Glossary

Radiographic Testing (RT) is a non-destructive testing (NDT) method that uses X-rays or gamma rays to examine the internal structure of a material or component. Just like medical X-rays, this technique produces an image (radiograph) that shows variations in thickness, density, or composition. Defects such as cracks, porosity, voids, inclusions, and incomplete welds appear as differences in contrast or shading on the radiograph, allowing inspectors to identify internal flaws without cutting or damaging the part.

The process involves placing a radiation source (X-ray tube or gamma ray isotope) on one side of the object and a detector or film on the opposite side. As the radiation passes through the material, some of it is absorbed depending on the material’s density and thickness, while the remainder exposes the film or digital detector. Areas with flaws or reduced thickness allow more radiation to pass through, producing darker spots, while denser areas appear lighter. Modern RT often uses digital radiography, which provides faster results and easier image storage compared to traditional film.

Applications: RT is widely used in aerospace, automotive, oil & gas, power generation, and construction to inspect welds, castings, pipelines, and critical structural parts.

Advantages: It provides a permanent visual record of the inspection, can reveal internal and volumetric flaws, and works on a wide range of materials and thicknesses.

Limitations: It requires strict safety precautions due to radiation exposure, can be costly and time-consuming compared to other methods, and may struggle to detect very fine surface defects that ultrasonic or dye penetrant testing would catch.