slip on welding neck flanges 1.Standard:ANSI B16.5,DIN2573 ... connecting pipe.Flange Type: Welded flange, Welding neck flange, Male and female facing flange, Hubbed ... b, welding flange, welding neck flange, welding neck flange, socket weld flange with neck , slipon plate flange c ... joint faceFlange production standard Chinese Standard:GB/T9112-2000(GB9113.1-2000~GB9123?4-2000) American Standard:ANSI B16.5 ...