Abstract
We report a novel non-destructive evaluation method (NDE) that relies on the magnetic properties of the inherent ferromagnetic phase in austenitic stainless steel (SUS) parts to assess the state of damage. The effects of the volume fraction, internal stress, and shape anisotropy of the ferromagnetic phase on the electromagnetic impedance signal used in the NDE are discussed on the basis of experimental results for cold-rolled SUS 304 steel plates of different thicknesses with and without stress relief annealing. In particular, the influence of shape anisotropy is clarified on the basis of measurements conducted on 0.5-mm-thick samples both parallel and perpendicular to the rolling direction. The results of the measurements show that the parameters obtained by the proposed method are indicative of damage.