Catch-all word for any irregularity in weld or base metal, such as a pore, an inclusion, lack of fusion or a crack, whatever its size. It turns into a defect, and must be repaired, only when its type, size or frequency fails the acceptance criteria of the governing code. Inspectors guard the distinction, because writing up a defect commits the job to a repair.
It's a discontinuity, a 1/16 pore, and the code allows it, so it's not a defect, sign it off.
Say discontinuity until you have checked the code; calling it a defect on the floor commits everyone to a repair.
Also heard as
- flaw
- imperfection
Related terms
Porosity
Gas bubbles trapped in weld metal as it freezes, showing as round holes on the surface or on film.
Lack of fusion
Weld metal that failed to fuse with the base metal or a previous pass at some boundary.
VT
Visual testing: inspecting welds by eye with gauges, lights and magnifiers, the first and most-used NDE method.
CWI
Certified Welding Inspector: the AWS inspection credential, and the usual job title for the person checking welds.