Radiographic testing is a volumetric non-destructive testing method based on the absorption of ionising radiation by matter.
The technique consists of placing the sample between the radiation source and a sensitive film. The radiation that spreads through the sample is more or less absorbed, depending on the density of the material it encounters. The residual radiation that has passed through the material irradiates the film which, once developed, can be interpreted to highlight certain compactness defects of the component.
The processing depends on many factors (quality of the film, type of isotope, activity of the radioactive source, nature and thickness of the examined material) and requires safety conditions for the operator and the environment. Radiography makes it possible to check: welding, pipe corrosion, the structure of composite materials, cracks, blows, porosities, shrinkage in mechanical parts.
X-rays in non-destructive testing are obtained from an X-ray device. This radiation gives a very sharp image, but the equipment is, in addition to the dependence on a power source, relatively bulky and vulnerable. It does not lend itself very well to on-the-spot checks.
Gamma radiation is obtained from a artificial radioactive isotope (Selenium 75). These sources are autonomous and do not require power, unlike the X-ray device.
Gammagraphy is similar to X-rays, but the image quality is slightly less good. The main advantage lies in the energy of the radiation, which allows better penetration than X-rays and the greater compactness of the radiation generator. The machines containing the isotopes (gamma radiators) make it easier to use them on site.
For special applications such as pipelines, Apragaz can use a Crawler, a wheeled RX unit that goes from weld to weld within the pipeline.
Finally, if the safety requirements do not allow X-rays to be taken on your site, we make our bunker or RX box available to carry out the examinations in our facilities.
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