NDT Penetrant Testing 5 — Questions and Answers
Question 1: What NDT Level certification is required to interpret and evaluate PT indications per ASNT SNT-TC-1A?
- Level I only
- Level II or Level III (Correct answer)
- Level III only
- No certification is required
Correct answer: Level II or Level III
Per SNT-TC-1A, Level II and Level III personnel are qualified to interpret and evaluate PT indications and accept or reject parts.
Question 2: What is the effect of excessive water pressure during the rinse step in water-washable penetrant testing?
- It improves fluorescence brightness
- It can wash penetrant out of shallow or wide discontinuities, causing missed indications (Correct answer)
- It causes the developer to streak
- It increases dwell time effectiveness
Correct answer: It can wash penetrant out of shallow or wide discontinuities, causing missed indications
Excessive water pressure during rinsing can force penetrant out of open discontinuities, particularly shallow ones, leading to missed indications.
Question 3: Which discontinuity geometry retains penetrant MOST effectively, producing the strongest indication?
- Wide open groove
- Tight, narrow, deep crack (Correct answer)
- Broad, shallow scratch
- Smooth rounded porosity
Correct answer: Tight, narrow, deep crack
Tight, narrow, deep cracks maximize capillary retention of penetrant and produce strong, well-defined indications after developer application.
Question 4: When using solvent-removable penetrant (Method C), how should excess penetrant be removed from the surface?
- Spray directly with solvent to flood the surface
- Wipe with a dry cloth, then solvent-dampened cloth (Correct answer)
- Immerse the part in solvent bath
- Use an air knife followed by water mist
Correct answer: Wipe with a dry cloth, then solvent-dampened cloth
Solvent removal requires first wiping with a dry cloth to remove bulk penetrant, then using a lightly solvent-dampened cloth to clean remaining surface penetrant without flooding.
Question 5: A linear indication in PT is defined as one whose length is how many times greater than its width?
- 2:1
- 3:1 (Correct answer)
- 5:1
- 10:1
Correct answer: 3:1
Per ASME Section V, an indication is considered linear when its length is at least three times its width.
Question 6: What is the main reason penetrant testing cannot be used on porous materials like powder metallurgy parts without special precautions?
- The dye chemically reacts with metal powders
- Porosity throughout the material causes background bleedout that masks real indications (Correct answer)
- UV light cannot penetrate porous surfaces
- Developers cannot adhere to porous surfaces
Correct answer: Porosity throughout the material causes background bleedout that masks real indications
Bulk porosity in porous materials causes penetrant to bleed out everywhere, creating a uniform background that obscures relevant indications from actual defects.
Question 7: Which post-cleaning method is MOST effective for removing penetrant materials from a part after inspection is complete?
- Dry brushing only
- Solvent soak followed by vapor degreasing (Correct answer)
- Cold water rinse at low pressure
- Dry compressed air blow-off
Correct answer: Solvent soak followed by vapor degreasing
Solvent soaking followed by vapor degreasing thoroughly dissolves and removes penetrant, developer, and emulsifier residues from the part surface and discontinuities.
NDT Penetrant Testing 5
What NDT Level certification is required to interpret and evaluate PT indications per ASNT SNT-TC-1A?