Iron and steel: introduction

Iron is cheap and strong and the most used metal in the world. Iron, as produced in the blast furnace is called pig iron. This is brittle because it contains about 4% carbon and other non-metal impurities. Most of this iron is converted into a variety of steels by removing nearly all the carbon, and adding small quantities of different metals. The different steels are alloys which are mixtures of metals. They have different properties such as toughness, hardness, corrosion resistance, etc.

Some background

The method of using carbon to reduce iron oxide to iron was very probably discovered accidentally in prehistoric camp fires. Here, charcoal would have been the source of carbon. The iron was used to make tools and weapons and gave its name to the Iron Age.

Early in the 18th century, Abraham Darby in Shropshire discovered a method of converting coal to coke as a source of carbon. This led to the modern blast furnace.

In the mid 19th century, Henry Bessemer developed a steel-making process that used oxygen to burn off some of the carbon in cast iron. The Basic Oxygen Steelmaking process was introduced in the 1950s and now accounts for about two-thirds of steel production.

Iron and steel: fact file

World production	Iron	560 million tonnes per year
World production	Steel	750 million tonnes per year
UK production	Iron	13 million tonnes per year
UK production	Steel	18 million tonnes per year
Manufacture		Blast furnace / Basic Oxygen Steelmaking
Raw material		Iron ore, coke and limestone

Steel production figures include recycled steel which explains why the production of steel is greater than that of iron.

Most iron is converted into steel. A little is cast to make components such as the engine blocks of vehicles.

	Construction	32%
	Automotive	18%
	Mechnical engineering	13%
	Metal goods	12%
	Packaging	10%
	Electrical engineering	4%
	Other transport	3%
	Other	8%


Map	Aerial view of plant

Unlabelled blast furnace diagram	Labelled blast furnace diagram

Unlabelled diagram of the BOS process	Labelled diagram of the BOS process

Iron and steel: on the web

last update March 2006