NDT Visual Testing Fundamentals 4 — Questions and Answers
Question 1: During visual inspection of a pressure vessel, an inspector finds a 'blister' on the inner surface. This most likely indicates:
- Weld spatter accumulation
- Hydrogen-induced blistering from wet H₂S service (Correct answer)
- Normal surface roughness from rolling
- Coating delamination from heat
Correct answer: Hydrogen-induced blistering from wet H₂S service
Blisters on internal pressure vessel surfaces in sour service are classic indicators of hydrogen-induced cracking (HIC) where hydrogen diffuses into the steel.
Question 2: Which magnification level is typically the MAXIMUM recommended for unaided visual testing without an optical aid?
- 1x (unaided eye) (Correct answer)
- 2x
- 4x
- 10x
Correct answer: 1x (unaided eye)
Unaided direct visual testing uses 1x magnification (no optical aid); any magnification above 1x requires an approved optical aid.
Question 3: What is the significance of a 'witness mark' left on a component during fabrication visual inspection?
- It marks a defective area for repair
- It documents that a specific inspection checkpoint was completed (Correct answer)
- It indicates a material hardness test location
- It records the original surface finish standard
Correct answer: It documents that a specific inspection checkpoint was completed
Witness marks (stamps or paint marks) confirm that an authorized inspector examined and accepted the component at a defined checkpoint.
Question 4: For weld visual inspection, 'overlap' (also called cold lap) is best described as:
- Weld metal that protrudes beyond the joint without fusing to the base metal (Correct answer)
- Excess weld reinforcement above the base metal surface
- A crack running parallel to the weld axis
- Base metal burned through by excessive heat input
Correct answer: Weld metal that protrudes beyond the joint without fusing to the base metal
Overlap is an imperfection where weld metal flows beyond the toe of the weld and lies on the base metal surface without metallurgical fusion.
Question 5: When documenting a VT finding, which piece of information is LEAST critical to include in the inspection report?
- Location of the discontinuity using a reference system
- Dimensions and orientation of the discontinuity
- The inspector's shift supervisor's home address (Correct answer)
- Date and identification of the inspector
Correct answer: The inspector's shift supervisor's home address
A supervisor's personal address is irrelevant to inspection documentation; location, dimensions, inspector ID, and date are all required fields.
Question 6: A weld exhibiting 'lack of penetration' (LOP) would appear visually as:
- A groove along the weld toe on the face side
- An unfused gap visible at the root of the weld on the back side (Correct answer)
- Excess convexity of the weld cap
- Random pores visible on the weld surface
Correct answer: An unfused gap visible at the root of the weld on the back side
Lack of penetration appears as an unfilled groove or gap at the weld root, often visible when the back side is accessible for inspection.
Question 7: The ASME Boiler and Pressure Vessel Code Section V Article 9 governs:
- Ultrasonic examination procedures
- Visual examination methods and requirements (Correct answer)
- Radiographic examination standards
- Magnetic particle examination
Correct answer: Visual examination methods and requirements
ASME BPVC Section V, Article 9 specifically covers visual examination requirements including methods, lighting, and personnel qualification.
NDT Visual Testing Fundamentals 4
During visual inspection of a pressure vessel, an inspector finds a 'blister' on the inner surface.
This most likely indicates: