What Is Phased Array Ultrasonic Testing?
Phased Array Ultrasonic Testing (PAUT) uses a multi-element transducer array in which
individual elements are excited with precisely controlled time delays. These delays steer and
focus the ultrasonic beam electronically — without moving the probe — enabling a single PAUT
scanner to generate multiple beam angles, focal depths, and scan modes in a single pass.
The result is a significant advancement over conventional single-element UT: broader angular
coverage, electronic focusing at multiple depths, real-time multi-view imaging (A-scan, S-scan,
B-scan, and C-scan simultaneously), and the ability to address complex geometries that would
require multiple probe positions under conventional UT procedures.
Key PAUT imaging modes:
- S-scan (Sectorial scan): Fan-shaped sweep through a defined angular range — the
standard imaging view for weld inspection, showing the full weld cross-section in a single
image
- E-scan (Electronic scan / Linear scan): Sequential firing of a fixed-angle beam along the
array aperture — equivalent to multiple single-element probes in a single pass
- B-scan: Cross-sectional depth view along the scan axis — used for corrosion mapping and
thickness profiling
- C-scan: Top-view amplitude or time-of-flight map — used for corrosion mapping and
composite inspection