Square tubes are formed from coils and then ran through a series of dies. They are are welded from the inside to form their shape. Square tubes are generally used for maintenance and structural purposes. Some examples of applications would be building construction, railings, and sign posts. They are measured by their outside dimensions and their wall thickness.
Square Tube is commonly available in Aluminum, Stainless Steel, Hot Rolled Steel and Cold Rolled Steel.It can be cut to your exact specifications.