Rating for special materials? 2

[benzy4]

How can I know the rating (Similar to ASME B16.34 or EN12516-1) of special materials like:

ASTM A182 F60
ASTM A182 F316 Ti
MONEL K500 UNS N05500
CW-6MC -N7M

Thanks!!!

 

[apf]

Both ASME B16.34 and B16.5 provide an appendix that allows the calculation of a pressure temperature rating. ASME B16.34:2004 Appendix B

 

[ymjaffar]

u will get the pressure rating in B16.34 as a group number.

 

[franen]

It's a frequent problem in valve design...
If you have the mechanical properties of the material at the different temperatures(for example from ASME II) you can easily define a rating according to ASME B16.34 Appendix (But you cannot mark the valve as ASME B16.34!)
Otherwise I think you need to test the material and define its properties and obtain the approval for that use of a certified institute (at least for European market).
Regards
Francesca

 

[benzy4]

Thank you franen.

You have explained exatly my problem!
Mechanical properties of special materials at the different temperature are impossible to find.
I always search this kind of data, but if the material is not included in ASME II-D or in some EN standard the game is over.

 

[Sweguy]

Hi guys

Materials in pressure bearing parts must be listed in those standards otherwise they are not approved as pressure bearing material, thereby you can`t use that material. I think you can verify your own material according to the standards but then you have the obligation to prove that it can be used as pressure bearing material and in which pressure/temp combinations. If you can convince standard institute about the material you can get a approval to use it, that approval is only valide for your company.

Monel K500 is not a pressure bearing material, One name of Monel as casting is M-35, I think it is ASTM A494 M-35.
In the innerparts K500 is often used in stems and other parts that take loads, then Monel 400 can be used in parts that are not subjected to higher loads.

What I mean is that it is necissary to stick to valid materials in pressure bearing parts and then in inner parts you can those any material you want.

 

[benzy4]

Hi Sweguy,

you are right.
Materials like UNS N05500 or A182 F60 are all in my material list approved by our notified body.
In any case all valve manufacturer produce today pressure retaining parts (like body & bonnet) in F60, but we have no idea about the pressure/temperature rating. Today we compare the chemical composition in order to find a similar material included in B16.34 or in EN12516. Bat this assumption create approximation and doubts.

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