Question

identify the following weld defect.

whiskers
porosity
cold start
undercut
cracking

Explanation:

Analyze the visual evidence

The provided image displays a close-up photograph of a weld bead with a distinct, continuous longitudinal groove or depression running along the toe of the weld where the weld face meets the base metal. This groove represents a reduction in the cross-sectional thickness of the base metal.

Identify the defect type

Using the Welding Defects knowledge point, we evaluate the options:

• Whiskers: Unmelted electrode wire protruding through the root of the weld.
• Porosity: Gas pockets or cavities trapped within the weld metal.
• Cold start: Lack of fusion at the beginning of the weld run due to insufficient heat.
• Undercut: A groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal.
• Cracking: Fracture-type interruptions within the weld or base metal.

The visual evidence of a groove melted into the base metal along the edge of the weld bead corresponds directly to the definition of an undercut.

Answer:

• Whiskers
• Porosity
• Cold start
• Undercut (Correct answer)
• Cracking