Radiographic Testing (RT) is a volumetric method that uses ionizing radiation to form images that can be used to determine quality, assess damage or simply gather information. Conventional RT using film continues to be a mainstay in the construction of pipelines, vessels, tanks and facilities.
Radiographic Testing (RT) has long been the go-to method for determining the acceptability of welds in pipelines, pressure vessels, tanks and castings. RT is typically performed using either X-Ray or Gamma ray as the source of penetrating radiation. Both sources produce electromagnetic radiation, with energy and intensity being a variable. Material type, thickness, and shooting technique are factors in determining the type of source to be used.
Applications for Radiography:
Examination of welds, castings, forgings, and composites
Corrosion detection and the measurement of wall thickness (profile radiography)
Advantages of Radiography:
Utilized for examination of a wide variety of material types
Is sensitive to evident changes in thickness caused by corrosion/erosion, voids in material, certain weld flaws and to material density changes
Detects both surface and subsurface defects
Creates permanent record of the inspection
Limitations of Radiography:
Safety precautions are required for the safe use of radiation
Access to both sides of the specimen is required
Orientation of the test piece and certain flaws is critical
Requires several steps to produce final, interpretable radiograph