... 1) Spec.: OD: (8-580)mm, WT: (1-30) 2) Main material: 304, 304L, 321, 3 Stainless Steel Seamless 1) Spec ... .: OD: (8-580)mm, WT: (1-30) 2) Main material: 304, 304L, 321, 316, 316L, 317, 310S, etc.3 ... ) Main technical standards: GB/T14975-94, GB/T14976-94, JIS G3468, ...