The diameter of longitudinal welded pipe production line is a pipe production line which integrates welding, finishing, pipe processing and heat treatment of pipe and casing. The ERW steel pipe production line imports the forming equipment and technology developed by German SMS Meer Company, and is equipped with the world's most advanced non-destructive testing equipment, high frequency welding equipment and heat treatment of welding equipment.


Welding of formed steel pipe is the core part of welded pipe production line, and welding quality directly determines the qualified rate of products. With the continuous development of power components and power electronics technology, as well as the demand for induction in heating, smelting and welding equipment, induction welding equipment technology has also been unprecedented development opportunities. From transistor to SCR, IGBT is gradually used in MOSFET, and the power and frequency of inductor are gradually increased.


The ERW pipeline unit absorbs the development experience of similar units in the world. Combining with the development of advanced high frequency induction technology in the world, the high power high frequency induction welding technology based on EFD IGBT is adopted. The device can be used as an induction welding machine, and the load can be replaced by a contact welding machine. Contact welding has the advantages of high efficiency and low power consumption, but its disadvantage is easy to leave scratches on contact blocks and EDM burns. Therefore, in view of the user's continuous improvement of the quality requirements of high frequency induction welding in the 20th century, it has been widely used in the 1990s.


The welding principle of contact welding is basically the same as that of induction welding. The difference is that induction welding requires the coil to be placed on the formed steel pipe, and contact welding extrudes the two edges of the strip through contact boots. Induction welding current is induced by high frequency current output from coil, while contact welding current is directly used by high frequency power supply current. Therefore, the efficiency of contact welding is obviously higher than that of induction welding, and it is easy to produce contact scratches and spark burns.