The length of weld under examination for each exposure shall be such that the thickness of the material at the diagnostic extremities, measured in the direction of the incident beam, does not exceed the actual thickness at that point by more than 6%. The beam of radiation must be directed to the middle of the section under examination and must be normal to the material surface at that point, except in special techniques where known defects are best revealed by a different alignment of the beam. Theoretically, industrial radiographers could radiograph any solid, flat material (walls, ceilings, floors, square or rectangular containers) or any hollow cylindrical or spherical object. Non-metal components such as ceramics used in the aerospace industries are also regularly tested.
Other tested materials include concrete (locating rebar or conduit), welder's test coupons, machined parts, plate metal, or pipewall (locating anomalies due to corrosion or mechanical damage). The vast majority of radiography concerns the testing and grading of welds on pressurized piping, pressure vessels, high-capacity storage containers, pipelines, and some structural welds. Gamma radiation sources, most commonly iridium-192 and cobalt-60, are used to inspect a variety of materials.
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After World War II new isotopes such as caesium-137, iridium-192 and cobalt-60 became available for industrial radiography, and the use of radium and radon decreased.Ī portable wireless controlled battery powered X-ray generator for use in non-destructive testing and security. X-rays and gamma rays were put to use very early, before the dangers of ionizing radiation were discovered. Soon these found various applications, with one of the earliest users being Loughborough College. By using radioactive sources such as radium, far higher photon energies could be obtained than those from normal X-ray generators. Soon after the discovery of X-rays, radioactivity was discovered. Radiography started in 1895 with the discovery of X-rays (later also called Röntgen rays after the man who first described their properties in detail), a type of electromagnetic radiation.
It is also possible to perform tomography nearly in real time ( 4-dimensionnal computed tomography or 4DCT). The examination can be performed in static 2D (named radiography), in real time 2D ( fluoroscopy), or in 3D after image reconstruction ( computed tomography or CT). After crossing the specimen, photons are captured by a detector, such as a silver halide film, a phosphor plate, flat panel detector or CdTe detector.
Industrial Radiography uses either X-rays, produced with X-ray generators, or gamma rays generated by the natural radioactivity of sealed radionuclide sources. It plays an important role in the science and technology needed to ensure product quality and reliability. Industrial radiography is a modality of non-destructive testing that uses ionizing radiation to inspect materials and components with the objective of locating and quantifying defects and degradation in material properties that would lead to the failure of engineering structures.
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