Red Rust on 316
Red Rust on 316
(OP)
Hi all,
I'm just wondering if red rust is possible on 316? I've received a few 316 bolts that were used in coastal applications and they appear to show some slight red rust residue between the 316 washer and 316 bolt, but besides this they appear to be structurally sound. My understanding is that 316 will not show red rust and will undergo pitting instead. I'm wondering if this is due to carbon steel rusting and contamination somewhere in the system, and rainwater brought it the interface between bolt and washer. Any input?
Thanks,
M
I'm just wondering if red rust is possible on 316? I've received a few 316 bolts that were used in coastal applications and they appear to show some slight red rust residue between the 316 washer and 316 bolt, but besides this they appear to be structurally sound. My understanding is that 316 will not show red rust and will undergo pitting instead. I'm wondering if this is due to carbon steel rusting and contamination somewhere in the system, and rainwater brought it the interface between bolt and washer. Any input?
Thanks,
M





RE: Red Rust on 316
Or it could be from iron contamination on the surface of the bolt or nut or washer.
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Plymouth Tube
RE: Red Rust on 316
RE: Red Rust on 316
RE: Red Rust on 316
As long as oxygen and water are available, iron ions in the iron chloride corrodant solution can be precipitated out as rust.
RE: Red Rust on 316
http://www.assda.asn.au/index.php?option=com_conte...
316 that has been properly passivated should not show significant red rust unless it has been in service for many years in the splash zone or similar.
RE: Red Rust on 316
If you have new hardware and you are curious, find some white Head and Shoulders shampoo.
Coat the hardware with a thin layer of shampoo and let it sit.
If you see any blue spots there is free iron on the surface.
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Plymouth Tube
RE: Red Rust on 316
I have never heard of this trick before. Do you know what the reaction/precipitate is?
RE: Red Rust on 316
RE: Red Rust on 316
This used to be a regional issues around the country, some places were white and others were blue.
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Plymouth Tube
RE: Red Rust on 316
Nick
RE: Red Rust on 316
I started wondering why there would be ferricyanide in a shampoo - and then I thought about calcium ions. Calcium ions interfere with the action of soaps and some detergents by precipitating out the soap (and building up "soap scum") - typically this is controlled by adding EDTA to shampoo, which will complex with the calcium ions and prevent binding elsewhere. However, I suspect ferricyanide would be more effective than EDTA at calcium control.
Hm.
RE: Red Rust on 316
The presence of Fe changes the molecule form and hence its color.
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Plymouth Tube
RE: Red Rust on 316
Thanks!
RE: Red Rust on 316
RE: Red Rust on 316
RE: Red Rust on 316
I am already refered to as the mad scientist within my company. I do not need information like this, it will only add fuel to the fire! Now off to find some H&S!!!