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ANNA UNIVERSITY - COIMBATORE THE KAVERY ENGINEERING COLLEGE
M.KALIPATTI, METTUR (TK), SALEM (DT) – 636453DEPARTMENT OF MECHANICAL ENGINEERING
STRENGTH OF MATERIALS LABORATORY MANUAL
IV SEMESTER MECHANICAL ENGINEERING (R-2008 SYLLABUS)
Name of the student: ______________________________________________
Register Number : ______________________________________________
Prepared By
Sasikumar.M & Sudhagar.M
Department of Mechanical Engineering
Strength of Materials Lab
INDEXThe Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Ex. No Date Name of the experiment Page No Marks
ObtainedStaff
signature Remarks
1 TENSION TEST ON A MILD STEEL ROD 5
2 DOUBLE SHEAR TEST ON MILD STEEL 11
3 DOUBLE SHEAR TEST ON ALUMINUM 15
4 IMPACT STRENGTH TEST (CHARPY’S TEST)
19
5 IMPACT STRENGTH TEST ( IZOD TEST)
23
6 BRINELL HARDNESS TEST 27
7 ROCKWELL HARDNESS TEST 31
8 DEFLECTION TEST ON SIMPLY SUPPORTED BEAM (MILD STEEL)
35
9 COMPRESSION TEST ON HELICAL SPRING
39
10 TORSION TEST ON MILD STEEL ROD 43
11 EFFECT OF HARDENING IN IMPACT RESISTANCE OF STEEL
45
12 STUDY OF MICROSCOPIC EXAMINATION OF HARDENED AND TEMPERED SAMPLE
51
13 STUDY OF MICROSCOPIC EXAMINATION OF UNHARDENED SAMPLES
53
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
SYLLABUS
STRENGTH OF MATERIALS LAB (Common to Mechanical & Production)
LIST OF EXPERIMENTS
1. Tension test on a mild steel rod
2. Double shear test on Mild steel and Aluminum rods
3. Torsion test on mild steel rod
4. Impact test on metal specimen
5. Hardness test on metals - Brinnell and Rockwell Hardness Number
6. Deflection test on beams
7. Compression test on helical springs
8. Strain Measurement using Rosette strain gauge
9. Effect of hardening- Improvement in hardness and impact resistance of steels.
10. Tempering- Improvement Mechanical properties Comparison
(i) Unhardened specimen
(ii) Quenched Specimen and
(iii) Quenched and tempered specimen.
11. Microscopic Examination of
Hardened samples and
(ii) Hardened and tempered samples.
LIST OF EQUIPMENT (For a batch of 30 students)
1. Universal Tensile Testing machine with double 1
2. shear attachment – 40 Ton Capacity
3. Torsion Testing Machine (60 NM Capacity) 1
4. Impact Testing Machine (300 J Capacity) 1
5. Brinell Hardness Testing Machine 1
6. Rockwell Hardness Testing Machine 1
7. Spring Testing Machine for tensile and compressive loads (2500 N) 1
8. Metallurgical Microscopes 3
9. Muffle Furnace (800 C)
Quantity: one each. Total Number of Periods: P=45The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 1 TENSION TEST ON A MILD STEEL RODDate :
AIM:To conduct tension test on the given specimen and determine the following
Yield Stress
Nominal stress
Actual breaking Stress
Ultimate stress
Percentage of elongation
Percentage reduction in cross sectional area / E
APPARATUS REQUIRED:
Universal Testing Machine (UTM)
Mild steel specimen
Ruler
Divider
Vernier caliper
THEORY:
The tensile test is most applied one, of all mechanical tests. In this test ends of test piece are
fixed into grips connected to a straining device and to a load measuring device. If the applied load is
small enough, the deformation of any solid body is entirely elastic. An elastically deformed solid
will return to its original from as soon as load is removed. However, if the load is too large, the
material can be deformed permanently. The initial part of the tension curve which is recoverable
immediately after unloading is termed. As elastic and the rest of the curve which represents the
manner in which solid undergoes plastic deformation is termed plastic. The stress below which the
deformations essentially entirely elastic is known as the yield strength of material. In some material
the onset of plastic deformation is denoted by a sudden drop in load indicating both an upper and a
