Fracture-resistance testing of pipeline girth welds using bend and tensile fracture specimens

摘要

Structural-Integrity Assessments of pipe girth welds play a key role in the design and safe operation of pipeline systems. Current practices for structural-integrity assessments advocate the use of geometry-dependent resistance curves so that crack-tip constraint in both the test specimen and the structural component is similar.Thus, testing standards now under development to measure fracture resistance of pipeline steels often employ single-edge-notched (SE(T)) specimens under tension.This paper presents an investigation of the ductile-tearing properties for a girth weld of an API 5L X-80 pipeline steel using experimentally measured crack-growth-resistance curves (also termed J-R curves).Testing of the girth-weld pipeline steels employed clamped SE(T) specimens and three-point bend (SE(B)) specimens with weld centreline cracks to determine the J-resistance curves.The experimental toughness data enables further evaluation of crack growth resistance properties of pipeline girth welds.