Strain Cyclic Characteristics and Ratchetting Behaviors of High-Speed Railway Train Axle Steel EA4T

At room temperature, the cyclic softening/hardening characteristics and ratchetting behaviors of axle steel EA4T were experimentally observed by considering uniaxial and non-proportional multiaxial cyclic loading paths. The effects of loading conditions and loading paths on low-cycle fatigue behaviors were discussed. The experimental results are obtained as follows: Firstly, under strain controlled monotonic tension, the yield strength of axle steel EA4T depends on the loading strain rate (rate-dependent). Secondly, under symmetrical strain controlled cyclic load, axle steel EA4T shows cyclic softening characteristics, and the cyclic softening characteristics depend on strain amplitude, strain rate and non-proportional multiaxial cyclic strain loading paths. Finally, under asymmetric stress controlled cyclic load, the ratchetting behaviors of axle steel EA4T is greatly dependent on the stress level, stress rate and multiaxial stress loading paths.