lower yield point. However, some materials do not exhibit a sharp yield point. During plastic
deformation, at larger extensions strain hardening cannot compensate for the decrease in section
and thus the load passes through a maximum and then begins to decrease. This stage the “ultimate
strength”’ which is defined as the ratio of the load on the specimen to original cross-sectional area,
reaches a maximum value. Further loading will eventually cause ‘neck’ formation and rupture.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
OBSERVATION:
1. Given material of specimen = _____
2. Initial diameter of specimen d1 = ____
3. Initial gauge length of specimen L1 = ______
4. cross-section area of specimen A1 = _____
5. Final length after specimen breaking L2 =______
6. Diameter of specimen at breaking place (Neck Dia.) d2 = ______
7. Cross section area at breaking place (Neck area) A2 = ______
8. Load of yield point = ______
9. Ultimate load of specimen =______
10.Breaking load of specimen = ______
TABULATION:
SL.NOLOAD
( KN)EXTENSION(mm) STRESS
(N/mm2)STRAIN
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
FORMULAE USED:
Yield Load 1) Yield Stress = N/mm2
Cross Sectional Area
Ultimate Load 2) Ultimate Stress = N/mm2
Cross Sectional Area
Breaking Load 3) Nominal Breaking Stress = N/mm2
Cross Sectional Area of Specimen
Breaking Load 4) Actual Breaking Stress = N/mm2
Neck Area
Change in length 5) Percentage of Elongation = x 100 % Original gauge Length
Change in area 6) Percentage reduction in = x 100 % Area of cross section Original area
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
TENSILE TESTING MACHINE
GRAPH:
Where,P– Proportional LimitE – Elastic limitYU – Upper Yield PointYL – Lower Yield PointThe Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
S – Ultimate Tensile strengthB – Fracture point
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE:
1. Measure the original length and diameter of the specimen. The length may
either be length of gauge section which is marked in the specimen with a
preset punch.
2. Insert the specimen into grips of the test machine and attach strain
measuring device to it.
3. Begin the load application and record load versus elongation data.
4. Take readings more frequently and record as yield point is approached.
5. Measure elongation values with the help of dividers and a ruler.
6. Continue the test till fracture occurs.
7. By joining the two broken halves of the specimen together the final length
and diameter of specimen.
RESULT:
Different parameters of the given specimen are.
1. Yield stress = __________N/mm2
2. Ultimate stress = __________ N/mm2
3. Nominal breaking stress = __________N/mm2
4. Actual breaking stress = __________N/mm2
5. Percentage of elongation = __________ %
6. Percentage reduction in
Cross sectional area = __________ %
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 2 DOUBLE SHEAR TEST ON MILD STEEL RODDate :
AIM:
To determine shear stress by conducting shear test on the specimen under double shear.
APPARATUS REQUIRED:
Universal Testing Machine
Double Shear assembly box
Vernier caliper
Test specimen
THEORY:
A type of force which causes or tends to cause two contiguous parts of the body to
slide relative to each other in a direction parallel to their plane of contact is called the
shear force. The stress required to produce fracture in the plane of cross-section, acted on
by the shear force is called shear strength.
Place the shear test attachment on the lower table, this attachment consists of
cutter. The specimen is inserted in shear test attachment & lift the lower table so that the
zero is adjusted, then apply the load such that the specimen breaks in two or three pieces.
If the specimen breaks in two pieces then it will be in single shear & if it breaks in three
pieces then it will be in double shear.
