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Quality and Inspection Process Knowledge
Quality and Inspection Services
Radiography (x-ray) is an NDI method used to inspect material
and components, using the concept of differential adsorption of penetrating
radiation. Each specimen under evaluation will have differences in density,
thickness, shapes, sizes, or absorption characteristics, thus absorbing
different amounts of radiation. The unabsorbed radiation that passes through the
part is recorded on film, fluorescent screens, or other radiation monitors.
Indications of internal and external conditions will appear as variants of
black/white/gray contrasts on exposed film, or variants of color on fluorescent
screens.
LIMITATIONS: Compared to other nondestructive methods of
inspection, radiography is expensive. Relatively large costs and space
allocations are required for a radiographic laboratory. Costs can be reduced
considerably when portable x-ray or gamma-ray sources are used in film
radiography and space is required only for film processing and interpretation.
Operating costs can be high because sometimes as much as 60 percent of the total
inspection time is spent in setting up for radiography. With real-time
radiography, operating costs are usually much lower, because setup times are
shorter and there are no extra costs for processing or interpretation of film.
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