... , The flange structure type: Flat plate welding type, Flat welded loop loose type, Butt weld edge loose type, Butt weld loop loose type, Butt weld, Joint ... ), b, The public diameter: 6 ~ 4000mm c, Flange structure type: welding, socket welding, threaded connection, loose, butt weld and blind flange d, Flange ...