[maxvortex]

OK 

What do i get when i heat up some metal sheet and when its still hot, I put in the cold water.
Do I get hydrogen oxide or something else ? 

2.) If I make the same process without putting metal sheet into water, will this produce better or pure oxide ? Simply put, which oxide is better ?

[Arkcon]

OK 

What do i get when i heat up some metal sheet and when its still hot, I put in the cold water.
Do I get hydrogen oxide or something else ? 

Water is hydrogen oxide.  You can't just make stuff up, people have been cooling heated metals in water since before written history, and have researched the topic fully.  You can Google and use Wikipedia to start to understand.  As for books, General Chemistry by Pauling has a very accessible section on metallurgy.

2.) If I make the same process without putting metal sheet into water, will this produce better or pure oxide ? Simply put, which oxide is better ?

That really depends on the application you have in mind.

[maxvortex]

I think that we have misunderstanding here :-) and it's my mistake.
I meant, if i heat up iron sheet and if i cool it in the water, do i get:
FE203  or some other reaction.

I'm interested just in chemical reaction. 
That's why i want to know the difference between oxidation in water and oxidation without water.

[Borek]

In general you need atmospheric oxygen to oxidize iron to Fe(III). Or at least without atmospheric oxygen solutions of Fe(II) are stable.