Bronze tank and galvanized carbon steel in seawater 2

[Hercules28]

Do you see any big issues having a big bronze tank and threading galvanized carbon steel on it?
Room temperatures and the environment is sea water.

Thanks,

Herc.

 

[TVP]

Can you provide the expected duration for immersion? Expected lifetime?

 

[EdStainless]

Yes, I see a number of issues.
Dealloying of the bronze is probably going to happen.
There is also the risk of galvanic corrosion of the steel adjacent to the bronze.

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Plymouth Tube

 

[Hercules28]

TVP, 3 years

 

[Hercules28]

Are there any diagrams I can take a look at to see corrosion rate for this setup?

 

[moltenmetal]

Unless you install dielectric unions to isolate the bronze from the zinc-coated steel, you will have a 1.5 volt, high current battery actively dissolving away the galvanized pipe the whole time the thing is in service. Even in a situation where the seawater is deoxygenated by virtue of being in a totally closed loop, I'd be concerned.

As to service life: that depends on lots of stuff. It might last a while, but it's still bad practice. It would be bad practice in fresh water services without corrosion inhibitors, and it certainly is bad practice in seawater.

 

[TomDOT]

I'm with moltenmetal. A galvanic difference that high in seawater will lead to rapid corrosion.

 

[TVP]

Herc,

You might be able to get 3 years out of this type of arrangement, if a number of things are optimized (coating, preload/stress in threads, etc). The technical points that everyone else noted are the relevant items of concern. I wouldn't even consider using this type of arrangement, and strongly encourage you to find another solution that doesn't have such inherent corrosion issues.