Another name for square pipe, that is, steel pipe with equal side length. It is made of strip steel by technological treatment. It is the process of strip steel unpacking, leveling, curling, welding to form round pipe, then rolling the round pipe into square pipe, and then cutting to the required length. On the market, the size of small specifications is usually 6 meters, and that of large specifications is 12 meters. Other specifications can be produced according to the usage.