Q: I was thinking of ordering some Duplex Zeron 100 bolts for some mild sulfuric acid. How does that compare to Alloy 20? My alloy 20 bolts are suffering some mild corrosion.
A: Zeron bolts do offer a higher level of general resistance to corrosive environments compared to grades 2205 and 2507. Yet a Duplex bolt in grade Zeron 100 will not really offer more corrosion resistance compared to Alloy 20 in a sulfuric acid environment (of course this depends on your exact corrosive environment). Since you are having issues with the Alloy 20 fasteners moving to Duplex Zeron would not be recommended. We would suggest considering a higher level of protection from sulfuric acid, and to try a Hastelloy C276 bolt which offers excellent resistance to sulfuric acid even in hot conditions.