Differences between Hastelloy and Incoloy? 5

[TerryJones]

Hi there,

just wondering, could anyone, please, tell me the most crucial differences between the two? I did the googling but found nothing really concrete.

 

[cloa]

http://en.wikipedia.org/wiki/Hastelloy

http://en.wikipedia.org/wiki/Incoloy

Hastelloy is Nickel-molydenum mostly alloy so it very good for reducing conditions.
Incoloy is SuperAlloy of Iron-Nickel-Chromium so it is good for both reducing and oxidising conditions.

 

[stanweld]

They are trade mark designations of two different originating companies for groups of alloys developed by each. You need to better define which alloy grades; e.g., Hastelloy Alloys' 276, B, B2, X, OR Incoloy Alloys' 800, 800H, 825, etc. Or better yet, define by UNS designation.

 

[EdStainless]

These are tradenames for families of grades and not specific alloys.
Hastelloy is owned by Haynes.
The most common of these grades are Ni-Cr-Mo alloys (listed in order of content)such as C276 and C22. But the name is also used for Ni-Mo alloys and other specialty grades. Many of these alloys were developed for a specific application and need to be used carefully to optimize performance.
Inconel and Incoloy are owned by Special Metals (previously Inco).
In general Incoloy are Fe based alloys, think of them as hopped up stainless grades. Most of them were designed for high temperature service though some are used in chemical applications.
Inconel grades are all Ni based and are mostly for high temperature service, though usually under specific conditions.

Corrosion-Resistant Alloys
HASTELLOY® B-3® alloy
HASTELLOY® HYBRID-BC1® alloy
HASTELLOY®C-4 alloy
HASTELLOY® C-22® alloy
HASTELLOY® C-22HS® alloy
HASTELLOY® C-276 alloy
HASTELLOY® C-2000® alloy
HASTELLOY® G-30® alloy
HASTELLOY® G-35® alloy
High-Temperature Alloys
HASTELLOY® S alloy
HASTELLOY® W alloy
HASTELLOY® X alloy
HAYNES® 25 alloy
HAYNES® R-41 alloy
HAYNES® 75 alloy
HAYNES® HR-120® alloy
HAYNES® HR-160® alloy
HAYNES® HR-224® alloy
HAYNES® NS-163® alloy
HAYNES® 188 alloy
HAYNES® 214® alloy
HAYNES® 230® alloy
HAYNES® 242® alloy
HAYNES® 263 alloy
HAYNES® 282® alloy
HAYNES® 556® alloy
HAYNES® 617 alloy
HAYNES® 625 alloy
HAYNES® 625SQ® alloy
HAYNES® 718 alloy
HAYNES® X-750 alloy
MULTIMET® alloy
HAYNES® Waspaloy alloy
HAYNES® Ti-3Al-2.5V alloy
HASTELLOY® N alloy

INCONEL® alloys INCOLOY® alloys
INCONEL® alloy 600 INCOLOY® alloy 800
INCONEL® alloy 601 INCOLOY® alloy 800H/800HT®
INCONEL® alloy 601GC® INCOLOY® alloy 803
INCONEL® alloy 603XL INCOLOY® alloy 825
INCONEL® alloy 617 INCOLOY® alloy 832
INCONEL® alloy 625 INCOLOY® alloy 864
INCONEL® alloy 625LCF® INCOLOY® alloy 890
INCONEL® alloy 686 INCOLOY® alloy 903
INCONEL® alloy 690 INCOLOY® alloy 907
INCONEL® alloy 693 INCOLOY® alloy 908
INCONEL® alloy 706 INCOLOY® alloy 909
INCONEL® alloy 718 INCOLOY® alloy 925
INCONEL® alloy 718SPF™ INCOLOY® alloy 945 - 945X
INCONEL® alloy 725 INCOLOY® alloy MA956
INCONEL® alloy 740 INCOLOY® alloy DS
INCONEL® alloy X-750 INCOLOY® alloy 020
INCONEL® alloy 751 INCOLOY® alloy 028
INCONEL® alloy MA754 INCOLOY® alloy 330
INCONEL® alloy MA758 INCOLOY® alloy 25-6HN
INCONEL® alloy 783 INCOLOY® alloy 25-6MO
INCONEL® alloy N06230 INCOLOY® alloy 27-7MO
INCONEL® alloy C-276 INCOLOY® alloy A-286
INCONEL® alloy G-3
INCONEL® alloy HX
INCONEL® alloy 22

