NAME: SUBJECT: INSTRUCTOR:
AB130: MACHINE DESIGN FOR AB PRODUCTS
COURSE & YEAR: LABORATORY NO. & TITLE: DATE: RATE:
BSABE 4B LABORATORY #4
Materials in Machine Design ❖ Simply, the strength is a maximum
resistance by the material to the
Content deformation. Similarly, tenacity is the ability
5.1 Mechanical Properties of Materials of a material to resist rupture due to a tensile
force.
5.2 Classification of Metals and Alloys
5.3 Review of Basic Manufacturing Processes
5.4 Standards Sizes of Materials
5.5 Materials Selection and Specifications
MECHANICAL PROPERTIES OF MATERIALS
The mechanical properties are those which affect the
mechanical strength and ability of a material to be
molded in suitable shape. Some of the typical
mechanical properties show huge applications in
space and automobile industries. These properties 2. Stiffness
are associated with the capability of the materials to ❖ It is the ability of a material to resist
resist mechanical forces and load and they are deformation under stress. Modulus of
measured in terms of the behavior of the material elasticity is the measure of stiffness.
when subjected to a force. Mechanical properties ❖ Material which suffers slight deformation
may be determined to provide either design data for under load has a high degree of stiffness or
the engineer or as a check on the standard of raw rigidity. Steel beam is stiffer or more rigid
materials. Mechanical properties may be changed than aluminium beam.
by heat treatment process and the working ❖ Finally, it means that the ability of material to
temperature. Mostly, the strength, toughness and resist elastic deflection is known as stiffness.
hardness of materials are to be measured after the
metal forming process. The main objective of the
paper is to give the overview of the importance of
mechanical properties of the materials, testing. This
paper, includes the concepts of strength, plasticity,
malleability, stiffness, elasticity, brittleness, ductility,
toughness, resilience, fatigue, creep and shown how
improper understanding of properties can lead to
have confusion. The engineering concepts of
mechanical properties dominate the teaching in the
technological universities over natural sciences.
MECHANICAL PROPERTIES DEFINITION
1. Strength and Stress-Strain Curve
❖ Strength of the materials refers to the ability
of a material to resist the externally applied
forces without breaking or yielding. 3. Elasticity
❖ The maximum stress is that any material
withstands before destructive is called its ❖ It is the property of materials to regain its
ultimate strength Stress and strain curve of original shape after deformation when the
the material obtained during tensile test external forces are removed. Example is the
describe its ductility and yield strength extension or compression of a spring.
❖ The stress and strain curve is used to obtain ❖ Steel is more elastic than rubber.
Young’s modulus of materials by comparing ❖ Elasticity is a tensile property of the material.
stress and strain value up to elastic limit. ❖ Proportional limit and elastic limit indicate
❖ The Ability of materials to sustain loads elasticity. It is also known as Nonpermanent
without undue failure or distortion is known deformation.
as strength and it is known that the ability of
a material to provide an equal reaction to an
applied force (tensile, compression, shear)
without rupture.
, NAME: SUBJECT: INSTRUCTOR:
AB130: MACHINE DESIGN FOR AB PRODUCTS
COURSE & YEAR: LABORATORY NO. & TITLE: DATE: RATE:
BSABE 4B LABORATORY #4
❖ Breaking of a material with little permanent
distortion simply states the property of
brittleness. Brittle materials when subjected
to tensile loads snap off without giving any
sensible elongation.
❖ Usually, the tensile strength of brittle
materials is only a fraction of their
compressive strength. Examples of brittle
materials are glass, bricks, cast iron etc…
❖ It is also a tendency of a material to fracture
when subjected to shock loading or a blow.
Material that shatters is also a brittle
4. Plasticity material.
❖ It is the ability of material to undergo some 7. Malleability
degree of permanent deformation without
rupture or failure. That means, this is the ❖ It is the ability of materials to be rolled,
property of a material to deform permanently flattened or hammered into thin sheets
under the application of a load. without cracking by hot or cold working.
❖ Plastic deformation will take place only after ❖ Malleable material should be plastic but it is
the elastic range has been exceeded by the not essential to be strong and malleability is
process of slipping when the shear stress on considered as a compressive quality.
the slip plane reaches a critical value. Examples for malleability Al, Cu, Sn, Pb, soft
❖ Displacement caused by slipping is steel, wrought iron. This is the property of a
permanent and the crystal planes do not material to deform permanently under the
return to their original positions even after application of a compressive load.
the removal of the stresses. ❖ A material which is forged to its final shape
❖ Applications are forming, shaping, is required to be malleable. Forging, Rolling
extruding, hot & cold working process, processes are malleability.
forging, ornamental work, stamping, rolling, 8. Toughness
drawing, pressing, etc.. Aluminium is a good
plasticity material. ❖ It is the ability of a material to withstand
bending without fracture due to high impact
5. Ductility
loads. Toughness of material decreases
❖ It is the property of a material which enables when it is heated.
it to draw out into thin wire with the ❖ Thus mild steel is said to be much tougher
application of a tensile force. than a glass.
❖ Ductile materials are gold (most ductile ❖ This property is desirable in parts subjected
material), mild steel, copper, aluminium, to shock and impact loads.
nickel, zinc, tin. ❖ It can be also defined as property of
❖ Ductility usually measured by the terms, absorbing energy before fracture.
percentage elongation and percentage ❖ To the opposite of brittleness, the ability of a
reduction in area. Ductility is thought of as a material is to resist fracture under shock
tensile quality. loading.
❖ Ductile material combines the properties of ❖ Basically, two main impact tests for
plasticity and tensile strength. It is also measuring the toughness of material in
mentioned as a capacity of a material to Joule are available namely Izod and Charpy
undergo deformation under tension without test.
rupture or the ability of a material to 9. Resilience
withstand cold deformation without fracture.
❖ The property of a material to absorb energy
and to resist shock and impact loads are
known as resilience.
❖ Generally, it is mentioned by the amount of
energy absorbed per unit volume within
elastic limit. This is essential for spring
materials.
❖ Two kind of resilience are available. Proof
resilience: Maximum energy which can be
stored in a body up to elastic limit is called
the proof resilience. But the Proof resilience
6. Brittleness
, NAME: SUBJECT: INSTRUCTOR:
AB130: MACHINE DESIGN FOR AB PRODUCTS
COURSE & YEAR: LABORATORY NO. & TITLE: DATE: RATE:
BSABE 4B LABORATORY #4
per unit volume is called modulus of ❖ There are many hardness measurement
resilience. methods available namely, Moh‘s scale,
Vicker‘s hardness, Rockwell hardness,
10. Creep
Knoop test, and Brinell hardness.
❖ When a part is subjected to a constant ❖ Usually, hardness of material is measured
stress at high temperature for a long period by the depth or area of an indentation left by
of time, it will undergo a slow and permanent an indenter with a specific force applied for
deformation called creep. a specific time.
❖ Property is considered in designing IC ❖ Moh‘s scale of hardness measurement is
engines, boilers, turbines. Simplest type of given in table 1. The measurement can be
creep deformation- viscous flow calculated by the element and the acting of
❖ Plastics, rubber and amorphous materials load as shown in table 1. Diamond is the
are very temperature sensitive to creep. hardest material; it can be penetrated or cut
❖ Stress for a specified rate of strain at a by another diamond.
constant temperature is called creep Table1. Moh’s scale of Hardness (Scale value in number)
strength.
❖ When a material sustains steady loads for Scale Element Applying load for penetration
long periods of time, the material may
continue to deform until they may tend to 1 Talc Can be crushed by a finger nail
fracture under the same load. This is called
creep. 2 Gypsum Scratched by a finger nail
❖ If a load is applied and left on the sample for
months or years, the sample will slowly 3 Calcite By a bronze coin
extend. In metals with high melting
temperatures, creep becomes a problem at 4 Fluorite By glass
higher temperatures.
❖ Creep and Stress Rupture Testing are
5 Apatite By penknife
designed to analyze the amount of stress a
material can safely withstand until failure
6 Orthoclase By Quartz
and elongation. These are important
indications for products in the aerospace,
automotive, power generation, medical, oil & 7 Quartz By Hard steel file
gas and many other industries.
8 Topaz By Corundum
11. Fatigue
9 Corundum By Diamond
❖ It is a failure of materials under cyclic loads.
❖ When a part is subjected to a repeated or
fluctuating stresses, the fracture takes place 10 Diamond Only by diamond
under a stress whose maximum value is less
than the tensile strength of the material. For 13. Machinability
instance, the components of high speed
❖ Machinability is defined as the ease with
aero and turbine engine are of this type.
which a material can be machined such as
❖ This is the property of a material to withstand
drill, lathe work, cutting etc.
continuously varying and alternating loads.
❖ Machinability of metal is indicated by
If a part is loaded once to a stress near the
percentage (%) that is known as
yield stress, it will not break.
machinability index.
❖ However, if it is loaded repeatedly to this
❖ Standard metal used for the 100%
level, it will eventually break. This failure is
machinability rating is the free-cutting steel.
called fatigue. Fatigue is an important goal
Materials with good machinability may be
in the design of moving machinery.
cut with relatively little power and low cost.
12. Hardness ❖ Alloys containing more than 10% Si are the
most difficult to machine because hard
❖ Property of a material to resist penetration
particles of free silicon cause rapid tool
by another material is known as hardness.
wear.
❖ It embraces many different properties such
as resistance to wear, scratching, CLASSIFICATION OF METALS AND ALLOYS
deformation etc..
❖ Hardness of materials can be meant like Metals and alloys are essential materials in modern
resistance to abrasion, deformation or society, used in a wide range of applications from
indentation. construction and transportation to electronics and
medical devices.
AB130: MACHINE DESIGN FOR AB PRODUCTS
COURSE & YEAR: LABORATORY NO. & TITLE: DATE: RATE:
BSABE 4B LABORATORY #4
Materials in Machine Design ❖ Simply, the strength is a maximum
resistance by the material to the
Content deformation. Similarly, tenacity is the ability
5.1 Mechanical Properties of Materials of a material to resist rupture due to a tensile
force.
5.2 Classification of Metals and Alloys
5.3 Review of Basic Manufacturing Processes
5.4 Standards Sizes of Materials
5.5 Materials Selection and Specifications
MECHANICAL PROPERTIES OF MATERIALS
The mechanical properties are those which affect the
mechanical strength and ability of a material to be
molded in suitable shape. Some of the typical
mechanical properties show huge applications in
space and automobile industries. These properties 2. Stiffness
are associated with the capability of the materials to ❖ It is the ability of a material to resist
resist mechanical forces and load and they are deformation under stress. Modulus of
measured in terms of the behavior of the material elasticity is the measure of stiffness.
when subjected to a force. Mechanical properties ❖ Material which suffers slight deformation
may be determined to provide either design data for under load has a high degree of stiffness or
the engineer or as a check on the standard of raw rigidity. Steel beam is stiffer or more rigid
materials. Mechanical properties may be changed than aluminium beam.
by heat treatment process and the working ❖ Finally, it means that the ability of material to
temperature. Mostly, the strength, toughness and resist elastic deflection is known as stiffness.
hardness of materials are to be measured after the
metal forming process. The main objective of the
paper is to give the overview of the importance of
mechanical properties of the materials, testing. This
paper, includes the concepts of strength, plasticity,
malleability, stiffness, elasticity, brittleness, ductility,
toughness, resilience, fatigue, creep and shown how
improper understanding of properties can lead to
have confusion. The engineering concepts of
mechanical properties dominate the teaching in the
technological universities over natural sciences.
