Development of hot-pressed plugging T-joint for oil and gas pipelines

Plugging T-joint is a maintenance tool required for hole plugging operations on pipeline, and its safety underpressure directly determines operational safety of the main pipeline. To meet the needs for maintenance and emergencyrepair of high-pressure large-diameter oil and gas pipelines, a new type of large-diameter X70 pipeline hotpressedplugging steel T-joint is developed using the finite element analysis method. The X70 high-strength material isused as the T-joint back plate, so that the T-joint weight is reduced, welding efficiency is improved and welding stressis decreased in contrast to Q345R. Eliminating intersecting welding seams, such pipeline plugging T-joint has overcomethe technical challenge in traditional welded plugging T-joints that intersecting welding seams can not be detected, improved the operational safety of plugging T-joints, and utilized the stress/strain testing instrument for the first time toconduct pressurized T-joint simulated application monitoring. Valuable experiences have been gathered for future design, manufacture and quality control of similar products, because the data collected offer good reproducibility and regularity.