Tube to tube sheet welding at inner face (shell side) of Tubesheet 3

[EngineerEPC]

Dear All,

Has anyone come across Tube-to-tubesheet welding at inner face (shell side) of Tubesheet. Sorry if it is a foolish question.
I am baffled as to how it is accomplished.
Please refer below snaps from EN-13445 part-3 for reference.

Thanks and regards

 

[EdStainless]

I have never seen it done like the picture.
I have seen it done as a butt weld with the tube mated to the hub on the backside of the tubesheet.
Very special torches, semi-automatic, lots of setup and validation work.

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P.E. Metallurgy, consulting work welcomed

 

[EngineerEPC]

Hello EdStainless,

Thank you for the reply.
Regarding butt weld with tube mated to hub on backside of tubesheet, EN-13445 part-3 has that sketch also. Please refer below.
Actually, I am enquiring about the manufacturing steps. (which tubes are welded 1st, then their NDE requirement,etc)
Thanks and regards

 

[EdStainless]

The only HX like this that I have personally been involved with were acid coolers.
They would weld a group of tubes adjacent to each other in one area.
Then while those were being inspected they would weld in a different portion of the tubesheet.
The inside of each tube was given a visual inspection (video borescope) and dye pen.
They would also go in through access ports and video borescope inspect the outsides of every weld.
The in-process weld data was also being logged. Any deviation flagged that weld for additional inspection.
It wasn't uncommon to see 1-2% of the tubes plugged prior to pressure testing.
Considering that this was a zero tolerance application.

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P.E. Metallurgy, consulting work welcomed

 

[EngineerEPC]

Hello EdStainless,

Thank you very much for the comprehensive reply. It is now much clear to visualise.
Cheers

 

[fleischfresser]

This tube to tube sheet joint is used by several manufacturer.
See Code Case 2428-4 "Attachment of Tubes to Flat Tube sheets Using Complete Penetration Welds Section VIII, Division 1"

See also:

https://www.borsig.de/information/d...rs-for-ethylene-cracking-furnaces/pageflip#14

Regards - Juergen