FRACTURE RESISTANCE AND FATIGUE CRACK GROWTH CHARACTERISTICS OF RAILROAD WHEELS AND AXLES

The effects of chemical composition, temperature and loading rates on the plane strain fracture toughness K sub I sub c of railroad wheels have been determined. Similarly, the effects of these variables were determined for grade U and F railroads axles. The carbon content was determined to be the principal factor controlling K sub I sub c. Sensitivity to loading rate (K sub I sub d) was seen to be a function of the microstructure. Estimates have been made of the minimum size of crack, which could result in the failure of wheels and axles under adverse service conditions. Also investigated were the effects of chemical composition, heat treatment, temperature, stress ratio (R), environment and peak loads on the fatigue crack growth characteristics of wheels and axles. It was seen that the effects of R could be predicted by the Forman equation and that crack growth rates were predominantly affected by R. Otherwise, all values fell within the same scatterband. Predictions of crack growth to criticality as a function of cycles were made for wheels and axles. Based on these calculations, it was concluded that detection of subcritical flaws with a good degree of confidence would only be possible for the classes A and sub A wheels and the grades U and F axles.

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 138 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00196980
  • Record Type: Publication
  • Report/Paper Numbers: FRA/ORD-77/50 Final Rpt., DOT-TSC-FRA-77-20
  • Contract Numbers: DOT-TSC-617
  • Files: NTL, TRIS, USDOT
  • Created Date: Aug 28 1979 12:00AM