Phased Array Ultrasonic Testing (PAUT)

Phased Array is universally capable of assessing almost any damage mechanism where conventional ultrasonic flaw detectors have been used.  Weld inspection and crack detection are common applications, and these tests are done across a wide range of industries including oil and gas, petrochemical plants, power generation and chemical industries, especially for the construction of new piping, pipelines, vessels and structural welded materials.  Phased Array can also be effectively used to profile remaining wall thickness in corrosion survey applications when surface condition and part geometry allows.

A Phased Array probe is made up of multiple small ultrasonic element, each of which can be pulsed individually. By varying the timing of the pulse of each individual element, the ultrasonic beam can be ‘steered’ to a specific angle and focal distance – i.e. a number of beams can be swept through the examined object.

Applications for Phased Array:

  • Weld inspection
  • Volumetric inspection of forging or casting materials
  • Erosion and corrosion mapping

Flaws that Phased Array can detect:

  • Weld flaws such as lack of fusion, slag inclusions, porosity, surface connected and embedded cracks, and incomplete penetration
  • Erosion or corrosion – pitting, material loss and root erosion
  • Inherent discontinuities in forged or casting materials such as laminations, forging bursts, cold shuts, hot tears and inclusions
  • Environmentally or process induced damage such as Microbiologically-Influenced Corrosion (MIC), Hydrogen Induced Cracking (HIC), thermal fatigue cracking, caustic cracking and stress corrosion cracking

There are a multitude of phased array benefits due to its universal capability to perform so many inspection tasks.  Here are some advantages of Phased Array:

  • Information can be displayed in multiple display formats (examples below), which help in more accurate interpretation of flaws.
    • 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
    • S-Scan displays an end view of the specimen at the current position of the probe
  • The data can also be captured and stored so it can be reviewed by the inspector and used for future reference and inspections.
  • The replayed data can be processed and displayed in various ways using the instrument used to acquire the data or on analysis software that provides additional processing capabilities.


Limitations of Phased Array:

  • Accessibility to a clean smooth surface
  • Material of piece being scanned.  Course grained materials and exotic allows can attenuate Phased Array UT energy the same way it will attenuate conventional UT energy and cause limitations to the inspection.

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XCEL NDT Inspection Services

With offices geographically located throughout the central United States, XCEL NDT is ready to service your NDT needs.