Fatigue Crack Propagation in Rail Steels

In order to establish safe inspection periods of railroad rails, information on fatigue crack growth rates is required. These data should come from a sufficiently large sample of rails presently in service. The reported research consisted of the generation and analysis of fatigue crack growth data of 66 rail samples taken from existing track all over the United States. Additional information concerns mechanical properties, chemical composition, microstructure, and fractographic features. A statistical analysis was performed to evaluate possible correlations with fatigue crack growth properties and microstructural parameters. Weak correlations were found with carbon, manganese and oxygen content, and with the fraction of pearlite. A subsequent phase of this research program is discussed.