Longitudinal seam welding machine series are mainly used for welding longitudinal seam of thin sheet.They can be used to weld tubes, cylinders, cones, flat sheets, sinks, tank shells, and open ended boxes. A wide variety of materials can be welded, including aluminum, stainless steel, hastelloy, titanium, inconel, galvanized, aluminized, and other materials. It adopts cantilever type, and it is mainly composed of frame, fingers-type clamping unit, water-cooling mandrel, travelling carriage, crossing slider, wire feeder and torch holder. Water-cooling mandrel is designed according the work pieces' diameter and length to ensure the strength. The top of mandrel is inserted water-cooling insert with groove for heat-sink cooling. It is adjustable in mandrel height to handle various material thicknesses.