Six Most Common NDT
Methods:
•
Visual
•
Liquid Penetrant
•
Magnetic
•
Ultrasonic
•
Eddy Current
•
X-ray
Visual Inspection:
This is the most basic and common inspection method. Visual inspection tools
include magnifying glasses mirrors fiberscopes, and borescopes. Portable video
inspection unit with zoom allows inspection of large tanks and vessels etc. Robotic
crawlers permit observation in hazardous or tight areas, such as air ducts,
reactors, pipelines.
Liquid Penetrant Inspection:
•
A liquid with high surface wetting
characteristics is applied to the surface of the part and allowed time to seep
into surface breaking defects.
•
The excess liquid is removed from
the surface of the part.
•
A developer (powder) is applied to
pull the trapped Penetrant out the defect and spread it on the surface where it
can be seen.
•
Visual inspection is the final step
in the process. The Penetrant used is
sometimes is a fluorescent dye and the inspection is done under UV light to
increase test sensitivity.
