... , LF2, LF3, Q235, 20#, 45#, 20Mn. 16Mn,Q345, etc.face: RF, FFsurface treatment: black painting, anti-rust varnish, anti-rust oil ... , shipbuilding, construction, etc.other types of flange: WN flange, blind flange, plate flange, socket weld flange, threaded flange, ring joint flange, etc. OEM to special requirement.pipe ...