What could a very light irregularly-shaped small image in a pipe weld on a radiograph indicate?

A very light irregularly-shaped small image in a pipe weld on a radiograph typically indicates the presence of tungsten inclusion. This occurs when tungsten from the electrode used in the welding process becomes trapped in the weld metal. Tungsten has a lower radiographic density compared to steel, which means it will appear lighter on the radiograph. As such, its irregular shape can represent the inconsistent inclusion within the weld bead.

Understanding this phenomenon is essential for radiographic testing. Tungsten inclusions can cause localized weaknesses within the weld, potentially affecting the integrity of the joint. The identification of such inclusions through radiography is crucial for ensuring the quality and safety of welded structures. Other factors, such as air inclusion, moisture presence, and oxide layers, would generally manifest differently on a radiograph, making tungsten inclusion a more fitting interpretation for the described radiographic feature.