NDT - Non-Destructive Testing Liquid Penetrant Testing Process Questions and Answers

Question 1

An NDT technician applies a visible dye penetrant to a non-porous component.
After the appropriate dwell time, the excess penetrant is removed, and a non-aqueous wet developer is applied.
Which of the following is the PRIMARY function of the developer in this process?

Accepted Answer

To act as a blotter, drawing the penetrant out of discontinuities to form a visible indication.

Answer

To chemically react with the penetrant and change its color for better visibility.

Answer

To provide a protective coating over the test surface to prevent contamination.

Answer

To act as a solvent that dissolves the penetrant trapped in discontinuities.

Question 2

A liquid penetrant inspection is being performed on an aluminum casting. Which of the following pre-cleaning methods would be considered detrimental to the inspection's sensitivity because it might close or smear over the very discontinuities the test is designed to find?

Accepted Answer

Grit blasting

Answer

Vapor degreasing

Answer

Wiping with a solvent-moistened lint-free cloth

Answer

Alkaline cleaning

Question 3

When comparing Type I (Fluorescent) and Type II (Visible) liquid penetrant systems, which statement is generally correct regarding their sensitivity?

Accepted Answer

Type I is more sensitive because the human eye is more readily drawn to a glowing indication against a dark background.

Answer

Type II is more sensitive because the red dye has higher contrast under normal light.

Answer

Both types have equivalent sensitivity, and the choice is based only on lighting availability.

Answer

Sensitivity is determined by the removal method (e.g., water-washable vs. solvent-removable), not the dye type.

Question 4

A technician is performing a solvent-removable visible dye penetrant test. During the excess penetrant removal step, the technician sprays the solvent remover directly onto the test surface before wiping. What is the most likely negative consequence of this action?

Accepted Answer

It can flush the penetrant out of shallow discontinuities, leading to missed flaws.

Answer

It will be impossible to apply the developer afterward.

Answer

It will cause the penetrant to dry too quickly, preventing it from entering flaws.

Answer

It will create a chemical reaction that makes the developer non-absorbent.

Question 5

After completing a liquid penetrant inspection and evaluating the results, what is the critical final step in the process before returning the component to service?

Accepted Answer

Post-cleaning the component to remove all inspection materials.

Answer

Applying a second coat of developer to confirm the indications.

Answer

Heating the component to bake the developer into a permanent record.

Answer

Documenting the results, as no further action is needed for the component itself.

Question 6

During a liquid penetrant inspection, an inspector notes a large, fuzzy red indication on the developer. The indication does not have sharp, clear edges. Which of the following is a plausible cause for this type of indication?

Accepted Answer

Excessive penetrant was left on the surface before developer application.

Answer

Insufficient penetrant dwell time was allowed.

Answer

A very fine, tight crack is present.

Answer

The developer was applied too thinly.