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

Abstract

The main rotor blade bolt for the 540 helicopter rotor system of the AH-1G, UH-1C, and UH-1M helicopters is proposed to be improved by substituting plasma-sprayed tungsten carbide coating on the outer shank of the 4340 steel bolt for the present cadmium or chromium plate. This study was undertaken to determine the effects of these coating systems on the fatigue behavior of 4340 steel in environments likely to be encountered in service. Both axial tension- tension and rotating bending fatigue testing of coated specimens were carried out in air and in 3.5% NaCl solution. The NaCl environment causes reductions in fatigue strength of bare and coated 4340 steel. The severity of the degradation depends on the coating applied and the type of fatigue test utilized.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1976
Accession Number
ADA033253

Entities

People

  • Joseph L. Morrossi
  • Milton Levy

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Air Platforms
  • Ground and Sea Platforms
  • Space

DTIC Thesaurus Topics

  • Army Aviation
  • Chromium
  • Corrosion
  • Engineering
  • Fatigue Life
  • Fatigue Tests (Mechanics)
  • Films
  • Lubricants
  • Materials
  • Military Research
  • Resistance
  • Solid Film Lubricants
  • Solid Lubricants
  • Tensile Strength
  • Tungsten
  • Tungsten Carbides
  • Turbines

Fields of Study

  • Materials science

Readers

  • Electrical Engineering
  • Materials Science and Engineering.
  • Surface Engineering/Surface Coating Technology.