What adjustment must be made to evaluate discontinuities oriented at an angle to the entry surface?

To evaluate discontinuities that are oriented at an angle to the entry surface, angulating the search unit is essential. This adjustment allows the ultrasonic waves to be directed at the correct angle to effectively interact with the discontinuities, enhancing the likelihood of detecting them. Angulation changes the path of the sound waves, optimizing their interaction with the material and helping to produce a more accurate representation of any flaws present.

Proper angulation can help determine the characteristics of the discontinuities, such as their size and shape, which may be missed if the transducer is aimed directly at the material without adjustment. This technique is particularly important because many defects are not perpendicular to the surface, and without angling the search unit, the detection capability may be significantly reduced.

While other adjustments, like changing the frequency, increasing gain, or adjusting pulse width might impact the sensitivity or clarity of the signals, they do not directly address the need for optimal wave orientation to effectively interrogate angled discontinuities.