THE EFFECT OF SURFACE LAYER ON PLASTIC DEFORMATION AND CRACK PROPAGATION

The relationship between the increase in the surface layer stress and number of fatigue cycles was established for 4130 steel (yield strength = 180,000 psi). Confirming the results found for aluminum (2014-T6) and titanium (6A1-4V), fatigue failure occurred when the surface layer stress attained a critical value. The crack propagation rate was measured for 4130 steel at yield strengths of 180,000 and 100,000 psi. The results showed that the SLE treatment improved the crack resistance. Pressure vessels of 4130 steel have been obtained and processed for fatigue testing. Welded specimens of 4130 steel have been made by butt-welding plates and machining out appropriate strips. The microstructure and hardness profile were determined and the specimens readied for test. A four-point fatigue apparatus and associated mechanism for detecting fatigue failure was designed and constructed. (Author)

• Corporate Authors:

  Martin Marietta Aerospace

  Orlando, FL  United States  32805
• Authors:
  • Kramer, I R
• Publication Date: 1972-12

Media Info

• Pagination: 29 p.

Subject/Index Terms

• TRT Terms: Cracking; Failure; Pavement layers; Plastic deformation; Surface course (Pavements)
• Uncontrolled Terms: Crack propagation
• Old TRIS Terms: Surface layer elimination
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00044644
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: AMMRC-CR-71-2/5
• Contract Numbers: DAAG46-70-C-0102
• Files: TRIS
• Created Date: Sep 4 1973 12:00AM