... SO), socket welding flange, lap joint flange (LJF), welding neck flange (WNF), blind flange, orifice flange, reducing flange, pad ... type flange, loose hubbed flange, welding plate flange, welding neck collar, welding-on collar, loose plate flange, companion flange ... so on.Facing method: rust preventing oil, spray paint (black, yellow), hot galvanization, cold galvanization or colored electroplate, ...