Free Tool
Weld Discontinuity Map
Tap any point on the weld cross-section to see which discontinuity lives there, what causes it, and how it's found. Learning discontinuities by LOCATION is how the CWI exam expects you to think.
Groove-weld cross-section
Excessive reinforcement
geometric
- Location
- Weld face (crown), built up above the surrounding base metal.
- Cause
- Too much weld metal / slow travel; creates a sharp toe transition and stress concentration.
- Inspection
- Visual + a bridge cam or V-WAC gauge measures crown height against the acceptance limit.
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Practice 5 Welding / CWI exam questions
Real questions — each with an instant AI explanation.
Welding / CWI · Question 1 of 5
Which welding process uses a non-consumable tungsten electrode?
Pick an answer to see the explanation + an instant AI breakdown.
Frequently Asked Questions
Where does undercut occur in a weld?
Undercut is a groove melted into the base metal at the weld TOE and left unfilled by weld metal. It is a surface discontinuity usually caused by excessive current, arc length, or an incorrect work or travel angle, and its depth is measured against the code limit.
What is the difference between incomplete fusion and incomplete joint penetration?
Incomplete fusion is weld metal that failed to fuse to the base metal or to a previous bead — it can occur along the groove sidewall or between passes. Incomplete joint penetration is at the joint ROOT, where the weld did not extend through the joint thickness as required. Both are commonly found with ultrasonic testing.
Which discontinuity is almost always a defect?
Cracks. A crack is the most serious discontinuity and is generally rejectable regardless of size. Other discontinuities — porosity, undercut, slag — become defects only when they exceed the acceptance criteria of the governing code or specification.
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