... plate flange, welding neck collar, welding-on collar, loose plate flange, companion flange and so on.Facing method: rust preventing oil, ... , cold galvanization or colored electroplate, powder coating and so on. Detailed information as follows:1.Standard:ANSI,ASTM,ASME,DIN ... : connecting pipe line and keep its leakproofness; convenient for replacing pipe line; easy to separate and check the situation of ...