Stefania Bertonati (asker) Dec 1, 2011:

un po' più di contesto.. Wrought iron has a very low carbon content and very few contaminants. It can have a visible grain, produced by forging or rolling (page 114) the iron and slag together in the production process. It is soft, ductile and has been replaced by carbon steel for most applications due to its inferior strength.
Cast iron is made up of iron, carbon and small amounts of silicon. There are different types, including grey, white, ductile and malleable. They are differentiated by the formation of carbon in the iron matrix and alloying elements. Generally, cast iron has good dampening properties and machinability, is resistant to fatigue and corrosion and is difficult to weld due to the high carbon content

Stefania Bertonati (asker) Dec 1, 2011:

@Manuela da qui non sembra che "wrought iron" sia "acciaio dolce":
Types of iron and steel
Cast iron has already been mentioned above.
Wrought iron

If all the carbon is removed from the iron to give high purity iron, it is known as wrought iron. Wrought iron is quite soft and easily worked and has little structural strength. It was once used to make decorative gates and railings, but these days mild steel is normally used instead.
http://www.chemguide.co.uk/inorganic/extraction/iron.html