21 Weld Inspection & Testing Practice Questions & Answers

1. 1. A welding inspector finds a small area of scattered porosity in a completed fillet weld. Under the applicable acceptance criteria for that job, porosity of that size is allowed. How should this indication be classified?

   • A.A defect, because the inspector recorded it on the visual examination report form
   • B.A discontinuity only if it also appears on the root side of the same joint
   • C.A defect, because any gas cavity in the weld metal is rejectable on every job
   • D.A discontinuity, because it interrupts the uniform structure but stays inside the limits✓ Answer

   A discontinuity is any interruption in the typical structure of a weldment. It becomes a defect only when it exceeds the acceptance criteria of the governing code or contract document. Since this porosity is within the stated limits, it remains a discontinuity, and the identical indication could be a defect under a stricter standard.

   Source: AWS A3.0, Standard Welding Terms and Definitions; AWS QC10, Specification for Qualification and Certification of SENSE Level I-Entry WeldersReport a problem with this question

2. 2. A weld is inspected against a criterion that limits undercut to the lesser of 10% of the base metal thickness or 1/32 in [0.8 mm]. The plate is 1/4 in thick and the measured undercut is 0.028 in deep. What is the correct disposition?

   • A.Reject, because any measurable undercut at the weld toe is always rejectable
   • B.Reject, because the governing limit is 0.025 in and the undercut exceeds it✓ Answer
   • C.Accept, because undercut is measured in length along the toe, not in depth
   • D.Accept, because the governing limit is 1/32 in and the undercut is under it

   The criterion says the lesser of the two values governs. Ten percent of 1/4 in is 0.025 in, which is smaller than 1/32 in (0.031 in), so 0.025 in is the limit. The measured 0.028 in exceeds that limit, making this undercut a defect.

   Source: AWS QC10, Specification for Qualification and Certification of SENSE Level I-Entry Welders, visual acceptance criteria for undercutReport a problem with this question

3. 3. Weld metal has flowed out over the base metal surface at the toe of a fillet weld and formed an unfused protrusion with a sharp notch beneath it. Which discontinuity is this, and what is the usual cause?

   • A.Excessive convexity, caused by an electrode too large for the fillet size called out
   • B.Underfill, caused by too few passes to bring the face up to the plate surface
   • C.Undercut, caused by travel speed too fast or arc length too long for the joint
   • D.Overlap, caused by travel speed too slow or amperage too low for the joint✓ Answer

   Overlap, also called cold lap, is weld metal that has flowed onto the base metal without fusing to it. It happens when the puddle runs ahead of the arc because travel is too slow or the current is too low, and the unfused notch it leaves acts as a stress riser.

   Source: AWS A3.0, Standard Welding Terms and Definitions, definition of overlapReport a problem with this question

4. 4. A groove weld cross section shows that the weld metal did not extend through the full thickness of the joint, although each deposited pass is fused to the one beside it. Which discontinuity is described?

   • A.Underfill, often from stopping short of filling the groove to the base metal surface
   • B.Suckback, often from excessive root heat drawing the root bead into the joint
   • C.Incomplete fusion, often from surface oxides or a wrong electrode angle in the groove
   • D.Incomplete joint penetration, often from too small a root opening or too large a root face✓ Answer

   Incomplete joint penetration means the weld metal does not extend through the joint thickness, and it is a geometry and heat problem at the root. Incomplete fusion is different: it is a failure to fuse to the base metal or to an adjacent bead, and here the passes are fused to each other.

   Source: AWS A3.0, Standard Welding Terms and Definitions, definitions of incomplete joint penetration and incomplete fusionReport a problem with this question

5. 5. A multipass groove weld is radiographed and shows dark elongated lines running along both edges of one intermediate pass, sometimes called wagon tracks. What is the most likely cause?

   • A.Sulfur in the base metal segregating to the bead edges as the weld solidified
   • B.Slag left in the side notches of the previous pass by incomplete interpass cleaning✓ Answer
   • C.Arc length far too long, letting air draw into both sides of the molten puddle
   • D.Moisture in the electrode covering releasing hydrogen gas along the bead edges

   Wagon tracks are slag inclusions trapped in the notches along both sides of a previous bead. Slag floats to the surface and lodges at the bead toes, so if it is not chipped, ground, or brushed out before the next pass, the following bead seals it into the weld.

   Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, weld discontinuitiesReport a problem with this question

6. 6. A welder breaks the arc abruptly at the end of each bead and small star-shaped cracks appear in the depressions left at the bead ends. What corrective technique should the welder use?

