Connecting duplex, monel and aluminum / bronze in seawater service
Connecting duplex, monel and aluminum / bronze in seawater service
(OP)
A flanged Aluminium Bronze valve is connected to a Duplex (22%cr) vessel. Our client has specified the gasket material to be Monel. The media is Seawater. The SW temperature may vary from 15degC to 45degC. Is galvanic corrosion a concern with this configuration?





RE: Connecting duplex, monel and aluminum / bronze in seawater service
Just remember a 22% Cr duplex will not fully resist cevice corrosion in seawater.
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Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Connecting duplex, monel and aluminum / bronze in seawater service
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Connecting duplex, monel and aluminum / bronze in seawater service
RE: Connecting duplex, monel and aluminum / bronze in seawater service
Since there is a chance for galvanic corrosion, would you recommend using a non-conducting material in the gasket i.e. rubber?
Sjones,
What is your main concern at this temperature? FYI customer plans to use some kind of corrosion inhibitor (chemicals) there is also a 3mmm corrosion allowance on the vessel. Oxygen level at normal operation will be approx 300ppm. Design life is 25years.
RE: Connecting duplex, monel and aluminum / bronze in seawater service
WHat I would recommend, (but maybe not practical at this point in time) would be to install a duplex stub about 12 incges long off the vessel, then connect the valve, This would at least provide an equal ratio.
RE: Connecting duplex, monel and aluminum / bronze in seawater service
RE: Connecting duplex, monel and aluminum / bronze in seawater service
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Connecting duplex, monel and aluminum / bronze in seawater service
RE: Connecting duplex, monel and aluminum / bronze in seawater service
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Connecting duplex, monel and aluminum / bronze in seawater service
When dealing with cutomers, I'd just just suggest that you (a) answer the mail; that is, provide the answer to the question the curtomer asks, but then (b) provide the answer to the question he didn't ask.
It may not help as often as we would like, but I've seen customers change course based on this type of feedback (most recently just 2 weeks ago, in fact). Occasionally I even submit responses to solicitations that essentially suggests (in nice terms, of course) the customer is asking the wrong question.
RE: Connecting duplex, monel and aluminum / bronze in seawater service
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm