Corrosion rates of 316SS in different % of Sulfuric Acid

turduckin,
Just indicative, 20% sulphuric acid at 20 deg C would cause a corrosion rate of over 100 micrometers/year on SS 316 and over 1000 micrometers/year at 80 deg C even in small concentration (1-5%). But again, the internet is overflowing with free information on corrosion resistance of most type/grades of stainless steels, or perhaps you would have to spend some money for very specific data presented by various labs in printed form or otherways.
cheers,
gr2vessels

Depending on what you plan to do with the information, I would suggest caution. There are available tables of corrosion rates for 316 SS in sulfuric acid. We had a bright young project engineer that used those tables to decide that a 316 SS pump case was adequate for pumping 98% sulfuric acid to our Alky unit at less than 90 °F. He predicted something like 0.002" per year. But the velocity and temperature inside a running pump is hard to predict. We corroded through 0.750" of 316 SS in about two weeks. The piping in this system was 316 SS with Alloy 20 elbows. The piping is holding up well. These corrosion rates are very sensitive to both concentration and temperature, and very high velocities can override both. This project engineer should have noted that all of the other sulfuric acid pumps in the refinery were solid Alloy 20 construction. And even those had occasional corrosion problems. Perhaps you could give more details about your application.

Johnny Pellin

I agree with Johnny Pellin, corrosion effect can be very difficult to predict even with the best tables etc in front of you, sometimes it is simply prior experience in a like service that provides the best advice. You are better off advising all the info/detail that you have in the hope that someone else has experience that can assist you.

One key point to remember with acids and materials, the lower the acid strength the more corrosive the solution.
If you are dealing with 5% H2SO4 you would need lined or HB2 pump 95% A20 should work.

turduckin....

Try GOOGLE using "sulfuric acid" "corrosion" and 316...

I belive this is what you are looking for...


Tell us more about your project and the use of various dilluted acids...

-MJC

See the isocorrosion curve at the following website: