Weâ??ve listed three main types of steel pipe for customers in last essay. They are standard pipe which contains seamless steel pipe and welded pipeline; line pipe and Oil Country Tubular Goods. Today, we will show friends another three categories of it. Pressure Tubing: Used among industrial and pressure application, pressure tubing are produced using seamless manufacturing. Mechanical tubing: Used for mechanical and structural application and is produced by ERW and seamless manufacturing. They conform to ASTM specification. Structural Tubing: Used for support or retention purpose. This tubing can be round or square and are produced by ERW manufacturing. They are used for fences, construction and other misc. support needs.