For conducting effective tests, how should the sound beam contact a discontinuity?

For conducting effective tests in ultrasonic testing, the sound beam should ideally contact the discontinuity perpendicularly. This orientation allows for the maximum transfer of ultrasonic energy into the discontinuity, leading to better reflection and detection of the flaw. When the beam strikes the discontinuity at a perpendicular angle, the reflection is stronger and more easily interpretable on the display. This enhances the sensitivity and reliability of the test results, making it far more likely to identify and evaluate the nature of the discontinuity.

In contrast, if the sound beam strikes the discontinuity at an angle or incidental contact, it may result in reduced reflection and potentially missed or misleading measurements. An angle may cause some of the sound energy to reflect away from the receiver, which can lead to underreporting of flaws or errors in sizing them. Therefore, ensuring the sound beam's perpendicular contact with the discontinuity is fundamental for accurate and reliable ultrasonic inspections.