Tag: Monel K500 for salt water corrosion resistance

Monel Bolts for Saltwater Wharf

Q: We are installing bolts into a refinery wharf.  After doing a test run on a few A316 stainless steel bolts, they came back heavily corroded. Do you have an coating that can be used for salt water applications that would prevent this? Or do can you advise on another material?

A: I don’t recommend a coating but I can recommend a better material to handle the saltwater situation. Here I would suggest using either Monel or titanium bolts. Monel bolts are the go-to material for many marine applications. It is available in two forms Monel 400 which offers a strength of 83ksi ultimate tensile strength and age hardened Monel K500 for extreme strength of 160ksi UTS. Titanium bolts are also and excellent choice for saltwater corrosion. They offer excellent resistance to both rapid velocity and stagnant seawater, up to a mile deep. Titanium grade 5 fasteners are 4 times stronger than 316 at half the weight.

A4-80 vs Monel K500 Fasteners in Sea Water

Q:  For a marine project will 316SS cold worked (grade A4-80) hold up in strength pretty close to Monel K500? And what is the price comparison?
A: Thanks for contacting and good question.  The major difference is the strength and corrosion resistance. You will have decent strength of a A4-80 bolt with a min tensile of 116 KSI however K500 bolts will have around 160KSI. However even more of an issue will be the corrosion resistance in sea-water. The Monel K-500 will be immune and has no corrosion rate in sea-water, whereas the A4-80 will get attacked over time. The alloy K500 will be more expensive but if you so you have to balance the costs versus the risk of failure.