Radiographic Testing (RT)

SNS offers full Radiographic services for code-compliant inspections of welds and fabricated items, employing gamma ray (isotope) or x-ray sources for conventional film radiography, or utilizing state of the art computed radiographic (CR) and digital radiographic (DR) systems. We can deliver these services at our clients’ job sites via our mobile field lab vehicles, or at our in-house NDT laboratory facility in Conroe, Texas.

Radiographic Testing (RT), or radiography, is a volumetric NDT method used to perform inspections that detect internal discontinuities in all material types. It can be an option for both field and shop work. RT is predominantly used for weld inspection or testing of castings and forgings using one of two source types: x-ray or gamma ray (isotope) radiation, including iridium-192, cobolt-60, or selenium.

When employing radiography, the part is exposed to the radiation source while a film is positioned behind the part to be inspected. The film is then developed and interpreted. Based on the actual indications on the film and density differences, a determination can be made regarding the size and orientation of imperfections within the material, as well as their location relative to the weld. A determination can then be made to characterize the indication, and on whether or not the defect passes or fails, based on the applicable code criteria for acceptance or rejection.

Newer radiographic technologies include Computed Radiography (CR), which utilizes flexible and reusable electromagnetic screens, and Digital Radiography (DR), which captures digital images instantaneously on solid plates. Both of these technologies replace conventional x-ray film and eliminate the need for the chemicals required to process the film (and related requirements for chemical disposal). In addition, CR and DR eliminate the need for film storage and archiving, since the information is stored electronically and is viewable on any computer. Historic conventional film records can also be digitized and stored as electronic media.