Phased Array Ultrasonic Testing is the present and future of NDT which is an advanced technique of Ultrasonic testing. It utilizes a set of probes made up of small ultrasonic transducer elements, each of which is pulsed individually with computer-calculated timing. The term ‘phased’ refers to the timing, and the term ‘array’ refers to the multiple elements. It creates ultrasound beams that can be steered, scanned, swept, and focused electronically for fast inspection. This technique is used to detect flaws that cannot be easily found with conventional non-destructive testing methods such as radiography. It is often also combined with TOFD (time-of-flight diffraction) since the modern acquisition units and scanners can accommodate both methods simultaneously, which many codes allow for the substitute of Radiography.
PAUT can be done manually, in semi-automated or a fully automated mode. PAUT is able to create detailed and accurate cross-sections of a part. It is also particularly useful in situations where there is less room for mechanical scanning because it’s able to sweep the beam without moving the probe. Results are immediate, can be viewed as well as emailed for further analysis.
Applications
High-speed inspection using single-axis scans instead of conventional raster scan
Inspection of highly complex geometry components
Small, simple probe assembly with multiple beams from a single probe
Better detection in austenitic materials and dissimilar metal (DM) welds
Imaging and recordable data in manageable file sizes viewable by all parties as needed.
Can be used in lieu of Radiography with no safety hazards
Advantages
Volumetric inspection of forging or casting materials
Weld inspection of vessels, pipelines and plates
Weld inspection of complex geometries, such as nozzle-welds
Erosion and Corrosion mapping
Code case inspection in combination with Time of Flight Diffraction (TOFD)
Codes and Standards
ASME Boiler and Pressure Vessel Code, Section V, Article 4, Mandatory appendices IV, V, Non mandatory Appendix P
EN 16018, Non-destructive testing – Terminology – Terms used in ultrasonic testing with phased arrays
ISO/WD 13588, Non-destructive testing of welds – Ultrasonic testing – Use of (semi-) automated phased array technology
ASTM, E2700 Contact Ultrasonic Testing of Welds using Phased Arrays
ASTM, E2491 Evaluating Phased Array Characteristics of Phased Array Ultrasonic Testing Instruments and Systems