Effects of Weld Geometry Size on the Pressure-Bearing Capacity of an API X80 LSAW Pipe

Abstract

The weld joint is the weakest zone of a longitudinal-seam submerged arc welded (LSAW) pipe, which has great effects on its in-service properties and safety. The weld geometry and shape of the weld joint are important factors that affect the mechanical properties of the pipe. In this work, two-dimensional (2D) and three-dimensional (3D) finite element models (FEMs) of a large-diameter, heavy-wall API X80 LSAW pipe were established, and the stress distribution of the pipe was calculated to simulate the in-service gas transmission pipeline. Results showed that the stress distribution calculated by both 2D and 3D models are similar. Consequently, the effects of weld geometry, softening of heat affected zone (HAZ), and strength matching of the weld joint on bearing pressure capability of the pipe were analyzed, and the results showed that the bearing pressure capability of the pipe can be improved by controlling these parameters. These results are beneficial in providing references for welding parameter design and improved properties of the X80 LSAW pipe.