Is the tested material sound-conductive? In this case, an ultrasonic test would be the first choice in order to detect inhomogeneity and defects within the full volume of the inspected object.
As volume test method, the ultrasonic test benefits from the acoustic reflection and permeability at the interface of various materials. Thereby, the complete quality of pipes, weld seams and cast metal parts, joining plastics can be assured – beyond the examination of the material surface.