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Corrosion protection of soft aluminum tube in 44% salt water concentration??

I need to protect soft aluminum tubing that sees minimal pressure (less than 100 PSI) but sees saltwater concentrations of 40 to 44%. This exposure is half atmospheric air/ half salt water. The tubes are heated with steam to a maximum temperature of 249 F. Can any version of anodize provide 1,000+ hours of protection for these tubes?

Pete Gruendeman
refrigeration designer - La Crosse, Wisconsin, USA
November 29, 2011

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No way. You need a thin hex chromate conversion and powder coat.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

November 30, 2011

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It might prove a little difficult to Powdercoat the internal tube surface?

William Doherty
Trainer - Salamander Bay, Australia
December 3, 2011

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Hi, William.

I assumed that the steam was inside the tubes, and the outside was exposed to a mix of air and salt water, but Indeed it isn't clear whether the inside or the outside of the tubes is exposed to the air and saltwater.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 5, 2011

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December 7, 2011

Well, I guess my initial response was a little tongue in cheek.
Obviously the internal tube surfaces could be coated if they were straight initially and formed post coating.
A difficult, but not impossible, process though it may be.
If this was the answer, then the next question would be what Powder?
I would think a Fusion Bond Epoxy over the Chromate?
Regards,
Bill

William Doherty
Trainer - Salamander Bay, Australia

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December 16, 2011

I have a similar application where I need to resolve corrosion also.

I am using tooling of SS316, which is dipped in a saline solution to 500° C.

Our intention is a titanium plating to extend the productive life of my toolings is that possible or do you have a better option?

Adrian Lopez
- Guaymas, Sonora, Mexico