strength of material lab manual

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

TABULATION:

SL.NOLOAD

( KN)EXTENSION(mm) STRESS

(N/mm2)STRAIN

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

GRAPH:

Where,P– Proportional LimitE – Elastic limitYU – Upper Yield PointYL – Lower Yield PointS – Ultimate Tensile strengthB – Fracture point

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 = __________ %

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 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

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

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.

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.

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

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

Exp. No: 5 IMPACT STRENGTH TEST (IZOD TEST)

Date :

AIM:

To determine the impact strength of the given specimen by Izod impact test.

APPARATUS REQUIRED:


Izod specimen

Vernier caliper.

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


FORMULAE USED:

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 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


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

Exp. No: 6 BRINELL HARDNESS TEST

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

TABULATION:

S.No

Name of the

Material

Load(Kgf)

P

Diameter ofImpression

Mean dia of

Impression

(mm)

‘d’

Area‘A’mm2

Brinell HardnessNumber(BHN)

d1

(mm)

d2

(mm)

1

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

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



Exp. No: 7 ROCKWELL HARDNESS TEST

Date :

AIM:

To determine the Rockwell hardness Number of given specimen.

APPARATUS REQUIRED:

1. Rockwell hardness testing machine

2. Penetrates

3. Test specimen.

TABULATION:

S.NoName of the

Material

Load

(Kgf)

Load

(N)Penetrates Scale

Dial

Reading

Rockwell

Hardness

Number

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




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

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’

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 ReadingMean

Deflection

()

mm

Young’s

Modulus

(E)

N/mm2

Loading Unloading

1

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) =

COMPRESSION TEST ON HELICAL SPRING

MODEL GRAPH

OBSERVATION:

Diameter of the rod (d) = mmDiameter of the spring (D) = mmInner diameter of spring (D1) = mmHeight of the spring (h) = mmNumber of turns (n) =

MmMean radius of spring ( R) =d + D1

2

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)

TABULATION:

Sl.

No

Applied

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)

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

Exp. No : 10 TORSION TEST ON MILD STEEL

Date :

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.

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:

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

PROCEDURE:

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

Exp. No: 11 EFFECT OF HARDENING IN IMPACT RESISTANCE OF STEEL

Date :

AIM:

To determine the effect of hardening in impact resistance of steel before and after

hardening.

APPARATUS REQUIRED:


Muffle 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


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.

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


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

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.

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.

strength of material lab manual

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