Q: I have a waste water purifying situation where I’m using chlorine to treat the water. In addition to the acidic solution produced the fastener will also experience high loads, so I’m also concerned with stress corrosion cracking. Currently Super Duplex 2507 is not doing the job. Any recommendations on materials?
A: One material worth considering is Hastelloy C22 fasteners. These fastener are excellent in wet chlorine environments and can be used if ferric chloride is produced incidentally (Hastelloy B2 and Hastelloy B3 cannot handle ferric chloride). In addition, Hastelloy C22 is also know for providing resistance to stress corrosion cracking as well as pitting and crevice corrosion and has a typical ultimate tensile of 111ksi and yield strength of 52ksi