Essential Information for Everyone on Industrial Radiography

Industrial radiography is a test method that uses high energy radiation to take an extraordinary view of objects. Radiography is a common medical procedure done to check bone fractures and body organ condition. It is also used in various industrial fields to test materials. It has an important purpose in engineering as it is employed to pin down concealed flaws in materials. High energy radiation used for this particular purpose is x-rays or gamma rays.

Gamma radiation is the most intense of all types of radiation. That is why it is found in the edge of the electromagnetic spectrum. It can penetrate almost anything. Sources of gamma rays used for inspecting various materials are iridium-192 and cobalt-60. This method of testing is often applied in inspection of welds, pressure vessels, pipelines, and high capacity storage vessels. High frequency radiation can be used to inspect any solid material, like ceilings or floors and rectangular containers or cylindrical solids.

Inspection can be carried out in different ways. First is the panoramic approach wherein the source of radiation is at the center of the object being tested. As a result this is only applicable in hollow vessels like tanks and pipes. The film material where the images are recorded shall be installed outside the surface of the test object. This approach can be impracticable at certain situations, such as when the center of the object being tested is difficult to reach.

The second approach is similar to the above method but the radiation source does not have to be placed in the center. The third method places the source of radiation in the exterior, while the fourth approach is applicable for flat objects like metal plates. In all these methods, the radiographic plate records the exposure on the opposite side. There are other methods of exposing objects to radiation but there is no need to elaborate them further in this article. Anyway, the manner of exposing an object depends on its physical attributes.

A radiographic film records the image that shows varying exposures depending on the amount of radiation that reaches each spot of the film and this is generally called a radiograph. The radiograph is retained as a negative image and is not printed as in photography because printing will only cause loss of fine details on the image.

Radiography has no way of indicating external or surface flaws of materials. Dye penetrant inspection will have to be carried out for purposes of identification of surface cracks on materials. Usually, an ocular inspection is done before radiographic exam is done to find out any external defects that will impose a negative impact on the radiographic image. Materials with irregular surfaces should be smoothened first.

Radiography should be carried out in well controlled conditions with adept professionals because this is a delicate operation. The use of gamma radiation or x-rays is extremely dangerous. When mishandled, high energy radiation can lead to serious health consequences and even death.

Radiographic testing is one of the many nondestructive methods of material testing. Other methods are videoscope inspection, PMI, liquid penetrant inspection, and electromagnetic testing.