Metals are good conductors of heat and electricity. They are usually shiny, malleable, and ductile. The main types of metals are ferrous (containing iron) and non-ferrous. Ferrous metals include pig iron, cast iron, wrought iron, and various types of steel depending on carbon content. Non-ferrous metals include aluminum, copper, brass, lead, and tin. Metals can be protected from corrosion through processes like tarring, painting, galvanizing, and electroplating which form protective coatings.

1. METALS

2. METALS
A metal is an element, compound, or alloy that is
a good conductor of both electricity and heat.
Metals are usually shiny, malleable and ductile.
* Ductility is a solid material's ability to deform
under tensile stress; this is often characterized
by the material's ability to be stretched into a
wire. Malleability, a similar property, is a
material's ability to deform under compressive
stress; this is often characterized by the
material's ability to form a thin sheet by
hammering or rolling.

3. METALS
Metals and their alloys are the backbone of
all engineering projects. Various metals
are used in one form or the other.
Metals are found as compounds like oxides,
carbonates, phosphates and sulphides
etc. in nature. These compounds, are
known as ores, are treated to remove the
impurities and get the metal.

4. Metals Classification
Metals
Ferrous
Metals
Non-ferrous
Metals

5. Ferrous and Non-Ferrous
Metals

6. Metals Classification
 Ferrous metals, wherein iron is the main
constituent. We use them in floors doors and
windows. Common ferrous metals in use are
cast iron, wrought iron and different forms of
steel.
 Non ferrous metals, wherein iron is not the
main constituent. Aluminum copper zinc, lead,
tin all are classified as non ferrous metals.

7. Occurrence Of Iron
Iron is never available pure in nature. It has to be
extracted in the form of pig iron from various iron
ores.
Pig iron is the crudest and wrought iron is the purest
form of iron. The ores from which iron is extracted
are:
 Magnetite: (Fe3O4). It contains 70 to 75% iron.
 Haematite: (Fe2O3). It contains 70 % iron.
 Iron Pyrites: (FeS3). It contains 47% iron but is
not preferred because of higher sulphur content
which makes it brittle.
 Siderite: (FeCO3). It contains 40% iron.

8. METALS
Ferrous metals:
The basic component obtained is pig iron. Pig
iron is converted into cast or wrought iron. It is
very hard and brittle and difficult to bend. It
does not rust very strong in compression. I f
we re melt pig iron we obtain cast iron. Cast
iron is used in rainwater pipes, grating covers.
Wrought iron is far different from pig iron and
cast iron. It catches rust. It is ductile and
malleable that is it can be easily bend.

9. METALS
Pig iron through various other furnace
processes forms steel.
 Steel
When iron is re melted from its ore by
commercial processes, it contains more
carbon than is desirable. To become steel, it
must be melted and reprocessed to reduce the
carbon to the correct amount,
Steel in itself changes shape. They are used in
roofs , slabs, beams, columns,

10. METALS
Variation of steel.
These depend on the carbon content present in
them.
 Mild steel:(0.15%)
These are prone to rusting and corrodes
easily. This can easily welded.
 High carbon steel:(0.8-1.5%)
High percentage of carbon which makes it
more harder , stronger and difficult to weld. It
is mostly used for tools and equipments.

11. Difference Between Cast Iron
and Wrought Iron
1. Wrought iron is more stable, pure and
stronger, compared to cast iron.
2. Wrought iron is smelted slowly, whereas cast
iron undergoes a faster smelting process.
3. Wrought iron is best outdoors, whereas cast
iron is a good indoor decorative element.

12. METALS
ALLOYS OF STEEL
 Stainless steel :Incase of ferrous metals if we
add chromium to steel we get stainless steel. It
is water proof and does not rust.
 Tungsten steel: When we add tungsten to
steel we get tungsten steel which is used in
bulbs, magnets.

