Ultrasonic Flaw Inspection

A surface examination method

Ultrasound is an excellent technology for the detection of defects in materials because it is extremely sensitive to small changes or discontinuities in the materials. Ultrasonic testing can be used to detect defects such as …

  • Crack – a line on the surface of something along which it has split without breaking into separate parts.
  • Inclusion – a body or particle recognizably distinct from the substance in which it is embedded.
  • Porosity – the quality of being porous, or full of tiny holes.
  • Shrink – become or make smaller in size or amount; contract or cause to contract.
  • Disbonding –  destruction of adhesion between a cathodic coating and its substrate by products of a cathodic reduction reaction.
  • Delamination – mode of failure in materials that can cause layers to separate, forming a mica-like structure of separate layers, with significant loss of mechanical toughness.

 

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KrautKramer USN52 UT Shearwave Unit

In addition, Ultrasonic technology can be used to characterize the defects present in a test piece by enabling the estimation of quantities such as the length of inclusions, crack lengths and depths, percent porosity and the degree of disbonding. Many components lend themselves to ultrasonic testing including castings, forgings, powdered metals, and sprayed coatings. As the technology develops, ultrasound is becoming useful on components of increasingly complex geometry.

UT Shear Wave in lieu of Radiography for Weld Inspection

Radiography is commonly used to inspect welds that are fabricated as per a specific ASME code. Radiography is a reliable method but it has one major limitation; all work in the inspection area has to be stopped and the workers vacated to avoid x-ray exposure. This can impair work progress and delay the job. UT shear wave in lieu of radiography is quite attractive as it does not affect any work being done in the vicinity. Some major companies have chosen UT Phased Array Shear Wave in lieu of Radiography. UT inspection is done strictly as per the applicable code.