Pipeline defects are routinely found in the oil and gas industry. Most often they are minor, and do not affect the integrity and safety of the pipeline. However, in some cases, identifying and repairing critical defects is mandated to ensure long term integrity, which also entails choosing an appropriate repair technique. In this case study, we present a metallurgical examination of a 1949-vintage Grade X52 pipe containing an internal crack that was first identified at a client site. Laboratory examination confirmed that the feature was a pre-existing imperfection or defect, which had been weld repaired around the time of manufacturing or installation. Grinding marks and a distinct weld zone with three welding passes were observed in the region surrounding the crack. Scanning electron microscope (SEM) fractography of the crack surface indicated the presence of columnar grains close to the inside surface that are typical of a carbon steel weld. Energy dispersive x-ray spectroscopy (EDS) analysis indicated that the corrosion products consisted of iron