... carbon steel 4.Standard: ASTM A 16.5, ASTM A16.47,ISO, nameASTM A 16.5 carbon steel Flangeshapesocket weld flange, ... Stainless Steel, Alloy Steel CertificateAPI, ASME, and ISO9001: 2000Surface treatmentblack painting, anti-rust varnish, anti-rust oil, hot-galvanized, etc.Applicationspetroleum ... , gas, chemical, metallurgy, electric station, shipbuilding, construction ASTM A 16.5 carbon steel Flange