COPPER: Manufacture, Properties, Applications, types of copper alloys

 COPPER

Copper is one of the most widely used
non-ferrous metals in
industry. It
is extracted from ores of copper such as copper glance, copper pyrites,
melachite and azurite. Copper ores are found in the state of Sikkim and Bihar
of India and Bharma.

Manufacture

Copper ore is first ground and
then smelted in a reverberatory or small blast furnace
for producing an impure alloy.
Then the air is blown through the molten metal to  remove sulphur and iron contamination to
obtain blister copper in the
converter. Copper
is then refined further using electrolysis
processes.

Properties

Pure copper is soft, malleable
and ductile metal with a reddish-brown appearance. It is
  a good conductor of electricity. It is non-corrosive under ordinary conditions and
resists weather very
effectively. Its
tensile strength varies from 300 to 470 MN/m2 and melting point is 1084°C. It
is one of the best conductors of heat and it is highly resistant to corrosion.
This non ferrous metal can withstand severe bending and forging without
failure. It does not cast well. If copper is heated to red heat and cooled
slowly it becomes brittle, but if cooled rapidly it
becomes soft, malleable
and ductile. It can be welded at red heat.

Applications

Copper is mainly used in making
electric cables and wires for electric machinery, motor winding, electric
conducting appliances, and electroplating etc. It can be easily forged, casted,
rolled and drawn into wires. Copper in the form of tubes is used widely in heat
transfer work 
mechanical engineering field. It is used for
household utensils. It is also used in production
  of boilers, condensers, roofing etc. It is
used for making useful alloys with tin, zinc,
nickel  and aluminium. It is used to form
alloys like
brass, bronze and gun
metal. Alloys of
copper are made by
alloying it with zinc, tin, and lead and these find wide range of applications.
Brass, which is an alloy of copper and zinc, finds applications in utensils,
household fittings, decorative objects, etc. Bronze is an alloy of copper and
tin and possesses very good corrosion resistance. It is used in making valves
and bearings. Brass and bronze can be machined at high
speeds to fine surface finish. 

The following copper alloys are important

1.      
Copper-zinc alloys (Brasses)

2.      
Copper-tin alloys (Bronzes)

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