   • A.Increase travel speed near the end so the puddle freezes with less shrinkage
   • B.Grind the crater flush after each bead and continue without changing technique
   • C.Pause and back-step to fill the crater before breaking the arc at each stop✓ Answer
   • D.Raise the arc length at the stop so the puddle cools more gradually in place

   Crater cracks form because the last of the puddle solidifies in a thin, dished section that cannot resist shrinkage stresses. Pausing or back-stepping to build the crater up to full cross section before breaking the arc removes the thin section and prevents the crack.

   Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, crater cracks and arc terminationReport a problem with this question

7. 7. While positioning work, a welder briefly strikes the electrode on the plate several inches away from the joint, leaving a small melted spot. Why is this a reportable problem on code work?

   • A.The spot removes the mill scale and lets rust form faster than the rest of the plate
   • B.The spot quench-hardens a small heat-affected area that can start a crack in service✓ Answer
   • C.The spot draws current away from the joint and lowers penetration on the next pass
   • D.The spot proves the machine polarity is wrong and the weld must be redone entirely

   An arc strike melts and then rapidly quenches a tiny spot of base metal, leaving a hard, brittle microstructure with a small heat-affected zone and often microcracks. Because it sits outside the weld where nothing reinforces it, it becomes a crack initiation site, so the arc should be struck only in the joint or on a run-off tab.

   Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, arc strikesReport a problem with this question

8. 8. Cracks are found in a heavy restrained steel weldment two days after the welding was finished and the joint passed visual inspection. Which three conditions must all be present for this type of cracking?

   • A.Diffusible hydrogen, a hardened susceptible microstructure, and tensile restraint stress✓ Answer
   • B.Excessive weld reinforcement, a sharp toe angle, and cyclic loading in service
   • C.High sulfur content, a deep narrow bead shape, and solidification at high temperature
   • D.Trapped slag, damp flux on the plate surface, and slow cooling through the joint

   Delayed cracking after the weld has cooled is hydrogen-induced (cold) cracking, and it needs hydrogen, a susceptible hard microstructure, and restraint stress at the same time. Removing any one of the three stops it, which is why low-hydrogen practice, preheat, and interpass temperature control are the standard preventive measures.

   Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, hydrogen-induced crackingReport a problem with this question

9. 9. Of the discontinuities an entry welder must recognize, which one is treated as the most severe and is essentially never acceptable in code work?

   • A.Clustered porosity, because grouped gas cavities weaken one localized region of the bead
   • B.Slag inclusions, because trapped nonmetallic solids reduce the load-carrying cross section
   • C.Incomplete joint penetration, because unfused root land leaves the joint below full thickness
   • D.Cracks, because their sharp planar tips concentrate stress and propagate under load✓ Answer

   Cracks are planar discontinuities with extremely sharp tips, so stress concentrates at the tip and the crack grows under service loading. That growth behavior is why visual acceptance criteria for entry-level welds state no cracks, with no allowable size at all.

   Source: AWS QC10, Specification for Qualification and Certification of SENSE Level I-Entry Welders, visual acceptance criteriaReport a problem with this question

10. 10. A fabricated steel frame pulls out of square as the welds cool, even though every weld passed visual inspection. What is the fundamental cause of this distortion?

    • A.Filler metal shrinking at a different rate than the base metal because alloys differ
    • B.Residual magnetism in the plate pulling the assembly as the arc field collapses
    • C.Grain growth in the heat-affected zone increasing the total volume of the joint
    • D.Non-uniform heating and cooling causing uneven expansion and contraction in the parts✓ Answer

    Distortion comes from non-uniform heating and cooling: the heated metal expands while the cold surrounding metal restrains it, then the weld contracts as it cools and pulls the parts. Balanced welding sequences, back-step and skip welding, fixturing, presetting, and keeping welds no larger than required all control it.

    Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, distortion and its controlReport a problem with this question

11. 11. A welder must find a crack that is open to the surface of an aluminum weldment. Which nondestructive examination method is appropriate?

    • A.Liquid penetrant testing, which works on nonmagnetic metals and finds surface openings✓ Answer
    • B.Eddy current testing, which is the only method rated for cracks in cast aluminum weldments
    • C.Radiographic testing, which is the standard method for tight surface cracks in light alloys
    • D.Magnetic particle testing, which uses a yoke field and finds surface openings in any metal

    Liquid penetrant testing depends on capillary action drawing dye into an opening at the surface, so it works on any clean nonporous material regardless of magnetic properties. Magnetic particle testing is ruled out because aluminum is not ferromagnetic and cannot hold the magnetic field the method requires.

    Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, nondestructive examination methodsReport a problem with this question

12. 12. When magnetic particle testing is performed on a carbon steel weld, why is the part magnetized in two directions about 90 degrees apart?

    • A.The second direction demagnetizes the part so residual magnetism does not disturb the arc
    • B.Two passes double the applied field strength so deeper subsurface flaws become visible
    • C.Reversing direction dries the wet particle bath so the indication holds its shape longer
    • D.Indications are strongest when a flaw lies across the field, so both orientations get covered✓ Answer

    A flaw disturbs the magnetic field and creates a leakage field most strongly when it lies perpendicular to the field lines, and a flaw parallel to the field may produce no indication at all. Magnetizing in two directions roughly 90 degrees apart ensures discontinuities of any orientation are crossed by the field in at least one of the two passes.

    Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, magnetic particle testingReport a problem with this question

13. 13. An inspector needs a permanent record of internal volumetric discontinuities such as scattered porosity and trapped slag in a thick groove weld. Which method fits, and what is its main weakness?

    • A.Magnetic particle testing, which images volumetric flaws but only in ferromagnetic steel
    • B.Radiographic testing, which images volumetric flaws but can miss tight planar flaws✓ Answer
    • C.Liquid penetrant testing, which images volumetric flaws but requires a long dwell time
    • D.Ultrasonic testing, which images volumetric flaws but leaves no film or printed record

    Radiography passes radiation through the weld and records density differences on film or a digital detector, which is ideal for volumetric flaws that have measurable thickness. Its weakness is orientation sensitivity: a tight planar flaw such as lack of fusion or a crack lying across the beam removes almost no material from the beam path and may not show.

    Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, radiographic testingReport a problem with this question

14. 14. Why is visual examination described as the first and most cost-effective inspection method, and what is its principal limitation?

    • A.It needs little equipment and is done before and during welding, but reveals surface flaws only✓ Answer
    • B.It needs certified operators and is done between passes, but reveals planar flaws only
    • C.It needs no lighting control and is done only after welding, but reveals internal flaws only
    • D.It needs a couplant and is done after cooling, but reveals base metal laminations only

    Visual examination uses simple tools such as gauges, a straightedge, a mirror, and a light, and it can be applied before, during, and after welding so problems are caught before more weld metal is deposited on top of them. Its limitation is that it detects only what reaches the surface, so subsurface flaws require another method.

    Source: AWS QC10, Specification for Qualification and Certification of SENSE Level I-Entry Welders, visual examination requirementsReport a problem with this question

15. 15. A drawing calls out a 5/16 in fillet weld. Which inspection tool is intended to check that requirement on the finished weld?

    • A.A fillet weld gauge, which reads leg size and shows convex or concave face contour✓ Answer
    • B.A hi-lo gauge, which reads leg size and shows internal misalignment across the joint
    • C.A taper gauge, which reads leg size and shows the included angle of the groove
    • D.A wire feed gauge, which reads leg size and shows deposition rate for the pass

    A fillet weld gauge is shaped to seat against both legs of the fillet so the welder can read whether the leg size meets the drawing and whether the face is convex or concave. A hi-lo gauge measures misalignment and root gap, and neither a taper gauge nor a feed device measures fillet size.

    Source: AWS EG2.0, Guide for the Training of Welding Personnel: SENSE Level I-Entry Welders, weld gauges and visual inspection toolsReport a problem with this question

16. 16. In a guided bend test of a groove weld coupon, the specimen is bent so that the weld root is on the outside, convex surface. What is this test arrangement designed to reveal?

    • A.The hardness gradient across the heat-affected zone from the fusion line outward
    • B.The tensile strength of the deposited weld metal compared with that of the base metal
    • C.Root-side flaws such as incomplete penetration or lack of fusion opening under tension✓ Answer
    • D.Face-side flaws such as undercut or surface porosity opening under compression loading

    Whichever surface is on the outside of the bend is in tension, and tension opens up discontinuities on that surface. Placing the root outward therefore puts root-side problems such as incomplete joint penetration and lack of fusion in tension, which is exactly what the inspector is judging: the soundness of the fusion.

    Source: AWS B4.0, Standard Methods for Mechanical Testing of Welds, guided bend test orientationsReport a problem with this question

17. 17. A fillet weld procedure needs a cross section examined to confirm root penetration, effective throat, leg size, and the number of passes. Which destructive test is standard for this?

