LAUSR

ABSTRACT The behaviours of ultrasonic peening treatment induced effects near the edges of weld toe were investigated. The deformed weld toe profiles were observed and numerical models were established to calculate the stress concentration factor for the middle and the edges of the specimen. Micro-hardness profiles were also measured in the subsurface layer. The results revealed that comparing with the middle position the stress concentration is lower, the macro deformation is larger, and the strain hardening characterised by the increase of hardness is less significant at the edges. Finite element analysis was employed to predict the residual stress distribution under different peening sequences and it was found that tensile stresses appeared at the starting edge, and relatively smaller compressive stresses existed at the ending edge. The optimal peening strategy should be starting the treatment inside and moving out towards the edges.