FORMULAE USED:
Ultimate Shear Stress () = W N/mm2
2A
Where,
‘ ‘ - Ultimate Shear strength (N/mm2)
‘W’ - Ultimate load in (N)
‘A’ - area of the specimen in mm2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
OBSERVATION:
Given material of specimen = Mild steel
Diameter of specimen rod = ------
Maximum Shear Load = ------
TABULATION:
Specimen
Diameter of
the specimen
‘d’ (mm)
Cross
Sectional
area ‘A’(mm2)
Maximum
Shear Load
‘W’ (kN)
Ultimate
Shear stress
‘’ ( N/mm2)
Mild steel Rod
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE:
1. The diameter of rod is measured using vernier caliper.
2. The specimen is inserted in position in double shear assembly box and is gripped
between the compression plates of universal testing machine.
3. The universal testing machine is switched on.
4. A suitable load is selected.
5. Left side valve is kept in a closed position and right side loading valve is gradually
opened and the load is applied on the specimen till it shear.
6. The maximum load taken by the specimen at that time is noted.
7. Then the machine is stopped and the ultimate shear strength of the specimen is
noted.
RESULT:
The ultimate Double shear stress of the Mild steel specimen is_____________ N/mm2.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 3 DOUBLE SHEAR TEST ON ALUMINIUM RODDate :
AIM:
To determine shear stress by conducting shear test on the specimen under double shear.
APPARATUS REQUIRED:
Universal Testing Machine
Double Shear assembly box
Vernier caliper
Test specimen
THEORY:
A type of force which causes or tends to cause two contiguous parts of the body to
slide relative to each other in a direction parallel to their plane of contact is called the
shear force. The stress required to produce fracture in the plane of cross-section, acted on
by the shear force is called shear strength.
Place the shear test attachment on the lower table, this attachment consists of
cutter. The specimen is inserted in shear test attachment & lift the lower table so that the
zero is adjusted, then apply the load such that the specimen breaks in two or three pieces.
If the specimen breaks in two pieces then it will be in single shear & if it breaks in three
pieces then it will be in double shear.
FORMULAE USED:
Ultimate Shear Stress () = W N/mm2
2A
Where,
‘ ‘ - Ultimate Shear strength (N/mm2)
‘W’ - Ultimate load in (N)
‘A’ - area of the specimen in mm2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
OBSERVATION:
Given material of specimen = Aluminum rod
Diameter of specimen rod = ------
Maximum Shear Load = ------
TABULATION:
Specimen
Diameter of
the specimen
‘d’ (mm)
Cross
Sectional
area ‘A’(mm2)
Maximum
Shear Load
‘W’ (kN)
Ultimate
Shear stress
‘’ ( N/mm2)
Aluminum rod
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE:
1. The diameter of rod is measured using vernier caliper.
2. The specimen is inserted in position in double shear assembly box and is gripped
between the compression plates of universal testing machine.
3. The universal testing machine is switched on.
4. A suitable load is selected.
5. Left side valve is kept in a closed position and right side loading valve is gradually
opened and the load is applied on the specimen till it shears.
6. The maximum load taken by the specimen at that time is noted.
7. Then the machine is stopped and the ultimate shear strength of the specimen is
noted.
RESULT:
The ultimate Double shear stress of the Aluminum specimen is_____________ N/mm2.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 4 IMPACT STRENGTH TEST (CHARPY’S TEST)Date :
AIM: To determine the impact strength of material of the given specimen by charpy’s
impact test.
APPARATUS REQUIRED: Impact testing machine
Charpy’s test specimen
Vernier caliper.
