NDT Penetrant Testing 2

Question 1

What is the primary purpose of the dwell time in liquid penetrant testing?

Accepted Answer

To allow the penetrant to seep into surface discontinuities by capillary action

Answer

Dwell time allows the penetrant to remain on the surface long enough for capillary action to draw it into any open discontinuities.

Question 2

Which type of penetrant system uses an emulsifier applied after penetrant to make excess penetrant water-washable?

Accepted Answer

Post-emulsifiable penetrant system

Answer

Post-emulsifiable (PE) systems require a separate emulsifier step after penetrant dwell to render the surface penetrant removable with water.

Question 3

According to ASME standards, what is the minimum dwell time for penetrant when testing for lack of fusion in welds at room temperature?

Accepted Answer

10 minutes

Answer

ASME standards typically specify a minimum 10-minute dwell time for most weld discontinuities under standard temperature conditions.

Question 4

What type of discontinuity CANNOT be detected by liquid penetrant testing?

Accepted Answer

Subsurface voids

Answer

LPT relies on capillary action into surface-open discontinuities; subsurface defects with no opening to the surface cannot be detected.

Question 5

What is the function of the developer in liquid penetrant testing?

Accepted Answer

To draw penetrant back out of discontinuities and provide a contrasting background

Answer

Developer acts as a blotter to pull entrapped penetrant out of discontinuities and provides a white background that enhances contrast of the indication.

NDT - Non-Destructive Testing Practice Test

NDT - Non-Destructive Testing Practice Test

NDT Penetrant Testing 2