Technical Overview of Iron, Steel and Stainless Steel

Iron is an element of the periodic table, which is actually pure find it is almost impossible.
As very tender and oxidizable, is therefore always linked to a small percentage of carbon which gives hardness thus forming an alloy, precisely the steel. The steel then is the alloy of iron and carbon and more increases the more the percentage of carbon steel acquires hardness at the expense of malleability. What is commonly called “iron” is actually a piece of mild steel (mild steel is carbon steel with little 0.01%). The steel can be up to a maximum of about 2% of carbon (hard steels). In addition to 2% and up to 5% max of the alloy takes the cast name (even harder than steel but more fragile, glass type).
 
Else are the stainless steels; Steels to which is added Nickel and Chromium in varying proportions that give it the characteristic of not oxidize (= stainless steel) that is never rust, of course must be well defined with the entry “Stainless Steel” and not steel, which it means a Unlike the cost of production of sheet metal base of about 4 times more than steel, and on the semi-finished as round tube or square / rectangle up to 6 times greater.
 
I hope this is a help to deepen and understand the best possible estimates to be compared with each other.

Excerpt from Wikipedia and the magazine “L’inossidabile”