Question

identify the following weld defect.
porosity
whiskers
cracking
undercut
cold start

Explanation:

Analyze the visual evidence

Using the Welding Defects and Undercut Defect knowledge points

The image shows a completed weld bead on a metal plate. Along the top edge of the weld bead, there is a distinct, dark, continuous groove or depression melted into the base metal that has not been filled by the weld metal.

Evaluate the options

Using the Undercut Defect knowledge point

• Porosity: This defect appears as small cavities or gas pockets on the surface or inside the weld, resembling tiny holes or a sponge-like texture. The image does not show gas pockets.
• Whiskers: This defect refers to short lengths of electrode wire sticking through the root of a weld, which is not present here.
• Cracking: This appears as linear fractures or breaks in the weld metal or heat-affected zone, which is not visible in this image.
• Undercut: This is a groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal. The dark groove along the top edge of the bead in the image perfectly matches this definition.
• Cold start: This refers to a lack of fusion at the beginning of a weld due to insufficient heat, which does not match the continuous groove along the top edge.

Answer:

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