Steel pipes are made by two different processes. First, raw steel is converted into a more workable form. Next, the pipe is formed on a continuous or semicontinuous production line. Finally, the pipe is cut and modified to meet the customer's needs.

Black and galvanized steel pipes are both made of steel, but galvanized pipes have a zinc coating while black pipes do not. Therefore, galvanized pipes are more expensive and more durable.

EN 10219-Cold formed welded structural sections of non-alloy and fine grain steels.

JIS G3454-Carbon steel pipes for pressure service.

EN 10216-Seamless steel tubes for pressure purposes. Unalloyed steel tubes with specified room temperature properties.

The seamless square tube is a long strip of steel having a hollow section and no seam at the periphery, and is a square tube formed by a seamless tube passing through the four sides of the mold.