Flange standard issues
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Do flanges of the same standard have different dimensions for carbon steel and stainless steel? For example, in the case of DN25, when measured with a ruler, the pore size of carbon steel is significantly larger. . . Why?
It makes no sense. ASME B16.5 has little to do with the material; it is only related to the hole diameter and LB
Could it be that one is the national standard and the other is the American standard?
I took a close look; they are all HG/T20592
This post was last edited by niat8888 on 2015-10-10 07:56. You need to observe everything carefully. . . The outer diameter of the flange may also vary, as may the thickness of the flange’s connections. . There’s nothing strange about it. For example, the series available for carbon steel pipes and stainless steel pipes are different. The thickness of the flange has only a minimum value, with no specific dimension specified. Generally, the thickness of this flange is selected in conjunction with the pipe fitting. .
When the standards are the same, i.e., both are DN25, but the pore sizes differ, then the pressure ratings must be different; a larger pore size in carbon steel implies a higher pressure
The standard has little to do with the flange material; it is only related to the grade；
For DN25 flanges: PN2.5 and PN6 are 4-Φ11, while PN10 is 4-Φ14
The standards for pipeline accessories are being aligned with international ones; in your case, it seems that different pressure grades were chosen for the design.
Since it is likely a processing issue, the standards are only for reference; as long as it remains within the allowable error range, it can be used