it was related to unit 3 EME which includes engineering materials and properties of materials.

1. ( EME)

2.  Engineering Materials: Types and applications
of Ferrous &Nonferrous metals
 Ferrous metals- cast iron and carbon steels
 Non ferrous metals- copper, aluminium, lead,
tin, etc.
 Timber- soft wood and hard wood,
seasoning of wood
 Abrasive material, silica, ceramics, glass,
graphite, diamond,
 Plastic and polymer

3.  For improving the quality of life human beings are always
in search of better and newer materials. Either materials are
used as they occur naturally or different materials are
produced using natural materials.
 They use these Materials for making houses, clothing, tools,
weapons, utensils, musical instruments, printing etc. Use of
various materials is learnt by mankind in different ages.
 In the beginning of human life on Earth there was Stone
Age, people used only natural materials, like stone, clay,
skins, and wood. Later when people found copper and
learned how to make it harder by alloying, the Bronze Age
started around 3000 BC.

4.  The use of iron and steel started around 1200 BC.
Use of Iron and steel was advantageous in wars. The
next big discovery was the development of a
commercial cheap process for making steel around
1850 AD. This enabled development of railroads, high
rise buildings and modern infrastructure of the
industrial world. The success of a particular civilization
was dependent on the best material known to that
civilization.

10.  For Overall development of society we have to
realize the importance of engineering materials, so
we discussed some points here –
 Extraction and processing of raw material develops:
Efficient, cleaner and systematic methods of raw-
material extraction are developed.
 Industrial growth takes place: New industries for
manufacturing new products are created.
 Infrastructure Improves: Power, transport and
communication improves.

11.  Technical education improves: To work in
industry skilled man power is required. Technical
education improves.
 Gross National Product of the country improves:
Improvement in material production leads to
increase in GNP.
 Standard of living of people improves: Salaries
and wages of trained personnel improves which
leads improvement in overall living standard of
people.
 Technological and economic development takes
place.

12.  Metal and their alloy
 Non- Metals and
 Composite materials

13.  1.0 Ferrous metals: In Ferrous metals Iron (Fe) is the
major constituent. Examples: Cast Irons and Steels.
They are strongest material available. They are used for
making bridges, railway lines, railway engines, railway
wagons, strong parts of automobiles, steel wires, rods,
plates etc.
 2.0 Non-Ferrous metals are those metals in which
major constituent is other than Iron (Example: Gold,
Silver, Copper, Zinc, Brass, Tin, Bronze, and Lead
etc.). Their mechanical strength is less.

14.  Synthetic Non-Metals such as plastics and adhesives
do not exist in nature, they are manufactured from
natural substances such as oil, coal and clay. They have
good mechanical strength and can be easily
manufactured. Plastics are extensively used from
utensils to structural members. Synthetic adhesives are
used for joining.
 Natural Non-Metals: Some non-metals such as wood,
rubber, glass, emery, ceramic, diamonds, oils and
silicon are naturally occurring. They are obtained from
nature and given desired shape for use

15.  Composite materials are combination of
two or more materials. They exhibit
different properties then those materials
of which they are made of. Some
example composite material are fiber
glass, Clad metals, Cemented Carbides,
Reinforced plastics etc.

16.  Ferrous materials are those materials in which
chief constituent is Iron. In these materials
Iron is mixed with Carbon, Silicon,
Chromium, Nickel, Manganese etc. to form
alloys such as Steels and Cast Irons.
 Ferrous materials are classified into two
categories namely Steels and Cast Irons based
on Carbon content in them

17.  Steels: Steels are those alloys of Iron and Carbon in
which carbon content is less than 2%. Depending
upon % of other alloying elements, Steels are further
named as Carbon Steels, Stainless Steels or Tool steels.
 Cast Iron: Cast Irons are those alloys of Iron and
Carbon in which Carbon content is 2% to 6.67%.
Cast Irons are normally produced from cupola furnace.
Depending upon % of Carbon and other alloying
elements various Cast Irons are produced.

