NDT Penetrant Testing 4 — Questions and Answers
Question 1: Which penetrant testing method uses Method C classification?
- Water-washable penetrant
- Post-emulsifiable hydrophilic penetrant
- Solvent-removable penetrant (Correct answer)
- Post-emulsifiable lipophilic penetrant
Correct answer: Solvent-removable penetrant
Per ASTM E1417, Method C refers to solvent-removable penetrants where excess penetrant is removed using a solvent-dampened cloth.
Question 2: Which discontinuity type is penetrant testing LEAST effective at detecting?
- Tight fatigue cracks
- Broad shallow laps
- Very wide open discontinuities (Correct answer)
- Forging cracks
Correct answer: Very wide open discontinuities
Very wide open discontinuities may not retain enough penetrant through the cleaning step to produce a detectable indication.
Question 3: What is the purpose of the pre-cleaning step before applying penetrant?
- To roughen the surface for better penetrant adhesion
- To remove contaminants that could block discontinuity openings or cause false indications (Correct answer)
- To heat the part for improved penetrant flow
- To apply a thin primer coat
Correct answer: To remove contaminants that could block discontinuity openings or cause false indications
Pre-cleaning removes oils, paint, rust, and other contaminants that could seal discontinuity openings and prevent penetrant entry or cause false indications.
Question 4: A technician is inspecting an austenitic stainless steel weld. Which penetrant specification controls sulfur and halogen content to prevent material damage?
- ASTM E165
- ASTM E1417
- AMS 2644 (Correct answer)
- ASME Section V Article 6
Correct answer: AMS 2644
AMS 2644 specifies limits on sulfur and halogen content in penetrant materials used on nickel alloys and austenitic stainless steels to prevent stress corrosion cracking.
Question 5: What type of crack is typically found in aluminum castings and is commonly detected by PT?
- Hydrogen-induced cracking
- Hot tears (Correct answer)
- Delayed cracking
- Lamellar tearing
Correct answer: Hot tears
Hot tears form in castings during solidification when thermal stresses exceed the strength of the partially solidified metal and are readily detected by PT.
Question 6: In visible dye penetrant testing, what color is the indication typically produced against the developer background?
- Yellow-green
- Red or pink (Correct answer)
- Blue
- Orange
Correct answer: Red or pink
Visible dye penetrants use red or pink dye that bleeds out of discontinuities to create red indications against the white developer background.
Question 7: Which test panel is commonly used to verify penetrant system performance before inspection?
- Charpy impact specimen
- TAM panel (aluminum alloy cracked panel) (Correct answer)
- Brinell hardness block
- Gleeble test coupon
Correct answer: TAM panel (aluminum alloy cracked panel)
The TAM panel contains thermally cracked aluminum specimens of known discontinuity sizes and is used to verify penetrant system sensitivity and technique consistency.
NDT Penetrant Testing 4
Which penetrant testing method uses Method C classification?