Properties, Composition and Industrial Applications of Engineering Materials and Metal Joining Processes.

MODULE IV
Properties, Composition and
Industrial Applications of
Engineering Materials.
By
Girish B Kallihal M.Tech (Machine Design)
Assistant Professor
Mechanical Engineering Department
S T J Institute of Technology, Ranebennur
Mo: 966 396 32 39

ENGINEERING MATERIALS
• The substances which are useful in the field of
engineering are called Engineering materials.
A particular material is selected is on the basis of
following considerations
1. Properties of material (Mechanical, Physical, Chemical,
Manufacturing).
2. Cost of material
3. Availability of material
4. Service in life of material
5. Appearance of material
2Girish Kallihal. STJIT, Ranebennur

Classification of Engineering
Materials

Engineering Materials
1 Metals
I. Ferrous
a) Pig Iron
b) Cast Iron
c) Wrought Iron
d) Steel
II. Non-Ferrous
a) Aluminum
b) Copper
c) Nickel
d) Brass
e) Bronze
f) Lead
g) Tin
h) Zinc
i) Gold
j) Silver
2) NON-Metallic
I. Synthetic Materials
a) Plastics
b) Ceramics
c) Composites
II) Natural Materials
a) Wood
b) Rubber
c) Diamond
d) Glass
e) Oils
f) Silicon

Metals
• Metal is an elemental substance in pure form. while an alloy is formed in
two or more metals mixed together to form a homogeneous mixture .
• Ex: Iron and Steel .
CLASSIFICATION OF METALS
1. Ferrous Metals
2. Non Ferrous Metals
1. Ferrous Metals
• Ferrous is derived from Latin word “Ferrum” which means Iron . The
metals which contain iron as its main element called as ferrous metals .
• Ferrous metal pocess high strength and relatively low cost. They are used
in applications where weight is not the primary influencing factor.
• Ex. Pig Iron , Cast Iron, Wrought Iron , Steel .

Pig Iron
• It is the first stage of iron directly extracted from the ore through
Blast furnace.
• These contain high percentage of carbon about 3.5 to 4.5 percent
along with silicon and other constituents like Sulphur, manganese
and phosphorous
• These contents which make it very brittle and not directly used as
a metal.
• Pig iron is produced in blast furnace and poured in moulds, in
preparation for conversion in to wrought iron, cast iron and steel .

WROUGHT IRON
• It is produced by pig iron in a puddling furnace.
• In this carbon content will be very less.
Chemical Composition
• It contains about 99.8% of iron
• 0.02% of carbon, 0.12% of silicon.
• Small amount of Manganese, Phosphorous, Sulphur.
Properties
• Wrought iron is soft.
• Highly Ductile and very high Toughness.
• Due to low carbon content the melting point will be very high.
Application
• Due to high Corrosion resentence property it is used in making of steam
and water pipes.
• For making Engine bolts and railway couplings.

CAST IRON
• It is produced when pig iron is remelted in cupola furnace.
Chemical composition
• It contains greater than 90% of iron
• About 2 to 4.5% of carbon .
• 1 to 3% of silicon and small amount of Sulphur, manganese and
phosphorous
Properties
• It is very strong but brittle.
• It has relatively low melting Point and is wear resistant.
• Posses good fluidity.
• It has poor ductility and malleability.
Applications
• It is used to manufacture of lathe bed, Railway Track.
• Fly wheels Machine frames, columns. Etc.,

STEEL
• Steel is an alloy of iron and carbon which is produced by oxygen steel
making process (or) by electric arc furnace.
• In the oxygen steel making process molten pig iron is blowed by oxygen so
that oxidization takes place resulting lowers the carbon content in the
alloy.
• In electric arc furnace Scrap steel (or) Recycled steel is introduced in the
furnace and remelted along with some other additions to produce end
product.
Chemical Composition
• It contains 0.5 to 1.5% of carbon.
• Small amount of Silicon, Manganese, Phosphorous, Sulphur.
Classification of steel
a) Carbon steel
b) Alloy steel
c) Tool Steel

a) Carbon steel• Carbon steel contains primarily iron and carbon.
• Other elements present in small amount are Sulphur, manganese ,
phosphorous.
Carbon steels again classified into three types
(i) Low carbon steel (ii) Medium carbon steel (iii) High Carbon steel
(i) Low carbon steel
• It contains carbon about .05 to 0.3%.
• The rest will be iron
Properties
• It is soft and ductile.
• Good machinability.
• Good toughness.
• Good formability and weldability.
Applications
• Chains, bolts , nuts, keys.
• Boiler plates.
• In structural sections like channels, beams. 10Girish Kallihal. STJIT, Ranebennur

