Identify and Correct Common Weld Defects

A. Finished-Project Specification

Outcome: a completed defect log covering every sample examined, with each identified defect described by correct terminology, measured where a gauge applies, connected to one or more probable causes, and assigned a disposition of accepted, monitored, repaired, sectioned, destructively tested, or remade. Where the disposition is "repaired," the chapter's finished work also includes one completed and reinspected repair weld carried out under instructor authorization on a practice defect.

B. Sample Set Schedule

Sample Source	Process	Minimum Samples	Analysis Focus
Chapter 7–8 coupons	SMAW	2	Arc-start quality, bead profile, undercut, spatter, arc strikes
Chapter 9 fillet joints	SMAW	1	Fillet size, toe fusion indicators, slag inclusion indications
Chapter 11 coupons	GMAW	2	Bead profile, porosity, undercut, spatter
Chapter 12 joints	GMAW	1	Fillet or butt profile, penetration indicators, crater condition
Chapter 13 coupons	FCAW	1	Slag inclusion indications, worm tracks, bead profile
Chapter 15 coupons	GTAW	1	Oxidation, crater, contamination indicators, bead consistency

If fewer than the minimum sample count remains from earlier chapters, substitute instructor-supplied reference samples for the same process and record their origin as "instructor-supplied" on the defect log.

C. Material Takeoff

• Samples: the minimum sample set described in Section B, cooled, cleaned, and identified.
• Reference samples: one accepted reference sample per process for side-by-side comparison.
• Consumables for the single authorized repair: matching electrode, wire, or filler rod identified by the same classification used to produce the original sample.
• Documentation materials: defect log sheets, marker, camera or phone camera, sufficient for one entry per sample.
• Fastener and hardware schedule: not applicable. This chapter produces an inspection record and, where authorized, one repair weld, not a fastened assembly.

D. Acceptance Standards

Check	Standard
Terminology	Each identified condition is named using the terms defined in Reference Conventions, not generic phrases such as "looks bad"
Measurement	Undercut depth and fillet size are recorded using the approved gauge wherever the defect type requires a gauge reading
Probable cause	Each defect entry lists at least one probable cause from each relevant category considered, not a single unexamined guess
Crack handling	Any surface crack is recorded, set aside, and referred to the responsible instructor; no learner-directed grinding or repair is performed on a cracked sample
Disposition	Every sample receives one disposition: accepted, monitored, repaired, sectioned, destructively tested, or remade, with the reasoning recorded
Repair authorization	No repair weld is struck until the corrective-action notes for that sample are complete and reviewed by the responsible instructor
Repair result	The completed repair is reinspected against the original criteria used for that sample's process and joint type

E. Preparation — Review Criteria and Confirm Sample Safety

1. Review the approved visual-inspection criteria and defect terminology. Confirm the Reference Conventions table and the criteria from the chapter that produced each sample before beginning analysis.
2. Confirm the samples are cool, cleaned, identified, and safe to handle. Do not analyze a sample that has not cooled to a safe handling temperature or is not clearly labeled by process and origin.
3. Record process, material, joint, position, consumable, and settings when known. Complete the Sample and Analysis Record panel for each sample before inspecting it.

F. Visual Inspection Under Controlled Conditions

1. Inspect samples under adequate lighting. Reposition the sample or the light source until the full bead length and both toes are clearly visible.
2. Use magnification, mirror, gauges, and straightedge where approved. Apply magnification to suspected fine porosity or hairline cracks and a mirror to the reverse side of butt samples with an approved penetration indicator.
3. Examine starts, stops, craters, toes, face, edges, and adjacent base metal. Inspect the full length of each bead or joint, not only its midpoint.

G. Identify Porosity, Undercut, and Overlap

1. Identify surface porosity by location, size, distribution, and recurrence. Note whether porosity clusters at starts, stops, or along the full bead length.
2. Distinguish visible pores from slag pits, spatter scars, or cleaning marks. Use magnification to confirm a true pore versus a surface mark before recording it.
3. Identify undercut along weld toes. Sight along the toe line under raking light to locate any groove cut into the base metal.
4. Measure undercut only with the approved gauge and criteria. Record the measured depth and length of each undercut location.
5. Identify overlap or cold lap at the toe. Look for weld metal that has flowed onto the base metal surface without fusing to it.

