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rusting speed on bare car metal

rusting speed on bare car metal

(OP)
Hello everyone,
I have a very specific question to ask, and chose to try this forum. Unfortunately I don´t come from the material science department and can´t answer it myself. Some people are arguing that the rust on the car in the following photos can´t have appeared in a matter of days, so I want to ask the people who actually know about these matters. I want to keep the discussion strictly apolitical and scientific.

http://img139.imageshack.us/img139/3253/bostonbigsd9.jpg
The car said to be pictured a few hours after an alleged israeli strike.

http://img128.imageshack.us/img128/6398/ambulancebigcz5.jpg
The car pictured a week later near a red cross station (which is situated some hundred meters from the mediterranean)

Many people argue that the amount of rust is too much for a few hours/one week of rusting. I tend to say that this is not the case, considering salt water vapor doing it´s work and the paint being scratched off in places. Also, does high explosives/a shaped charge going off nearby accelerate the rusting process?

Thanks in advance for answers (or apologies if this topic is deemed to inappropriate and sensitive),
Stefan

RE: rusting speed on bare car metal

Sure it's possible but I'm so old that about 90% of what I do everyday was impossible when I was in shcool.    

Do a search for flash rust.  I search for "flash rust" on Google and this was the first listing.  

http://www.camaros.net/shop/resto_3.html

Tom

Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com

RE: rusting speed on bare car metal

If the paint has already been removed, and the bare metal is exposed to ambient conditions near the Meditteranean (salt water, high temperature, high humidity), then this type of rusting is quite possible.  Regarding the explosives, it is possible that the residue left on the surface is corrosive to steel, but I am not an expert on the composition of explosive reaction byproducts.

RE: rusting speed on bare car metal

I think of chain-link fences that near the coast.  After a storm they are clean (from the blowing sand).  Within a day of two they are orange.
This is very superficial rusting, it can almost be wiped off, but it starts quickly.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm

RE: rusting speed on bare car metal

In general on vehicles, a high corrosion rate would be near 2mm/year. This rate is for vehicles that are near an ocean and the roads are heavily salted for an extended winter.  
One factor would be, what was in the explosives that hit these parts?  There may be chemicals that are FAR MORE CORROSIVE than salt and water.

RE: rusting speed on bare car metal

Rustbucket,
Re "In general on vehicles, a high corrosion rate would be near 2mm/year."
-- That's excessive, even for 'high.' Vehicles would rust out in 1-2 years.  Manufacturers use electro-galvanized steel and several coats of paint to prevent that.  Even offer 100,000 mile warranties against rust-through.

Difficult to judge from a few photos without knowing the initial coating and the effects of the explosive heat and mechanical forces.  Nitrates are generally not corrosive, but maybe other possible residues.  

Mild steels used in auto bodies can rust in seconds, as when pickled clean, rinsed and exposed to air.  Pre-to galvanized usage, auto sheel was mostly just phosphated prior to painting.  Some newer, micro-alloyed bake-hardening steel resist rusting better, but probably N/A to the vehicle in the photos.

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