Titanium gr5 and CF8M stainless steel Galvanic Corrosion

[SMOKES]

Hi am exploring a design that uses Titanium 6AL-4V GR5 for cost reduction;the part would be contact with a cast cf8m part, it will be submerged salt water mix of Sodium Bromide, Sodium Chloride @ 20 to 50°C at a max 35bar pressure. Would the design get away with galvanic corrosion and an eddy current. If not what stainless material would be recommended for this application?
Any reference links would be helpful thanks

 

[adamgnt]

Hi Smokes,

Is the Ti being used for corrosion resistance or because of loading requirements? If the contact point isn't under any high load, I find thin walled nylon 6/6 or equivalent plastic bearings solve the problem outright by isolating dissimilar metals from each other. Even if your contact point isn't a bolted connection, perhaps you make use of this approach in your application.

Cheers!
--Adam

 

[cloa]

Titanium tends not to have bad long term galvanic effects while initially enhancing corrosion because of what is called polarisation where by the galvanic effect is minimised.

 

[EdStainless]

But rather I would question the suitability of cast CF8M for use in this environment at all.
I would expect some localized etching of the SS, but if you do have some inhomogeneity or surface condition issues with the SS then you could get rapid local attack.
Either electrical isolation or coating of the Ti would be the ways to minimize this.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube