Thick, Long Seam Welding System and Method for Distortion Control and Non Post Weld Heat Treatment of Pipeline Hot Tap Fittings

摘要

#$%^&*AU2017272290B220181220.pdf#####ABSTRACT A method for limiting fitting distortion when welding a fitting to an in-service pipeline where the fitting includes a thick, longitudinally extending, seam located between fitting halves - involves welding, on each side of the fitting, a middle third section of the seam in a pyramidlike fashion using an inward progression starting from an end of the middle third section along a profile of a seam bevel, and welding outer third sections of the seam using an outward progression from an end adjacent to the middle third section along a profile of the seam bevel. The welding of each of the three sections per side includes a temper bead welding technique of at least two layers to provide stress relief in lieu of traditional post weld heat treatment.-1~1 0 NJ 0 H-