NDT Magnetic Particle Testing Methods 3

Question 1

What is the key distinguishing characteristic of fluorescent magnetic particles compared to visible (dry) particles?

Accepted Answer

They fluoresce under ultraviolet light, providing higher contrast

Answer

Fluorescent particles contain fluorescent dyes that glow brightly under UV-A (black) light, producing high contrast against the dark background and improving sensitivity.

Question 2

What is the typical UV-A wavelength range required for fluorescent magnetic particle inspection?

Accepted Answer

315–400 nm

Answer

UV-A light in the 315–400 nm range (with peak effectiveness near 365 nm) excites the fluorescent dyes in magnetic particles to produce visible indications.

Question 3

Which carrier liquid is preferred for fluorescent wet magnetic particle testing because it provides better particle mobility?

Accepted Answer

Water-based conditioner

Answer

Water-based conditioners (containing rust inhibitors and wetting agents) are often preferred for fluorescent wet MT because they provide excellent particle mobility and are environmentally friendlier than oil.

Question 4

What minimum ambient visible light level is required at the inspection surface when using fluorescent magnetic particles?

Accepted Answer

Less than 2 foot-candles (20 lux)

Answer

ASTM E1444 requires the ambient white light at the inspection surface to be no greater than 2 foot-candles (20 lux) so fluorescent indications are clearly visible under UV-A light.

Question 5

When should the concentration of fluorescent magnetic particle bath be checked?

Accepted Answer

Before each inspection shift and after replenishment

Answer

Bath concentration should be verified before each inspection shift and after replenishing the bath to ensure consistent sensitivity throughout the inspection process.

NDT - Non-Destructive Testing Practice Test

NDT - Non-Destructive Testing Practice Test

NDT Magnetic Particle Testing Methods 3