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Optimizing Probe Active Aperture for Phased Array Weld Inspections

Phased array ultrasonic testing (PAUT) has become a popular nondestructive technique for weld inspections in piping, pressure vessels, and other components such as turbines. This technique can be used both in manual and automated modes. PAUT is more attractive than conventional angle-beam ultrasonic testing (UT), as it sweeps the beam through a range of angles and presents a cross-sectional image of the area of interest. Other displays are also available depending on the software. Unlike traditional A-scan instruments, which require the reconstruction of B- and C-scan images from raster scanning, a phased array image is much simpler to produce from line scans and easier to interpret. Engineering codes have incorporated phased array technology and provide steps for standardization, scanning, and alternate acceptance criteria based on fracture mechanics. The basis of fracture mechanics is accurate defect sizing. There is, however, no guidance in codes and standards on the selection and setup of phased array probes for accurate sizing. Just like conventional probes, phased array probes have a beam spread that depends on the probe’s active aperture and frequency. Smaller phased array probes, when used for thicker sections, result in poor focusing, large beam spread, and poor discontinuity definition. This means low resolution and oversizing. Accurate sizing for fracture mechanics acceptance criteria requires probes with high resolution. In this paper, guidance is provided for the selection of phased array probes and setup parameters to improve resolution, definition, and sizing of discontinuities.



ASME, 2020, “Use of Alternative Ultrasonic Acceptance Criteria,” ASME Code for Pressure Piping, Section B31.3, Appendix R, American Society of Mechanical Engineers, New York, NY, pp. 477–479

Birring, A., 2010, “Sizing Discontinuities by Ultrasonics,” Materials Evaluation, Vol. 68, No. 11, pp. 1208–1215

Birring, A., 2014, “Ultrasonic Inspection of Welds in Corrosion Resistant Alloy Piping,” Materials Evaluation, Vol. 72, No. 12, pp. 1468–1474

Birring, A., 2020a, “Application of Phased Arrays for Corrosion Resistant Alloy (CRA) Welds,” Journal, e-Journal of Nondestructive Testing, Vol. 25, No. 5

Birring, A., 2020b, “TOFD Principle, Limitations, Calibration and Inspection,” Journal, e-Journal of Nondestructive Testing, Vol. 25, No. 6

Broek, D.,2012, Elementary Engineering Fracture Mechanics, 4th ed., Kluwer Academic Publishers, London, Dordrecht, Netherlands

BSI, 2019, BS 7910: Guide to Methods for Assessing the Acceptability of Flaws in Metallic Structures, British Standards Institution, London, UK

Ginzel, E., A.G. Ekhlas, M. Matheson, P. Cyr, and B. Brown, 2014, “Near Field length Compensation Options,” Journal, e-Journal of Nondestructive Testing, Vol. 19, No. 6

Krautkrämer, J., and H. Krautkrämer, 1990, Ultrasonic Testing of Materials, 4th ed., Springer-Verlag Berlin Heidelberg New York


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