Bulk Wave Electro Magnetic Acoustic Transducer (EMAT) Inspections

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IRISNDT uses EMAT bulk waves to track piping metal losses while the part is in service at high temperature (up to 650 oC (1200 oF)). This non-contact method does not need a couplant. It can inspect through coatings, and needs minimal (if any) surface preparation. EMAT can generate longitudinal or shear waves to assess thickness. IRISNDT operators integrate different sets of magnets and radio frequency (RF) coils to obtain thickness measurements at various ranges.


  • Dry (no couplant) thickness measurement applications
  • Internal thinning wall measurements i.e. sulfidation corrosion


  • Measures the thickness of parts up to 127 mm (5 inch)
  • Does not need wedges and couplant, making the inspection easy and fast
  • Is less sensitive to surface conditions such as dirt or coating than traditional ultrasound tests
  • Can display A, B, and C-scans
  • Implements changes in sound velocity to correct for temperature changes


  • Can only be used for thickness spot checks
  • Surface preparation might be needed if external corrosion/pits are present; rough surfaces can impede good sound transmission by attenuating the signal
  • The insulation must be removed at the test location
  • If the surface where the EMAT probe is placed has external corrosion/pits, it must be ground flat

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Learn more about how IRISNDT applies Advanced Ultrasonic Inspection Techniques Electromagnetic Acoustic Transducers (EMAT)