Question

identify the following weld defect.

porosity
whiskers
cracking
undercut
cold start

Explanation:

Analyze the visual evidence

Using the Welding Defects knowledge point, we examine the provided image of the weld bead. Along the top edge of the weld bead, there is a distinct groove or depression melted into the base metal that has not been filled by the weld metal. This groove runs parallel to the toe of the weld.

Evaluate the options

• Porosity: This defect presents as small cavities or gas pockets on or within the weld bead, which are not visible here.
• Whiskers: This refers to short lengths of electrode wire sticking through the root of the weld, which is not shown.
• Cracking: This would appear as linear fractures in the weld bead or heat-affected zone, which are absent.
• Undercut: This is a groove melted into the base metal adjacent to the weld toe and left unfilled by weld metal, matching the visual evidence perfectly.
• Cold start: This typically refers to lack of fusion at the beginning of a weld due to insufficient heat, which does not match this continuous groove.

Answer:

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