Coating of carbon fibre epoxy pipe line in sea necessary?

[boeri]

Is an extra anti-corrosion coating on a carbon fibre filament wound pipe line, used on a sea depth of about
3000 m, required? And if so, what would be a good material?

many thanks in advance

Tom

 

[Goahead]

Hi,
an informative article on
Composite Fabrication by Filament Winding
can be found at

http://www.tifac.org.in/news/acfil.htm#axial

While it is affirmed that composites present excellent corrosion resistance, it should be noticed that different matrix materials are available. Different resins and additives provide special properties.
Even within the category of Epoxy, recommended for Marine applications, a wide range of resins are available.

For additional information the corrosion resistance properties of the specific product selected should be investigated with the manufacturer.

Regards,

http://www.welding-advisers.com/

 

[SJones]

An interesting application. What will be the fluid on the inside of the pipe? It raises the question as to degradation rates as the pipe wall will now face both an internal product and external environment of pressurised seawater both of which could degrade the properties of the composite. Long term testing for qualification as per ISO 14692 should be performed for both environments (don't know whether this can be done simultaneously). It may be that you will have to keep seawater away from the composite in order to maintain the properties over the lifetime of the pipeline without having to use so much extra material as to render it uneconomic. At which point, a coating for seaater exclusion may be one solution. As for an anti-corrosion coating, in the sense that it is applied to a carbon steel pipe, the simple answer is: No!

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[edrush]

Isn't vinyl ester the matrix of choice for corrosion resistance? Although I have never designed anything for a marine environment, vinyl ester would be the first material I would consider. Cheap compared to epoxy. Strong. Not sure how much water is absorbs. Might need to UV cure it if filament winding, but it should make a good pultrusion resin.

What were you thinking of coating it with? More resin?