Ultrasonic methods of non destructive testing use beams of mechanical waves of short wavelength and high frequency, transmitted from a probe and detected by the same or other probes. An oscilloscope display with a time base shows the time it takes for a ultrasonic pulse to travel to a reflector (a flaw, the back surface or other free surface) in terms of distance travelled across the oscilloscope screen. The height of the reflected pulse is related pulse is related to the flaw size as seen from the transmitter probe. The relationship of flaw size, distance and reflectivity are complex, and a considerable skill is required to interpret the display.

Ultrasonic examination is utilized as a non-destructive testing method to carry out a wide variety of testing tasks enabling Victor Aviation technicians to conduct internal material defect examinations and make measurements of a component. The testing process may be performed in an immersion tank or on the surface of the material to be examined using a couplant and piezoelectric sensors. For applications where a couplant is not desired we use electromagnetic acoustic transmission using EMAT sensors which require no couplant.

C-Scan Presentation

C-scan presentations provide a plan-type view of the location and size of test specimen features. The plane of the image is parallel to the scan pattern of the transducer. C-scan presentations are produced with an automated data acquisition system, such as a computer controlled immersion scanning system. Typically, a data collection gate is established on the A-scan and the amplitude or the time-of-flight of the signal is recorded at regular intervals as the transducer is scanned over the test piece. The relative signal amplitude or the time-of-flight is displayed as a shade of gray or a color for each of the positions where data was recorded. The C-scan presentation provides an image of the features that reflect and scatter the sound within and on the surfaces of the test piece.