Standard: German standard DIN, American Standard ANSI, ASME, British Standard BS, Japanese standard JIS, Italian standard UNI, Germany and China Standard GOST standard GB, HG, JB and so on. Our steel pipe flanges national standards GB 1) Nominal pressure: 0.25Mpa ~ 42.0Mpa a, Series 1: PN1.0, PN1.6, PN2.0, PN5.0, PN10.0, PN15.0, PN25 .0, PN42 (main series) b, Series 2: PN0.25, PN0.6, PN2.5, PN4.0 which PN0.25, PN0.6, PN1.0, PN1.6, PN2.5, PN4 A total of six grades of 0.05 flange size flange system belongs to Germany, represented by the European flange system, the rest of the United States of America as represented by the flange flange system. In GB standard, belonging to the European flange system of nominal maximum level for 4Mpa, belonging to the Inter-American system of nominal level flange maximum 42Mpa.