Hi All,
Can anyone please explain me the procedure to calculate the minimum and maximum bolting torque required for the steel flanges for ASME VIII Apex 2 for big flanges?
Any code reference to calculate the torque?

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Regards,
Praphulla Phirke

Hi Praphulla

About your question, I calculated in this way:
- Change the kind of flange through fig.2-4
- Change the gasket in table 2-5.1
- Calculate the moment arms (table 2-6)
- Calculate the internal efforts NC-3658-1 PAG 153
- Calculate forces 2-11 pag 361
- Calculate bolt loads 2-5 pag. 353
- Now about the torque required I utilize the norm DIN 8855 to determine the tight torque as load tensile strength of the bolt chose.

Be very careful! Bolt torque is not the same thing as bolt load

Bolt torque is merely an indication of the resistance encountered when trying to turn a nut. If you specify torque, you're making gross assumptions on how that input force will relate to the residual bolt load. It must be remembered that the same torque applied to one bolt may actually result in a completely different stress value on a similar bolt within the same flange! This common misconception often results in unsuccessful hydro tests, damaged components, forced shutdowns and, irate End Users!

Here's an interesting link which provides further insight: The Common yet Dangerous Misconception of "Torque"

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"If it leaks, just give it another whack" ;-)
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