Q: I’ve been using Monel 400 bolts for a coastal operation that is built in polluted, stagnant saltwater. I’m been having some slight corrosion – nothing drastic, but wanted to check if there was another material that would last longer.

A: For this situation I would suggest titanium bolts. Titanium screws can handle both rapidly moving seawater as well as stagnant water. Monel 400 bolts can sometimes see corrosion in stagnant waters. Titanium bolts also offer excellent protection in polluted waters. My only concern would be that the waters are polluted with strong acids. In that case the Monel may be a better option because titanium screws cannot handle acidic corrosion as well as Monel screws. titanium screws for saltwater corroion

Q: I’m working in a reverse osmosis facility that purifies seawater for drinking water. We are experiencing some corrosion in some of our valve attachments which I’m assuming is from the salt water. Any recommendations on a fastener that won’t corrode in these conditions?

A: Your best bet would be a titanium bolt. Titanium is almost completely resistant to chloride corrosion and can even withstand stagnant sea water. If high strength isn’t a concern that you could go with Grade 2 bolts, which are relatively inexpensive. For strength above, 70 ksi tensile, then I’d suggest grade 5 titanium bolts which offer much higher strength, up to 148 ksi UTS.