Effect of Welding Residual Stress on Fatigue Performance of the Welded Joints Treated by Ultrasonic Peening

Abstract

The fatigue tests of Q235B steel unload longitudinal fillet welded joints containing high welding residual stress were carried out. And the effect of welding residual stress on fatigue performance of the welded joints treated by ultrasonic peening has been studied. Specimens were divided into four groups: as welded, specimens treated by ultrasonic peening(UP), specimens treated by stress relief treatment(SRT) and specimens treated by both ultrasonic peening and stress relief treatment(UP+SRT). Test results show that the effect on fatigue performance of the welded joints treated by ultrasonic peening from welding residual stress is small. It is safe that using the small specimens treated by ultrasonic peening and not containing high welding residual stress to appraise the fatigue performance improvement on large-scale welded structures which are as the same junction style and thickness as the small.