microstructural Changes in Service

Case History---Peer-Reviewed
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Abstract

Multiple in-service fractures of torsion springs were experienced in the same system, which was the support assembly to the electrical pickup for an electric-powered vehicle, similar to a subway rail car or electric trolley car. Scanning electron microscopy and metallographic examinations determined that the fractures initiated due to electric arc damage. Intergranular quench cracks at the spring surface through the transformed untempered martensite provided crack initiations for fatigue that propagated during operation.

Keywords

Spring fracture Fatigue Stray current Arc damage Untempered martensite Quench cracking Torsion spring 

References

  1. 1.
    J.R. Davis (ed.), ASM Metals Handbook Volume 12: Fractography (ASM International, Materials Park, 1987), pp. 280–281Google Scholar
  2. 2.
    J. Shigley, Mechanical Engineering Design, 3rd edn. (McGraw-Hill, New York, 1977), p. 298Google Scholar
  3. 3.
    J. Landes, W.T. Becker, R. Shipley, J. Raphael, “Stress analysis and fracture mechanics,” in ASM Handbook Volume 11: Failure Analysis and Prevention (ASM International, Materials Park, 2002), p. 472Google Scholar
  4. 4.
    G.E. Totten, M. Narazaki, R.R. Blackwood, “Failures related to heat treating operations,” in ASM Handbook Volume 11: Failure Analysis and Prevention (ASM International, Materials Park, 2002), p. 208Google Scholar
  5. 5.
    W.T. Becker, S. Lampman, “Fracture appearance and mechanisms of deformation and fracture,” ASM Handbook Volume 11: Failure Analysis and Prevention (ASM International, Materials Park, 2002), pp. 578–579Google Scholar
  6. 6.
    J.R. Davis (ed.), ASM Metals Handbook Volume 12: Fractography (ASM International, Materials Park, 1987), pp. 3, 224, 281, 335Google Scholar
  7. 7.
    T. Gross, “Micromechanisms of monotonic and cyclic crack growth,” in ASM Handbook Volume 19: Fatigue and Fracture (ASM International, Materials Park, 1996), p. 49Google Scholar
  8. 8.
    P. Lukas, “Fatigue crack nucleation and microstructure,” in ASM Handbook Volume 19: Fatigue and Fracture (ASM International, Materials Park, 1996), p. 96Google Scholar

Copyright information

© ASM International 2014

Authors and Affiliations

  1. 1.Materials TestingApplied Technical Services, Inc.MariettaUSA
  2. 2.Failure Analysis and MetallurgyApplied Technical Services, Inc.MariettaUSA

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