18. Carbon Steels and their classification based on % of
Carbon: Higher percentage of carbon in steel makes it harder
and tougher.
Carbon Steels are classified into following four categories:
a) Low carbon steel , C %- 0.05-0.15
b) Mild steel,C %- 0.16-0.29
c) Medium carbon steel ,C %- 0.3-0.59
d) High carbon steel C %- 0.60-1.7

19. s.
no
Type of carbon steel % of carbon properties applications
1 Low carbon steel 0.05-0.15 soft, ductile , very
little hardenability,
good corrosion
resistance.,good
weld ability.
Welded or
Seamless tubes,
Thin sheets, Wire
rods, Nails,
Rivets,
,Stampings etc.
2 Mild carbon steel 0.16-0.29 Soft, ductile,
Little
hardenability,go
od weladbility
Forgings,
Stampings,
Structural
sections (i.e.
Angles,
Channels,
Beams, wire
Rods, Ribbed
bars etc.), Plates,
Steel Castings

20. s. no Type of
carbon steel
% of carbon properties applications
3 Medium
carbon steel
0.30-0.59 Good strength and
ductility. good
hardenability and
weldability. They
can be hot or cold
worked.
Drop forgings,
Plates for boiler
drums, Marine
Shafts and
axles, High
tensile wires
and tubes,
Locomotive
wheels, Wire
ropes, hammers
etc.
4 High carbon
steel
0.60- 1.7 good
hardenability,
ductility and
weldability are
low.
for making
Cutting Tools,
Punches & Dies
and high
strength Rails.

21.  a) Low Carbon Steel or Dead mild steel: They have carbon content
in the range of 0.05 – 0.15%. These steels are very soft, ductile and
have very little hardenability. They have good corrosion resistance.
They have good weld ability. They can be easily cold worked and they
acquire hardness through cold working. They are used for making
Welded or Seamless tubes, Thin sheets, Wire rods, Nails, Rivets, and
Stampings etc.

 b) Mild Steel: They have Carbon Content from 0.16% - 0.29%. These
steels are soft, ductile and have very little hardenability. They acquire
hardness through cold working. They have good weldability. They are
used for making Forgings, Stampings, Structural sections (i.e. Angles,
Channels, Beams, wire Rods, Ribbed bars etc.), Plates, Steel Castings
etc.


22.  c) Medium Carbon Steel: They have Carbon Content from
0.3%-0.59%. These steels have good strength and ductility. They
have good hardenability and weldability. They can be hot or cold
worked. They get hardened quickly while cold working, due to
this they require frequent annealing while cold working. They are
suitable for making Drop forgings, Plates for boiler drums,
Marine Shafts and axles, High tensile wires and tubes,
Locomotive wheels, Wire ropes, hammers etc.
 d) High Carbon Steel: They have Carbon Content from 0.6% to
1.7%. These steels have very good hardenability. There ductility
and weldability are low. They become so hard after quenching
that tempering is normally required to reduce their brittleness and
make them tougher. They are mostly used for making Cutting
Tools, Punches & Dies and high strength Rails.

23. It is purest form of iron which
contains 99.8 % of iron and
produced by melting pig iron
in puddling furnace.

24.  Cast Iron: Cast Iron is produced by
melting Pig Iron* in Cupola furnaces
or some other furnace (i.e. Induction
furnace etc.). The chemistry of Pig Iron
is suitably modified in cupola furnace to
produce different grades of Cast Iron.

25.  Cast Iron has low tensile strength, but good
compressive strength and good corrosion
resistance. Cast Irons are very brittle and
have no plasticity as a result they can not be
forged.
 It has self lubricating properties due to
presence of free carbon and is therefore used
for making surfaces over which sliding takes
place (such as lathe bed etc.)

26.  a) Gray Cast Iron : In this Cast Iron most of the
carbon is present in the form of free graphite. Under
microscope this carbon is visible as flakes.
 If a piece of this material is broken its fractured section
shows the grayish color and that is why it is known as
Gray Cast Iron. The gray color is due to presence of
free carbon in the form of graphite flakes. In Gray
Cast Irons the Carbon content in combined form (i.e. in
the form of Fe3C) may vary from 0.3% to 0.9%.

