Ultrasonic Testing
Ultrasonic Testing uses sound waves of short
wavelength and high frequency to detect flaws or measure
material thickness. Such mechanical waves can travel
large distances in fine grain metal, in the form of
a divergent wave with progressive attenuation.
Ultrasonic Testing involves pulsed beams of ultrasound.
In the simplest instruments a single probe, hand-held,
is placed on the specimen surface. An oscilloscope
display with a time-base shows the time that it takes
for an ultrasonic pulse to travel to a reflector (a
flaw, the back surface, or other free surface) in
terms of distance across the oscilloscope screen -
the so-called A-scan display. The height of the reflected
pulse during Ultrasonic Testing is related to the
flaw size as seen from the transmitted probe. The
relationship of flaw size, flaw distance and flaw
reflectivity are complex and considerable skill is
required to interpret the display.
It is used to test welds, castings and wrought products
e.g. rolled plate or forgings.
Other Traditional NDT Methods
Radiography
Positive Material Identification
Dye Penetrant Inspection
High Pressure Testing
Magnetic Particle Testing
Visual Inspection
