Lsaw steel pipe (longitudinal double submerge arc welding steel pipe/dsaw steel pipe) is one kind of the saw pipes, it is made of steel plates of hot rolled by jcoe or uoe forming technology. Our company usually produce the pipes by jcoe technology, the jcoe means the forming process, as j shape firstly, then c shape, and then o forming, e forming process at last, while inner & outside welding and cold expansion after welding. Compared with uoe lsaw pipes, our productive line could produce more sizes, od406mm-1620mm, pipe length: 2m-18m, the thcikness from 6.35mm-60mm and our lsaw pipes has its superiority: Longitudinal double submerge arc welding steel pipe(lsaw steel pipe) is made of steel plates of hot rolled by jcoe and uoe. Jcoe means the forming process, as j shape, c shape, o forming, inner&outside welding and cold expansion after welding. It only has one straight seam on the pipe body. 1. Feature: large diameter, thick wall, high pressure&low temperature resistance 2. Test: chemical component analysis, mechanical properties (ultimate tensile strength, yield strength, elongation), technical properties (flattening test, blow test, impact test, dwt test), exterior size inspection, hydrostatic test, x-ray test, ut test. 3.Application:the bas e metal and weld metal were tested according to the pipe specification api spec 5l psl1, widely used for liquid delivery, such as oil, gas, water and seashore, ground constructions.