Pipe flange standards
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In the examples of flange markings for steel pipe flanges, gaskets, and fasteners given in HG/T20592~20635-2009, such as HG/T20592 Flange PL100 (B) -2.5 RF Q235-B, what is the unit of the pressure rating “2.5” for the flange? The previous standard HG/T20592-97 clearly specified “MPa,” but I think it’s easy to get confused about this. What are others’ opinions?
In version 09, bar is defined as kgf/cm^2; this standard change is really annoying
I don’t know why it was changed to units of bar; maybe it’s to be more in line with international standards
The standards specify only dimensionless numbers; the allowable pressure varies for different combinations of materials and temperatures.
I want to know too, oh, I don’t quite understand. . . . . . . . . . . . .
In HG/T20592-2009, it is no longer 2.5 but 25. The unit is bar; it used to be Mpa, but I’m not sure why it was changed to MPa.