THEORY:
In manufacturing locomotive wheels, coins, connecting rods etc. the components
are subjected to impact (shock) loads. These loads are applied suddenly. The stresses
induced in these components are many times more than the stress produced by gradual
loading. Therefore, impact tests are performed to asses shock absorbing capacity of
materials subjected to suddenly applied loads. These capabilities are expressed as (i)
Rupture energy (ii) Modulus of rupture and (iii) Notch impact strength. Two types of notch
impact tests are commonly-
Charpy test
Izod test
In charpy’s test, the specimen is placed as 'cantilever beam'. The specimens have V-
shaped notch of 45°. U- Shaped notch is also common. The notch is located on
tension side of specimen during impact loading. Depth of notch is generally taken as
t.5 to t/3 where ’t’ is thickness of the specimen.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
TEST SPECIMEN:
OBSERVATION:
Breath of specimen (b) = ________ mm
Depth of specimen (d) = ________ mm
Length of specimen (l) = ________ mm
Depth of notch (d1) = ________ mm
TABULATION:TABULATION:
Specimen
Dimensions of Specimen Impact Energy
Observed‘ k ’
ImpactStrengthI = k / A
Breath‘b’
Depth‘d’
Length‘l’
Depth ofNotch
‘d’
mm mm mm mm J J / m2
MODEL CALCULATION:
Area of cross- section of specimen (A) = b X (d-d1) mm2
Impact energy observed (K) = _______ J
Impact strength (I) = K/A J/m2
FORMULAE USED : The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Notch Impact Strength I =K/A J/m2
Where,
I = Notch impact strength in J/m2
K = Impact energy absorbed by specimen in Joules
A = Area of the cross section of specimen below notch before test in m2
PROCEDURE:1) The hammer is raised and locked.
2) The pointer is set at maximum position of graduated energy of dial.
3) The safety load bar is placed horizontally arms of projecting bars.
4) The trigger is released and pendulum is allowed to swing. This actuates the pointer
to move in the dial.
5) See that no person is on within range to swing of pendulum.
6) The specimen is placed in such a way that notch is opposite to the direction of the
pendulum for contact centering of specimen. The end stop is provided.
7) The latches are released and pendulum is allowed to strike on specimen (or)
bending the specimen is noted in the dial.
8) Then the impact energy required for the rupture of the specimen is directly
measured on indicator.
RESULT : The Charpy impact strength is calculated as,
The impact strength of the given specimen (I) = J/m2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 5 IMPACT STRENGTH TEST (IZOD TEST)Date :The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
AIM:
To determine the impact strength of the given specimen by Izod impact test.
APPARATUS REQUIRED:
Impact testing machine
Izod specimen
Vernier caliper.
THEORY:
In manufacturing locomotive wheels, coins, connecting rods etc. the components
are subjected to impact (shock) loads. These loads are applied suddenly. The stresses
induced in these components are many times more than the stress produced by gradual
loading. Therefore, impact tests are performed to asses shock absorbing capacity of
materials subjected to suddenly applied loads. These capabilities are expressed as (i)
Rupture energy (ii) Modulus of rupture and (iii) Notch impact strength.
Two types of notch impact tests are commonly-
Charpy test
Izod test
In Izod test, the specimen is placed as ‘cantilever beam’. The specimens have V-shaped
notch of 45°. U- Shaped notch is also common. The notch is located on tension side
of specimen during impact loading. Depth of notch is generally taken as t.5 to t/3
where’t’ is thickness of the specimen.
TEST SPECIMEN:
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
OBSERVATION:
Breath of specimen (b) = ________ mm
Depth of specimen (d) = ________ mm
Length of specimen (l) = ________ mm
Depth of notch (d1) = ________ mm
TABULATION:TABULATION:
Specimen
Dimensions of Specimen Impact Energy
Observed‘k’
ImpactStrengthI = k / A
Breath‘b’
Depth‘d’
Length‘l’
Depth ofNotch
‘d’
mm mm mm mm J J / m2
MODEL CALCULATION:
Area of cross- section of specimen (A) = b X (d-d1) mm2
Impact energy observed (K) = _______ J
Impact strength (I) = K/A J/m2
FORMULAE USED:
Notch Impact Strength I =K/A J/m2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Where,
I = Notch impact strength in J/m2
K = Impact energy absorbed by specimen in Joules
A = Area of the cross section of specimen below notch before test in m2
PROCEDURE:
1. The hammer is raised and locked.
2. The pointer is set at max. position of graduated energy of dial.
3. The safety load bar is placed horizontally arms of projecting bars.
4. The trigger is released and pendulum is allowed to swing. This actuates the pointer
to move in the dial.
