AUT uses conventional and specialized transducers to introduce sound in the test materials. These transducers are mounted to automated robotic crawlers, which articulate to cover large areas of the vessel or piping surface. The data collected is then displayed in color in multiple A-Scan, B-Scan, C-Scan and D-Scan images.
A-scan representation is the view in which the signal amplitude is shown as a vertical excursion from the horizontal sweep time trace.
The B-scan and D-scan presentations are two-dimensional views of cross-sectional planes through the test object on different axis. This imaging is helpful in distinguishing mid-wall inclusions such as laminations and blistering, from back-wall discontinuities like erosion and corrosion.
The C-scan image is a two-dimensional plan view of the object. Indication of depth is color coded to provide the image with qualities, which resemble a topographical map viewed from the inspecting surface. |
