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Extraction of Metals

Alloys - containing Iron.

The alloys of iron
are steel, manganese steel, stainless steel and titanium steel.

Steel is a mixture of iron and carbon.
The amount of carbon may range from 0·1% to 1·5%
giving steels of different properties.
The exact composition of the steel can be monitored
by atomic emission spectroscopy during production.
Over half of the steel used each year in the UK is recycled.

Low carbon steel (less than 0·25% carbon) is called mild steel.
Mild steel is cheap, strong and easily shaped.
It is the main metal for construction
and is used to make bridges, buildings, ships and vehicles.

High carbon steel (more than 0·5% carbon) is stronger
than mild steel but it is more brittle.
High carbon steel is used to make tools and cutters.

Steel has the disadvantage of needing a protective coating
(for example paint) or it will react with oxygen in the air and rust.
Rusting is the reverse of the process in the blast furnace.

Manganese steel is an alloy
of iron (84%), manganese (15%) and carbon (1%).
Manganese steel is extremely hard
and is used for railway points and dredging equipment.

Stainless steel is an alloy of iron (80%),
chromium (15%), nickel (4%) and carbon (0·5 to 1%).
Stainless steel is strong and hard,
with a very high resistance to corrosion (due to chromium).
It is used for cookware, cutlery and industrial chemical plant.

Titanium steel may contain 0·5 to 2% titanium
with varying amounts of other metals
including chromium, nickel and vanadium.
Titanium steel is very hard and
finds uses in aircraft and armour plating.

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