Effect of Stainless Steel on copper

[mak72]

We have a threaded copper header (AHU)that should be connected to carbon Steel piping. We planned to install dielctric sleeves between copper falnge and carbon steel flange but the problem is unavailability of Copper flange. The supplier is providing stainless steel flange instead of copper flange.
Now I have two problems
1. combination of copper header with stainless steel flange.
2. Dielctric between Stainless steel and Carbon steel
Can Anybody explain me the effect of stainless steel on copper

 

[EdStainless]

What is the environment?
If it is an electrically conductive fluid then you are at risk of galvanic corrosion of the Cu. The SS will be much more noble under most conditions.

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Plymouth Tube

 

[mak72]

Fluid is Chilled water.

 

[Metalguy]

If your piping has pipe hangers, they should be insulated too. Electrons will travel from the carbon steel anode sites (corrosion areas)way down the pipe to a non-insulated hanger, up to the steel beams and down to the stainless or copper side if they are connected to the steel, thus completing the electrical circuit.

You can easily use an ohmmeter to measure the resistance across an insulated flange.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[strider6]

one factor you've to consider is the area ratio of the two metals. in fresh water coupling of similar areas of copper and ss should not cause galvanic corrosion but if the area of ss is higher that then area of copper then you can have serious galvanic corrosion on copper.
"stainless steel and copper tubes can usually be
joined without problems resulting, but accelerated corrosion
of the copper tube is likely to occur if it is attached to a
stainless steel tank"

http://www.npl.co.uk/upload/pdf/bimetallic_20071105114556.pdf

http://www.bssa.org.uk/topics.php?article=89

http://www.corrosionist.com/Galvanic_Corrosion.htm

S.

Corrosion & Rust Prevention Control

 

[mak72]

Thnx for your response