Super Duplex UNS S32750 Cold Forming & Post Weld Heat Treatment (ASME VIII-1) 2

[CuMo]

Similar topic discussed previously here but I'm still a bit unsure.

https://www.eng-tips.com/viewthread.cfm?qid=375032

We have a 12"NB pipe spool made from Super Duplex UNS S32750.
Due to cost implications we would like to roll it from 10mm thk plate.

If I work out the resulting strain as per UG-79 it works out at around 3.2%
and one should think we should be alright without subsequent PWHT but since it is the first
time I encounter this issue I would appreciate if someone could shed some more light on this topic.

Reading through UHA-44 and table UHA-44 doesn't seem to help a great deal....

According to this article:

https://www.imoa.info/download_files/stainless-steel/Duplex_Stainless_Steel_3rd_Edition.pdf

"The duplex grades require a more generous bend radius than austenitic grades or need intermediate annealing in severe or complex forming because of their lower ductility. "

Appreciate your help!

 

[XL83NL]

VIII-1 leaves you without further info in UHA-44. This doesnt mean, as you may have noticed, no additional requirements (like e.g. post forming heat treatment) are required to guarantee optimal material performance.
I would refer to API TR-938-C, as I did in the link you mentioned.

See below section API TR-938-C para 7.5;

7.5 Cold Working and Hot and Cold Bending
Solution annealing is generally required by Code or purchaser specifications after cold work exceeds 10 %
deformation for 22 % Cr DSSs and on all cold worked or bent (hot or cold) components of 25 % Cr DSSs (except on
heat exchanger U-bends). If the cold deformation will exceed 15 %, an intermediate anneal may also be required.
This applies to tube and pipe cold bending and other cold forming operations. Except for the issues regarding
avoidance of SSC, higher limits might reasonably be considered if the fabrication equipment is capable of dealing with
high-strength DSSs.

Furthermore you could check material data sheets from reputable manufacturers.

 

[EdStainless]

Doesn't this need to be made to the pipe specification?
In order to meet SA790 it would need to be autougenously welded and solution annealed.

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P.E. Metallurgy, Plymouth Tube

 

Agree with EdS; see SA-790 for manufacturing guidance.
(a) Welding with filler metal creates an untenable situation for post-weld annealing.
(b) Welding without filler metal (autogenous) makes post-weld annealing essential.
'
The best weld you can make is the one you don't have to make, and that is especially true for duplex SS, so be careful what you are getting yourself into with this approach.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[EdStainless]

I should add that when you solution anneal SDSS it is tricky.
You have to get the temperature correct or you mess up the austenite/ferrite ratio.
And you have to quench fairly hard in order to keep from forming detrimental secondary phases.

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P.E. Metallurgy, Plymouth Tube

 

[XL83NL]

Valuable comments Ed & IM. Never looked at it that way

 

[CuMo]

Awesome! You're the best!
Respect!