1.2.27
Longitudinal Wave Inspection
Ultrasonic technique, normally using straight beam methods, in which
longitudinal waves are the dominant form.
1.2.28
Mid-Screen Reflection
Reflection whose amplitude is equal to one-half the useable screen height
on the CRT.
1.2.29
Megahertz (MHz)
One million hertz per second frequency.
1.2.30
NDT Level I
An NDT Level I individual should be qualified to properly perform specific
calibrations, specific NDT, and specific evaluations for acceptance or
rejection determinations according to written instructions, and to record
results.
1.2.31
NDT Level II
An NDT Level II individual should be qualified to set up and calibrate
equipment and to interpret and evaluate results with respect to applicable
codes, standards, and specifications.
1.2.32
NDT Level III
An NDT Level III individual should be capable of establishing techniques
and procedures; interpreting codes, standards, specifications, and
procedures; and designating the particular NDT methods, techniques, and
procedures to be used.
1.2.33
Node
Distance a shear wave travels in a straight line from the inspection
surface before being reflected by the opposite surface.
1.2.34
Pulse Repetition Rate
Number of spaced pulses of sound per second sent into the material being
inspected.
1.2.35
Range Control
Means of expanding the pattern obtained on the CRT so that any portion of
the total distance being tested can be presented.
1.2.36
Reference Reflector
Standard reflector 1.52 mm 0.06 inch diameter reference hole in the IIW
reference block. Other approved blocks may have a different diameter
reflector.
1.2.37
Reflector
Boundary, consisting of an opposite side, crack, or separation, or a
distinct change in material such as slag or porosity that reflects the
SECTION 05091A
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