316 and 304 pH value that passive films braks?

[aligali]

hi dears
i am looking for a pH values that pasive films of these alloy breaks?
thanks

 

[EdStainless]

In what environment? Cl, Fl, S compounds, temperature and so on.
There are curves in papers by Effird that give temp, pH, Cl limits.
For example: 100ppm Cl, 110F, pH=7 or 10ppmCl, 40F, pH=5

You have to make sure that you are talking the correct steel chemistry also. The older corrosion work on 316 was almost all done with steel that had roughly mid-range chemistry. That product no longer exists. People used to commonly use 316 in cooling water with 500ppm Cl, today anything over 200ppm is pushing your luck.

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Plymouth Tube

 

[strider6]

as Ed said you should at least define the environments (seawater, water, acid...) then is possible to give you a reply..

S

Corrosion Prevention & Corrosion Control