(ii) Medium carbon steel
• Carbon content about 0.3 to 0.6%.
• The remaining will be iron.
Properties
• High tensile strength.
• Improved toughness.
• Good bending strength.
• Wear resistance.
Applications
• To manufacture shafts, gears.
• Connecting rods.
• Loco tires.
• Rotor shafts.

(iii) High Carbon steel
• It has carbon content about 0.6% to 1.5%.
• It has an iron content about 96% to 97%.
Properties
• High resistant to wear and tear.
• High yield strength and low impact strength.
• Ductility is less than medium carbon steel.
Applications
• It is used to manufacture of steels, chisels , screws.
• Drill manufacturing.
• It is used to manufacture lath tools and reamers.
• Ball bearings and springs.

b) Alloy steels
• Alloy steels are produced by adding elements other than carbon to improve
specific properties.
• The principal alloying elements used are nickel, magnesium, chromium, silicon,
copper.
Alloying elements are added to improve properties such as
I. Improve cast ability, weldability, machinability.
II. Improve strength.
III. To maintain strength at elevated temperature.
IV. Improve corrosion resistance.
The commonly used alloy steels are
A. Stainless steel
B. Nickel
A) Stainless steel
• Stainless steel do not gets stained and very good resistance to corrosion.
• It mainly consist of 18% of chromium, 8% of nickel and 0.03% of carbon.
• The rest is majorly iron and small amount of magnesium, silicon, sulphite.
• They are used in manufacturing kitchen equipment's, springs , shaving blades

b) Nickel steel
• In this type of steel nickel is the alloying element .
• It contains 3% of nickel and 0.2 to 0.35% of carbon.
• These are piston rods, axels, parts of ships.

c) Tool steels
• Tool steels are special type of steels with carbon
content in the range of 0.8 to 1.2%.
• The alloying elements used In this are tungsten,
vanadium , cobalt, chromium.
• A very common example of tool steel is High
Speed Steel(HSS). It contains 0.7 to 0.8% of
carbon, 1.2 to 20% of tungsten, 3 to 5% of
chromium and others.
• It is used to make drill bits, lathe tools, milling
cutters, reamers.

NON FERROUS METALS
• Non ferrous metals are engineering materials do not contain iron.
• They include strength to weight ratio, good resistance to corrosion, light
weight, high electrical and thermal conductivity, ease of fabrication.
• Ex: Aluminium, Copper, zinc, lead, tin.
1) Aluminium
• aluminium is a silvery, soft and ductile material. In its ore form aluminium
is found as hydrated aluminum oxide (or) Bauxite.
Properties
• Light weight and easy workability.
• Non-magnetic and good reflector of light.
• Highly ductile.
• Good electrical and thermal conductivity.
• Due to passivation phenomena, it has ability to resist corrosion.

Applications
• Metallurgical applications : Aluminium is used as de-oxidizer in the
production of iron and steels.
• Electrical industry : aluminium is used to make cables, motors,
rotors etc
• Aircraft industry : used for making aircraft parts due to light weight
and corrosion resistance properties.
• Automotive industry : Due to light weight it is used in automobile
industry.
• In packaging industry : it is used to make foils and drinking cans.
• Construction industry : it is used to make windows, doors, solar
panels , roofing's.