H. Identify Profile, Fill, and Termination Defects

1. Identify excessive convexity, concavity, inconsistent width, excessive reinforcement, and poor contour. Compare the bead face against a straightedge and against the accepted reference sample.
2. Identify incomplete fill, crater depression, and abrupt starts or stops. Note whether the crater was filled using the approved method taught in the chapter that produced the sample.
3. Identify excessive spatter and arc strikes. Distinguish scattered acceptable spatter from heavy spatter that indicates an unstable arc, and locate any arc-strike crater outside the intended weld path.

I. Identify Cracks, Slag Inclusions, and Fusion Indicators

1. Identify surface cracks and stop evaluation for qualified review. Set the sample aside immediately upon finding a crack and record it on the defect log.
2. Do not grind over a crack to hide it. Leave the crack visible for the responsible instructor's review.
3. Identify visible slag inclusions or trapped slag indications. Look for surface pitting or worm-track indications consistent with trapped slag, particularly on FCAW samples.
4. Identify fusion concerns from toe shape, bead placement, cold profile, or destructive-test evidence while acknowledging visual limitations. Record fusion concerns as an indication requiring further evaluation rather than a confirmed internal condition.
5. Identify burn-through, excessive penetration indication, distortion, and melted edges where applicable. Note these conditions on butt-joint and thin-material samples in particular.

J. Compare, Document, and Reason to Probable Cause

1. Compare each defect with accepted reference samples. Place the sample under inspection beside its matching accepted reference sample for the same process.
2. Record location and photograph each defect. Mark the location on the sample and capture a photograph referenced by the defect log entry.
3. Identify possible machine-related causes. Consider polarity, output stability, worn contact tip, feeder condition, and duty-cycle limits.
4. Identify possible parameter-related causes. Consider amperage, voltage, wire speed, and travel speed relative to the approved starting range recorded for the sample.
5. Identify possible technique-related causes. Consider arc length, work angle, travel angle, filler timing, and hand movement.
6. Identify possible fit-up, cleaning, gas, consumable, or material causes. Consider joint gap, surface contamination, shielding-gas coverage, wrong or damaged consumable, and unidentified base metal.
7. Do not assign a single cause without considering alternatives. Record every category considered on the defect log, even where only one is judged most likely.

K. Disposition and Authorized Repair

1. Select whether the sample should be accepted, monitored, repaired, sectioned, destructively tested, or remade. Base the decision on the defect type, size, location, and recurrence recorded on the defect log.
2. Determine whether sufficient base material remains for repair. Check remaining thickness at any location where defect removal would remove base metal.
3. Define the approved defect-removal method. State the specific method — grinding, gouging, or mechanical removal — approved for the defect and sample.
4. Define re-preparation, cleaning, fit-up, preheat, parameter, or technique changes where supplied by the qualified procedure. Record only changes supported by the approved procedure or instructor direction; do not invent a value.
5. Do not invent a repair procedure for structural or code welds. Confirm the sample is a noncritical practice coupon before proceeding with any learner-directed repair.
6. Remove a practice defect only under instructor control. Obtain authorization before grinding, gouging, or otherwise removing any defect.
7. Inspect the excavated area before rewelding. Confirm the defect has been fully removed and the surface is clean before continuing.
8. Reweld using the approved corrected setup. Apply the machine, parameter, and technique corrections identified in the corrective-action notes.
9. Allow cooling and clean the repair. Follow the same slag- and spatter-removal steps used in the original process chapter.
10. Reinspect the repaired area using the original criteria. Apply the same acceptance standards used for the sample's process and joint type.
11. Compare repaired and original conditions. Record whether the repair eliminated the original defect without introducing a new one.

L. Documentation and Log Completion

1. Prepare corrective-action notes for porosity, undercut, fusion concerns, spatter, and poor profile. Complete one entry per defect type identified across the sample set.
2. Record whether the correction addressed the likely cause. State the evidence supporting that conclusion, such as the reinspection result.
3. Update the learner defect log and recurring-error plan. Note any defect type that recurred across more than one sample and the plan to address it in future chapters.