Nondestructive Examination Methods Flashcards

When performing liquid penetrant testing, what is the purpose of the dwell time?

Answer: To allow the penetrant to seep into surface-breaking discontinuities

Dwell time allows the penetrant to enter surface-breaking discontinuities through capillary action.

Which ultrasonic testing technique uses two separate transducers, one for sending and one for receiving?

Answer: Pitch-catch

The pitch-catch (through-transmission) technique uses separate transmitter and receiver transducers.

In radiographic testing, what does a higher kilovoltage (kV) setting primarily affect?

Answer: Penetrating power of the X-rays

Higher kV increases the energy and penetrating power of X-rays, allowing inspection of thicker materials.

What type of magnetic particle indication appears as a tight, sharp line and is typically associated with a crack?

Answer: Sharp linear indication

Cracks produce sharp, well-defined linear indications because the magnetic flux leakage is concentrated at the tight discontinuity.

An eddy current test is being performed on a non-ferromagnetic tube. Which property does NOT significantly affect the eddy current signal?

Answer: Magnetic permeability

Non-ferromagnetic materials have a relative magnetic permeability of 1, so permeability does not affect eddy current signals in these materials.

In visual testing (VT), a weld convexity that exceeds the allowable limit is best described as:

Answer: Excessive reinforcement

Excessive reinforcement refers to weld bead height that exceeds the code-specified maximum convexity limit.

Which RT artifact appears as a lighter area on the film and may be caused by back-scattered radiation?

Answer: Back scatter

Back scatter from structures behind the film cassette causes a lighter (less dense) area on the radiograph, often appearing as a 'B' marker image.