ERW Welding Seam Method

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Seam welding is rolled by a pair of cylindrical electrode plate instead of the spot welding electrode, and the workpiece are relatively moved, to produce one of the nugget mutually overlapped sealing seam welding method. Seam welding is widely used in oil drums, cans tank, radiator, aircraft and fuel tanks, as well as jet engines, rockets, missiles in sealed container sheet welding.

Seam welding with the electrode is circular rolling plate, roll diameter of the disc is generally 50-600mm, common diameter of 180-250mm. Roll disc thickness of 10-20mm. In addition to the form of the roulette cylinder bilateral chamfer, but also can be made into the form of a single measurement chamfered to fit hemming joint seam welding. Different depending on the contact surface width ω workpiece thickness 3-10mm, the spherical radius R of 25-200mm. Cylindrical roller tray is widely used in a variety of welding steel and superalloys, spherical roller tray is easy because of the heat, indentation transition uniform, commonly used in the welding of light alloys. Roulette usually external cooling. Non-ferrous metals and stainless steel welding time, with clean tap water, welding general steel, in order to prevent rust, commonly cooled 5% aqueous solution containing borax. Roulette sometimes used internally circulating cooling water, especially welding aluminum welder, but its structure is much more complex.

According to the rotation of the feed roller tray way points can be divided into a continuous seam weld seam welding, seam welding and stepping intermittent seam welding. Continuous seam welding, roll pan continuous rotation, constant current through the workpiece. This method is easy to make the surface overheating, electrode wear serious, and therefore rarely used. However, when the high-speed seam welding (4-15m / min) every half cycle of 50Hz AC will form a solder joint, the zero crossing of the AC equivalent resting time, which in turn is similar to the following intermittent seam welding, and thus in the system cylinder, cooperage obtain applications. Intermittent seam welding, the continuous rotation roulette, discontinuous current through the weld, formed by another shingling nugget components. Since the current intermittently through in the resting time, roll pan and the workpiece to be cooling, which can increase the life of the roulette, reduce the heat-affected zone width and deformation of the workpiece to obtain optimum welding quality. This method has been widely used in a variety of 1.5mm below the seam welded steel, high temperature alloys and titanium alloys. Intermittent seam welding, due to constantly leave the roulette weld zone, the nugget in the case of crystallization pressure is reduced, making it easy to produce hot surfaces, shrinkage and cracking (as in welding at high temperature alloys). Although the weld nugget shiplap length of more than 50%, after a little bit of molten metal can be filled before the shrinkage, but in the end it is difficult to avoid shrinkage.