Traditional Ultrasonic inspection uses high frequency sound energy to conduct examinations and perform measurements. Considerable information may be gathered during ultrasonic testing such as the presence of discontinuities, material or coating thickness. The detection and location of discontinuities is enabled by the interpretation of ultrasonic wave reflections generated by a transducer. These waves are introduced into a material and travel in a straight line and at a constant speed until they encounter a surface. The surface interface causes some of the wave energy to be reflected and the rest of it to be transmitted. The amount of reflected vs. transmitted energy is detected and provides information on the size of the reflector, & therefore the discontinuity encountered.

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Some of the most common Ultrasonic applications are:

  • Flaw detection (cracks, inclusions, porosity, delaminations etc.)
  • Erosion/Corrosion thickness gauging
  • Assessment of bond integrity
  • Estimation of grain size in metals
  • Estimation of void content in composites and plastics
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Info from ultrasonic inspection can be presented in a number of formats:

  • A-Scan displays the amount of received ultrasonic energy as a function of time
  • B-Scan displays a profile view (cross-sectional) of a specimen
  • C-Scan displays a plan type view of the specimen & discontinuities
  • Hybrid/Stitched displays a C-Scan plan view with A and/or B Scan views along with C-Scan views that have been woven together to illustrate a clearer picture of the damaged areas of a specimen. The stitched views are used for larger specimens & surface areas.

Some of the major advantages of ultrasonic testing are:

  • Detects surface and subsurface defects
  • Depth of penetration vs. other test methods is superior
  • Only single sided access is required with a pulse-echo technique
  • High accuracy regarding estimating discontinuity size and shape
  • Minimal specimen preparation is required
  • Instantaneous results produced by using electronic equipment
  • Detailed images can be produced with automated systems
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