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Q&As since 1989


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External use of stainless steel

I operate a small workshop in Mullingar , Ireland, and I am having difficulty with a job we done recently. We fabricated and fitted stainless steel external railings to a building in Dublin , the architect specified 304 grade, a few weeks after erection , rust spots started appearing, I don't think the stainless was contaminated with mild steel as we are very careful about that in the workshop, What are the rules with stainless steel externally? is there some way of removing the tarnish and sealing the metal?

Regards,

John O Reilly
Fabricator - Mullingar, Co Westmeath, Ireland
2004

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One way of improving the corrosion resistance of stainless steel is to electropolish it. Most of the 300 series ss is very easy to do.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004

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2005

Electro polishing is a good finish, it gives a bright aspect. You can also use scouring passivation (matt aspect) but all those "treatments" must be done in specific areas and usually for little pieces .
You should check what was written on the architectural specification, I don't know the American Regulations but usually those texts must precise what kind of final aspect the architect requires .
If you don't want to have problems use the 316 l one with electropolishing finish, we use it for surgery and ship chandling .

Philippe Guyot
TSA INOX - Fecamp France