BOLT TORQUE for UNS 8810 2

[91873634542]

Dear All,

Anybody know bolt torque for UNS 8810 ?
we plan to apply hydraulic bolt tightening for CCR dome

Thank you
EP

 

[TGS4]

The selection of a particular bolt preload (whether applied by torque, tensioning, or otherwise) is a complex problem. It involves a lot more than just the metallurgy of the bolt and/or flanges.

You need to do a lot more work in this regard.

However, if you choose to disregard this advice, please feel free to use 6,345 as an appropriate torque.

 

[91873634542]

thank you,
what unit is it ? ft.lbs or Nm

 

[TGS4]

Face-Palm

 

[Duwe6]

8810 has a 25ksi yield. Pay an engineer to calc it for you, and test for the applied torque with your lube, and your surface finish, and your thread pitch and diameter, to get you to about 50% of 25ksi.

Been said many times in several Fora; you cannot calculate torque vs. tension in bolts. Too many unknown variables. You [someone] has to "ask the bolt" what torque is needed.

Other option is to measure bolt extension/elongation. Than CAN give you a calculated value, based on Modulus of Elasticity and loaded area of bolt.

 

[vpl]

TGS4

That's what happens when you give a number. Someone will ignore all the cautions and limitations and run with it -- never checking on the validity.

Patricia Lougheed

******

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[TGS4]

I know vpl, I know. Apparently sarcasm doesn't translate well. I hoped that the lack of units would be a tip. I guess sometimes you need to be as subtle as a sledgehammer...

 

[ione]

In some countries double-facepalm is used as well