X-ray radiography

X-ray radiography is the X-ray form of radiographic testing: an X-ray tube projects radiation through a weld onto film or a digital detector, and internal defects, porosity, slag, lack of fusion, and cracks, show as density changes on the image. Compared with gamma sources, the X-ray tube gives a finer image and switches off between shots, so it is preferred in the shop where mains power and shielding are available; gamma isotopes (iridium-192, cobalt-60) take over for site and confined work. An image quality indicator on each shot proves sensitivity, and acceptance follows ISO 5817 quality levels referenced by the class welding rules. Tight planar cracks aligned across the beam can escape detection.