Magnetic Particle Testing Methods Flashcards
7 cards from real NDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Magnetic Particle Testing Methods flashcards as text
What is the key distinguishing characteristic of fluorescent magnetic particles compared to visible (dry) particles?
Answer: They fluoresce under ultraviolet light, providing higher contrast
Fluorescent particles contain fluorescent dyes that glow brightly under UV-A (black) light, producing high contrast against the dark background and improving sensitivity.
What is the typical UV-A wavelength range required for fluorescent magnetic particle inspection?
Answer: 315–400 nm
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.
Which carrier liquid is preferred for fluorescent wet magnetic particle testing because it provides better particle mobility?
Answer: Water-based conditioner
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.
What minimum ambient visible light level is required at the inspection surface when using fluorescent magnetic particles?
Answer: Less than 2 foot-candles (20 lux)
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.
When should the concentration of fluorescent magnetic particle bath be checked?
Answer: Before each inspection shift and after replenishment
Bath concentration should be verified before each inspection shift and after replenishing the bath to ensure consistent sensitivity throughout the inspection process.
What is the ASTM E1444 acceptable fluorescent particle bath concentration range when measured using a centrifuge tube (pear-shaped)?
Answer: 0.2–2.4 mL per 100 mL (petroleum vehicle) or 0.1–0.4 mL (water)
ASTM E1444 specifies 0.1–0.4 mL per 100 mL for water-conditioned bath and 0.2–2.4 mL per 100 mL for petroleum-based bath as acceptable concentration ranges.
Dry magnetic particles are most commonly used in which application?
Answer: Field inspection of welds and castings at elevated temperatures
Dry particles are preferred for field inspection of rough-surface welds and castings, especially at elevated temperatures where wet bath methods are impractical.