Double Seam Pipe : Pipe having two longitudinal seams formed by the submerged-arc welding process or the gas metal-arc welding process or the combination welding process. (Spec 5L)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}