US Patent 10335890 Seam welding method and vehicle body

In a seam welding method, a pressing force applied to workpiece by roller electrodes is reduced and an energization to the roller electrodes is stopped when the roller electrodes pass at least a portion where metal sheets are temporarily fastened together through spot welding, and the pressing force to the workpiece by the roller electrodes and the energization to the roller electrodes are restored after the roller electrodes have passed the spot welded portion.