As per B16.5, 600# flanges shall have Raised face thickness 6.35, what if, that thickness is reduced to 2.5mm (by mistake while machining of flanges). As Sec. VIII-1, App-2 is silent about raised face thickness, so what factors I should consider while designing flange as per App-2 or I should consider as this as standard flange only?
Do we need to consider other factors such as limited torque for bolt tightening of flanges?

As per ASME B16.5 tolerance on raised face is plus minus 0.5mm

You can calculate the flange as per appendix 2.

Also app 2 doesnt speak about raised face thickness.

My concern is the crushing of that raised face due to the bolt load.
I hope it is incorrect.

AI will not accept it for a U stamped job.

Hope this helps.
Regards
ASD23789

If correctly calculated per Appx. to I would have no concern.
mauro

Dear npccmechanical:

Sorry, you mislead yourself with a wrong requirement that nowhere appears in code.
You wrote: "As per B16.5, 600# flanges shall have Raised face thickness 6.35…."
Kindly, look at B16.5-2009 6.4.1:

May we agree that "REGULARLY" is not "SHALL" ?

Furthermore: please look at B16.5-2009 6.3.2:


So, as your flange is still covered by B16.5, you can straightforward go ahead with this flange acc. to VIII-1 UG-44(a) with no need to make any calculation of App. 2 as far as your design conditions covered by flange Pressure-Temperature rate.

Well, you are right, in this case you should put your logo on the flange, I believe it is not permitted to machine a flange made by another flange manufacturer maintaining its logo.
mauro

Thanks shmulik

Dear Mr. Mauro:

I respectfully differ regarding to flange restamp. I would say that it is not mandatory since B16.5 does not address it.

I dont think there is any problem as long as the face of the flange is machined properly (AARH).