Influence of Ultrasonic Treatment on Welded Joint Fatigue Performance in JG590 Steel

JG590 steel is one of high strength, low alloy and high toughness engineering machinery steels, and its tensile strength is not less than 590MPa. The fatigue failure is one of the main forms of the welding structure failure. This paper studies the influence of the ultrasonic treatment on welded joint fatigue performance. Through the experiments, the paper compares the fatigue performance on as-welded welding joint with the performance on ultrasonic impact treatment welding joint. The results show that the ultrasonic treatment reduces the stress concentration factor by improving the geometry of the toe of weld’ area. It transforms the welding residual tensile stress on the surface of the welded joint into compressive stress, and makes the surface of the toe of weld’ area hardening. The fatigue strength of welded joint is increased by 114%, and the fatigue life increased by 133~184 times.