2) Copper
• Copper is the oldest metal of man kind. It is extracted from the ore called Copper
pyrites.
• Extraction is carries out in a reverberator furnace where ore is refined.
• The two main alloys of copper are brass and bronze.
Properties
• High electrical conductivity.
• High thermal conductivity.
• Good corrosion resistance.
• Light weight.
• High ductility.
Applications
• Copper in the form of tube used in refrigerators, air-conditioners.
• Due to high electrical conductivity copper is used in electrical tubes, cables.
• Used to make popular alloys like brass and bronze.
• Used to make roofing , flushing drains.
• Used to make door knobs. 18Girish Kallihal. STJIT, Ranebennur

3) Lead
• Lead Is a soft and malleable metal obtained from its ore Galena.
properties
• Lead is a soft and malleable metal.
• It has poor tensile strength, high coefficient of thermal expansion.
• High antifriction properties and can melted very easily.
• Lead is toxic In nature.
Applications
• To manufacture water pipes due to its corrosion resistance.
• In making of bullets.
• Sheathing materials for high voltage cables due to its high ductility, low
temperature and corrosion résistance.
• Solders since it has low melting point.
Alloys of lead
• Alloys of lead are (i) solder (ii) Babbit metal (iii) lead alloys made out of
lead , antimony, arsenic (iv) lead antimony alloy (v) lead foils.

4) Nickel
• It is a tough silver coloured metal extracted from sulphide ores.
• It is used for coating iron and steel products, vessels.
Properties
• Good resistence to corrosion.
• Very ductile.
• Can be easily cast.
• High melting point.
• Can be drawn into wires.
Applications
• It is an alloying element for steel to increase the tensile strength and antifriction
properties.
• Used as a catalyst for many chemical reactions.
• Used in vessel for heating and boiling.
• Used in medical equipment.
Alloys of nickel are
• (i) monel metal (ii) German silver (iii) nichrome (iv) hastelloy.

5) Zinc
• Zinc is a white metal can be extracted from zinc sulphide.
Properties
• It is a conductor of electricity.
• It has relatively low melting point.
• It is resistence to corrosion.
• Good cast ability.
• Can be recycled.
Applications
• Galvanizing to protect iron and steel from corrosion they are immersed in
liquid zinc.
• Galvanized steel to produce automobile parts.
• It is used to manufacture sheets for roof covering applications.
Alloys of zinc
• (i) cadmium-zinc alloy (ii) magnesium alloy (iii) copper zinc alloy (iv) lead
zinc alloy (v) iron zinc alloy.

6) Tin
• Tin is a silvary-white metal obtained from an oxide called tin stone by
reverbratory furnace.
Properties
• Soft malleable and ductile.
• It is corrosion resistant from water.
• Lt has low melting point 232c.
Applications
• Tin is coated on steel containers for storing food and water.
• Used for roofing material due to its light weight and corrosion resistence.
Alloys for tin are (i) pewter (ii) Britannia metal.

7) Silver
• Silver is a naturally occurring material which is soft and white.
Properties
• It is ductile and malleable.
• It has highest electrical and heat conductivity.
Applications
• I making of jewellary and ornaments.
• Currency coins.
• Mirrors.
• In printed circuit boards as a paints.
• Used in photography.

8) Gold
• Gold is a bright yellow, dense, soft malleable and ductile metal.
Properties
• It is chemically non reactive.
• Good resistant to corrosion.
• Good conductors of electricity.
• Gold is a expensive material.
Applications
• Making of ornaments and jewellary.
• Used to protect space ships from x-rays and solar radiation.
• In making of trophies, medals, cups in sports industry.
• In India many of statues of worshipped gods.
• Heat shield electronic circuits.

9) Brass
• Brass is an alloy of copper and zinc.
Properties
• Excellent machinability
• Good strength
• Corrosion resistance
• Conductivity
• Recyclable
• Strength at cryogenic temperatures
Applications
• Ornamentals, doors, furnitures
• Electrical components
• Decorative and protective finishes
• Plumbing

10) Bronze
• Bronze is an alloy of copper and tin.
Properties
• Extremely malleable and durable
• Corrosion resistance
• Good conductor
• Tough and ductile
Applications
• Ship propellers and submerged bearings
• Guitar and piano strings
• Bells
• Medals
• Door and window frames. Etc.,

Polymers
A polymer (poly-, "many" + mer, "part") is a
large molecule, or macromolecule, composed
of many repeated subunits.
IUPAC definition: A molecule of high relative
molecular mass, the structure of which
essentially comprises the multiple repetition
of units derived, actually or conceptually, from
molecules of low relative molecular mass.

