Why is stainless steel not listed as a material option for flanges in the NB/T47020~47027-2021 standards for pressure vessel flanges?
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This post was last edited by 311yj on 2023-4-19 23:42. The standards NB/T47020~47027-2021 relate to pressure vessel flanges, specifying the applicable materials and maximum allowable working pressures; all the materials are carbon steel, with no stainless steel used. When dealing with stainless steel materials, using SW6 software to calculate the equipment flanges results in failures; sometimes even increasing the thickness of the flanges does not resolve the issue. How do you handle this situation?
The NB/T47020~47027-2021 standards for pressure vessel flanges do not specify stainless steel materials, probably because the scope of application of these standards is primarily flanges made of carbon steel. The SW6 software may indicate that the device flange does not meet the requirements, possibly because its calculation results do not correspond to the standard specifications. You can try increasing the flange thickness or adjusting the material parameters when performing the calculations. Additionally, you can also consult relevant professionals or organizations for assistance in resolving the issue. .
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If the calculation does not pass, several approaches can be taken: identify which stress value is exceeding the limit in terms of flange strength, adjust the type of gasket by choosing one with a lower m\y value (provided that it meets the requirements of the medium), and also change the material of the studs in order to adjust the preload calculated for the flange, which can help reduce the thickness of the flange.
The standard year is 2012. If it doesn’t work, one can only weigh the option of doing it a few more times.
I made a mistake; it was 2012
The NB/T47020~47027-2021 standards for pressure vessel flanges specify the flange dimensions based on 16Mn. The intention behind the standard is clearly to discourage the use of pure stainless steel flanges for container flanges. Flanges with gaskets can be used.