Ratchetting strain experiments with a pearlitic steel under rolling/sliding contact

Abstract

Ratchetting strain measurements of a pearlitic steel in rolling/sliding contact have been made at a number of contact pressures. Ratchetting strain was a non-linear function of contact pressure and the number of contact cycles. The most important feature of the non-linearity is the asymptotic way in which the strain rate gradually decreases to reach near saturation over a significant portion of the total rolling contact fatigue life. The experimental data suggest that two parameters, an initial strain increment and strain rate, are needed to describe ratchetting behavior. A critical strain to crack initiation in likely to be an additional controlling factor for surface-initiated rolling contact fatigue dominated by shear band cracking.