5. See that no person is on within range to swing of pendulum.
6. The specimen is placed vertically ie cantilever position in such a way that notch is
opposite to the direction of the pendulum for contact centering of specimen. The
end stop is provided.
7. The latches are released and pendulum is allowed to strike on specimen (or)
bending the specimen is noted in the dial.
8. Then the impact energy required for the rupture of the specimen is directly
measured on indicator.
RESULT : The Izod impact strength is calculated as,
The impact strength of the given specimen (I) = J/m2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Brinell hardness Testing Machine
LOADING TABLE:
S.NoBall
diameter
‘D’ in mm
Loading in ‘Kg’
( P )
Ferrous (Steel & Iron)
(30D2)
Non – Ferrous
Brass (10D2) Aluminum (5D2)
1 10 3000 1000 500
2 5 750 250 -
Exp. No: 6 BRINELL HARDNESS TESTThe Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Date :
AIM:
To determine the brinell hardness number of the given specimen.
APPARATUS REQUIRED: Brinell Hardness Testing Machine
Brinell Microscope
Ball Indenter (5,10 mm)
Test specimens
THEORY:
Hardness represents the resistance of material surface to abrasion, scratching
and cutting, hardness after gives clear identification of strength. In all hardness
testes, a define force is mechanically applied on the test piece for about 15
seconds. The indenter, which transmits the load to the test piece, varies in size
and shape for different tastes. Common indenters are made of hardened steel or
diamond.
In Brinell hardness testing, steel balls are used as indenter.
Diameter of the indenter and the applied force depend upon the thickness of the
test specimen, because for accurate results, depth of indentation should be less than 1/8 th
of the thickness of the test pieces. According to the thickness of the test piece increase,
the diameter of the indenter and force are changed.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
TABULATION:
S.No
Name of the
Material
Load(Kgf)
P
Diameter ofImpression
Mean dia of
Impression
(mm)
‘d’
Area‘A’
mm2
Brinell Hardnes
sNumber(BHN)
d1
(mm)
d2
(mm)
1
2
3
MODEL CALCULATION:Name of the Specimen =
Applied Load (P) = Kg
Ball diameter (D) = mm
Diameter of the impression ‘d1’ = mm
Diameter of the impression ‘d2’ = mm.
Surface Area of Impression (A) =
DD - (D2 – d2 ) ] mm2
2
Brinell Hardness Number (P/A) = _____________ Kg/mm2 Or BHN
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE:
1. The type of ball indenter of specified diameter is selected and fixed in machine
head.
2. The surface of specimen is to be cleaned from dust, oil etc. before placing it on
the test platform.
3. The platform with specimen is raised until gap between indenter and specimen
is minimum. Now the machine is switched on.
4. The load-applying lever is released to original position.
5. A minor load is applied manually while the specimen is made contact with the
indenter.
6. The platform is lowered and the machine is switched off.
7. Then with the help of brinell microscope the diameter of impression is measured
and tabulated.
8. Then with the help of brinell microscope the dia of impression is measured in
two directions at right angle to each other and average dia to be taken and
tabulated.
9. The above procedure is repeated for different specimen with minimum three
readings in each specimen.
RESULT:
The Brinell hardness number of
1. ____________with _______ Ball diameter = __________ BHN
2. ____________with _______ Ball diameter = __________ BHN
3. ____________with _______ Ball diameter = __________ BHN
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Rockwell hardness Testing Machine
LOAD TABLE:
Material Penetrates Load (Kgf) Scale
Relatively soft Material Diamond cone(1200 ) 60 A
Purely hard Material 1/16” Ball point 100 B
Hard Material Diamond Cone (800) 150 C
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 7 ROCKWELL HARDNESS TESTDate :
AIM:
To determine the Rockwell hardness Number of given specimen.
