Rectangular tube is a kind of hollow square section light thin-walled steel tube, also known as steel cold-formed profiles. It is made of Q235 hot-rolled or cold-rolled strip or coil as the base metal, which is shaped by cold bending and then welded by high frequency. The corner size and edge straightness of hot rolled square tube with extra thick wall can reach or even exceed the level of resistance welding cold formed square tube except for wall thickness thickening.

Classification of rectangular pipe: seamless steel pipe and welded steel pipe (slotted pipe) hot rolled seamless square pipe, cold drawn seamless square pipe, extruded seamless square pipe and welded square pipe