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[TerryJones]

Thanks very much guys!

 

[metman]

Ed,
beautiful description. this needs to be a fax and would do it but overwhelmed at work. Also would seem like plagerism -- best excuse I could comeup with.

Design for RELIABILITY, manufacturability, and maintainability

 

[Annie007]

As I am looking for the diference of these two as well, can I just add another question regarding which material for Thermowell subjected to suphuric acid application 10-60%? The Instrument handbook by Bella Liptak recommended Hastelloy B for Sulphuric Acid application but Incoloy was not mentioned to any application instead Inconel was mentioned? ANyone who knows the reason? Our company's engineering spec says to use Incoloy Thermowell/TW for a spec that involves >60% sulphuric acid and Hastelloy B for <60% sulphuric Acid so my theory is that Incoloy is better than Hastelloy when the application which happen to be sulphuric acid is above 60%. Anyone(Mettalurgist) who can confirm that?
Many thanks.

 

[stanweld]

Your Company's Engineering Spec is derelict in that it does not specify the particular Incoloy Alloy. I can assure you that many of the Incoloy Alloys, as listed by Ed above, will not be effective in your defined service.

 

[Annie007]

I forgot to mentioned it is Incoloy 825. So Incoloy 825 is not recommended for Sulphuric Acid as some vendors claim? How detrimental it is gonna be(like approx how long before a 16mm TW will get a hole in it being eaten/corroded by 10-50% Sulphuric acid application(10C-100C)? Can you mentioned an application/process medium where Incoloy 825 can be used (i.e caustic, lime solution, flocculant)?
Many Thanks.

 

[EdStainless]

Annie, you need to find very specific data for alloys in acid service. In general concentrated acids (>94%) are not very corrosive. Strong acids (>75%) have very specific alloys to handle each type of acid. The same is true for weak acids (<10%).
Acids in the middle may not have any metals that work, or may require exotic alloys.
Acid service requires careful research.
Do you have access to the MTI MS series of books? The detail information on acid service. Sulfuric is MS-1.
For a thermowell in sulfuric I would go B-2. period.
I am sure that 825 would work fine up to about 20% and below 35C since 304 is used in this service.

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[stanweld]

Annie007,
For the full range of concentrations and temperatures defined, Incoloy Alloy 825 will not prove effective. Go with Ed's advice.

 

[mrfailure]

From the Handbook of Corrosion Data article on sulfuric acid exposure:

"Nickel-base iron-chromium-molybdenum-copper alloys, such as Incoloy 825, provide excellent service in applications where chlorides are present. Incoloy 825 is highly resistant to all concentrations of sulfuric acid at temperatures below 65^o C (150^o F). Its corrosion resistance is enhanced by the presence of oxidizing salts; therefore, it is suitable for use in mixtures containing nitric acid, ferric sulfate, and cupric sulfate."

Aaron Tanzer

http://www.lehightesting.com

 

[metengr]

I think you should spend some time to review the document below before you make any decisions regarding material performance in sulfuric acid;

http://www.stainless-steel-world.net/pdf/10057.pdf

 

[Annie007]

Thank you guys. I guess more research, but for now I will go with what the Instrument Handbook says, which definitely is already proven.

 

[EdStainless]

Another great resource is

http://tools.outokumpu.com/spt/corrosion/corrstart.asp

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