Nickel Based Alloy
Nickel Based Alloy
(OP)
What is the minimum amount of Nickel content for an alloy to be considered a Nickel Based Alloy? This question came up on API 510 examination. Also please provide the source for this information if possible.
Thanks
Ron
Thanks
Ron





RE: Nickel Based Alloy
Not sure though on the above, but that's what Ive understood so far.
RE: Nickel Based Alloy
Excellent question.
The alloys that I have commonly heard referred to as "nickel alloys", such as Hastelloy, Inconel, Haynes 230, etc, do have greater than 50% Ni content. Another good example is A286 alloy, which is corrosion/heat resistant but is considered an "iron-based alloy" due to an iron content above 50%. Here's what AR-MMPDS-01 has to say about A286: "Composition — The complex-base alloys comprising this group range from those in which iron is considered the base element to those which border on the nickel-base alloys. All of them contain sufficient alloying elements to place them in the “Superalloy” category, yet contain enough iron to reduce their cost considerably."
On the other hand, there is HS188 (Haynes 188) which is considered a "cobalt alloy", but only has a Co content of about 39%.
It would seem that to be considered a "nickel alloy" the Ni content percentage would just need to be greater than any other element.
Hope that helps.
Terry
RE: Nickel Based Alloy
RE: Nickel Based Alloy
http://www.specialmetals.com/documents/Incoloy%20a...
metengr or EdStainless are more knowledgeable than I on the exact requirements within the ASTM system of when an alloy qualifies as nickel-base, iron-base, etc.
RE: Nickel Based Alloy
http://www.nickelinstitute.org/NickelUseInSociety/...
Stainless steels in the high-chromium, high-nickel ranges merge into other groups of heat resisting alloys. Where their iron content falls below approximately 50%, they are assigned to other alloy classifications because they cease to be considered stainless steels. This is generally considered to be the tipping point where a transition from ferrous-based to nickel-based alloys occurs - when the alloy contains less than 50% iron and the next most prevalent element is nickel.
Others may have a different perspective, but this has been my understanding.
Maui
www.EngineeringMetallurgy.com
RE: Nickel Based Alloy
RE: Nickel Based Alloy
RE: Nickel Based Alloy
RE: Nickel Based Alloy
So AL-6XN is 48% Fe, it is Fe based.
Alloy 33 is 33% Cr, but nothing else is greater, so it is Cr based.
In the old days they used the 50% rule for being Fe based and hence gave AL-6XN a N UNS number.
This is not how it is done today.
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RE: Nickel Based Alloy
Is this the reasoning why e.g. 800(H/HT) alloys are defined as nickel alloys under B31.3 table A-1?
RE: Nickel Based Alloy
They labeled alloys as Inconel if the major element was Ni, and Incoloy if it was Fe.
However many of the Incoloy grades are less than 50% Fe and so they were grouped with Ni based alloys back when.
They really are Fe based alloys.
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RE: Nickel Based Alloy
Regards,
Terry
RE: Nickel Based Alloy
At first I got scared, thinking he doesnt know *^&% what he's talking bout, but after some explanation, I found it was actually a pretty good statement.
Just like you implied, putting Hastelloy C-276 on the BOM simply restricts one to use Haynes' C-276 alloy, because of the trademark/-name.
From now on I simply call all alloys alloys, followed by their UNS number.
RE: Nickel Based Alloy
As XL83NL noted and you already surmised, Inconel, Hastelloy, etc. are tradenames, and thus including them on drawing specifications restricts the sourcing of the material. Specific to Alloy 718, there are 5 different melt sources for this alloy in the USA alone (Special Metals, Cartech, ATI Allvac, Electralloy, Universal Stainless).
RE: Nickel Based Alloy
My 2 cents worth is that the question is wrong. It is obviously ambiguous but probably the test composer(s) thought the correct answewr was 50%.
I like meteng and Edstainless take the best but predominent is not a number so that does not satisfy the test question.
Design for RELIABILITY, manufacturability, and maintainability
RE: Nickel Based Alloy
there are a number of alloys in use today that are called Ni alloys that are only 35% Ni, but they are also <50% Fe.
Bogus question for sure. This is one where you fill out the paperwork and request the documented solution and sources for the information. Hole their feet to the fire.
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RE: Nickel Based Alloy
Aaron Tanzer
RE: Nickel Based Alloy
RE: Nickel Based Alloy
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