Galvanic Corrosion 2

[doomster]

Is it okay to attach Magnolia Bronze on a carbon steel? Will it not be prone to galvanic corrosion? Please see attached image for your reference.
The material will not be submerge in water, but the surrounding temperature will be at 50-55 deg C.


Thanks!

 

[Dhurjati Sen]

Dear doomster,

Due to area effect, I think it is okay.

Regards.

DHURJATI SEN
Kolkata, India

 

[doomster]

Thanks Dhurjati Sen,

What do you mean on the area effect?
I've checked the galvanic series and bronze and carbon steel have a significant gap on the hierarchy.
Would it still be okay since it will not be submerged on water?


Regards

 

[Dhurjati Sen]

Dear doomster,

One of the main tenets of Galvanic Corrosion - the Area Effect.

According to the Galvanic Series, bronze is nobler than carbon steel, so CS would corrode. Imagine a situation where you have a large bronze component attached to a small CS component. The CS would get corroded in no time.

In your case, the bronze part is smaller, it is attached to a comparative larger CS component, so chance of Galvanic Corrosion is negligible.

Also, as the parts will not be submerged in water, possibility of Crevice Corrosion is remote (as some Galvanic Corrosion would still occur in the adjoining CS).

Regards.

DHURJATI SEN
Kolkata, India

 

[TugboatEng]

Galvanic corrosion requires an electrolyte so as long as the area isn't wet there will be no galvanic corrosion. The press fit of the bushing does a very good job at keeping moisture out even in wet environments.

 

[Chumpes]

Hello
I confirm galvanic corrosion requires an electrolyte
no electrolyte = no galvanic corrosion
regards

 

[GarryB1957]

Yes Galvanic corrosion requires an electrolyte. You say the item is at 50-55 degrees centigrade, is this a constant temperature? What is the relative humidity and relative air temperature? Is the carbon steel coated? Is the bolt packed with grease?

It is wrong to think a structure in the atmosphere will not corrode due to lack of electrolyte. Electrolyte can be present at levels undetectable to humans, cooling of a structure in an atmosphere with a high relavtive humidity can cause water to dew out on the structure surface. This will allow for corrosion to exist at a lower rate than an immersed structure due to the high resistivity of the available electrolyte.

 

[MJCronin]

Magnolia Bronze is a trade name ... not a specific type ...

https://magnoliabronze.com/

MJCronin
Sr. Process Engineer