The residual stress, texture and surface changes in steel induced by cavitation

Abstract

In an investigation of the destruction of materials by cavitation, samples made of steel (quenched and tempered 42 CrMo 4 and normalized Ck 45) were tested in an ultrasonic vibration apparatus. As well as the material loss, the residual stress, texture, lattice distortion, microhardness and topography of the surface layer of these samples were examined. The results indicate that shock waves during the incubation period are the main cause of plastic deformation of the material. The yield strength of the material during the cavitation attack is reduced by the high frequency dynamic load. The changes observed in the material are similar to the events produced by flow cavitation or shot peening. This means that the mechanical stresses in vibrational and flow cavitation are essentially similar and in many respects the cavitation-induced deformation mechanism is comparable to that of shot peening.