Oil Line Pipes 1.Standard:BS, GB, DIN, ASTM, API 2. ... ,B), St37, St52, St42, Q.. 3.Outer Diameter:8-24mm Oil Line Pipes Spiral Seam double-side submerged arc welded steel ... 4. Casing steel pipe 5. Seamless steel pipe/tube 6. Oil tube 7. hot-galvanized steel pipe Ssaw Oil Line Pipes (L415, L320, L450)