Observation of Rolling Contact Fatigue Cracks by Laminography Using Ultra-bright Synchrotron Radiation

Micro computed laminography imaging using ultra-bright synchrotron radiation (SRCL) was applied to the observation of flaking defects under rolling contact fatigue (RCF) of a high strength steel. Specially fabricated inclusion rich steel plate specimens were employed for the experiments. RCF fatigue tests were carried out near the measurement hatch of SRCL for successive observation of crack initiation and growth behaviors. Specimens before and after the initiation of flaking were observed by SRCL, and the flaking defects and cracks under the surface were successfully detected. The shape and location of RCF crack obtained by SRCL imaging were almost coincident with those obtained by SEM, and detail process of crack initiation and flaking in RCF process can be discussed.