Tag: steel pickling

Bolts for Steel Pickling in HCl: Hastelloy and Tantalum

Q: I’m using HCl in a pickling process and have used Hastelloy C276 bolts to protect my equipment but am still having corrosion issues. Any ideas?
A: In pickling processes ferric chloride is created which is a strong oxidizer and most pickling process are at elevated temperatures – Hastelloy C276 doesn’t perform well in strong oxidizers. Steel placed in HCl, not only removes rust but creates a chemical reaction where iron combines with chlorine in HCl, making FeCl3. To prevent corrosion from both the hydrochloric acid which is a strong acid and the ferric chloride which is a strong oxidizer, you may want to try Hastelloy C2000 bolts or tantalum bolts. Hastelloy C2000 features strong acid protection of C276, plus its very resistant to oxidizers. Tantalum is the ultimate for corrosion resistance in HCl pickling process but offers less strength.

Hastelloy C22 bolts for hydrochloric acid steel pickling

Q: We are running a steel pickling process are considering switching from a sulfuric acid process to hydrochloric acid. Our system currently uses Inconel 625 bolting. With this be sufficient?

A: Inconel 625 is a good material for acid corrosion but for large system of hydrochloric acid, especially with the corrosion that can occur with fumes and vapors, you may want to try a Hastelloy C22 or even tantalum if the Inconel 625 does not hold up. Both perform very well in hydrochloric acid. Tantalum fasteners have the best corrosion resistance and are essentially immune to HCl but limited strength. Hastelloy especially grade C22 while not as corrosion resistant as tantalum has very good corrosion resistance to HCl and good strength as well.