Why alloy 925 material not available in ASME SEC II PART A&B....: 2

[ramesh349]

Hi...

i am designing a vessel with having fasteners material of Alloy 925(UNS N09925). It is a U-stamped vessel. I could not able to trace the material in ASME Sec II materials for design purpose. Can you please share the history about the material and where it is available.

Please advise me.

Thanks in advance,
Ramesh Kumar

 

[metengr]

Alloy 925 material has not been considered by the ASME B&PV Code committee because a User or design firm, like yourself, has not requested a need through the code committee to use this material in boilers and pressure vessels. A search of this material indicated it is being used for oil and gas applications.

http://www.specialmetalswiggin.co.uk/products/incoloy-alloy-925

 

[ramesh349]

Thanks metengr....for your quick response.

Can we use alloy 925 material, even If it is not covered with in ASME?. Because, clearly bolt material was mentioned in client data sheet and also it is a U stamp vessel. in this case can i proceed with the same material or else i have to fallow any code rules?.

Is there any reason behind it, why the ASME not consider alloy 925 material?

 

[SnTMan]

ramesh349. a small amount of googling brings up this:

http://www.pressbolt.com/uns n09925_incoloy alloy 925_specification_for_bolts_press_bolt.html

Perhaps the cited Code Case will solve your problem.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[TGS4]

No, you cannot use it for U-Stamped construction - currently.

However, as metengr pointed out, no one has asked the BPV Committee to add such a material. If I were you, I would ask. Start by requesting a Code Case for the material, and then follow up by requesting that the material be added permanently.

That's how this whole ASME Codes and Standards work. There's not some all-knowing all-powerful group of super-engineers (although we like to believe that we are, the truth is that we're just a bunch of regular engineers with a passion). It works as a collaborative community - engineers need something, so they ask for it. Engineers see something wrong, or have better/newer information, they come forward and collaborate on a better way. You can think of the Codes and Standards community as the original social network that started over 100 years ago - everything is crowd-sourced with volunteers.

Now, go do your part and contribute.

 

[metengr]

ramesh349;
Are the bolting materials listed on the data report as part of vessel design? See UG-12 in ASME Section VIII, Div 1. If so, alloy 925 material cannot be used because there are no allowable stresses to use for design.

If the bolting materials are not part of vessel design, you can use material at your own risk.

Again, alloy 925 is not listed as pressure retaining material because it has not been asked for use by a pressure vessel engineering organization or owner/user. If you feel there is a need, you can request a code case from ASME Section VIII, Div 1 committee.

 

[XL83NL]

@SnTMan; CC 2218 is not part of the 2015 Code Case overview anymore, so therefore it cant be used (as TGS4 indirectly implied).
It was part of previous code cases, see e.g.

http://files.asme.org/catalog/codes/printbook/13883.pdf

 

[ramesh349]

Thanks to everyone....for your guidelines about my query.

i will proceed with your reply accordingly.


Once again thank you so much.

 

[SnTMan]

XL83NL. OK good to know. I made no attempt to follow that up, only offered it to the OP. Wonder why it was withdrawn?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[metengr]

Most likely it was used in a specific application, and the Standards committee did not bother to incorporate the CC into the Code book section. It happens unless you have a PM that shepherds the CC for incorporation.

 

[SnTMan]

OK, well one thing further I might offer. It is not that unusual for a client to specify a non-permitted material, in which case you can offer an alternate.

SB-425 (N08825) seems to have a nearly identical nominal composition. Explain the situation and let 'em accept / reject it.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[EdStainless]

925 is an age hardening version of 825, so people use it to achieve higher strengths.

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P.E. Metallurgy, Plymouth Tube