MECHANICAL PROPERTIES DEFINITION
1. Strength and Stress-Strain Curve
❖ Strength of the materials refers to the ability
of a material to resist the externally applied
forces without breaking or yielding. 3. Elasticity
❖ The maximum stress is that any material
withstands before destructive is called its ❖ It is the property of materials to regain its
ultimate strength Stress and strain curve of original shape after deformation when the
the material obtained during tensile test external forces are removed. Example is the
describe its ductility and yield strength extension or compression of a spring.
❖ The stress and strain curve is used to obtain ❖ Steel is more elastic than rubber.
Young’s modulus of materials by comparing ❖ Elasticity is a tensile property of the material.
stress and strain value up to elastic limit. ❖ Proportional limit and elastic limit indicate
❖ The Ability of materials to sustain loads elasticity. It is also known as Nonpermanent
without undue failure or distortion is known deformation.
as strength and it is known that the ability of
a material to provide an equal reaction to an
applied force (tensile, compression, shear)
without rupture.
, NAME: SUBJECT: INSTRUCTOR:
AB130: MACHINE DESIGN FOR AB PRODUCTS
COURSE & YEAR: LABORATORY NO. & TITLE: DATE: RATE:
BSABE 4B LABORATORY #4
❖ Breaking of a material with little permanent
distortion simply states the property of
brittleness. Brittle materials when subjected
to tensile loads snap off without giving any
sensible elongation.
❖ Usually, the tensile strength of brittle
materials is only a fraction of their
compressive strength. Examples of brittle
materials are glass, bricks, cast iron etc…
❖ It is also a tendency of a material to fracture
when subjected to shock loading or a blow.
Material that shatters is also a brittle
4. Plasticity material.
❖ It is the ability of material to undergo some 7. Malleability
degree of permanent deformation without
rupture or failure. That means, this is the ❖ It is the ability of materials to be rolled,
property of a material to deform permanently flattened or hammered into thin sheets
under the application of a load. without cracking by hot or cold working.
❖ Plastic deformation will take place only after ❖ Malleable material should be plastic but it is
the elastic range has been exceeded by the not essential to be strong and malleability is
process of slipping when the shear stress on considered as a compressive quality.
the slip plane reaches a critical value. Examples for malleability Al, Cu, Sn, Pb, soft
❖ Displacement caused by slipping is steel, wrought iron. This is the property of a
permanent and the crystal planes do not material to deform permanently under the
return to their original positions even after application of a compressive load.
the removal of the stresses. ❖ A material which is forged to its final shape
❖ Applications are forming, shaping, is required to be malleable. Forging, Rolling
extruding, hot & cold working process, processes are malleability.
forging, ornamental work, stamping, rolling, 8. Toughness
drawing, pressing, etc.. Aluminium is a good
plasticity material. ❖ It is the ability of a material to withstand
bending without fracture due to high impact
5. Ductility
loads. Toughness of material decreases
❖ It is the property of a material which enables when it is heated.
it to draw out into thin wire with the ❖ Thus mild steel is said to be much tougher
application of a tensile force. than a glass.
❖ Ductile materials are gold (most ductile ❖ This property is desirable in parts subjected
material), mild steel, copper, aluminium, to shock and impact loads.
nickel, zinc, tin. ❖ It can be also defined as property of
❖ Ductility usually measured by the terms, absorbing energy before fracture.
percentage elongation and percentage ❖ To the opposite of brittleness, the ability of a
reduction in area. Ductility is thought of as a material is to resist fracture under shock
tensile quality. loading.
❖ Ductile material combines the properties of ❖ Basically, two main impact tests for
plasticity and tensile strength. It is also measuring the toughness of material in
mentioned as a capacity of a material to Joule are available namely Izod and Charpy
undergo deformation under tension without test.
rupture or the ability of a material to 9. Resilience
withstand cold deformation without fracture.
❖ The property of a material to absorb energy
and to resist shock and impact loads are
known as resilience.
