Nondestructive characterization of the surface integrity of cold surface hardened components

Nondestructive characterization of surface and subsurface properties is of increasing interest in industry and science. As destructive methods are inadequate for testing large devices (e.g. gear wheels for wind engines) or small series, nondestructive techniques for the assessment of their surface integrity are mandatory. Especially surface hardened components have to be examined in practice, as they tend to show varying properties regarding surface hardness, hardness penetration depth and residual stress profiles. Since the surface integrity has a major influence on the functional performance of components, assessment and monitoring of the surface properties is crucial. In this study, the results of a new technique for surface hardening (cold surface hardening) were investigated for the first time applying an emerging nondestructive measuring method: the photothermal near-surface layer characterization. © 2010 German Academic Society for Production Engineering (WGP).