Seamless Stainless Steel Pipe Standard:321, 304, 304L, 316, 316L, 347, 310S; Standard: GB/T14975/14976, ... /T14976, GB 13296, ASTM A213, ASTM A312; (2)Steel grade: 321(0Cr18Ni10Ti), 304(0Cr18Ni9), 304L(0Cr19Ni10), 310S(0Cr25Ni20), 316(0Cr17Ni12Mo2), 316L ... black painted to prevent rust;(5)Marking: as per customer's requirement