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Wave User Manual
Version 4
Table 25
–
AWS sizing options
Option
Meaning
Transfer Loss
The Transfer Loss is the gain (dB) to compensate for the difference of
attenuation between a reference standard and the part to be inspected.
AWS C Rounded
It allows you to choose the rounding method for the C parameter (0.1 dB
or 1 dB precision).
The AWS C rounded parameter is a material attenuation factor. It is expressed in terms
of dB. It relates the sound attenuation. It can assume positive or negative values
depending on sound path length (in inches). These values can be rounded to the unit or
decimal according to customer needs.
12.6
API
You are able to perform discontinuity evaluation according to American Petroleum
Institute (API)
Recommended Practice for Ultrasonic Evaluation of Pipe Imperfections by using
the Amplitude Distance Differential Method (ADDM)
, also known as API Recommended
Practice 5UE.
This evaluation method is a combination of amplitude comparison and a 6 dB drop in
echo amplitude to determine the radial depth of a discontinuity. It assumes that radial
depth of a discontinuity affects either the amplitude of the received echo signal and the
differential time of flight of the incident ultrasonic wave as it passes through the
discontinuity.
12.6.1
Perform an API Calibration
To perform calibration, you must have a calibration block with a reference reflector such
as a notch or a side-drilled hole. Couple your probe with your standard block and try to
maximise the echo from the reference reflector. Depending on your range size and the
sound path associated to your reflector, the refracted echo can be located outside of the
reference window. You can move the reference window (forward/backward) through the
A-Scan until it encompasses the echo by just clicking on the touch panel. You can also
enlarge or reduce the window width by directly clicking on the window and then adjusting
it according to your needs. At that point, amplitude echo must show a value between
5%FSH and 100%FSH, and a proper gain setting may take place if necessary. You must
also set the
dr
(the reference reflector diameter) to perform calibration. When the gate is
correctly placed, and the echo amplitude reaches the appropriate value, press
Calibrate
.
Wave will automatically calculate the
API k
factor (a derived factor for calculating depth).
Set the trigger (Gate or API) and then go to the measurements bar to set which values will
be displayed in the top of the screen.
