I am building a "water welder" (electrolyzes water and burns the
resulting H2 and O2) and was wondering about the chemical compatibility
of 5% H2SO4 and 304 stainless steel from room temp to 80C or so.
I know 316 stainless is best for H2S04, but I'd like to use 304 since
it is cheaper and more common. I have read conflicting data on the web
about the compatibility of 304 with H2S04. Does anyone have any
According to this website from a stainless steel cable manufacturer,
304 has severe incompatibility with dilute H2SO4 (whereas 316 is ok):
To verify this, consult a true reference in a library such as an
engineering handbook or contact any manufacturer of 304 - they should
have all of this information. If in doubt, go with the 316, there's
good reason it's more expensive.
The previous cursory reply is correct. 304SS will not work at 80C.
Excellent technical information on the compatibility of stainless
steels with sulfuric acid may be found on the web. However, you will
NOT find it by using a search engine like Google or Yahoo. A detailed
answer to your question can be found in INCO Publication 1318
(catalogue 1318), titled "The Corrosion Resistance of Nickel
Containing Alloys in Sulfuric Acid and Related Compounds" (1983) on
the Nickel Institute web site. It is an 88 page publication that you
can download as a 1.16Mb acrobat file. Refer to Figures 6 through 8 on
pages 8 through 10 from Kiefer and Renshaw's work originally
published in Corrosion magazine back in 1950.. At 80C Type 304 will
corrode very much faster than Type 316, over 25.4mm/yr. 304 is
Go to www.nickelinstitute.org
Then point to the button marked "Technical support", and click on
"Technical Literature" on the pull down menu, and under "First
Use" select "Stainless steels"
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