how long does it take rust to form?

Question

i'm looking for averages, record lows, and record highs. please provide sources, or else all you're telling me is hearsay(which is useless to me).

i'm looking less for HOW it rusts, and more about HOW FAST. how long does it take something to rust. i need sources for this, also.

Answer 1

Since rust is oxidization of metal, it would change according to the metal in question and its environment (more oxygen would make it rust faster, as would more salt). Some metals, like gold, essentially don't rust at all.

Answer 2

And of course the answer is: It varies.

The rate at which iron will rust is very dependent on lots of factors. The main ones are the relative humidity, the purity of the iron and the cleanliness of the suface. There is (reputedly) an iron monolith in India that is many hundreds of years old that has never rusted; this is because the relative humidity is very low and the iron is very pure. There are claims it was made by an extra-terrestrial life form, but you can believe that or not, as you wish. Most iron contains tramp metals or impurities that can set up galvanic cells and these will promote rusting, so it is best to have pure metal. As far as cleanlines is concerned, if the iron is coated with a protective coating such as oil or grease, it will take longer for the water in the air to get to the iron, so it will not rust very fast. However, if you get a piece of pure iron and thoroughly clean it in a good aqueous wash (preferrably including an acid dip between the wash and final rinse), you will see the surface turn a very pale green in front of your eyes - this is ferrous oxide/hydroxide. Normal rust is brown coloured and is due to the formation of ferric oxide/hydroxide mixture. Rust also needs oxygen to form. Let me suggest an experiment you could do, but it would only be fair if you report your findings on this website. Get four pieces of iron, say some cheap nails, all from the same batch, but make sure they are not galvanized or stainless steel. Thoroughlyly clean them up with some emery paper or other suitable abrasive system. Put them each into different glass jars. Leave one alone, put some tap water into the second, put some boiled tap water into the third (having boiled it for at least five minutes) and put the same boiled water into the fourth, but tip a good layer of mineral oil or melted wax onto the top of the water in the fourth jar. Check them every day and assess the level of "rustiness"; this can be done by their change in colour. Watch what happens to the metal and look for anything strange. Now explain your observations.

(Unfortunately this one doesn't give fastest, slowest or average)

Answer 3

I've spent some time searching google for some rules concerning the application of paint after grit blasting as it is often desirable to get paint on before any surface deterioration but drawn a blank. I think I recall seeing a company standard years ago which called for paint to be applied within two hours of grit blasting however this is, as you say hearsay. You might find an expert at The Institute of Metal Finishing http://www.uk-finishing.org.uk/terminology.htm

Answer 4

Iron reacts with the oxygen of the air and forms oxides of iron or rust. It happens readily but you do not see it readily with naked eyes. It takes some time for the rust to be thick enough like the brown formation we know of as rust. Rust formation slows down because the initial layer prevents the oxygen and iron from getting in contact and reacting.

Answer 5

It depends on the material that is rusting, the temperature and humidity of the surrounding environment

Answer 6

when iron reacts with oxygen it forms ferrous oxide which peels off the surface of metal and .
results in rusting of metals.this happens in few 4-5days.
.

Answer 7

within 24 hours if you leave it out in the rain, my grill i just bought was left in the rain over night and shows rust on the open steel parts

Answer 8

Bare Metall like Iron within seconds of contact with the athmosphere (oxygen manly)
Take care!

Answer 9

if you mean when it turns color well that will take 2-3 days on a moist environment

Answer 10

19 hours ago