Galvanic corrosion inconel/8630 1

[Pisces2]

Is there a problem with coupling Inconel 625/825 with AISI 8630 in seawater?
I dont think there is but I need to tie it down with facts.
Difference in voltage is -0.2, 8630 has largest area.

 

[mcguire]

There is definitly a problem for the alloy steel in this situation. There would be a problem for the steel even without the galvanic couple.

 

[TVP]

I completely agree with mcguire. Uncoated steel in a seawater environment will experience substantial corrosion. Adding a galvanic couple to a more noble metal like a nickel-based inconel alloy will only exacerbate the problem. You may need to look into a protective coating for the steel component, or consider making it out of something else.

 

[rustbuster1]

You should provide more information about function and service expectations. What is your reason for combining these metals?
At depths where oxygen content is very low, for example, this may pose no risk to either alloy (it obviously won't be a concern for the Nickel alloy). You do not say if the steel is coated - why would that not be the case anyway even if there was no dissimilar metal configuration?

 

[Pisces2]

Sorry gents, more info.
Exterior of 8630 is painted,interior is uncoated.
However where the inconel and 8630 are in contact it is a trapped volume with no replenishement of electrolyte.