• A thermoplastic polymer: It is one that can be
softened by heating and then formed into
desired shapes by applying pressure.
• Thermosetting polymers: These become
permanently hard at elevated temperatures
and pressures.

Ceramics
• Generally known as ‘Clay products’
• Ceramics are inorganic compounds of metallic
and non-metallic elements.
Ex: Glass, Brick, Spark plug etc.,
Cermets: A cermet is a composite material
composed of ceramic (cer) and metal (met)
materials

Classification of Ceramics
 Based on their composition, ceramics are
classified as:
i. Oxides
ii. Carbides
iii. Nitrides
iv. Sulfides
v. Fluorides, etc.

 Based on their application such as:
i. Glasses
ii. Clay products
iii. Refractories
iv. Abrasives
v. Cements
vi. Advanced ceramics.

• Glasses: glasses are a familiar group of
ceramics – containers, windows, mirrors,
lenses, etc. They are non-crystalline silicates
containing other oxides, usually CaO, Na2O,
K2O and Al2O3 which influence the glass
properties and its color.
• Clay products: clay is the one of most widely
used ceramic raw material. It is found in great
abundance and popular because of ease with
which products are made.
Clay products are mainly two kinds
1. Structural products (bricks, tiles, sewer pipes) and
2. Whitewares (porcelain, chinaware, pottery, etc.)

Ceramic Products

Composite Materials
A composite is a structural material that consists of two or more
combined constituents that are combined at a macroscopic
level and are not soluble in each other.
One constituent is called the reinforcing phase and the one in
which it is embedded is called the matrix.
The reinforcing phase material may be in the form of fibers,
particles, or flakes.
The matrix phase materials are generally continuous.
Examples of composite systems include concrete reinforced with
steel and epoxy reinforced with graphite fibers, etc.

Classification of Composite Materials
 Based on geometry of reinforcement
1. Particulate composite
2. Flake composite
3. Fiber composite
 Based on type of the matrix
1. Polymer matrix composite (PMC)
2. Metal Matrix Composites (MMC)
3. Ceramic Matrix Composites (CMC)
4. Carbon-Carbon Composites

Types of composites based on
reinforcement shape.

Fiber Composites
• Fiber composites consist of matrices reinforced
by short (discontinuous) or long (continuous)
fibers.
• Fibers are generally anisotropic and examples
include carbon and aramids.
• Examples of matrices are resins such as epoxy,
metals such as aluminum, and ceramics such
as calcium–alumino silicate.

Metal Matrix Composites
• Metal matrix composites (MMCs), as the
name implies, have a metal matrix.
• Examples of matrices in such composites
include aluminum, magnesium and titanium.
• Typical fibers include carbon and silicon
carbide.
• Metals are mainly reinforced to increase or
decrease their properties to suit the needs of
design.

Smart Materials
• These are also called as intelligent or
responsive materials,
• These are designed materials that have one or
more properties that can be significantly
changed in a controlled fashion by external
stimuli, such as stress, temperature,
moisture, pH, electric or magnetic fields, light,
or chemical compounds.

Types of Smart Materials
• Piezoelectric materials
• Shape Memory Alloys (Phase transition)
• Magnetostrictive
• Electro-Rheological materials
• Magneto-Rheological materials

Shape Memory alloys
• Shape Memory Alloys are metal alloys which
can undergo solid-to-solid phase
transformation and can recover completely
when heated to a specific temperature.
These materials has two phases
1. Austenite- high temperature phase
2. Martensite- Low temperature phase

MECHANICAL PROPERTIES
• The characteristics of material that describe the
behaviour under the action of external loads are
referred as its mechanical properties.
The common mechanical properties are as follows
1. STRENGTH 8. BRITTLENESS
a) Tensile Strength 9. HARDNESS
b) Compressive Strength 10. CREEP
c) Shear Strength 11. FATIGUE
2. STIFFNESS 12. RESILIENCE
3. ELASTICITY 13. MACHINABILITY
4. PLASTICTY 14. WELDABILITY
5. DUCTILITY 15. CASTABILITY
6. MALLEABILTY
7. TOUGHNESS

1.Strength
It is defined as the ability of a material to resist loads
without failure.
a) Tensile Strength: The tensile strength or tenacity is
defined as the ability of material to resist a
stretching (tensile) load without fracture.
b) Compressive strength : The ability of a material to
resist squeezing (compressive) load without fracture
is called compressive strength.
c) Shear strength : The ability of a material to resist
transverse loads i.e. loads tending to separate (or cut)
the material is called shear strength.

