Abstract: The fatigue properties of 2024T3 aluminum alloy welded joint treated by different peening methods were examined. The different effects on fatigue performance of high strength aluminum welded joints were compared with each other by carry out a series tests using two different peening treatment samples. Results show that by applying synchronized hammer peening to the weak part of joint when weld was going on, trailing peening, may refine the grains near weld line, hardening the surface of weld toe and amend the distribution of residual stress. Because of these results the position of fracture of joint was moved from weld toe to weld line. Compared to the joints treated by peening after welding, the fatigue strength of weld joint treated by trailing peening was enhanced by more than 102%.

Key words: Fatigue strength, Cycling, Residual stresses, Trailing peening