Hubbed full name with neck flat welding flange welded steel pipe flanges English name: Slip-on referred SO. With neck flat welding flange plate with welded flange is the same pipe, pipe fittings inserted into the flange connection with the device through a fillet or pipe flanges. Sealing surface forms with neck flat welding flange are: raised face (RF), concave (FM), convex (M), the tongue surface (T), and groove (G), the whole plane (FF). Diameter range with a neck flat welding flange: DN10 ~ DN600 Scope: PN series PN2.5 ~ PN40; Class Series Class150 ~ Class1500 flange material: carbon steel, mainly 20 # steel, Q235 material. Manufacturing process: forging. Product Quality: ISO9001: 2008 quality management system certification, ISO14001 environmental management system certification, OHSAS18001 occupational health and safety management system, pressure pipe special equipment manufacturing license, the State Power Corporation, China National Petroleum Corporation a supply network members