Just search for google with keywords as" sulfuric acid isocorrosion chart".

Lee SiHyoung,
WorleyParsons Oman Engineering,

The reference on material selection in Sulfuric Acid:
https://store.nace.org/21943026-032b-4de7-9835-477...

What temperature?
And what kind of structure? Tubes for a heat exchanger or a tank or a pressure vessel?

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P.E. Metallurgy, Plymouth Tube

Thanks Cap and Ed,

The max temp is 165F.

Q~

Based on my research, it is as below. (Note that it is for aerated condition as assumed and 10% of H2SO4)

1. SS 316 --> Not suitable as corrosion rate is more than 1 mm/year. (ref 1)
2. Hastelloy C-276 --> suitable as corrosion rate is below 0.13 mm/y (ref 2). There shall be proper wall thickness.
3. ALLOY 625--> suitable as corrosion rate is below 0.13 mm/y (ref 3). There shall be proper wall thickness.
4. Monel --> Not suitable. The option of Monel is only for the alternative to stainless steel when the corrosion rate of SS becomes high exposed to "deaerated condition".
(The corrosion rate exposed to "deaerated" or air-free is higher than aerated condition for SS. As SS has been already out of the option as No. 1 (from deaerated condition), the option of monel shall be out accordingly. ref 4





Ref 1 - Isocorrosion diagrams for (a) type 304, (b) type 316, and (c) type 317L stainless steels in aerated H2SO4 up to 50% concentration.
H. Abo, M. Ueda, and S. Noguchi, Boshoku Gijutso, Vol 23, 1974, p 341–346 (in Japanese)

Ref 2 - Isocorrosion diagram for alloy C-276 in H2SO4. The Corrosion Resistance of Nickel- Containing Alloys in Sulfuric Acid and Related Compounds,” Corrosion Engineering Bulletin 1, The International Nickel Company, 1983

Ref 3 - Isocorrosion diagram for alloy 625 in H2SO4, J.R. Crum and M.E. Adkins, Correlation of Alloy 625 Electrochemical Behavior with the Sulfuric Acid Isocorrosion Chart, Proc. NACE Corrosion/85 Symposium on Corrosion in Sulfuric Acid, National Association of Corrosion Engineers, 1985, p 23

Ref 4 - ASM Metals Handbook, Vol 13C Corrosion Environments and Industries, Corrosion by Sulfuric Acid / P663


Lee SiHyoung,
WorleyParsons Oman Engineering,

Thanks Lee, great reply I appreciate all your effort!

Any chance you have data on 17-4 PH or 15-5 PH? I searched but couldn’t find. We’re trying to select a retaining ring material.

Thanks,

Q~

No chance that a PHSS will survive.
Use high strength 625 for the rings.

There are other alloy options also; Alloy 20S, 31, 59, 825 are all in the same range as 276 and 625 for this concentration and temp.
But the real question is about trace impurities, any halides at all? That changes things a lot.

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P.E. Metallurgy, Plymouth Tube

Thanks, Ed.
Customer contacted regarding the impurities / halides. I saw where Rotor Clip claims to make custom C-276 if needed so we'll probably go that route.

Q~

Selection and Performance of Stainless Steel and other Nickel-Bearing Alloys in Sulphuric Acid (10057)

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

ASM has the Handbook of Corrosion Data, which includes a compilation of sulfuric acid testing data as well as a general article on the subject.