Scanning is to be done from one side of the weld prep plate using a 45 probe. You are to scan an unground 50mm thick butt weld from one side of the weld only. The plate is 20mm thick and full volumetric coverage of the weld plus 20mm heat affected zone is needed. Weld face is 20mm wide. A ragged, cluster of individual spikes is located and determined to be a defect.
Sound path varies, amplitudes vary with rotation and orbiting with the probe.
But the defect does not drop off completely when orbited. A sharp narrow defect signal is located during a standard A-scan of a weld. Rotation and orbit of the defect cause it to drop off quickly with lateral probe motion the signal remains constant in both amplitude and sound path. Given a butt weld in a 55mm thick plate, ground flush, you locate a large sharp narrow reflector with a soundpath of 154mm and exit point 128mm from the weld centreline using a 45 probe. Rolf Diederichs 1.