Rolling-Contact Hardening Evaluated by Indentation

Abstract

The operational degradation of surface layers due to a rolling contact process was simulated for Hadfield steel by a special testing rig. A specific limited state based on cumulative depletion of plasticity was achieved. Precise evaluation of the surface layer's mechanical parameters is necessary for a service life prediction. Very low depth of localized dislocation hardening process doesn´t allow the standard mechanical testing. The comparative instrumented indentation tests using Vickers and cylindrical indenter were used for evaluation of defined stage of surface degradation process. The intensity and reach of deformation hardening are partially limiting for particular methodology. The yield stress of surface layers was estimated according to an analytical model of uniaxial vs. indentation plastic flow ratio.