When to Passivate Stainless? 1

[dananay]

I am a Medical Manufacturing Engineer reviewing drawings for manufacturability. I am noticing every stainless steel part calls out "Passivate per ... ". Some parts are simple brackets and shims. Most parts are subject only to indoor cleaning solutions as found in hospitals. There are no autoclave requirements, no surgical cleaning requirements. The finished product is used merely for screening. I understand the passivation process enhances the inertness of the surface but under what conditions should it be called out?

 

[EdStainless]

Unless the SS part will be used in contact with carbon steel I would passivate it.
When it is properly done passivation assures you of getting a surface that is clean and stable. Without it you can get rust spotting, funny staining and other problems.

Autoclave service is easy, the general environment is usually worse. Often cleaners and sanitizers have chlorides in them (almost all soaps have chlorides, Ivory bar soap is few % and liquid soaps are even higher). Residue from cleaners can cause a lot of corrosion. Passivation at least gives you a fighting chance.

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Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[unclesyd]

Adding to EdStainless's reply, if possible passivate every piece you will save yourself answering the question "How Come" sometime down the line.