Square Tube has two types, one is rectangular tube, another is square tube.It is a hollow rectangular or square section of light thin-walled steel tube, also known as steel cold bending section. It is Q235 hot -rolled or cold-rolled strip or coil as the base material after cold bending forming and high-frequency welding made of square section shape and size of the steel. Except for the thickening of wall thickness, the angular dimension and edge straightness of hot -rolled ultra-thick square pipe can reach or even exceed the level of resistance welding cold-formed square pipe. Comprehensive mechanical properties are good, Weld ability, cold, hot processing and corrosion resistance are good, good low temperature toughness. We can supply black &galvanized steel square pipe.