What does resistance seam welding produce along a lap joint?

• A. A continuous seam weld
• B. A single isolated weld
• C. A series of separate weld points
• D. A melted area without welding

Answer: (A)

In resistance seam welding, heat is generated along the line of contact as rolling electrodes pass over the overlapped edges and current flows. The wheels press the sheets together and travel along the seam, so the metal at the contact area fuses continuously as the weld progresses. Because the welding path is continuous, the individual heated zones overlap to create one uninterrupted weld along the entire length of the lap joint. This is different from spot welding, which yields separate weld points. The result is a continuous seam weld along the lap joint.