Fracture resistance testing of pipeline girth welds with strength undermatch using low-constraint specimens

摘要

This work presents an exploratory experimental investigation of the ductile tearing properties for the girth weld of a typical C-Mn pipe internally clad with a nickel-chromium corrosion resistant alloy (CRA) using crack growth resistance curves (J - Δa curves). Here, the material of the external pipe is an API 5L Grade X65 pipeline steel whereas the inner clad layer is made of ASTM UNS N06625 Alloy 625 with different mechanical properties. Unloading compliance (UC) testing of the pipeline girth welds employed side-grooved, clamped SE(T) specimens with a weld centerline notch to determine the crack growth resistance curves. This exploratory experimental characterization provides additional toughness data which serve to evaluate the effectiveness of current procedures in determining experimentally measured R-curves for dissimilar girth welds.