Metal finishing Q&As since 1989

-----

Customer spec demands COR-TEN rail transport parts be powder coated

2003

Hello,

I am a Supplier Quality Engineer for a Rail Company in the Southern Tier of New York State. The question that I have for you is, if a customer specification calls for it, can COR-TEN Steel be effectively painted either using a wet spray or powdercoating system ?. If the surface of the component were mechanically etched with 120 grit sandpaper to remove the lose patina and other surface imperfections, and it was then sent thru a power wash/iron phosphate rinse, and powdered in a timely fashion to seal it from the atmospheric conditions, would this be an adequate process to protect this surface, and stop the inherent rust formation (patina on the outside of the steel). Any and all suggestions are welcome here, but keep in mind that beyond the reasoning that I shouldn't be painting it in the first place , my hands are tied to the customer specification, and I indeed have to Powdercoat it.

Also another question,

When referring to salt spray hours during testing, what would the correlation between salt spray hours and days be in real time, is it 100 hours = one year ?

And also where would I find documentation stating these correlations.

THANK YOU,

Jeffrey D Sawczyszyn
Supplier Quality Engineer for a Rail Company - Hornell , New York, USA

Yes, the procedure you outlined would be effective for preventing corrosion. You should contact US Steel, the manufacturer of Cor-Ten, for more information regarding corrosion prevention, etc. Also, there is no correlation between salt spray testing and actual performance. Salt spray testing a quality control test and does not properly simulate real-world use conditions. US Steel or your paint supplier should be able to provide more information on this subject.

Toby Padfield
Automotive module supplier - Michigan
2004