Q: What fastener material is best for boiling sulfuric acid?
A: Generally speaking, for 20-40% concentrations, Alloy 20 bolts will be the best bet for an economic solution. For all other concentrations in boiling H2SO4 you would have to use tantalum bolts, which can be costly. Though Hastelloy bolts work in sulfuric acid, they can’t handle boiling conditions.
Remember, corrosion can be tricky because there are many factors that can make a
material successful. Its best to review to our sulfuric acid corrosion curves on this page:
https://www.extreme-bolt.com/sulfuric-acid-corrosion.html