...Well I seen the wee magnetic icon on the coffee tins, so I knew they weren't aluminium. Just curious as to what type of steel they are made from? Never knew some would be steel plated with tin on top! ...
It's called a "tin of beans" because it's in a "tin can" which is usually a steel can coated with tin, ot "tinned". You can "tin" things with solder, and they used to do that originally, but people started to get lead poisoning because the solder was something like half lead and half tin and the lead dissolved in the food.
https://en.wikipedia.org/wiki/Tin_can So it's different today.
You could do a university degree course on tin cans and still only have, er, scratched the surface. Take a look at page 6 of this for a nice picture of one kind of can.
http://packaging.arcelormittal.com/...rMittal Packaging 2013 - Landscape format.pdf
The steel will be more or less 'mild' or very low alloy steel but specifically impurities (especially oxygen) will be carefully controlled ('killed' steels) and heat treatment will depend on the application:
http://www.twi-global.com/technical...s-made-using-different-deoxidation-practices/
This is all because most steels will rust, or dissolve in acid foods like canned fruits, so in cans they're coated to prevent that. The coating can be a paint or something like that instead, or even in addition.
So if you pick a random selection of cans you'll have all sorts of very complex technologies represented there.
In a can made from tin plated steel, the steel will be fractions of a millimetre thick, the tin coating fractions of a micrometre thick, and the passivation layers (chromium, oil) nanometres thick.
Zinc coatings like in galvanized stuff are a completely different animal, but all the same the coating is primarily to prevent corrosion, and usually thin compared with the steel component.
Galvanized steel is usually a grey colour, like a metal dustbin, and mrcharly makes a good point that fumes from burning galvanized things are bad for you.
Aluminium and galvanized steel can be difficult to tell apart by colour alone, but you'll know as soon as you pick them up or if you have a magnet handy.