High-frequency resistance welding basic principle: a pair of electrodes two leg edge contact with the tube, directly to the edge of the input frequency current tube, using high frequency current of the skin effect and proximity effect, so that the current is highly concentrated in the edge of the welded tube combined surface resistance of the metals themselves depend, to the edge strip rapidly heated to a soldering temperature, the pressing force of the roller press to complete the weld.
High frequency induction welding basic principle: a tube surrounded by an outer high-frequency current through the induction coil, the tube high frequency currents induced on the use of high frequency current skin effect and proximity effect, so that the current highly concentrated in the tube welding the edges of the surface, relying on the resistance of the metals themselves, the edge rapidly heated to a soldering temperature, the pressing force of the roller press to complete the weld.
Aiming at high frequency induction welding (HFIW) and high frequency contact welding (HFCW), which commanly are adopted in production of HFW pipe,this paper compared the difference between HFIW and HFCW from scope of application,energy consumption and quality costs.The most significant advantage of HFCW is low energy consumption，but its quality costs are higher than that of HFIW；If HFIW is configured properly，manufacturers will obtain the optimization in cost and quality. The specific performance is as follows:
1) pipe surface is smooth, especially compared to the inner surface of the weld smooth.
2) induction loop is not in contact with the wall, so the tube joints and surface quality requirements are relatively low, but also not as high as that may cause contact welding when the pipe surface burns.
3) because they do not exist electrode (slider) pressure, it does not cause local buckling deformation tube, tube surface coating does not cause abrasions, thus suitable for the manufacture of thin-walled tubes and coated pipe.
4) without electrodes, thus saving time and material saving, there is no question electrode power transfer from the workpiece causing instability and affect the quality of welding and other issues. However, high frequency induction welding energy loss is large, with the same power in the same size pipe welding system, its high welding speed contact method is only 1/2 to 1/3, and thus, the large diameter welded pipe system to use high-frequency contact method when appropriate.
Post time: Sep-11-2019