What does penetration mean in the context of a groove weld?

What does penetration mean in the context of a groove weld?

• A. The depth to which the weld metal fuses into the base metal.
• B. The width of the weld bead
• C. The heat of the arc at the weld
• D. The amount of filler metal used

Answer: (A)

Penetration is about how deep fusion goes into the base metal along the joint. In a groove weld, it means how far the weld metal fuses from the surface into the thickness of the joint. If the weld fuses through the full thickness, that’s full (or complete) penetration; if it fuses only partway, that’s partial penetration. This concept is about depth of fusion, not how wide the weld bead sits on the surface, nor about the arc heat alone or how much filler metal is used.

Penetration is about how deep fusion goes into the base metal along the joint. In a groove weld, it means how far the weld metal fuses from the surface into the thickness of the joint. If the weld fuses through the full thickness, that’s full (or complete) penetration; if it fuses only partway, that’s partial penetration. This concept is about depth of fusion, not how wide the weld bead sits on the surface, nor about the arc heat alone or how much filler metal is used.