Square steel pipe is also known as square and rectangular cold bending hollow steel,referred to as square pipe and rectangular pipe. It is a kind of joint name of square pipe and rectangular pipe,that is,the steel pipe with equal and unequal side length,it is made of strip steel processed by technology.

Generally,strip steel after unpacked,flattened,crimped,welded round pipe,then rolled into square pipe, and then cut into the required length. 

Production process classification

Of square steel pipe

According to the production process,square pipe is divided into:hot rolled seamless square pipe ,cold drawn seamless square pipe, extruded square pipe without dimension, welded square pipe.

The welded square pipe is divided into: (a) according to the process of an arc welded square pipe, resistance welded square pipe (high frequency, low frequency), gas welded square pipe, furnace welded square pipe (b) according to the weld of straight welded square pipe, spiral welded square pipe

Square tube material classification.

Square tube according to material: ordinary carbon steel square tube, low alloy square tube. General carbon steel is divided into: Q195, 0215.0235, 0275SS400, 20# steel, 45# steel, etc. : low alloy steel is divided into Q345, 16N, 0390, ST53-2, etc.