AWS Certified Welding Inspector — FundamentalsNondestructive Examination (NDE)Easy
A CWI is performing a visual inspection (VT) on a finished weldment. Which of the following discontinuities is characterized by a localized open cavity caused by the entrapped gas during solidification?
- AOverlap
- BUndercut
- CCrater crack
- DPorosity
Show answer & explanationAnswer & explanation
Correct answer: D. Porosity
Porosity is a common weld discontinuity caused by entrapped gases, appearing as spherical or elongated voids. It is a visual indication of gas entrapment during the welding process. The other options describe different types of discontinuities.
Why the other options are wrong
- A. Overlap is a protrusion of weld metal beyond the weld toe or weld root.
- B. Undercut is a groove melted into the base metal adjacent to the toe or root of a weld and left unfilled by weld metal.
- C. A crater crack is a crack in the weld crater, typically occurring at the end of a weld bead.
Porosity (Visual Inspection)
Porosity is a discontinuity in a weld caused by entrapped gas during solidification, appearing as spherical or elongated voids within the weld metal.
- Caused by gas entrapment during welding.
- Can appear on the surface or internally.
- Often looks like small, rounded holes.
Memory trick: Visual Weld Flaws: See the Gaps, Grooves, and Cracks.