Structural Steel Pipe : A cylindrical tubular member formed from plate steel with longitudinal and circumferential butt-welded seams and having a uniform wall thickness. (Spec 2B)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}