Nondestructive Examination Methods

Radiographic testing (RT) passes X-rays or gamma rays through the weld onto a film or digital detector. Voids, porosity, slag inclusions, and cracks appear as dark areas on the radiograph because less material absorbs the radiation. RT excels at finding volumetric defects but is less effective for tight planar defects oriented parallel to the beam. Ultrasonic testing (UT) sends high-frequency sound waves into the material and detects reflections from discontinuities. UT is superior for finding planar defects like lack of fusion and cracks, and it can determine the depth and size of indications with precision.