... Standard: GB/T 3091-2001, BS1387-1985, DIN EN10025, EN10219, ASTM SCH40, ASTMSCH804. Surface Finish: Galvanized, electro galvanized, black1)Weld form ... /4")2) Wall thickness: 2.5 - 8.18mm3) Standard: ASTM, GB/T3091-2001 Out DiameterWall ThicknessLengthInchmm mm meter1/221.3mm ... many production lines, production GB/T12770-2002, BS1387-1985, ASTM A-53, GB/T3091-2001 other standard pipe, complete product ...