1. API 5L, ISO 9001, ISO14001, OHSAS 18001, CE PED certification. 2. OD 16to 56 inch, thickness 0.3 to 1.6 inch. DSAW pipe is dual submerged arc welding pipe, also named SAWL(longitude submerged arc welding line); widely use as transmission line for oil, gas, nature gas, water and other high pressure pipe lines for onshore projects, offshore projects, chemical industry, city gas and water supply ...