API SPEC 5L Line Pipe
API SPEC 5L line pipe production process is divided into seamless steel pipe, ERW steel pipe, submerged arc welded pipe. But the main use of seamless steel pipe (the Seamless), straight seam high frequency resistance welding steel pipe (Electric-Resistance Arc Welding, abbreviated as ERW), LSAW (Longigudinally Submerged Arc Welding short LSAW), spiral submerged arc welded pipe (Spirally Submerged Arc Welding, short of SSAW) four.
LSAW pipe divided into UO (forming method of UOE), RB (RBE), the JCO (JCOE) and other kinds. Steel plate in the molding would be pressed into a U-shaped, and then pressed into the O-, and then the inside and outside submerged arc welding, after welding, usually at the end of the full length of the expander (Expanding) called UOE welded pipe, not expanding known as the UO pipe. Pressure steel plate roll bending (Roll Bending), and then the inside and outside submerged arc welding, after welding, expanding the RBE pipe, or not expanding the RB pipe. Molding plate according to the type J-O-C-order expanding JCOE pipe or not expanding JCO pipe after welding. LSAW pipes above, the use of common of UOE. The high frequency resistance welding tube ERW tube embryo through the skin effect and proximity effect in high-frequency current to the edge of the melt, and then squeeze rollers under pressure welding, which is characterized by no external filler metal, heat affected zone, high production efficiency. Spiral seam pipe the SSAW for long-distance line pipe has a long history, the pipeline in China is mainly used.