Ultrasonic inspection is a
nondestructive method in which beams of high-frequency sound waves are
introduced into materials for the detection of subsurface flaws in the
material. The sound waves travel through the material with some attendant loss
of energy (attenuation) and are reflected at interfaces (cracks or flaws). The
reflected beam is displayed and then analyzed to define the presence and
location of flaws or discontinuities.
The most commonly used ultrasonic
testing technique is pulse echo, wherein sound is introduced into a test object
and reflections (echoes) are returned to a receiver from internal imperfections
or from the part's geometrical surfaces. Applications include inspections for voids,
cracks, and laminations, inspections of welds and thickness measurements.