Materials Engineering, Evaluation, and Inspection

Radiography



Spectrum uses radiography to detect volumetric flaws such as voids, gas pores and solid inclusions while ascertaining the nature and dimensions of such defects in a broad range of materials, sizes, and shapes.

Radiography is a nondestructive technology that employs X-ray and Gamma ray beams to detect internal imperfections, wall thickness and corrosion. Test material is exposed to a uniform ray from a radioactive isotope or an X-ray generator while a special film medium is placed on the opposite side of the component being examined. Upon development of the film, thickness and density disparities appear as gradients of black. To interpret radiographic film, technicians must be knowledgeable not only about welding and welding imperfections, but also about whether or not detected discontinuities are in fact defects.

Radiography can be utilized for most metallic as well as non-metallic materials. Typical test subjects include weld and weld overlays, castings, forgings, valves and their components, machined parts, pressure vessels, and structural steel. Radiographic film represents an easily observed, enduring record of the tested component.

Radiographic film images are two-dimensional, so determining the depth of a discontinuity may require additional tests. The thickness of the component to be examined informs the choice of radiation source. For example, Cobalt 60 gamma radiography can penetrate approximately 23 centimetres, or 9 inches, into carbon steel. Portable X-ray tubes are able to penetrate up to 4 centimetres, or 1.5 inches, of carbon steel. Fixed facility X-ray generators are normally used for thicker material.

Due to potential radiation hazards, Spectrum adheres to strict federal and provincial regulations regarding radiography, including removal of personnel and sensitive equipment from the test area. Our well trained and highly qualified technicians have a reputation for making safety a number one priority.


Radiography Neutron


Applications

  • Metals, non-metals, composites and mixed materials
  • Used on pyrotechnics, resins, plastics, organic material, honeycomb structures, radioactive material, high density materials, and materials containing hydrogen

Limitations

  • Access for placing test piece between source and detectors
  • Size of neutron source housing is very large (reactors) for reasonable source strengths
  • Collimating, filtering or otherwise modifying beam is difficult
  • Radiation hazards
  • Cracks must be oriented parallel to beam for detection
  • Sensitivity decreases with increasing thickness


Radiography X-Ray


Applications

  • Metals, non-metals, composites and mixed materials
  • Used on all shapes and forms; castings, welds, electronic assemblies, aerospace, marine and automotive components

Limitations

  • Access to both sides of test piece needed
  • Voltage, focal spot size and exposure time critical
  • Radiation hazards
  • Cracks must be oriented parallel to beam for detection
  • Sensitivity decreases with increasing thickness


Radiography Gamma


Applications

  • Usually used on dense or thick material
  • Used on all shapes and forms; castings, welds, electronic assemblies, aerospace, marine and automotive components
  • Used where thickness or access limits X-ray generators

Limitations

  • Radiation hazards
  • Cracks must be oriented parallel to beam for detection
  • Sensitivity decreases with increasing thickness
  • Access to both sides of test piece needed
  • Not as sensitive as X-rays


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