Autofrettage of Weld Clad Components

A fatigue-resistant cladding concept confirms the presence of compressive residual stresses in a cylinder weld clad with 17-4 PH stainless steel while tensile residual stresses exist in an Inconel 625 clad layer. In this study, autofrettage of an Inconel 625 thick-walled clad cylinder is investigated with modified residual stress distributions obtained indicating that tensile residual stresses throughout the clad layer are transformed to compressive in nature, discontinuity stresses at the clad/substrate interface are almost entirely eliminated and compressive residual stresses exist to a depth of around 18 mm. Strain hardening effects and the assumption of an idealized interface are discussed.