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Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

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C.3 Pattern 3b<br />

Oblique incidence, travelling echo pattern, figure C.3 b At any probe position,<br />

the A-scan shows an extended train of signals (subsidiary peaks) within a<br />

bell-shaped pulse envelope. As the probe is moved each subsidiary peak<br />

travels through the pulse envelop, rising to its own maximum toward the<br />

center envelop and then falling. The overall signal may shown large (>+/-6dB)<br />

random fluctuation in amplitude.

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