Air-Cooled Inconel 625: plugsheet gaskets material 2

[FPPE]

Hello,

We are designing an Air-Cooled in inconel 625 and I would like to ask you if you think that gaskets in inconel 625 are needed for plugs in plugsheet or if we can use another material.
And if so, which would be the requested torque for the plugs.

Design temperature: 427 °C
Design pressure: 4 MPa
Plugs 1-1/8" ASA B1.1 12 UNF

Thank you in advance

 

[Christine74]

I'm used to seeing header plug gaskets specified as the same material grade as the header box itself. In some cases the header plugs are made from a slightly different material grade in order to avoid seizing/galling, but I don't know whether Alloy 625 threads have a tendency to gall. But I think the gaskets should be Alloy 625.


-Christine

 

[FPPE]

Thanks Christine.
Do you have some advice regarding torque for mentioned plugs-gaskets material?

For example, we generally use a torque of 495 Nm for plugs of the same size made of carbon steel (SA-105 or SA-350 LF2 CL1) with soft iron gaskets.
How can we calculate the torque in the case of Alloy 625?

Regards

 

[r6155]

Torque: see ASME PCC-1
Regards

 

[EdStainless]

625 commonly comes in two strength levels.
It would make sense to make the plug from the higher strength material if they are being screwed into material that is of the lower strength.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Christine74]

I'm not aware of any air-cooled heat exchanger standards that provided recommended torques for header plugs. I'm used to just seeing the air cooler manufacturer's recommended torque values for the header plugs followed, but I found a previous thread here that describes a method for determining the torque:

https://www.eng-tips.com/viewthread.cfm?qid=343259

-Christine

 

[r6155]

I insist: see ASME PCC-1
There is no secret, no problem in making a simple calculation. Obviously with a minimum personal effort.
Anyone who understands flange calculation can make the required torque.

Regards

 

[Christine74]

You can insist all you want but ASME PCC-1 only covers Bolted Flange Joint Assemblies (BFJAs), and a header plug is certainly not a flanged joint.


-Christine

 

[r6155]

To establish the required torque, the plug load must first be determined. For this
purpose, an algorithm has been developed that is derived from ASME BPVC Section VIII - Division 1,
Appendix 2

American Journal of Engineering Research (AJER)

http://www.ajer.org

Torque Tightening of Air Cooler Header Box Plugs

Wm1 = H + Hp =
Wm2=
......

AND MORE
Regards

 

[FPPE]

Thank you for all the answers.
Do you think that solid metal type gaskets are appropriate for these design conditions?
Could be a better solution to use stainless steel or soft iron gaskets instead of inconel 625?