Estimation of the depth of surface modification layer induced by cavitation peening

In this paper we propose an experimental method for estimating the depth to which the surface of a material is modified after being treated by cavitation peening. The estimate is made on the basis of two theories: plate theory and beam theory, in which the plastic strain in the modified layer is considered. As the depth of the compressive residual stress is an important factor for the fatigue strength and for stress corrosion cracking, a simple and straight-forward method to estimate the depth of the modified layer is needed. In the proposed method, measurements of the surface residual stress and the radius of curvature generated as a result of the plastic deformation introduced by cavitation peening are combined with either plate theory or beam theory. The most appropriate theory depends on the thickness of the specimen. The plate theory is more accurate than beam theory in the case of both a thin and thick specimens. The beam theory should be applied only in the case of a thick specimen.