Problems with using the 20592A series and the 12459 series together
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Logically, the 20592A series and the 12459 series, along with the 1b series of 20553, should be compatible with each other. But there’s a problem with DN65: both the flange and the outer diameter of the pipe are 76, while the outer diameter of this fitting is 73. How can it be used then? Are all other fittings part of the same series, while only this one has a different diameter specified in a separate series? Has anyone encountered a similar problem?
The DN125 one is different too. . . Both of these sizes are considered unsuitable for use
For British-style pipes used abroad (i.e., pipes in the large outer diameter series), there are basically two standards for the outer diameter: ASME B36.10 according to American standards and ISO 4200 according to international standards. The outer diameters of these British-style pipes are generally similar, with only significant differences at DN65 and DN125. The HG/T20592-A series and the 1a series of HG/T20553 (the 1a series is generally used, while the 1b series is rarely used) both use the ISO 4200 standard as a reference for the outer diameter of the pipes. In contrast, the GB12459 series relies on the ASME B36.10 standard for determining the outer diameter of pipes; therefore, issues may arise with DN65 when these standards are used together. Flanges in the American standard series are of the class type, whereas flanges of the international or European standard type use the PN series. Thus, when British-standard pipes are combined with PN-series flanges, there are inevitably some details-related problems regarding the alignment of the pipe outer diameters.
However, the outer diameter of the American standard flange 65 is also 76.1, and it doesn’t match the outer diameter of 12459 either. I also want to know whether such an error of 3 mm will cause any difficulties during welding, because previous construction teams never raised this issue, but the current contractor has pointed out this significant deviation in outer diameter.
When people choose pipes with an outer diameter of 1a, what standards are used for the fittings? Can 12459 still be used as a matching standard?
The flange standards are unreasonable. . Direct digital description: the outer diameter should be 73