27. Properties :
 It is very brittle and posses no ductility or plasticity as a result it
can not be forged. High brittleness makes it unsuitable for
making parts which are subjected to shock loading.
 It has good machinability.
 It has good compression strength (1250 Kg/Sq.cm) and low
tensile strength 650 Kg/ Sq. cm). Due to good compressive
strength it is most suitable for making Compressive load bearing
members such legs and beds of heavy machinery.
 It has good fusibility which makes it suitable for making
castings.
 Due to presence of free graphite it has self lubricating
property and hence it is suitable for making sliding surfaces.

28.  White Cast Iron :
 It is called white cast iron because its fractured section shows
whitish color. Most of the carbon present in this cast Iron is in
the combined form (i.e. iron carbide which is called Cementite).
Cementite is white in color and makes the structure white.
 Cementite is very hard and brittle. Cenmentite is formed due
to rapid cooling of iron after melting. It is due to this reason that
all the chilled parts of castings are hard and brittle.
 White cast iron is hard and brittle and highly wear resistant.
 Its fluidity is not good and is not suitable for general casting
purpose.

29.  c) Malleable cast Iron : It has fairly good amount of
malleability. It is produced in two steps. First cast iron
castings are produced by melting white cast iron in
cupola furnace. These castings are packed in Iron
boxes containing material rich in O2. These boxes are
kept for four days in annealing furnaces at a
temperature of 815oC to 1010oC and then allowed to
cool slowly along with the furnace. This allows
Cementite to decompose into iron and carbon.

30. d)Nodular Cast Iron : This is also known as Spheroidal
Graphite ( or simply SG) Cast Iron, Ductile Cast
Iron or High Strength Cast Iron. For its production
the shape of graphite present in cast iron is changed
from flakes to spheroids or nodules.
 This is achieved by adding magnesium metal to the
molten cast iron just after tapping. This magnesium
treated metal when cast into moulds gives SG cast iron.
This changed shape of graphite prevents formation and
propagation of cracks and enhances ductility of Cast
Iron. It has chemistry similar to gray cast iron

31.  Alloy Steels :
 All steels in addition to Iron and Carbon contain
other elements like silicon, manganese, sulphur and
phosphorous. In some steels special elements like
Nickel, Chromium, Molybdenum, Vanadium and
Tungsten etc. are added to enhance their mechanical
properties. These steels are called alloy steels.
 They have their properties as per the alloying elements
in them. These steels are named normally on the basis
of their principal alloying element.

32. These are various types-
Stainless steel
Tool steel
Spring steel

33.  Stainless steels : They are corrosion resistant steels.
Their principal alloying element is chromium, while
other elements like nickel, manganese can also be
present in small amounts.
 To impart high corrosion resistance to steels
Chromium up to 12% is added.
 The chromium present in steels reacts with O2 in air to
form a strong layer of chromium oxide on the surface
of the metal. This layer protects the metal from
corrosion. Stainless steels carrying more than 12%
chromium are known as true stainless steels.

34. These alloy steels have special application in
manufacture of cutting tools for those applications
where tools made of carbon steel will either fail to
perform or will have a very short life. They are put into
two categories namely :

35.  High Speed Steel : It is a high alloy tool steel used for
making cutting tools suitable for high temperature
applications.
 Main Constituents in HSS are Carbon, tungsten,
chromium, vanadium and molybdenum. High Speed
Steel has high wear resistance, high abrasion resistance and
high red hardness. They retain their hardness up to 620oC.
 The most commonly used high speed steel is 18-4-1
which carries 18% Tungsten, 4% Chromium, 1%
Vanadium, 0.7% Carbon and rest Iron.
 It has good red hardness, wear resistance shock
resistance and widely used for making cutting tools for
lathe, shapers, slotters, milling machines, drill etc

36.  Non ferrous Metals are those
which do not contain Iron. Most
commonly used nonferrous
metals are Aluminium, Copper,
Magnesium, Lead, Tin, Nickel,
Zinc etc. Also they form useful
alloys among themselves.

37. Non ferrous metals have following advantages
over ferrous metals
 Very good electrical and thermal conductivity
 Good castabilty
 Good formability
 Good cold working property
 High corrosion resistance
 Attractive appearance
 Lower density and high strength to weight
ratio.