13. METALS
Non ferrous metals
Aluminum:
It is white metal of high metallic luster, obtained
from bauxite. Aluminum is a relatively soft,
durable, lightweight, ductile and malleable metal
with appearance ranging from silvery to dull gray,
depending on the surface roughness. It is
nonmagnetic and does not easily ignite.
Aluminum is the most widely used non-ferrous
metal.
Used in construction of (windows, doors, siding,
building wire, etc.)
Transportation (automobiles, aircraft, trucks,
railway cars, marine vessels, bicycles, etc.)

14. Non-Ferrous Metals-Aluminum
 Due to its light weight, it is used in the
manufacturing of aircrafts and boats.
 Its other uses are window frames, saucepans,
packaging and insulation, pistons and cranks.

15. Non-Ferrous Metals-Copper
 It is another very important pure non ferrous metal. Its red in
colour, tough and ductile.
 It is very good electrical conductor and offers great
resistance to corrosion.
 Copper can work hard or cold but it needs frequent annealing
(is a heat treatment that alters a material to increase its
ductility and to make it more workable. It involves
heating material to above its critical temperature,
maintaining a suitable temperature, and then cooling.).
 Copper is mostly used in the manufacturing of electric wires,
cables and conductors.
 Its other uses are water and central heating pipes and
cylinders, Printed circuit boards.

16. Non-Ferrous Metals-Brass
 Another important non ferrous metal is Brass which
is not a pure metal but combination of Copper and
Zinc.
 It contains 65% copper and 35% Zinc. This non
ferrous metal is very corrosive, yellow in colour,
tarnishes (changes in color due to dust or dirt) very
easily.
 It is harder than copper and its good electrical
conductor.
 It is used for decoration for its bright gold-like
appearance; for applications where low friction is
required such as locks, gears, bearings, doorknobs,
casings and valves; for plumbing and electrical
applications; and extensively in musical instruments
such as horns and bells for its acoustic properties.

17. Non-Ferrous Metals-Lead
 is a pure and an important non ferrous metal. It is
the heaviest common metal.
- The other characteristics are its softness,
malleability and brightness.
 It is shiny metal when new but quickly oxidizes to a
dull grey. It has resistant to corrosion.
- Its uses are different than other non ferrous metals.
 It is used in protection against X-Ray machine,
Paints, roof coverings etc.

18. Non-Ferrous Metals-Tin
 is a pure non ferrous metal.
 It is white in color, soft and corrosion resistant.
 It is used inTinplate and making bronze.
 Bronze is an alloy of copper and tin. It is used for the
manufacture of household utensils.

19. PROTECTION OF METALS FROM NATURAL
ENVIRNMENT
By the adoption of these processes we can
reduce the chances of rusting.
 TARRING
 PAINTING
 GALVANIZING
 ELECTROPLATING

20. PROTECTION OF METALS FROM
NATURAL
ENVIRNMENT
Rusting and corrosion can be avoided by not letting
moist air coming in contact with the iron surface.
Following methods could be adopted to minimize
rusting and corrosion.
 TARRING
Iron is dipped in hot coal tar so that a film of it sticks
to the surface which protects the surface from rusting
and corrosion. Pipes or ends of poles to be embedded
in earth are usually given this protective treatment.
 PAINTING
Paints usually lead paints are applied on the surface
to be protected. Exposed metal surfaces as in case of
roof trusses and bridge structure are given this
treatment which has to be invariably repeated after
regular interval of time.

21. PROTECTION OF METALS
FROM NATURAL ENVIRNMENT
 GALVANIZING
Depositing a fine film of zinc on the iron/steel surface
is termed as galvanizing. The surface to be
galvanized is first cleared of all the foreign matters by
giving it an acid wash to be followed by a wash of
clean water. The surface is then dried and dripped in
molten zinc. The fine film of zinc that gets deposited
protects the surface from contact with atmosphere.
 ELECTROPLATING
By the process of electrolysis a thin film of nickel,
chromium, copper or zinc is deposited on the surface
to be protected.