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6.3 AVG Function
6.3.1 Summarize
In ultrasonic flaw detection, the shape, nature and direction of natural flaws are
different from each other, flaws with same echoes amplitude actually differ greatly,
thus introduce “equivalent size” to evaluate flaws size. Under same detect
condition, if the echo amplitude of natural flaw equal to that of regularly shaped
artificial flaw, the artificial flaw size is defined as the natural flaw equivalent size.
The curve used for describing relations among distance, amplitude and equivalent
size of regular reflector is called distance-amplitude-equivalent size curve, in
German called AVG, in English called DGS.
6.3.2 AVG Making
Operating Steps: (taking 2.5P20 normal probe, CS-1-5 test block, 200¢2 flat
bottom hole as an example).
(1) Set instrument and probe parameters;
(2) Calibrate instrument and probe;
(3) Make the probe tightly coupled on the CS-1-5 block, move probe to seek the
highest echo of flat bottom hole, refer to Figure 6-12;
(4) Enter AVG menu, adjust aperture to 2mm, equivalent of reference curve can
be set according to requirement (here take 1mm for example). Move gate A to
capture flat bottom hole echo, select "COMPLETE", then press [+] key to
confirm AVG making. Refer to Figure 6-13.
Figure 6-12 the Making Diagram of AVG Figure 6-13 AVG Waveform Display
225mm
25mm