APPARATUS REQUIRED:
1. Rockwell hardness testing machine
2. Penetrates
3. Test specimen.
THEORY: Hardness represents the resistance of material surface to abrasion, scratching and
cutting, hardness after gives clear indication of strength. In all hardness tests, a define
force is mechanically applied on the piece, varies in size and shape for different
tests. Common indenters are made of hardened steel or diamond.
Rockwell hardness tester presents direct reading of hardness number on a dial
provided with the m/c. Principally this testing is similar to Brinell hardness testing. It
differs only in diameter and material of the indenter and the applied force. Although there
are many scales having different combinations of load and size of indenter but commonly
'C' scale is used and hardness is presented as HRC. Here the indenter has a diamond
cone at the tip and applied force is of 150 kgf. Soft materials are often tested in 'B' scale
with a 1.6mm diameter steel indenter at 60kgf.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
TABULATION:
S.NoName of
the Material
Load
(Kgf)
Load
(N)Penetrates Scale
Dial
Reading
Rockwell
Hardness
Number
1.
2.
3.
4.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE:
1. Insert ball of dia. 'D' in ball holder of the m/c.
2. Make the specimen surface clean by removing dust, dirt, oil and grease etc.
3. Make contact between the specimen surface and the ball by rotating the
jack adjusting wheel.
4. Push the required button for loading.
5. Pull the load release lever wait for minimum 15 second. The load will automatically
apply gradually.
6. Remove the specimen from support table and locate the indentation so
made.
7. Repeat the entire operation, 3-times.
RESULT:
The Rockwell hardness number of
1. ____________with _______penetrate = __________ RHN
2. ____________with _______penetrate = __________ RHN
3. ____________with _______penetrate = __________ RHN
4. ____________with _______penetrate = __________ RHN
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 8 DEFLECTION TEST ON SIMPLY SUPPORTED BEAM (MILD STEEL)Date :
AIM:To find the values of Young’s modulus of the material of a simply supported beam
(mild steel) by conducting deflection test.
APPARATUS REQUIRED:1) Deflection of beam apparatus
2) Weight
3) Beam ( steel)
4) Deflect meter
5) Knife edge support
6) Loading hanger
7) Vernier caliper
THEORY: If a beam is simply supported at the ends and carries a point load at its centre,
the beam bends concave upwards. The distance between the original position of the beam
and its position after bending is different at different points along the length of the beam,
being maximum at the centre in this case. The difference is known is deflection.
FORMULA USED:
W a x (L2 ─a2 ─x2) Young’s Modulus E = N/mm2 6 I L
Where, bd3 I = Moment of inertia in ‘mm4’ = 12
W = Load applied in ‘N’
L = Effective span of the beam in ‘mm’
= Mean deflection of the beam in ‘mm’
x = Distance between the deflect meter and one knife edge in ‘mm’
a = Distance between the load hanger and another knife edge in ‘mm’
b = Breath of specimen in ‘mm’The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
d = Thickness of the specimen in ‘mm’
OBSERVATIONS:Effective span of the beam ‘L’ =
Breath of specimen in ‘b’ =
Thickness of the specimen in‘d’ =
Least count deflection of the beam =
Distance between the deflect meter and one knife edge ‘x’ =
Distance between the load hanger and another knife edge in ‘a’ =
TABULATION:
S.No
Load
applied
( W)
Kg
Load
applied
( W)
N
Deflect meter
Reading
Mean
Deflection
()
mm
Young’s
Modulus
(E)
N/mm2
Loading Unloading
1
2
3
4
5
6
7
8
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE: 1. Place the beam on the knife edges on the blocks so as to project equally beyond
each knife edge. See that the load is applied at the centre of the beam.
2. Note the initial reading of vernier scale
3. Add a weight of 50 N (say) and again note the reading of the vernier scale.
4. Go on taking reading adding 50 N (say) each time till you have minimum six
readings.
5. Find the deflection in each case by subtracting the initial reading of vernier scale.
Plot the graph between load and deflection. On the graph choose any two
convenient points and between these points find the corresponding values of W and
δ. Putting these values in the above relation, we can find the E.
