Copper Contamination Cracking in a Pipeline Repair Weld

Crack-like indications were identified in a gas transmission pipeline during a routine integrity assessment. Visual examination and CT scanning confirmed the presence of cracks on the pipe internal diameter and throughout the wall thickness near the weld seam. Fractographic and metallographic analysis indicated that the cracking occurred in numerous repair welds that were made prior to the final pipe seam weld. The presence of copper on crack faces and within internal cracks, as well as the intergranular path of those cracks, indicated the cracking occurred by copper contamination cracking associated with repair welding.