38. High cost, High shrinkage,
Lower strength at elevated
temperature

39.  Properties and usage of copper :
 High electrical conductivity : Used for making
cables and contactors.
 High heat conductivity : Used in heat exchangers,
heating vessels and appliances.
 Good corrosion resistance : Used to provide base
coating on steel prior to nickel and chromium
plating.
 High ductility : Can be easily cold worked, rolled,
drawn and spun. Looses ductility in cold working
requires annealing between the process.

40. Properties and usage of Zinc :
 High corrosion resistance : It is widely used
for providing protective coating on iron and
steel. It may be coated either by dip
galvanizing, Electroplating, Sheradising* or
just by painting.
 Low melting point and high fluidity: Makes it
most suitable for pressure die casting.

41. Properties and usage of Tin
 Good resistance to acid corrosion and used
as coating on steel container for food.
 It is soft, has good plasticity and can be easily
worked.
 It can be easily rolled into thin foils but can
not be drawn into wires due to low strength.
 It is used as alloying element in soft solders,
bronzes and bearing metals.

42. Properties and usage of
magnesium:
 It the lightest metal, weighing two third of
aluminum.
 It can be easily cast into fine shapes.
 Is has good ductility so it can be easily cold
worked.
 When in powder form, it is likely to catch fire,
requiring adequate fire protection measures
for its storage.

43. Properties and usage of lead :
 Good corrosion resistance : Used for water pipes
and roof protection.
 Good resistance to chemical action: Used for acid
baths and containers in chemical industry.
 Its soft heavy and malleable and can be easily
worked and shaped.
 Used as alloying element in making solders.
 It is alloyed with Brass and Steel to impart them
free cutting properties.

44. Properties and usages of Aluminium:
 High Electrical conductivity: Used for heavy
conductors and bus bars.
 High heat conductivity: Used in domestic utensils
and other heat conducting appliances.
 Good resistance to corrosion: Used for
manufacture of containers for chemical industry
and window frames etc. The corrosion resistance
can be further enhanced by anodizing*. (*Process
of increasing the thickness of natural oxide layer
on the metal surface. It is done through
electrolysis. Metal forms anode of electrical
circuit)

45. Properties and usage of Nickel
 Good resistance to both acid and alkali
corrosion. Widely used for food processing
equipment.
 Has high tensile strength and can be easily
hot or cold worked.
 It is plated on steel to provide corrosion
resistance surface.

46. -Brass – These are the
alloy of copper and zinc
-Bronze-They are alloys
of copper and Tin.

47.  Composite materials are combinations of
two or more materials which differ in
chemical composition and physical
properties and are insoluble in each other.
They are manmade or naturally occurring.
Examples: Natural Wood, Fiber glass used
for making bath tubs etc., imitation granite,
cultured marble, plywood etc. .

48. There are two major components of composite materials:
 a) Reinforcements i.e materials that provide
strength to the composite.
 b) Matrix i.e the material that holds the
reinforcement in place

49.  Natural Composites such as
wood , human body etc
 Synthetic composite all man
made composites such as fiber
glass, clad metal, plywood,
reinforced plastics et.

50.  Low density, high strength, high hardness and
stiffness.
 Corrosion resistant, weather resistant and
tailored surface finish
 Low thermal conductivity, low coefficient of
thermal expansion
 High dielectric strength, nonmagnetic, Radar
transparency
 Can withstand high temperature in corrosive
environment
 Good formability, good durability and good
damping properties

51.  High cost of raw material and manufacturing
 Matrix is weak giving rise to low toughness
 Environmental degradation takes place in
matrix.
 Composites ingredient can not be reused.
 Joining is difficult
 Difficult to analyze

52.  Used as a replacement material in various
engineering applications such as cylinder block
liners, vehicle drive shafts, automotive pistons,
bicycle frames etc
 Hockey sticks, vaulting poles, golf carts etc
 Fuel and chemical storage tanks
 Aerospace applications : helicopter blades, engine
couplings, ducts etc
 Marine : Boats , ships , hulls etc
 Electronic and recreational industries
 high voltage power transmission lines and heat sinks
for electronic components
 As bio compatible materials