What is Ultrasonic Thickness Testing?

May 10, 2021

Ultrasonic thickness testing is a commonly used nondestructive testing method for determining the wall thickness of a solid element, this is useful for determining the level of corrosion and thinning that has occurred on a vessels surface.

Ultrasonic thickness testing works by in the same way that a medical ultrasound would, it pulses ultra-high frequency sound waves through the test piece. Because sounds waves travel through metals and other solids at an almost constant speed, (some things that may affect the speed of sound included the temperature and other factors, however the impact of these is only minor) the thickness of that material can be calculated by timing how long it takes for the sound to be reflected back to its source. The sound waves used in this process are such high frequency that they cannot be heard by humans.

Some things that make ultrasonic testing advantageous over other methods, are:

  • It’s Non-Destructive
  • Only require access to one side of the test piece.
  • Equipment is portable
  • Cheap to perform
  • Good accuracy, in real word conditions.
  • Can be performed over paint, coatings, and linings.

Due to the variable speed of sound in each material, every different material that requires ultrasonic thickness testing requires calibration of the thickness gauge. Because of the calibration requirements, and the technical requirements of the interpretation of results its always best to have experienced technicians perform ultrasonic thickness testing.

Rapallo has a team of highly skilled NDT technicians that have decades of experience interpreting the results of UT, and other NDT methods, contact us for further information on the science behind MPI or to get a quote on any of our NDT services.  




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