Monel Fastners for HF Contaminated Industrial Water

Q: I have a process where I’m experiencing corrosion from my industrial water system. I’ve tried Hastelloy C276 bolts but they are corroding much faster than I would expect. The water only has low levels of Hydrofluoric Acid (HF). Any ideas would be great.

A: Hydrofluoric acid is an unusual acid that is extremely corrosive and will even corrode tantalum. Hastelloy C276 resistance to HF is relatively low too. For this situation I would suggest using Monel 400 bolts. Monel fasteners are one of few metals, aside from polymers that can protect from hydrofluoric acid corrosion and perform very well in industrial water situations.