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Corrosion of a fittings in a stainless steel vessel

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DustinMechEng

Mechanical
Feb 12, 2007
22
I am testing a structure inside a stainless steel vessel filled with sea water. The structure has a brass fitting and several titanium fasteners. Neither the fitting nor fasteners come in contact with the vessel or each other but will be aprroximately 1 foot away from the vessel walls and each other.

Will the brass fitting or titanium fasteners corrode? If so, can I use a sacrificial anode such as zinc to prevent corrosion? Is their any other way to prevent corrosion or isolate the fittings and/or fasteners?

Thanks for the help!
 
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Additional Note:

-The structure is plastic (non-conductive)
-There are no direct metal-to-metal contacts or any other electically conductive paths betweeen dissimilar metals aside from the salt water

My main question is whether dissimilar metals will produce a galvanic pair when immersed in salt water but not in direct contact.
 
Make sure that your brass parts are mad of an alloy suitable for seawater. A NiBronze, NiAlBronze, or a CuNi would work. If you use standard brass you will get selective dezincification.

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Rust never sleeps
Neither should your protection
 

It would be advisable to install a sacrificial anode in the tank. Two dissimilar metals in a salt solution constitutes a battery and the inferior metal will deplete. I sometimes used to put a piece of junk metal in a tank to feed the negative ion monster. Crude , but it works and ok if it does not contaminate your processs.

Offshore Engineering&Design
 
I disagree with Chief. If the dissimilar metals are not in electrical contact, there is no galvanic couple and no battery.
 
If you have multiple pieces of metal it is possible that there will be enough difference in potential between them that you will see some corrosion.
I am more concerned with the brass simply corroding on its own.

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Plymouth Tube
 
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