... certificate oil and gas pipe flange ,galvanized pipe flange ,hydraulic pipe flange 1. Type: oil and gas pipe flange,galvanized pipe flange,hydraulic pipe ... flange 2. Material: carbon steel, stainless steel and alloy steel flange3. Standard: ANSI, JIS, BS, DIN, UNI, EN, GB, AWWA, API ... Requirement7. Painting: yellow varnish, black paint. Rust oil and Zn plate8. Inspection: in-house and the third ...