Special Testing Problems References Chapter Separate Page Ultrasonic Testing of Pipeline Girth Welds Systems Basics Transducers Gated Information Surface Preparation Requirements Calibration Calibration Charts Evaluation of Signals Schematic Representation of GMAW discontinuities. The Schematic illustrates the main discontinuities found in GMAW welded joints. This correspondence programme has been provided since 1984. Introduction One of the largest applications of ultrasonic testing in NDT is weld inspection.
Techniques vary due to weld material, weld thickness, weld process and even code requirements.
The greater refracted angles used for thinner welds can veritably flood the piece with sound. Surface waves, mode conversions off lobes, divergence and near zone effects can all provide misleading signals. An ultrasonic technique for weld inspection should investigate the total weld volume plus a region either side of the weld considered to be the heat affected zone. When geometry permits, the weld should be inspected from at least two sides. A normal beam scan is usually performed over the metal on which the shear wave probe will traverse.