Radiographic Testing (RT)

Radiographic testing (RT) is a volumetric NDT method that passes X-rays or gamma rays through a weld onto film or a digital detector, where internal defects, porosity, slag, lack of fusion, and cracks, show as density changes on the radiograph. It images the full weld thickness, so it suits butt welds in plate and pipe, and an image quality indicator (penetrameter) on each shot proves the sensitivity achieved. Gamma sources (iridium-192, cobalt-60) serve site work where X-ray sets are impractical, at the cost of longer exposures and exclusion zones. Class welding rules set the RT extent and acceptance to ISO 5817 quality levels. Planar cracks tight to the beam can be missed, so RT pairs with UT.