It's that DSAW has a seam weld in the inside and outside of the pipe, while the LASW has a single seam weld on the outer surface, longitudinal or cross sectional.
LSAW Pipe (Longitudinal Submerged Arc-Welding Pipe), DSAW pipe (Double Submerged Arc Welded Steel Pipe), Both of them are made of Steel raw materials by Arc Welding way which take the steel plate as raw material, mold it by the molding machine, then do double-sided submerged arc welding. Through this process, the LSAW steel pipe will get excellent ductility, weld toughness, uniformity, plasticity and great sealing.
It's that DSAW has a seam weld in the inside and outside of the pipe, while the LASW has a single seam weld on the outer surface, longitudinal or cross sectional.