Seam Welder Working Principle
Weld welder is the welding parts assembled into a lap or butt joint and placed between the two roller electrodes, roller electrode pressure welding and rotating, continuous or intermittent pulse transmission, forming a continuous weld resistance welding machine The It can also be said that the seam welding machine is a kind of evolution of spot welding. The seam welding is widely used in the manufacture of joints requiring sealing, and is sometimes used to weld ordinary unclamped sheet metal pieces. The thickness of the metal material to be welded is usually in the range of 0.1 to 2.5 mm.
Seam welding joint forming process (intermittent) seam welding, each solder joint also under preload, power heating and cooling crystallization of three stages. However, due to the rapid change in the relative position between the roller electrode and the weldment during the welding, it is not so obvious that the three stages are differentiated from spot welding. It can be considered that: 1) under the direct pressing of the roller electrode, the metal being energized and heated is in the "energized heating stage". 2) is about to enter the roller electrode below the adjacent metal, subject to a certain preheat and roller electrode part of the pressure, the Department in the "preload phase." 3) just from the wheel electrode out of the adjacent metal, on the one hand began to cool, while still subject to the roller electrode part of the pressure, the Department of "cooling crystallization stage." Therefore, the welding area at the roller electrode and the metal material on both sides adjacent to it will be at different stages at the same time. For any weld on the weld, the process passed from the roller is the process of "preloading - energized heating - cooling crystallization". As the process is carried out under the dynamic, pre-pressure and cooling crystallization stage of the role of the pressure is not sufficient, should make the quality of seam welding joints generally worse than spot welding, prone to cracks, shrinkage and other defects.
Seam welding characteristics
1) seam welding and spot welding is the same as the heat - mechanical (force) joint welding process. In contrast, its mechanical (force) role in the welding process is not sufficient (except for step seam welding), the faster the faster the performance of the welding.
2) The seam welds are made of solder joints which are overlapped with each other, so the splitting at the time of welding is much more serious than spot welding, which makes it difficult to weld the high-conductivity aluminum alloy and magnesium alloy.
3) The surface of the roller electrode is prone to damage and the surface quality of the weld is deteriorated. Therefore, the dressing of the electrode is a particularly noteworthy problem.
4) Since the cross-sectional area of the seam weld is usually more than 2 times the length of the base material (the thinner the board), the damage will occur in the heat affected zone of the base metal. Therefore, the seam welding structure rarely emphasize the joint strength, the main requirements of its good sealing and corrosion resistance.