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Cleaning carbon contaminated 316 stainless steel

2006

Hi
please could you advise me regarding the possible chemical cleaning of a fabrication we recently manufactured in 316 stainless steel

The lighting mast in question is corroding because of small partials of carbon steel have become embedded in the stainless during the manufacturing folding process as the sheet makes hard contact with the press tooling.

This tooling mark is now showing signs of rusting as the structure is erected next to tidal river and therefore subject to salt in the atmosphere.

The finish on the mast is glass bead blast and I was hoping there is some chemical solution that could completely remove the carbon particles without discolouring the surface.
Thus alleviating the need to rectify the problem without the considerable expense of sanding and re-bead blasting on site.



I would be grateful for any advise you could offer regarding the above

Regards.

David Brian Thomas
Thomas Fabrications Ltd - Oxford, UK

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Use a phosphoric acid-type rust remover in a gel formulation. Brush on, let it work, rinse well. Probably a good idea to first test for appearance change in a hidden area.
An automotive chrome polish will also work, but more work.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2006

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Ferrous contamination of Stainless Steel is very common.
Your photo looks like it is as you describe.
Unfortunately recovering from this situation in finished products is difficult since it normally involves acid dipping or pastes to remove all stains and future affects.
I would suggest you contact a company who specialises in on-site treatments.
Best of luck,

Martin Rich
Ship Repair - Plymouth, UK
2006