Tag: Hastelloy Fasteners for HCl

Tantalum Screws for Hydrochloric Acid Resistance

Q: We currently use Titanium screws, and I would like to know pricing and lead time to replace them with Tantalum screws to improve their resistance to HCL.
A: What concentration and temp are you at with the HCl?  See the HCl Iso-Corrosion curve for Hastelloy C276.  Tantalum screws will definitely work in your application but may be overkill considering titanium is not very corrosion resistant against HCl. Depending on your applications temperature and concentration have you considered Hastelloy C276 screws? See the chart below. If you are below the 5mpy (mills per year 0.001″) the C276 fasteners should serve you well. If not, tantalum screws may be where you need to be.

Inconel 625 vs Hastelloy C276 in Hydrochloric Acid (HCl)

Q: We are altering the chemicals we use to regulate the pH level of our manufacturing process with hydrochloric acid. I’m using some Inconel 625 bolting – will this work in the HCl too?
 

A: Inconel 625 bolts offer a high level of corrosion resistance for many acids, may work for your application as well but without knowing the concetration and temperatures of the HCl acid it impossible to know.  However if you are replacing you bolts, you might want to consider Hastelloy C276 bolts as they would perform better in hydrochloric acid especially in higher concentrations than Inconel 625 for a similar cost. Here is a chart with more data.
https://www.extreme-bolt.com/hastelloy-c276-fasteners-flanges.html#Corrosion