... /API 5L/GRB/A335/ST37/ST52. Our factory manufacture galvanized pipe,steel pipe,square pipe,pipe fitting.1.Standard: ANSI B16.9/16.28, DIN ... .Size:OD: 1/2"- 48" 3.Schedules: SCH20, STD, SCH40, SCH80, SCH160,SCHXS ,SCHXXS 4.Material: ASTM A234WPB, St37, carbon steel ...