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Corrosion Fatigue Behavior of Coated 4340 Steel for Blade Retention Bolts of the AH-1 Helicopter

  • M. Levy
  • C. E. SwindlehurstJr.
Part of the Sagamore Army Materials Research Conference Proceedings book series (SAMC, volume 24)

Abstract

The main rotor blade bolt for the 540 roto system (AH-1G, UH-1C, UH-1M helicopter) is proposed to be improved by the substitution of plasma-sprayed tungsten carbide coating on the outer shank for the present cadmium or chromium plate. The WC coating was originally suggested to reduce the costly machining and plating operations required to recondition blade retention bolts for the AH-1G helicopter. Fretting-induced corrosion resulted in significnet surface pitting on the bolts after less than 500 hours of service. Based on prior results with a similar configuration bld for the 240 rotor system, a WC-coated bolt is expected to last over 3000 hours (the approximately design life of the airframe) as compared to about 300 hours for current Cd-plated new production bolts and about 500 hours for Cr-plated reworked bolts. Thus a significant cost savings has been projected if bolt reconditioning and replacement is eliminated.

Keywords

Fatigue Strength Fatigue Test Tungsten Carbide Corrosion Fatigue Fatigue Specimen 
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.

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References

  1. 1.
    Viglione, J., Jankowsky, E.J. and Ketchan, S.J., “Effects of Metallic Coatings on the Fatigue Properties of High Strength Steels”, Materials Protection and Performance, Vol. 11, March 1972, p 31–6.Google Scholar
  2. 2.
    Levy, M. and Morrossi, J., “Erosion and Fatigue Behavior of Coated Titanium Alloys for Gas Turbine Engine Compressor Applications”, Army Materials and Mechanics Research Center, AMMRC TR 76–4, February 1976.Google Scholar
  3. 3.
    Gould, A.J., “Corrosion-Fatigue of Steel Under Asymmetric Stress in Sea Water”, J. Iron and Steel Inst., Vol. 161, 1949, p 11–16.Google Scholar

Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • M. Levy
    • 1
  • C. E. SwindlehurstJr.
    • 1
  1. 1.U. S. Army Air Mobility Research and Development LaboratoryArmy Materials and Mechanics Research CenterUSA

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