Valves, meters and flanges need to be tapped in the main pipeline during site construction of natural gas and oil pipelines. At present, it is difficult to identify the straight seam position of high frequency resistance welding pipe. Some protrusions are installed very close to the welded pipe seam. Therefore, it is very necessary to study and analyze the influence of the installation of the owner on the foundation pipeline. The distribution of residual stress on high frequency straight seam resistance welded pipeline and its effect on the original residual stress at different welding positions of bumps on pipeline were analyzed by drilling. After the bulge installed on the pipeline is much larger than that of the parent pipeline, the stress rises sharply and the longitudinal residual stress of the weld affects it.
The Conduit


The distribution of residual stress in pipeline is closely related to its welding and forming process. HFW resistance welding is to form the cross section of circular billet after rolling. The skin effect and proximity effect of high frequency current are used to make the induced current highly concentrated at the edge of the opening edge. The pipe makes the temperature rise rapidly to the welding temperature, and the extrusion roll is extruded. The dimension and hydraulic test after welding are both important processes leading to the value of axial residual stress greater than that of circumferential residual stress. After high frequency welding, on-line heat treatment improves the structure and properties of the weld and heat affected zone, thus reducing the residual stress near the weld and the weld. The total residual stress on ERW pipeline is small, and the residual stress is larger than the circumferential residual stress. the maximum axial and circumferential yield strength of ERW pipeline is about 38% and 29% of the base metal. The residual stress of longitudinal weld near the pipe is lower than that of the pipe body. The axial and circumferential variation ranges from 24.5% to 33.6% and 16.4% to 21.5% of the base metal yield strength, with stress concentration.