... The public diameter: 6 ~ 4000mm c, Flange structure type: welding, socket welding, threaded connection, loose, butt weld and blind flange d, ... Unit flange a, threaded flange b, welding flange, welding neck flange, welding neck flange, socket weld flange with neck , slipon plate ... , Rotating flange f, Anchor Flange g, Surfacing / Cover welding flange 4) Flange sealing surface: flat, raised face, convex ...