The Uses of Iron

The iron that comes out of the blast furnace is known as pig iron The iron that comes out of the blast furnace is known as pig iron. It is impure. It contains around 3% to 4% carbon as well as some other non-metals. The pig iron smashes easily so is very brittle. Most of the iron that is produced is turned into a tougher, more useful metal called steel. Steel is mainly iron – usually over about 98%. So what must be removed from the pig iron to produce steel? CARBON

The carbon can be removed by blowing oxygen into the molten iron that has just come out of the blast furnace. The carbon burns off - turning into carbon dioxide gas which escapes easily. oxygen The vessel is then tipped over to pour out the molten steel molten iron (from the blast furnace)

The amount of carbon remaining in the steel gives the steel varying properties. Mild steel contains about 0.2 % carbon and can easily be shaped. Medium steel contains about 0.5 % carbon and is hard. Hard steel contains about 1 % carbon and is very hard. What happens to the hardness of steel as we increase the amount of carbon? Hardness increases when more carbon is present. What type of steel do you think would be used to make hammers? Give a reason for your answer. Hard steel as hammers need to be very hard. What type of steel do you think would be used to make car bodies? Give a reason for your answer. Mild steel as it can be easily shaped.

Image courtesy of Photolibrary Wales Recycling – Why? More and more people are being encouraged to start recycling iron/steel (as well as other materials). Why do you think this is so? Image courtesy of Photolibrary Wales