The purpose of an ultrasonic inspection is to identify flaws in materials and to measure the thickness of objects. Inspection may be manual or automated and is essential when the material is difficult to inspect visually. The most commonly used ultrasonic testing technique is pulse echo wherein sound is emitted into the test object and echoes are returned to a receiver from internal imperfections or from geometrical surfaces of the part.

One of the more common uses of this NDT technology is weld inspection on pipelines, where ultrasound is particularly adept at locating areas where the weld is not deep enough or fully complete.