White etching structures in annealed 52100 bearing steel arising from high-pressure torsion tests

Abstract White Etching Areas observed in failed rolling bearings have been associated with the presence of Severe Plastic Deformation conditions, which can be achieved by High-Pressure Torsion tests; thus, this technique was selected to produce White Etching Structures in annealed AISI 52100. Their origin arises from two main phenomena: Firstly, the relative movement between anvil/samples creates instabilities and interruption to plastic flow close to the surface of the sample. Secondly, the presence of hard discontinuities such as carbide clusters and non-metallic inclusions interrupt plastic flow inside the samples. Both phenomena seem to promote carbide dissolution in the ferritic matrix and so could produce not only White Structures but also White Etching Areas.