Effect of Pre-Strain on Fatigue Properties of NHH Rail
In the present study, fatigue tests have been performed to study the effect of pre-strain on fatigue properties of NHH (New Head-Hardened) rail. The objectives of this study were: (1) to observe the microscopic behavior of specimens during pre-strain process, (2) to research the influence of pre-strain on fatigue strength of NHH rail and (3) to investigate initiation and propagation behavior of the fatigue crack. The results showed that plastic pre-strain decreased the fatigue strength of NHH rail; fatigue limits had no obvious variation among the different pre-strain ratios. Fatigue cracks initiated in the microscopic cracking or slip lines that were originated in the pre-strain process and propagated from these sites in the later fatigue test.
Kikuo Kishimoto, Masanori Kikuchi, Tetsuo Shoji and Masumi Saka
W. X. Sun et al., "Effect of Pre-Strain on Fatigue Properties of NHH Rail", Key Engineering Materials, Vols. 261-263, pp. 1239-1244, 2004