Industrial Radiography One of the special applications of X-ray radiography is in weld inspection. When incomplete penetration or lack of fusion occurs, the welded metal cannot fully penetrate the joint. This is one of the most probable discontinuities in welding. Lack of fusion results in increased natural stress that may cause cracks to propagate. In radiography, the appearance is a dark area with well-defined and straight edges. Cracks, distortions, and deformations of components under pressure, temperature, and speed are among the issues that X-ray radiography can detect. The image above depicts a mechanical part that, due to high-speed rotation and stress, has developed a crack of 200 microns in width. This crack is clearly visible in Bahyar X-ray radiography.