GRAPH:
X-Axis - Deflection (mm)
Y-Axis - Load (N)
RESULT: The Young’s modulus of given mild steel material is
Theoretical (E) =
Graphical (E) =
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
COMPRESSION TEST ON HELICAL SPRING
MODEL GRAPH
OBSERVATION:
Diameter of the rod (d) = mm
Diameter of the spring (D) = mm
Inner diameter of spring (D1) = mm
Height of the spring (h) = mm
Number of turns (n) =
mmThe Kavery Engineering college Department of Mechanical
Mean radius of spring ( R) =d + D1
2 39
Strength of Materials Lab
Exp. No : 9 COMPRESSION TEST ON HELICAL SPRING
Date :
AIM:
To study the load deflection behavior of the helical spring and to determine the
Stiffness of spring and Modulus of rigidity.
APPARATUS REQUIRED:
Spring testing machine
A spring
Micrometer
Vernier caliper
Scale
FORMULA USED:
1. Stiffness of spring ‘S’
(Slope of W- curve)= W/ N/mm
2. Modulus of rigidity
(C) =
64 WR3n N/mm2
d4
‘W’ - applied Load (N)
‘R’ - Mean radius of the spring (mm)
‘n’ - No. of turns
‘’ - Deflection of the spring ( mm )
‘d’ - diameter of the spring Wire (mm)
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
TABULATION:
Sl.
No
Applie
d Load
(Kg)
Applied
Load
(N)
Compression due to the load Modulus of
rigidity
“C”
(N/mm2)
Stiffness
“S”
(N/mm)
Loading
(mm)
Unloading
(mm)
Mean
“”
(mm)
Mean
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
PROCEDURE:
1. Measure the diameter (d) of the spring bar forming the coil at 3 locations and take
the average value as the diameter of the bar.
2. Determine the mean radius(r) of the spring, record the number of turns (n).
Determine the pitch (p) of the spring and measure the free height of spring (h).
3. The compression spring is placed centrally on the bottom plate and the upper
plate is lowered such that it just touches the upper plate .
4. The pointer on the dial is set to zero. The Load is gradually applied.
5. Note the deflections for both loading as well as Unloading. Calculate the
average of the loads for the various deflections.
6. Unlock the testing machine and fix the spring in position. Make zero adjustment in
the dial by adjusting the weight on the spring.
7. Apply the load slowly note the deflections for both loading and unloading by 20N
steps. At least 6 readings have to be noted.
RESULT:
1. Stiffness of spring (S)
i) From calculation = ________ N/mm
ii) From graph = ________ N/mm
2. Modulus of rigidity (C)
i) From calculation = ________ N/mm2
ii) From graph = ________ N/mm2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No : 10 TORSION TEST ON MILD STEELDate :The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
AIM: To conduct torsion test on mild steel specimens to find the following
Modulus of rigidity
Maximum Shear stress
APPARATUS REQUIRED:
A torsion testing machine.
Twist meter for measuring angles of twist
A steel rule and Vernier Caliper or micrometer.
THEORY:
A torsion test is quite instrumental in determining the value of modulus of rigidity of
a metallic specimen. The value of modulus of rigidity can be found out thought
observations made during the experiment by using the torsion equation
FORMULA USED:
Torsion test of square rod
4.8 Tmax
Maximum Shear stress = b3
5.5 T LModulus of rigidity C = θ b4
T = Torque applied (Nmm)
C = Modulus of rigidity (N/mm2)
θ = Angle of twist (radians)
L = Gauge length (mm)
= Shear stress (N/mm2)
b = width of the square rod (mm)
OBSERVATION:
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Width of the square rod (b) = mm
Gauge length (L) = mm
TABULATION:
S.No
Angle of
Twist
(deg)
Tropotometer
reading
Kgf(cm)
Torque
NmmModulus of
rigidity (C)
N/mm2
1
2
3
4
5
6
7
8
9
PROCEDURE:
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
1. Select the driving dogs to suit the size of the specimen and clamp it in the machine by
adjusting the length of the specimen by means of a sliding spindle.
