What is weld overlap and how is it different from reinforcement?

• A. Overlap is excess weld metal with no fusion into the joint; reinforcement is additional weld metal along the surface for strength.
• B. Overlap is a decorative feature; reinforcement increases weld visibility.
• C. Overlap and reinforcement are the same thing.
• D. Reinforcement only occurs in the root pass.

Answer: (A)

Overlap is excess weld metal that fails to fuse into the joint, so it sticks out beyond the weld surface without joining to the base metal. Because it isn’t bonded to the joint, it doesn’t add strength and can create defects, cracks, or corrosion traps.

Reinforcement, on the other hand, is the extra weld metal placed to build up the weld size and increase strength by increasing the throat and cross-sectional area. When done correctly, reinforcement is fused to the base metal and contributes to the joint’s load-bearing capacity.

So the correct choice captures the idea that overlap is unfused, excess material, while reinforcement is the intentional, fused extra material that strengthens the weld. The other options mischaracterize overlap as decorative, suggest reinforcement changes visibility, claim they’re the same, or limit reinforcement to a root pass.