A: Hastelloy bolts are definitely ideal in this concentration of hydrochloric acid. Hastelloy C276 bolting is usable in these temperatures and concentrations, but can’t handle the yield strength you need. Hastelloy C276 has a yield around 49 ksi – about half your requirement. For your situation, you have two choices. Incoloy 925 bolts have similar corrosion resistance to alloy 825 which can take the HCl, yet they are age hardened to offer a lot higher strength than 825. Alloy 925 bolts have a yield around, 120ksi. In addition, you can also try Inconel 718 bolts which are an age hardened form of 625. Therefore it offers similar corrosion resistance but has a yield of 175ksi. Both will still show slight corrosion over time but will be the best options considering you high strength requirements.