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Ultrasonic Testing Flashcards

7 cards from real NDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Ultrasonic Testing flashcards as text

  1. What is the significance of the 'acoustic impedance mismatch' at a material interface?

    Answer: It controls the proportion of sound energy reflected versus transmitted at the interface

    The greater the acoustic impedance mismatch between two materials, the higher the percentage of sound energy reflected at the interface rather than transmitted through it.

  2. In phased array ultrasonic testing (PAUT), what enables steering of the beam without physically moving the probe?

    Answer: Electronic time delays applied to individual array elements

    PAUT steers and focuses the beam by applying precisely calculated electronic time delays to fire individual array elements in a controlled sequence.

  3. Which type of wave travels along the surface of a material and is useful for detecting shallow surface-breaking flaws?

    Answer: Surface (Rayleigh) wave

    Rayleigh (surface) waves travel along the material surface with particle motion that is elliptical, making them sensitive to surface and near-surface discontinuities.

  4. What does 'DAC' stand for in ultrasonic testing, and what is its purpose?

    Answer: Distance Amplitude Correction — compensates for signal loss with increasing sound path distance

    Distance Amplitude Correction (DAC) is a reference curve that accounts for natural signal amplitude decrease with increasing depth, enabling consistent flaw evaluation at all depths.

  5. When calibrating an angle beam transducer using an IIW block, which feature is used to set the beam index point (BIP)?

    Answer: The 50 mm radius curved surface

    The 100 mm (or 50 mm) radius curved surface of the IIW block is used to locate the beam exit point (BIP) by maximizing the reflection from the curved surface.

  6. In time-of-flight diffraction (TOFD) ultrasonic testing, what signals are used to detect and size flaws?

    Answer: Diffracted signals from the tips of a flaw

    TOFD detects and sizes flaws using diffracted signals from flaw tips; the time difference between upper and lower tip diffractions is used to calculate flaw height.

  7. Which factor causes 'mode conversion' when an ultrasonic beam strikes an interface at an angle?

    Answer: The change in wave velocity between the two media causing the beam to split into different wave modes

    Mode conversion occurs when a wave strikes an interface at an angle, causing some energy to convert from longitudinal to shear wave (or vice versa) due to velocity differences.