2. Measure the diameter at about three places and take the average value.
3. Choose the appropriate range by capacity change lever
4. Set the maximum load pointer to zero.
5. Set the protector to zero for convenience and clamp it by means of knurled screw.
6. Carry out straining by rotating the hand wheel in either direction.
7. Load the machine in suitable increments.
8. Then load out to failure as to cause equal increments of strain reading.
9. Plot a torque- twist (T- θ) graph.
10. Read off co-ordinates of a convenient point from the straight line portion of the torque
twist (T- θ) graph and calculate the value of C by using relation
RESULT:
Maximum shear stress =__________N/mm2
Modulus of rigidity C (From Calculation) =__________ N/mm2
Modulus of rigidity C (From Graph) =__________ N/mm2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No: 11 EFFECT OF HARDENING IN IMPACT RESISTANCE OF STEEL
Date :
AIM: To determine the effect of hardening in impact resistance resistance of steel before
and after hardening.
APPARATUS REQUIRED:
Impact testing machine
Furnace
Vernier caliper
Scale
PROCEDURE:
1. The hammer is raised and locked.
2. The pointer is set at maximum position of graduated energy of dial.
3. The safety load bar is placed horizontally arms of projecting bars.
4. The trigger is released and pendulum is allowed is to swing this actuates the pointer to
more in the dial.
5. The specimen is placed in such a way that notch is opposite to the direction of the
pendulum for contact centering of specimen the end stop is provided.
6. The latches are released and pendulum is allowed to strike on specimen or bending the
specimen is noted in the dial.
7. Then the input energy required for the rapture of the specimen is directly measured on
indicator.
8. Now another specimen is taken and kept into a furnace at 8500C to 9500C.
9. The specimen is the same piece is cooled suddenly in quenching media.
10. Now the variation in the input strength before and after hardening is studied.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
OBSERVATION:
Breadth of specimen (b):__________________
Depth of Specimen (d):___________________
Length of Specimen (L):___________________
Depth of notch (d1):______________________
TABULATION:
Specimen
Dimension of specimen Are of
cross
section
A (mm2)
Impact
energy
observed
K (J)
Impact
strength
I=K/A
(J/m2)
Breadth b
(mm)
Depth
d
(mm)
Length L
(mm)
Depth of
notch d1
(mm)
Before
hardening
After
hardening
MODEL CALCULATION:
Area of the cross section of specimen (A) = b (d -d1) mm2
Impact strength (I) = K/A J/m2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
RESULT: The charpy impact strength is calculated as,
1. The impact strength of the given specimen (Before hardening) = ________ J/m2
2. The impact strength of the given specimen (After hardening) = __________J/m2
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No : 12 STUDY OF MICROSCOPIC EXAMINATION OF HARDENED AND TEMPERED SAMPLES
Date :
AIM: To determine the microscopic examination of hardened and tempered samples (steel)
APPARATUS REQUIRED:
Specimen
Metallurgical microscope
COMPOSITION:
C=0.6%
Si=0.4%
Mn=0.1%
P=0.05%
S=0.05%
Heat treatment: yes
Mechanical treatment:: NIL
OBSERVATION: The structure contains tempered martensite. The given structure is identified as quenched
and tempered steel.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
Exp. No : 13 STUDY OF MICROSCOPIC EXAMINATION OF UNHARDENED SAMPLES
Date :
AIM: To determine the microscopic examination of unhardened samples
(medium carbon steel)
APPARATUS REQUIRED:
Specimen
Metallurgical microscope
COMPOSITION:
C=0.6%
Si=0.6%
Mn=0.8%
P=0.004%
S=0.004%
Heat treatment: NIL
Mechanical treatment: NIL
OBSERVATION: The structure contains pearlite and ferrite. The given structure is identified as medium
carbon steel.
The Kavery Engineering college Department of Mechanical
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Strength of Materials Lab
The Kavery Engineering college Department of Mechanical
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