2. Stiffness
It is the ability of material to resist deformation
or deflection under load. Within the elastic
limit, stiffness is measured by the modulus of
elasticity.

3. Elasticity: The ability of a material to deform
under load and return to its original shape
when the load is removed is called elasticity.
4. Plasticity: The ability of a material to deform
under load and retain its new shape when the
load is removed is called plasticity.

5. DUCTILITY: It is the ability of a material to be
deformed plastically without rupture under
tensile load. Due to this property material can
drawn out into fine wire without fracture.
6. MALLEABILTY : It is the ability of a material to
be deformed plastically without rupture under
compressive load. Due to this property metals
are hammered and rolled into thin sheets.

7. TOUGHNESS : It is defined as the ability of the
material to absorb energy up to fracture
during the plastic deformation. Toughness of a
metal offers the resistance to breaking when
force is applied.
8. BRITTLENESS : It is the property of sudden
fracture without any visible permanent
deformation.

9. HARDNESS : It is defined as the ability of a
material to resist scratching or indentation by
another hard body. Hardness is directly
related to strength.
10. CREEP : The slow and progressive
deformation of a material with time at
constant stress is called creep.
11. FATIGUE : Failure of material under repeated
or reversal stresses is called fatigue.
Machine parts are frequently subjected to
varying stresses and it is important to know
the strength of materials in such conditions. 53Girish Kallihal. STJIT, Ranebennur

12. RESILIENCE : It is a property of material to
absorb energy and to resist shock and impact
loads. It is measured by the amount of energy
absorbed per unit volume within the elastic
limit.
13. MACHINABILITY: The ease with which a
given material may be worked or shaped with
a cutting tool is called machinability.

14. WELDABILITY: It is the ability of material to
be joined by welding.
Weldability depends on chemical composition,
physical properties and heat treatment to
which they are subjected.
15. CASTABILITY : Castability of metal refer to
the ease with which it can be cast into
different shapes and is concerned with the
behavior of metal in its molten state.

Metal Joining Processes:
Welding, Soldering and Brazing

Introduction
• Metal fabrication involves joining of two
metals together.
Various processes are used to join the metals
together depending on
The material
thickness of the various parts to be joined and
Degree of permanency required

Methods of Joining
1. Welding
2. Soldering
3. Brazing

Welding
Welding may be defined as the metallurgical
joining of two metal pieces together to
produce essentially a single piece of metal.
Principle: The junction of the two pieces (parts)
to be joined are heated and then fused
together with or without the application of
pressure to produce single piece of metal.

Types of Welding
Welding processes are classified based on the
basic principles employed
1. Pressure welding
2. Fusion welding (Non-pressure welding)

 Pressure welding: In this type, the parts to
be joined are heated only up to the plastic
state and then fused together by applying
the external pressure.
Ex: Forge welding, Resistance welding
 Fusion welding: In this type, the joint of the
two parts is heated to the molten state and
allowed to solidify.
Ex: Arc welding, Gas welding

Arc Welding
• The welding in which the electric arc is
produced to give heat for the purpose of
joining two surfaces is called electric arc
welding.

How an arc is formed?
• The arc is like a flame of intense heat that is
generated as the electrical current passes
through a highly resistant air gap.

• It is a fusion welding processes which uses an
electric arc to produce the heat required for
melting the metal.
• The welder creates an electric arc that melts the
base metals and filler metal (consumable)
together so that they all fuse into one solid piece
of metal.
Arc Welding

Arc Welding

Girish Kallihal. STJIT, Ranebennur 66

Gas Welding (Oxy-Acetylene Welding)

TIG Welding
TIG welding is an electric arc welding process in which the fusion energy is produced by
an electric arc burning between the work piece and the tungsten electrode.

MIG Welding

Properties, Composition and Industrial Applications of Engineering Materials and Metal Joining Processes.

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