... steelASTM A105, SS400,ST37.2, ST35.3, ASTM A182 F304/304L/316/316L/321 and so ... flange, slip-on flange (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 ... connecting pipe line and keep its leakproofness; convenient for replacing pipe line; easy to separate and check ...