Q: I’m running a chlor-alkali process and have been using Duplex 2507 bolts. I choose them for their yield strength and corrosion resistance but am still having issues with the chlorine. Ideas?
A: Many chlor alkali processes use Titanium fasteners for its combination of high strength and chlorine resistance. Grade 5 offers 148 ksi UTS and 138 ksi yield which is superior to the strength of Duplex 2507 bolts. Though Duplex 2507 does perform very well in chlorine environments, because these process are generally very concentrated, the Titanium will be a better choice. Titanium bolts are immune to chloride and chlorine. The only precaution is not to use Titanium in dry chlorine where there is less than 1% water because it will rapidly corrode and could even ignite.