AWS Weld Discontinuities & Defects

Question 1

Which weld discontinuity is described as a groove melted into the base metal along the toe of the weld?

Accepted Answer

Undercut

Answer

Undercut is a groove or channel melted into the base metal at the weld toe or weld root that is left unfilled by weld metal.

Question 2

What is the primary cause of porosity in a completed weld?

Accepted Answer

Entrapped gas in the solidifying weld pool

Answer

Porosity is caused by gas that becomes entrapped in the solidifying weld pool before it can escape, forming voids or pockets.

Question 3

The term 'incomplete fusion' refers to which weld discontinuity?

Accepted Answer

A lack of bond between weld metal and base metal or between weld passes

Answer

Incomplete fusion (also called lack of fusion) occurs when the weld metal fails to fuse properly with the base metal or with adjacent weld passes.

Question 4

Overlap in a weld is best described as:

Accepted Answer

Weld metal protruding beyond the weld toe onto the base metal without fusion

Answer

Overlap is a condition where weld metal flows over the base metal surface beyond the weld toe but does not fuse with it, creating a mechanical notch.

Question 5

Crater cracks most commonly form at which location?

Accepted Answer

In the depression at the end of a weld bead where the arc was extinguished

Answer

Crater cracks form in the crater (depression) left at the end of a weld bead when the arc is extinguished, because the small pool cools rapidly under high restraint.

AWS Practice Test

AWS Practice Test

AWS Weld Discontinuities & Defects