1) Seam welding, like spot welding, is a welding process with combined thermal-mechanical (force) action. In comparison, its mechanical (force) effect is not sufficient in the welding process (except for step seam welding), and the faster the welding speed, the more obvious the performance.
2) The seam welding seam is composed of welding joints that overlap with each other, so the shunting during welding is much more serious than that of spot welding, which brings difficulties to the welding of thick plates of high conductivity aluminum alloys and magnesium alloys.
3) The surface of the roller electrode is prone to sticky damage and the surface quality of the weld is deteriorated, so the trimming of the electrode is a particularly noteworthy issue.
4) Since the cross-sectional area of the seam weld is usually more than twice the longitudinal load area of the base metal (the thinner the plate, the greater the ratio), the damage must occur in the heat-affected zone of the base metal. Therefore, the seam welded structure rarely emphasizes joint strength, and mainly requires good sealing and corrosion resistance.