Copper Valves in Carbon Steel Pipe
Copper Valves in Carbon Steel Pipe
(OP)
I have a question that revolves around the galvanic corrosion mechanism. If I use threaded bronze valves in a carbon steel boiler feedwater circuit, will there be a concern with galvanic corrosion in the threaded joint? (Temperature is 400F at 250 psi.)





RE: Copper Valves in Carbon Steel Pipe
http://www.corrosionist.com/Galvanic_Corrosion.htm
http://www.eci-ndt.com/gallery_a.htm
http://www.corrview.com/tech_p_10.htm
S
Metal Corrosion
RE: Copper Valves in Carbon Steel Pipe
Since carbon steel is more anodic on the galvanic series than coppor alloys, the corrosion would tend to be in the carbon steel.
But since the carbon steel will have the greater surface area in the system, won't that protect it?
We commonly put small sections of copper piping on carbon steel sprinkler lines and don't see corrosion. We do not do the opposite, though which would be a failure waiting to happen.
RE: Copper Valves in Carbon Steel Pipe
On the other this is at 400F and galvanic corrosion rates are exponential with temp.
Do you want to use bronze valves at 400F? Even without the CS pipe I would think that there is a risk of dealloying.
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Plymouth Tube
RE: Copper Valves in Carbon Steel Pipe
RE: Copper Valves in Carbon Steel Pipe
RE: Copper Valves in Carbon Steel Pipe
You better go back and check ASME B&PV Code , Section I, copper and copper alloys are limited for service -
SB-61 alloys are 550 deg F
SB-62 alloys are 406 deg F
I recognize that your application is for a boiler feedwater circuit, but personally, I would not recommend in this application because of allowable stress concerns and creep.
RE: Copper Valves in Carbon Steel Pipe
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Plymouth Tube
RE: Copper Valves in Carbon Steel Pipe
This is a paper found on the net regarding a case similar to that we are discussing:
"The leak on December 5, 2002, was located where the carbon steel pipe threaded into a bronze check valve. The leakage was attributed to galvanic corrosion at threaded onnections that contained dissimilar metals.
Based on this, an extent of condition review and ngineering evaluation was completed which was centered around threaded connections with dissimilar metals."
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S.
Metal Corrosion