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Q&As since 1989


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Electropolishing

As a materials engineer for a chemical manufacturing company we occasionally usepolishing as a means of improving the (internal) surface of stainless steel equipment for all the main reasons that it is normally used, improve oxide layer, surface roughness, etc. My question concerns electropolishing the Titanium stabilized versions of the 300 series stainless steels (AISI 316Ti / Werkstoffnr. 1.4571).

I would like to check if my memory serves me well. I seem to remember that when using EP on a 316Ti, that the Titanium Carbides present in the alloy were not polished in the same way and that after polishing they protruded above the surface. Is this correct and are there special techniques which need to be specified to prevent this ?

Mike Turner
- Dobbs Ferry, NY, U.S.A.
2003

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2003

This problem exist not only for carbides of titanium, but carbides of wolfram, carbides of vanadium and many other carbide-producing elements. Many carbides do not dissolve during electropolishing - carbides emerge above the surface and make it rough. There are two ways of removing carbides from the surface: 1. additional electrochemical treatment after polishing; 2. high-voltage electropolishing where carbides are removed by plasma.

adv.
We can show our methods by treating samples sent to us.

Anna Berkovich
Russamer Lab

Pittsburgh, Pennsylvania