... /8" to 64" 3,Standard: BS,DIN etc Socket-welding flange Production standard: GB/T9112~9124-2000 JB/T81-94 ... steel: 20# Q235 A234 WPBTypes: Welding Neck Flanges, Slip on Flanges, Threaded Flanges, Socket Welding Flanges, Blind Flanges, Orifice Flanges, ... Lap Joint Flanges, Ring Joint Flanges, Long Welding Neck Flanges, Figure ...