Sample practice questions

A few real questions from this free bank, with full explanations. Use the practice tool above for the whole set.

1. 1. Part A: Fundamentals

   In shielded metal arc welding (SMAW), what primarily protects the molten weld pool from atmospheric contamination?

   • a.An external supply of inert argon gas
   • b.The gaseous shield and slag produced as the flux coating on the electrode burns and melts
   • c.A granular flux fed continuously from a hopper
   • d.A vacuum chamber surrounding the arc

   Answer: b

   Explanation: SMAW (stick welding) uses a consumable electrode covered with a flux coating. As the arc heats the coating, it decomposes to create a shielding gas and forms a molten slag that both cover the weld pool, protecting it from oxygen and nitrogen. This is why SMAW needs no external gas bottle. Argon/CO2 shielding gas describes GMAW/GTAW; a granular flux from a hopper describes SAW.

2. 2. Part A: Fundamentals

   A welder deposits weld metal and the joint later cracks along the boundary between the base metal and the weld. This region is best described as the:

   • a.Heat-affected zone (HAZ)
   • b.Root face
   • c.Weld reinforcement
   • d.Toe of the weld

   Answer: a

   Explanation: The heat-affected zone is the base metal adjacent to the weld that did not melt but whose microstructure and properties were altered by the heat of welding. It is often the most metallurgically vulnerable region because rapid heating and cooling can harden it or reduce toughness. The root face is a joint-preparation dimension, reinforcement is excess weld metal, and the toe is where the weld face meets the base metal.

3. 3. Part A: Fundamentals

   Incomplete fusion in a weld is best described as:

   • a.A gas pocket trapped in the solidifying weld metal
   • b.A condition where the weld metal did not coalesce completely with the base metal or with adjacent weld beads
   • c.Excess weld metal extending above the base metal surface
   • d.A crater at the end of the weld bead

   Answer: b

   Explanation: Incomplete fusion (lack of fusion) occurs when the molten weld metal fails to fuse with the base metal or preceding passes, leaving an unbonded interface. It typically results from insufficient heat, contamination, or poor technique. It is a serious discontinuity because it creates a plane of weakness. A gas pocket is porosity; excess metal is reinforcement; the depression is a crater.

4. 4. Part A: Fundamentals

   Liquid penetrant testing (PT) is limited to detecting which type of discontinuity?

   • a.Deep internal cracks well below the surface
   • b.Discontinuities in any material regardless of surface condition
   • c.Discontinuities that are open to the surface being examined
   • d.Only discontinuities in ferromagnetic materials

   Answer: c

   Explanation: PT relies on a liquid dye seeping into flaws by capillary action, then a developer draws it back out to form a visible indication. Because the penetrant must enter the flaw, only discontinuities that break the surface can be detected. Unlike MT, PT works on non-magnetic materials such as aluminum and stainless steel, but it cannot find subsurface flaws.

5. 5. Part A: Fundamentals

   Undercut is a weld discontinuity best described as:

   • a.Weld metal that has flowed beyond the weld toe onto unfused base metal
   • b.A groove melted into the base metal adjacent to the weld toe and left unfilled by weld metal
   • c.Rounded cavities caused by trapped gas
   • d.A depression at the termination of a weld bead

   Answer: b

   Explanation: Undercut is a groove or channel melted into the base metal along the toe or root of a weld that is not filled by weld metal, reducing the effective cross-section and creating a stress riser. It is usually caused by excessive current, incorrect travel angle, or too-fast travel speed. Overflow onto unfused metal is overlap, gas cavities are porosity, and the end depression is a crater.

6. 6. Part B: Practical

   In the Part B practical, a weld replica (RMA-type gauge set) is most useful for:

   • a.Chemically etching the weld to reveal grain structure
   • b.Physically comparing a weld's profile and discontinuity size against standardized reference shapes and dimensions
   • c.Measuring the voltage used during welding
   • d.Recording the welder's certification number

   Answer: b

   Explanation: Replica gauges and weld measuring gauges provide standardized reference profiles and precise scales so an inspector can compare a weld's actual contour, undercut depth, or reinforcement height to fixed dimensional references. They translate a visual observation into a measured value that can be judged against acceptance criteria. They do not perform etching, electrical measurement, or record-keeping functions.

7. 7. Part B: Practical

   When an inspector measures a discontinuity that falls exactly at the maximum size permitted by the acceptance criteria, the correct disposition is generally to:

   • a.Accept it, because meeting the maximum allowable limit means it is within the criteria
   • b.Reject it automatically, because any measurable discontinuity is a defect
   • c.Ignore the measurement and rely on overall appearance
   • d.Double the limit before comparing

   Answer: a

   Explanation: Acceptance criteria define a maximum allowable value; a discontinuity that measures at or below that limit conforms and is accepted. A discontinuity only becomes a rejectable defect when it exceeds the allowable criteria. This distinction between a discontinuity (any interruption in the typical structure) and a defect (a rejectable discontinuity) is central to inspection judgment. Overall appearance never overrides measured criteria.

8. 8. Part B: Practical

   Which surface condition would an inspector evaluate purely by visual inspection in Part B, without any additional NDT equipment?

   • a.Internal slag inclusions deep within the weld
   • b.Subsurface lack of fusion between passes
   • c.Surface-breaking cracks, undercut, overlap, and weld profile
   • d.Hydrogen dissolved in the weld metal

   Answer: c

   Explanation: Visual inspection detects surface conditions: surface cracks, undercut, overlap, excessive reinforcement, and overall weld profile and size. Internal flaws such as buried slag, subsurface lack of fusion, or dissolved gases require volumetric methods like RT or UT and cannot be judged by eye. Knowing the limits of VT keeps the inspector from over-claiming what visual results prove.

9. 9. Part C: Code Book Application

   A Welding Procedure Specification (WPS) is best described as:

   • a.A written document providing direction to the welder for making production welds in accordance with code requirements
   • b.A record of a welder's personal certification test only
   • c.A supplier's invoice for filler metal
   • d.A drawing showing only the building's dimensions

   Answer: a

   Explanation: A WPS is the written qualified procedure that tells the welder the essential variables (process, filler, joint design, preheat, current, etc.) for producing a code-compliant weld. It provides direction for production welding and is supported by a PQR that proves those parameters produce sound welds. It is not a personal certification, an invoice, or a structural drawing.

10. 10. Part C: Code Book Application

    When a Part C question asks whether a particular weld is acceptable, the inspector should base the decision on:

    • a.Personal preference about how the weld looks
    • b.The most conservative value found anywhere on the internet
    • c.The acceptance criteria specified in the applicable code for that weld type and loading condition
    • d.The first number that appears in the code, regardless of context

    Answer: c

    Explanation: Acceptance decisions must come from the acceptance criteria of the applicable code, matched to the correct weld type (e.g., fillet vs. groove) and loading condition (statically vs. cyclically loaded), because criteria can differ between them. The inspector must locate the correct clause or table rather than grabbing the first number or relying on opinion. Reading the context that governs which criteria apply is essential.