NDT Liquid Penetrant Testing Process 2

Question 1

What is the minimum dwell time typically required for liquid penetrant to enter a tight fatigue crack in steel at room temperature?

Accepted Answer

5 minutes

Answer

A minimum of 5 minutes dwell time is typically required for penetrant to enter tight fatigue cracks in steel at room temperature.

Question 2

Which surface condition would MOST adversely affect the quality of a liquid penetrant test?

Accepted Answer

A thin oil film covering the part

Answer

An oil film blocks penetrant from entering discontinuities, making pre-cleaning the most critical preparatory step.

Question 3

After applying a water-washable penetrant, what is the danger of over-washing the part?

Accepted Answer

Penetrant trapped in discontinuities may be removed, causing false-negative indications

Answer

Over-washing can remove penetrant from shallow or wide-open discontinuities, causing relevant indications to be missed.

Question 4

A Type II penetrant system uses which fluorescent agent characteristic?

Accepted Answer

Dye that is visible only under UV-A (black) light

Answer

Type II penetrants contain fluorescent dye that glows under UV-A (ultraviolet) light, providing high contrast against the dark inspection background.

Question 5

What is the purpose of a non-aqueous wet developer in liquid penetrant testing?

Accepted Answer

To draw penetrant out of discontinuities and provide a contrasting background

Answer

Non-aqueous wet developer uses a carrier solvent that evaporates, leaving a white powder coating that draws penetrant out and creates contrast.

NDT - Non-Destructive Testing Practice Test