Maximum Allowable Stress for SB-677 N08904? 1

[HungM]

Hi, experts,

I am currently working on a Shell and Tube Heat Exchanger (STHE) design with the tube material specified as SB-677 UNS N08904. Table UNF-23.3 lists SB-677 UNS N08904, but I can't find the allowable stress values for it in Table 1B of Section II, Part D, Subpart 1. Does anyone know where to locate the allowable stress for SB-677 UNS N08904?

Thank you!

 

[IdanPV]

Hi,

Refer to Section II-B, SB-677, Paragraph 1.2, this product is now covered by Specification A312.
So, you may use the allowable stress per Section II-D, SA–312 for this grade.

I think that this grade should be removed from UNF-23 and put in UHA-23.

 

[HungM]

Hi, IdanPV,

Thank you for your suggestions. However, I think using SA-312 pipe material for tubing is inappropriate due to the wall thickness. A possible solution is to use the SA-249 N08904 welded tube specification, but based on our previous project experiences, seamless tube would be the top priority. Another option is A-269, but UHA doesn’t adopt A-269. Is there any Code case that allows for the use of A-269? Or is there a clear path to design an STHE with SB-677 N08904 tubing when using ASME BPVC 2023 Edition?

Furthermore, in the 2021 Edition, the Code does provide the allowable stress for SB-677 N08904, but this was deleted in the 2023 Edition...

HungM

 

[leon_har_dt]

Hi!
another way could be with SA213. This year N08904 is integrated in the SA213 (seamless tube).
Page 260 of the section II code, part D.

I hope it could be helpful.

Leo.

 

[IdanPV]

Hi,

A-269 not appears on UHA-23 and therefore, you are not allowed to use it.
What is the problem with SA-312? it is avilable at all NPS (DN) sizes and schedule numbers.

@leon_hr_dt, according to Section II-B, SB-677, Paragraph 1.2, this product is now covered by Specification A312, not 213.

 

[EdStainless]

There is no limit on the pipe specs for the size, it doesn't need to be a pipe size at all.
We made tube to pipe specs all of the time.
You might be better off using A249 and requiring a bit of additional QA (corrosion testing).
This tube will generally be at least as good as seamless.
I don't know of any practical test that a seamless tube will pass that a welded tube will fail.

This was moved because it is a Stainless Steel and not a Ni alloy.
At one time alloys that were less than 50% Fe were not considered steels.
Then people realized that they still had more Fe than anything else and started moving them.
This also happened to the 6%Mo alloys and some Incoloy grades.

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P.E. Metallurgy, consulting work welcomed

 

[HungM]

IdanPV, EdStainless,

So, based on your opinions, I can place a special order to have SA-312 pipe made to the tube size (in my case, 3/4” OD x BWG #10 – 3.048 mm)? I don’t have experience with this, but it seems like a viable solution. To summarize, using SA-312 as tubing is one possible solution, and another option is to use SA-249. Both materials are allowed in the licensor’s specifications, so I will clarify with the licensor.

leon_hr_dt,
In Sandvik 2RK65™ datasheet, SA-213 is included. So I will also propose the alternative to the licensor.

Better solutions are always welcome.

HungM

 

[EdStainless]

The issue is that A249 requires more testing than A312.
A312 basically requires nothing but a hydro which is worthless.
At least A249 would require ET and some destructive testing.


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

 

[fleischfresser]

Working with the code means be precise and read the code. Which edition is applicable?

Edition 2021
SB-677 UNS N08904 is mentioned in table Table UNF-23.3 as well in ASME IID, table 1b, line 37 and UG-4(a) will be met.

Edition 2023
SB-677 UNS N08904 is mentioned in table Table UNF-23.3 but not mentioned in ASME IID, table 1b and UG-4(a) will not be met.
Summary of change in ASME IID: Table 1B (2) Lines 36 and 37 deleted.
This is an inconsistency that has occurred several times in the past. However, as I have already mentioned, the UG-4(a) is not formally satisfied.

But you can use UG-15
"When there is no material specification listed in Subsection C covering a particular wrought product of a
grade, but there is an approved specification listed in Subsection C covering some other wrought product of that
grade, the product for which there is no specification may be used provided:
(a) .......The stress values for that specification given in the tables referenced in UG-23 shall be used.
.....


Regards - Juergen