... standard:ASTM A106 GRB/A53 GRB/API 5L/GRB/A335/ST37/ST52. Our factory manufacture galvanized pipe,steel pipe,square pipe,pipe fitting.1 ... , STD, SCH40, SCH80, SCH160,SCHXS ,SCHXXS 4.Material: ASTM A234WPB, St37, carbon steel, Alloy steel, stainless steel 5. ... anti rust oil, galvanizing 6.Type: seamless steel pipe,seamless pipe,carbon steel seamless pipe, 7.Special design available 8.Quality: ISO9001 ...