    • A.A nick-break test, in which a notched coupon is fractured to show the weld profile
    • B.A macroetch test, in which a cut section is polished and etched to show the weld profile✓ Answer
    • C.A reduced-section tensile test, in which a machined coupon is pulled to show the weld profile
    • D.A free-bend test, in which an unguided coupon is folded flat to show the weld profile

    A macroetch specimen is cut through the weld, polished, and etched with an acid solution so the fusion boundary, root penetration, throat, and individual passes become visible to the unaided eye. Break and tensile tests fracture the joint and cannot show a measured profile of the fused cross section.

    Source: AWS B4.0, Standard Methods for Mechanical Testing of Welds, macroetch examinationReport a problem with this question

18. 18. Which statement correctly distinguishes a Welding Procedure Specification from a Procedure Qualification Record?

    • A.The WPS certifies the individual welder's skill; the PQR certifies the shop's inspection program
    • B.The WPS lists the acceptance criteria for the weld; the PQR lists the codes the job is built to
    • C.The WPS gives the welder the variables to follow; the PQR records the test data proving them✓ Answer
    • D.The WPS records the test data from the coupon; the PQR gives the welder the variables to follow

    A WPS is the written instruction that tells the welder the process, filler metal, position, current, travel, preheat, and joint design to use. The PQR is the evidence document: it records the actual values used on a test coupon and the mechanical test results that prove a weld made to that WPS is sound.

    Source: AWS B2.1, Specification for Welding Procedure and Performance QualificationReport a problem with this question

19. 19. What is the difference between procedure qualification and welder performance qualification?

    • A.Procedure qualification proves the base metal is sound; performance qualification proves the filler is
    • B.Procedure qualification proves the person can weld; performance qualification proves the machine can
    • C.Procedure qualification proves the process works; performance qualification proves the person can✓ Answer
    • D.Procedure qualification proves the shop is accredited; performance qualification proves the code applies

    Procedure qualification tests the welding procedure itself, showing that a joint welded with those variables meets the required mechanical properties. Performance qualification tests an individual welder, showing that person can deposit sound weld metal following a qualified procedure in a given position and thickness range.

    Source: AWS B2.1, Specification for Welding Procedure and Performance QualificationReport a problem with this question

20. 20. Under widely used structural welding rules, when must a welder who holds a current qualification be requalified in that process?

    • A.When the process has gone unused beyond six months, or the welder's ability is questioned✓ Answer
    • B.When the welder changes employers, or the shop adopts a newer edition of the welding code
    • C.When the welder moves to a different joint design, or the filler metal diameter is changed
    • D.When twelve months pass since the last test, regardless of whether the process was used

    A welder's qualification stays in effect indefinitely as long as the process keeps being used, because continued use is itself evidence of maintained skill. Requalification is triggered when that process has not been used for more than six months, or when there is specific reason to question the welder's ability to make sound welds.

    Source: AWS D1.1, Structural Welding Code-Steel, welder qualification period of effectivenessReport a problem with this question

21. 21. Before fit-up, a trainee examines the oxygen-cut edges of the plates. Which condition on a cut face indicates the cutting travel speed was too fast?

    • A.A top edge that is rounded and melted over along the whole length of the cut
    • B.Heavy dross clinging to the bottom edge that must be chipped off before fit-up
    • C.Drag lines that trail sharply backward instead of running nearly straight down the face✓ Answer
    • D.A cut face that leans out of square with the plate surface along its full depth

    Drag lines record the path of the cutting oxygen stream through the plate. When travel outruns the oxidation reaction, the stream lags behind at the bottom and the lines trail sharply backward. A rounded top edge points to too slow a travel or too hot a preheat flame, and out-of-square angularity points to a torch held off perpendicular.

    Source: AWS C4.1, Criteria for Describing Oxygen-Cut SurfacesReport a problem with this question

Practice questions based on the AWS SENSE Level I (Entry Welder) written modules, ANSI Z49.1 safety practice, and AWS A2.4 welding symbols. This bank covers the KNOWLEDGE half of entry-level welding only — the workmanship and welder performance qualification tests are hands-on and cannot be practised here, and this is not preparation for the separate, performance-based AWS Certified Welder credential. AWS, SENSE, and NCCER are marks of their respective organizations; this site is not affiliated with or endorsed by them. Work from your program's current materials, and follow the welding procedure and drawings on your own job rather than any number you remember. About AWS SENSE →