Radiography is one of the non-destructive testing methods of parts and components, which is based on the difference in absorption caused by the radiations that have penetrated or in the tested part due to the difference in density and thickness of the parts, or the difference in absorption properties due to the difference in compounds, the absorption of radiation in different parts. The piece is not the same. The unabsorbed rays that pass through the part can be recorded on film or sensitive plates and displayed on a viewer or various electronic image recording equipment.

The word radiography usually evokes the process of photographing and making a permanent image on film or paper. However, in the concept, it refers to all radiographic tests. Neutron radiography is performed using neutron current which is more than electromagnetic radiation.

Industrial radiography is used to identify the characteristics of a part that shows the difference in thickness or physical density compared to the surrounding material. Large differences are easier to detect than small ones. In general, radiography can detect only those changes that have a significant difference in the direction parallel to the radiation. This means that the ability of the process to detect planar discontinuities such as cracks depends on the proper orientation of the part during testing.

Discontinuities such as voids and impurities, which have appreciable thickness in all directions, are easy to find provided they are not too small compared to the thickness of the part. , defects that have a 2% or more absorbance difference compared to the surrounding medium can be identified. The radiographic method is more useful when the defects are not flat.

applications:

Radiography is widely used in the inspection of casting and welding parts. It is also used in electronic circuits and semiconductors to detect cracks, wire breaks, unsoldered connections, foreign materials and component dislocations. The sensitivity of radiography to the types of defects depends on many factors, including the type of material, the type of defect and the production method. All ferrous metals and metals and composites can be radiographed.

Limitations:

Compared to other NDT methods, radiography is more expensive. High costs, need for more space, prevention of safety risks are among the reasons for the high cost of radiography.

Testing parts with high thickness is a very time-consuming process in projects and requires a very strong radioactive source (source) and more protection.

Small cracks in thick sections often cannot be detected, even when properly oriented.

Microdiscontinuities are not detected unless they are sufficiently distinguishable from the microstructure of the material.

Defects of laminations due to improper orientation cannot be detected in radiographs, because radiation absorption by laminations is not enough to create a difference with the surrounding environment.

A high dose of X-rays or gamma rays can damage skin and blood cells or cause blindness and infertility, in large doses it can cause severe disability or death. The protection of personnel, not only those involved in the radiographic work, but also those who are in the vicinity of the radiographic test, is of great importance. Safety requirements are associated with the application of economic, operational, time and environmental restrictions in the use of radiography for testing.