Iso-Corrosion Curves:
Sulfuric acid one of the most common acids used in industry presents a host of corrosion problems. To counteract this, there are a few specialty metal fasteners that can provide protection. Alloy 20 fasteners provide good performance in hot sulfuric acid. More specifically they offer good resistance to stress-corrosion cracking in boiling sulfuric acid at specific range of 20% to 40% concentration, as well as general sulfuric acid resistance. For higher concentrations, Inconel 625 experiences less than 5 mils (0.005”) per year in any concentration to 80% acid up to 100°F. Hastelloy C276 and C22 screws provide slightly better protection, than Inconel. Zirconium screws take protection to the next level, usable at temperatures well above boiling and at acid concentrations up to 70%. As with HCl, tantalum offers the best resistance to sulfuric acid but this comes with a high price tag.
Alloy 20 Sulfuric Acid Performance
Hastelloy B2 Sulfuric Acid Performance
Hastelloy B3 Sulfuric Acid Performance
Hastelloy C22 Sulfuric Acid Performance
Hastelloy C276 Sulfuric Acid Performance