... steel 3.ISO9001:2008 Weld Neck Slip on Lap Joint Flange Varieties: threaded flange, slip-on flange (SO), socket welding flange, ... 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 ...