9.3 B-scan
The single value B-scan display presentation that was described in Section 3.5 can be used to profile the inner surface of a part, as in corrosion inspections, or to plot the relative depth of laminar flaws. As noted earlier, a single value B-scan plots the depth of reflectors with respect to position as the transducer is moved across the test piece. The position tracking is typically done through the use of electromechanical devices known as encoders. These encoders are used in fixtures which are either manually scanned, or in automated systems that move the transducer by a programmable motor-controlled scanner.
The example below shows the depth profile of a reference block that contains a number of drilled holes and corroded spots. The display shows the current A-scan, the scanned profile, and the current thickness reading. Single value B-scans can typically be stored and played back for later analysis.
