ERW straight seam steel pipe is made by using the skin effect of high-frequency current to quickly heat the edge of the formed tube to the welding temperature and then perform extrusion welding. According to different power feeding methods, ERW welded pipe can be divided into high frequency contact welding and high frequency induction welding. Both use the skin effect and proximity effect of high-frequency currents, and at the same time pressure weld synthetic steel pipes under the action of squeeze rollers.
ERW contact welding straight seam steel pipe uses two electrodes or welding feet to respectively contact the two edges of the formed tube. The skin effect and proximity effect produced by high-frequency current are used to concentrate the welding current on the V-shaped gap, and the V-shaped gap The metal is instantly heated to the welding temperature, and the composite steel pipe is welded under pressure by the squeeze roller; ERW induction welding is to first form the hot rolled coil into a tube through the forming unit, and when the tube passes through the induction coil (high frequency The induction coil of the welder generates a high-frequency magnetic field due to the passing of high-frequency current), high-frequency induced eddy current will be generated in the tube, and then the skin effect and proximity effect of the high-frequency eddy current are used to make the eddy current intensive at the edge of the tube Because of the V-shaped notch, the formed tube is quickly heated to the welding temperature due to its own resistance, and the composite steel tube is pressure welded under the squeeze of the squeeze roller.
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