Influences on Stress Concentration of X70 Pipeline Circumferential Weld Joints of Several Welding Defects

In this paper, the finite element analysis software ANSYS was used to carry out stress analysis on X70 pipeline under working pressure with welding defects, such as undercut, pit, weld reinforcement and misalignment. The results indicated that in the above defects, the influence on the weld reinforcement of stress concentration is the lowest, misalignment is the second, undercut is a bit severe, and the influence on pit is the most severe. The weld reinforcement does not affect the static load strength of X70 pipeline circumferential weld joints, and the influence of misalignment more than 2 mm on stress concentration is obvious. The influence of undercut on stress concentration is more than that of misalignment, and the influence of pit increases with three-dimensional size increasing.