Industrial radiographic testing is an inspection technique based on the exposure to high energy ionizing radiation of radiographic films. The radiation is produced either by industrial grade high energy portable X-ray devices or γ-ray sources such as Ir 192 or Se 75.
The film, once exposed is then processed and fianlly viewed on an illuminated screen for visual interpretation of the image. Radiography gives a permanent record (the exposed film), which is a major advantage of the method and is widely used to detect volumetric flaws (surface and internal). The reliability and interpretive value of radiographic images depend on their sharpness and contrast and this is important for the inspector to detect flaws accurately.
An Image Quality Indicator (IQI) is placed on the part so that its image will be produced on the radiograph and a standard for sharpness and contrast can be determined.
Since strong ionizing radiation is used all national and international legislation related to the use, transportation of radioactive sources are followed and as such special conditions on the use of the method apply. Tests are performed according to ISO 17636, ASME V-2 and ASTM E94.