| Popis: |
Classical stress-life (S-N) curves were developed for AAR Class B wheel steel with specimens removed from the tread area of an as-forged railcar wheel. The specimen geometry was a standard hourglass fatigue test specimen with a low stress concentration (Kt) of 1.05. Fatigue testing was performed at stress ratios of −1.0, 0.05, 0.5 and 0.7. Testing was performed at ambient, 500°F and 1000°F using high current resistance or convection methods. Endurance limit data was obtained for all R-ratios, although for the 1000°F condition there did not appear to be a clear endurance limit transition. These endurance limit data were used to estimate the Sines parameters, A and α. |
