The majority of rail fatigue failures initiate internally at oxide inclusions in the head. Analytical models have been developed to assess the effects of residual, contact, and flexural stresses on initiation and growth of shell/transverse defects in rail. However, these models do not consider the effects of inclusion content on crack initiation. Therefore the present study was conducted to obtain such information for incorporation into the models. Four rails that had been tested at FAST and had exhibited a range of defect occurrences were obtained for this study. First, the microcleanliness was characterized. Next, 15-inch-long defect-free samples were fatigue tested in the cradle rolling load test machines at the Chicago Technical Center. The samples were examined periodically with ultrasonic test equipment. When incipient fatigue cracks were detected, the rolling load testing was terminated and the fatigue cracks were examined metallographically. The results showed that rolling contact fatigue initiation life was generally inversely related to oxide content. However when hardeness effects were considered, the results indicated that rolling load test life was only slightly dependent on microcleanliness.
Effect of inclusion content on fatigue performance of rail steels
Einfluß des Einschlußgehalts auf das Ermüdungsverhalten von Schienenstählen
1993
8 Seiten, 18 Bilder, 4 Tabellen, 3 Quellen
Aufsatz (Konferenz)
Englisch
Analysis of rolling contact fatigue helps develop tougher rail steels
British Library Online Contents | 1999
Probabilistic Fatigue Crack Growth of Detail Fractures in Different Rail Steels
British Library Conference Proceedings | 2020
|Overview of rail manufacturing changes for improved rail fatigue performance
Tema Archiv | 1993
|Very early stage rolling contact fatigue crack growth in pearlitic rail steels
Tema Archiv | 2011
|