In terms of quality, the high-frequency welded pipe unit has the advantages of good weld quality, small internal and external burrs, high welding speed and low power consumption, and can be widely applied and popularized. High-frequency welded pipe units can produce heterogeneous pipes normally. At the same time, square and rectangular pipes are produced. Because square and rectangular pipes have large section modulus, they can withstand greater bending force, which can save a lot of metal, save processing time and reduce components. The advantages of weight and so on, so it is promoted and used in all aspects of industry and agriculture.