❖ Generally, it is mentioned by the amount of
energy absorbed per unit volume within
elastic limit. This is essential for spring
materials.
❖ Two kind of resilience are available. Proof
resilience: Maximum energy which can be
stored in a body up to elastic limit is called
the proof resilience. But the Proof resilience
6. Brittleness
, NAME: SUBJECT: INSTRUCTOR:
AB130: MACHINE DESIGN FOR AB PRODUCTS
COURSE & YEAR: LABORATORY NO. & TITLE: DATE: RATE:
BSABE 4B LABORATORY #4
per unit volume is called modulus of ❖ There are many hardness measurement
resilience. methods available namely, Moh‘s scale,
Vicker‘s hardness, Rockwell hardness,
10. Creep
Knoop test, and Brinell hardness.
❖ When a part is subjected to a constant ❖ Usually, hardness of material is measured
stress at high temperature for a long period by the depth or area of an indentation left by
of time, it will undergo a slow and permanent an indenter with a specific force applied for
deformation called creep. a specific time.
❖ Property is considered in designing IC ❖ Moh‘s scale of hardness measurement is
engines, boilers, turbines. Simplest type of given in table 1. The measurement can be
creep deformation- viscous flow calculated by the element and the acting of
❖ Plastics, rubber and amorphous materials load as shown in table 1. Diamond is the
are very temperature sensitive to creep. hardest material; it can be penetrated or cut
❖ Stress for a specified rate of strain at a by another diamond.
constant temperature is called creep Table1. Moh’s scale of Hardness (Scale value in number)
strength.
❖ When a material sustains steady loads for Scale Element Applying load for penetration
long periods of time, the material may
continue to deform until they may tend to 1 Talc Can be crushed by a finger nail
fracture under the same load. This is called
creep. 2 Gypsum Scratched by a finger nail
❖ If a load is applied and left on the sample for
months or years, the sample will slowly 3 Calcite By a bronze coin
extend. In metals with high melting
temperatures, creep becomes a problem at 4 Fluorite By glass
higher temperatures.
❖ Creep and Stress Rupture Testing are
5 Apatite By penknife
designed to analyze the amount of stress a
material can safely withstand until failure
6 Orthoclase By Quartz
and elongation. These are important
indications for products in the aerospace,
automotive, power generation, medical, oil & 7 Quartz By Hard steel file
gas and many other industries.
8 Topaz By Corundum
11. Fatigue
9 Corundum By Diamond
❖ It is a failure of materials under cyclic loads.
❖ When a part is subjected to a repeated or
fluctuating stresses, the fracture takes place 10 Diamond Only by diamond
under a stress whose maximum value is less
than the tensile strength of the material. For 13. Machinability
instance, the components of high speed
❖ Machinability is defined as the ease with
aero and turbine engine are of this type.
which a material can be machined such as
❖ This is the property of a material to withstand
drill, lathe work, cutting etc.
continuously varying and alternating loads.
❖ Machinability of metal is indicated by
If a part is loaded once to a stress near the
percentage (%) that is known as
yield stress, it will not break.
machinability index.
❖ However, if it is loaded repeatedly to this
❖ Standard metal used for the 100%
level, it will eventually break. This failure is
machinability rating is the free-cutting steel.
called fatigue. Fatigue is an important goal
Materials with good machinability may be
in the design of moving machinery.
cut with relatively little power and low cost.
12. Hardness ❖ Alloys containing more than 10% Si are the
most difficult to machine because hard
❖ Property of a material to resist penetration
particles of free silicon cause rapid tool
by another material is known as hardness.
wear.
❖ It embraces many different properties such
as resistance to wear, scratching, CLASSIFICATION OF METALS AND ALLOYS
deformation etc..
❖ Hardness of materials can be meant like Metals and alloys are essential materials in modern
resistance to abrasion, deformation or society, used in a wide range of applications from
indentation. construction and transportation to electronics and
medical devices.
