L52027 External Weld Deposition Repair for Internal Wall Loss in Tees and Elbows - Further Validation

Abstract

Pipeline repair by direct deposition of weld metal, or weld deposition repair, is an attractive alternative to the installation of full-encirclement sleeves or composite reinforcement, particularly for repair of wall loss defects in bend sections and fittings. Previous work concluded that the static strength of straight sections of pipe, field bends, elbows, and tees can be fully restored when the after-repair minimum wall thickness is equal to or greater than the nominal wall thickness, provided that the weld metal strength is at least equal to the strength of the parent material and that the repair overlaps the perimeter of the wall loss by at least one nominal wall thickness. This criteria was validated by full-scale tests that included a limited number of wall loss locations and end-restraint conditions. To allow the confident use of this repair method, additional validation experiments were required for different wall loss locations and end-restraint conditions. The objective of this project was to further validate the criteria developed in previous work.