The seam (roll) welding special machine is the evolution of spot welder. It uses the roller electrode to replace the cylindrical electrode of spot welding and as the welding work piece moves between the rolling plates, the seal welding will generate weld nuggets which will overlap with each other so as to achieve welding effect. AC pulse current will be adopted. Roll welding is widely applied to light gauge welding of sealed container of oil drum, can, heating radiator, airplane and fuel tank, rocket and missile.
