NDT Liquid Penetrant Testing Process 5

Question 1

Why must a penetrant inspector allow their eyes to adapt to darkness before evaluating fluorescent indications?

Accepted Answer

To maximize eye sensitivity to low-level fluorescent light emitted by indications

Answer

Dark adaptation (at least 1 minute) increases the eye's sensitivity to faint fluorescent indications, reducing the chance of missing small discontinuities.

Question 2

What is the primary advantage of using a hydrophilic emulsifier (Method D) over a lipophilic emulsifier (Method B)?

Accepted Answer

Greater process control and reduced risk of over-emulsification

Answer

Hydrophilic emulsifiers are applied as a rinse or spray and are diluted, making the process less sensitive to contact time variations and reducing over-emulsification risk.

Question 3

Which penetrant testing process step is performed IMMEDIATELY before developer application?

Accepted Answer

Excess penetrant removal (washing/wiping)

Answer

Excess penetrant must be removed from the surface before developer is applied; applying developer over excess penetrant would mask indications.

Question 4

A test block (also called a reference block or comparator) is used in liquid penetrant testing primarily to:

Accepted Answer

Verify the performance and sensitivity of the penetrant system in use

Answer

Reference blocks contain controlled discontinuities that allow inspectors to verify the penetrant system is producing acceptable performance prior to and during inspection.

Question 5

When evaluating a penetrant indication, what does a 'ghost' or 'phantom' indication most often indicate?

Accepted Answer

Residual fluorescent penetrant left from a previous incomplete cleaning

Answer

Ghost indications are fluorescent residues from prior inspections or inadequate cleaning that reactivate under developer, not from actual present discontinuities.

NDT - Non-Destructive Testing Practice Test

NDT - Non-Destructive Testing Practice Test

NDT Liquid Penetrant Testing Process 5