Sealing surface requirements for NB/T47020 series flanges
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Previously, it was a non-metallic gasket with a thickness of 12.5 and a winding gasket with a thickness of 6.3. But today I checked, and it seems that the standards do not specify any particular requirements regarding roughness; however, HG/T20592 does provide such specifications. I would like to ask what exactly are the required standards for the roughness of the sealing surface on these pressure vessel flanges?
The specific requirements for the roughness of the sealing surface of NB/T47020 series flanges are not clearly specified in this standard. If specific values are needed, you can refer to other relevant standards such as HG/T20592, or determine the appropriate roughness based on the actual application conditions and the requirements of the sealing materials. The main criterion is to ensure good sealing, with the choice being made based on the actual conditions on site. .
NB/T47021 Flat welding flange type A 3 – Structural types and dimensions; NB/T47022 Flat welding flange type B 3 – Structural types and dimensions; NB/T47023 Long-neck butt welding flange 3 – Structural types and dimensions. The drawings for each structural type specify the requirements regarding the surface roughness of the sealing surface
Received, thank you. I checked, and it seems that the difference lies only in the type of flange, with no relation to the type of gasket, right?