NDT Penetrant Testing 3 — Questions and Answers
Question 1: Which developer form is applied as a wet suspension in a non-aqueous carrier solvent?
- Form a — dry powder developer
- Form b — water-soluble developer
- Form c — water-suspendible developer
- Form d — non-aqueous wet developer (Correct answer)
Correct answer: Form d — non-aqueous wet developer
Form d non-aqueous wet developer uses organic solvents as a carrier and is considered the most sensitive developer form for visible dye PT.
Question 2: At what temperature range is standard liquid penetrant testing considered valid per ASTM E165?
- 32°F to 100°F (0°C to 38°C)
- 50°F to 125°F (10°C to 52°C) (Correct answer)
- 40°F to 110°F (4°C to 43°C)
- 60°F to 150°F (16°C to 66°C)
Correct answer: 50°F to 125°F (10°C to 52°C)
ASTM E165 specifies the standard temperature range for PT as 50°F to 125°F (10°C to 52°C) without special qualification.
Question 3: What is the primary advantage of using fluorescent penetrant over visible dye penetrant?
- It does not require a developer
- It can detect subsurface flaws
- It provides greater sensitivity and contrast under UV light (Correct answer)
- It works on non-metallic materials only
Correct answer: It provides greater sensitivity and contrast under UV light
Fluorescent penetrants produce bright yellow-green indications against a dark background under UV light, offering significantly higher sensitivity than visible dye.
Question 4: Which penetrant sensitivity level is the HIGHEST per ASTM E1135 classification?
- Level 1/2
- Level 1
- Level 2
- Level 4 (Correct answer)
Correct answer: Level 4
ASTM E1135 classifies fluorescent penetrant sensitivity from Level 1/2 (lowest) to Level 4 (ultra-high sensitivity).
Question 5: In post-emulsifiable penetrant testing, what happens if the emulsifier dwell time is excessive?
- The penetrant becomes more fluorescent
- Penetrant is over-emulsified and washed out of discontinuities, causing missed indications (Correct answer)
- The developer adheres more uniformly
- Surface roughness indications are enhanced
Correct answer: Penetrant is over-emulsified and washed out of discontinuities, causing missed indications
Over-emulsification causes the emulsifier to penetrate into discontinuities and remove trapped penetrant, resulting in loss of relevant indications.
Question 6: Which material surface condition is MOST likely to cause a non-relevant indication in PT?
- Machined flat surface
- Surface scratch from handling
- Lapped surface with tight dimensional tolerances
- Press-fit joint line (Correct answer)
Correct answer: Press-fit joint line
Press-fit or mechanical joint interfaces can trap penetrant and produce non-relevant indications that mimic cracks.
Question 7: What is the recommended minimum black light intensity at the inspection surface for fluorescent PT per ASNT guidelines?
- 500 μW/cm²
- 1000 μW/cm² (Correct answer)
- 200 μW/cm²
- 2000 μW/cm²
Correct answer: 1000 μW/cm²
A minimum UV-A intensity of 1000 μW/cm² at the inspection surface is required to properly excite fluorescent penetrant indications.
NDT Penetrant Testing 3
Which developer form is applied as a wet suspension in a non-aqueous carrier solvent?