Radiography NDT (RT)
Radiographic testing uses radiation to spot internal defects in parts. X-rays work well with thinner materials whereas gamma rays are better for thicker materials.
The specimen is placed between the radiation source and a recording media. When the radiation falls on the part, the amount of radiation that exits the part in different locations is captured. A physical radiography film or a digital detector is used as the recording media.
The test allows us to obtain the shape and size of internal defects by changing the angle of radiation exposure.
We can use radiographic testing to pinpoint defects such as cracks, thinning, corrosion, voids, insufficient fusion, porosity, excess root penetration and laps.
Advantages of radiographic testing:
- Can test complex structures
- Documentation is permanent
- Works with a range of materials
- Needs minimum surface preparation
- Can record surface and subsurface defects
- Portability is possible for gamma ray testing
- Less misinterpretation of results compared to other methods
Disadvantages of radiographic testing:
- More expensive
- Needs two-sided access to specimen
- Not as effective for planar and surface defects
- High voltage and radiation can be harmful to personnel
- Skilled personnel needed for execution and accurate interpretation of results