Fatigue and fretting fatigue behaviour of a railway axle steel A4T

This paper presents an experimental and numerical study on fretting fatigue behaviour of an A4T steel (25CrMo4) widely employed in the manufacturing of railway axles. First, standard S-N curves describing the material fatigue properties within both LCF and HCF regimes were experimentally derived. Subsequent fretting fatigue tests were carried out using loading parameters determined via numerical analyses. A comparison of both results series in terms of the SWT fatigue parameter applicable to multi-axial loading conditions suggests a high potential of the combined experimental and numerical approach for predicting crack initiation at fretting fatigue. Further issues - scatter in basic fatigue data, size effect, material and friction modelling - and their significance for the lifetime prediction are briefly addressed.