slip on welding neck flanges 1.Standard:ANSI B16.5,DIN2573,JIS 5K,GB etc. 2.Material:Cr25Ni35,HK40,steel 3.ISO9001: ... Japanese standard, the Russian standard.Pipe flange standard system on the international 2,The international pipe flange standard system 1) The European ... rest are belonging to American Flange of Americas flange system. on GB standards, largest nominal pressure is 4Mpa of Europe flange ...