What is porosity and how can it be detected visually?

• A. Gas pockets in weld metal; visible as tiny holes or rough interior surfaces along the weld.
• B. A measure of the weld bead color.
• C. The rate of cooling after weld.
• D. The amount of spatter on surrounding metal.

Answer: (A)

Porosity is gas pockets trapped in the weld metal as it solidifies. Visually, you detect it by looking for tiny holes or pits in the weld, or a rough interior texture along the weld bead that hints at voids inside. These gas pockets can make the surface look bumpy or foamy, and deeper porosity may show up when the weld is sectioned or inspected more closely. Porosity arises from gas being trapped due to things like moisture on the metal or electrode, oil or contamination, or poor shielding coverage, so keeping metal clean and ensuring proper shielding helps prevent it. The other ideas don’t describe porosity: bead color, cooling rate, and spatter are not direct indicators of gas pockets in the weld.