protective coating for steel

[Tofflemire]

Hello Readers,

I am using STEEL MECHANICAL TUBING 5-1/2 OD x 1/2 WALL ASTM A53 as a ballast weight on a hydrophone. This ballast is attached to a 316 stainless steel cage. I am looking for coatings that can be applied to the steel that will hold up for at least 5 years to ocean deployments and surface scratches from the deck of a ship.
The real problem is that the paint gets scratched and then corrodes, and then this part looks bad. We considered going to 316 SS with the same dimensions but the price is 4-5 times more than the steel.

Thanks for any information you can provide

Tofflemire

 

[SJones]

You'll probably need to look at a typical offshore structure splash zone coating system to achieve the required performance. Review NORSOK M-501 for guidance. In its latest version, it has moved to a thin film epoxy; however, previous versions (from memory) worked on around 1000 microns of glass flake epoxy. Make sure that the paint manufacturer has a certified NORSOK M-501 qualification for any proposed system (ideally a glass flake epoxy). Several paint manufacturers used to list their NORSOK M-501 qualified systems on their web sites; International being one of them, but you may have to end up e-mailing them for their qualified System 7 materials.

Steve Jones
Materials & Corrosion Engineer

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