ME : AKERE MARK AYOKANMI

DEPARTMENT : PETROLEUM AND GAS

ENGINEERING

COURSE: MME211

MATRIC NUMBER: 230409025

GROUP : C

DATE : 22-04-2025

TABLE OF CONTENTS
EXPERIMENT 1: Tensile Test …………………………………….

EXPERIMENT 2: Hardness Test ………………………………….

EXPERIMENT 3: Cold working …………………………………

EXPERIMENT 4: Metallography ………………………………...

EXPERIMRNT 5 : Phase Diagrams……………………………….

 TENSILE TEST

OBJECTIVE
To understand stress-strain curve of materials, and learn how to use them to
determine various mechanical properties of ductile and brittle materials.

THEORY

Tensile Tests are very simple, relatively, inexpensive, and fully standardized.
Under the pulling type of loading something, it can be very quickly determined how the
material will react to these types of forces being applied in tension. As the materials are being
pulled, its strength and elongation can be found out. A lot of about a substance can be
learned from tensile testing. As the machine continues to pull on the material until it breaks, a
good, complete tensile profile is obtained. The curve shows how it reacted to the forces being
applied. In the tension test a specimen is subjected to a continually increasing one directional
tensile force while simultaneous observations are made of the elongation of the ductile
specimen.

INTRODUCTION
The aim of the experiment the aim of the experiment was to determine the
mechanical properties of mild steel under tensile loading. The mechanical properties which
were determined were young’s modulus, yield strength, ultimate strength, percentage
elongation after fracture, percentage reduction of area, nominal stress-strain diagram and true
stress-strain diagram 1.2 Theory of experiment Uniaxial tensile test is known as a basic and
universal engineering test to achieve material parameters such as ultimate strength, yield
strength, percentage elongation, percentage area of reduction and Young's modulus. These
important parameters obtained from the standard tensile testing are useful for the selection of
engineering materials for any applications required. The tensile testing is carried out by
applying longitudinal or axial load at a specific extension rate to a standard tensile specimen
with known dimensions (gauge length and cross sectional area perpendicular to the load
direction) till failure. The applied tensile load and extension are recorded during the test for
the calculation of stress and strain.

PROCEDURES
 1. Position the lower and upper clamps in their proper position to accommodate the
length of the test sample. Next, place the material between the tensile clamps.
Vertically align the sample from the grip ends i.e (the fixed grip) to the lower clamp (the
grip in charge of applying tension). This alignment will ensure that the specimen will
avoid side loading or bending during the test.
The alignment should be given much of the tester or technician’s attention, as it is the
most critical part of the process. The tester’s skill, as well as the type of grips used for
the test takes a vital role. Specimens made of fragile or brittle substances require the
 utmost care and caution during tensile tests. Mishandling specimens with the wrong
equipment can threaten the process and negatively affect the results. It may even cost
the specimen and may require a redo of the entire process.

 2. After securing the sample, attach the extensometer to its length While undergoes
testing, the extensometer will be monitoring and measuring any changes in the
material. After the extensometer is placed, double check the other equipment to make
sure they are in their correct positions.
 3. To begin the tensile stress test, slowly separate the tensile clamps at a constant
speed. Depending on the size and shape of the material, the tensile tester machine
can pull at a maximum speed of 20 inches per minute. The tensile testing would often
take five minutes or less for the material to fracture.
 4. During the test, the specimen will slowly elongate with the standardized speed. The
data gathering software will present the material’s test parameters, as well as the
changes in the gauge length. It will monitor the force placed upon the specimen and
display the stress-strain curve. The stress-strain curve is helpful in analyzing the
specimen’s behavior throughout the test.
 5. While the substance undergoes tension, the tester can observe how much
elongation is occurring in the process. The change in length brought about by the
pulling forces is a measurement called “strain”. There are two kinds of strain:
engineering strain and true strain.
Known as the most basic expression of strain, engineering strain is the comparison
between the material’s post-test length to its pre-test length. While similar to
engineering strain, true strain is the measurement of the immediate length of the
substance during the test.
6. Eventually, the specimen will begin to deform in the middle of its length. Changes in
the stress-strain curve will begin to appear during this phase. Once the specimen breaks,
the tensile testing has officially ended.

(CONTROLLED)0% SAMPLE READINGS

NO Elongation( Force( N) STRAIN STRESS(N/mm2)
mm)
1 0 0 0.00000 0.000
2 0.5 64.724 0.01883 3.060
3 1 144.158 0.03766 6.816
4 1.5 298.123 0.05650 14.096
5 2 547.211 0.07533 25.873
6 2.5 875.735 0.09416 41.406
7 3 1248.387 0.11299 59.025
8 3.5 1630.846 0.13183 77.109
9 4 2192.767 0.15066 103.677
10 4.5 2765.476 0.16949 130.755
11 5 3398.005 0.18832 160.662
12 5.5 4019.747 0.20716 190.059
13 6 4639.526 0.22599 219.363
14 6.5 5366.199 0.24482 253.721
15 7 6175.248 0.26365 291.974
16 7.5 6876.423 0.28249 325.126
17 8 7476.591 0.30132 353.503
18 8.5 7872.779 0.32015 372.235
19 9 8228.761 0.33898 389.067
20 9.5 8582.781 0.35782 405.805
21 10 8979.95 0.37665 424.584
22 10.5 9359.467 0.39548 442.528
23 11 9677.203 0.41431 457.551
24 11.5 9929.233 0.43315 469.467
25 12 10150.864 0.45198 479.946
26 12.5 10322.48 0.47081 488.061
27 13 10433.295 0.48964 493.300
28 13.4 10463.696 0.50471 494.737
29 13.5 10453.889 0.50847 494.274
30 14 10215.588 0.52731 483.007
31 14.5 9447.727 0.54614 446.701
32 14.7 9871.374 0.55367 466.732

STRESS-STRAIN CURVE FOR CONTROLLED SAMPLE

 STRESS
600

500

400
STRESS
300

200

100

0
0 0.1 0.2 0.3 0.4 0.5 0.6

STRESS-STRAIN FOR 20% SAMPLE

STRESS
700

600

500

400 STRESS

300

200

100

0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
 10% SAMPLE READINGS

N Elongation( m Force( N) STRAIN STRESS(N/

0 m) mm2)
1 0 0 0.00000 0.000
2 0.5 107.874 0.01923 5.079
3 1 185.346 0.03846 8.726
4 1.5 343.234 0.05769 16.160
5 2 558.98 0.07692 26.317
6 2.5 874.754 0.09615 41.184
7 3 1266.039 0.11538 59.606
8 3.5 1698.512 0.13462 79.968
9 4 2251.607 0.15385 106.008
1 4.5 2797.837 0.17308 131.725
0
1 5 3406.831 0.19231 160.397
1
1 5.5 4097.219 0.21154 192.901
2
1 6 4745.438 0.23077 223.420
3
1 6.5 5455.44 0.25000 256.847
4
1 7 6284.102 0.26923 295.862
5
1 7.5 7102.958 0.28846 334.414
6
1 8 7872.779 0.30769 370.658
7
1 8.5 8730.861 0.32692 411.057
8
1 9 9623.266 0.34615 453.073
9
2 9.5 10549.014 0.36538 496.658
0
2 10 11589.499 0.38462 545.645
1
2 10.5 12351.476 0.40385 581.520
2
2 11 12667.25 0.42308 596.387
3
2 11.5 12860.441 0.44231 605.482
4
2 11.7 12884.958 0.45000 606.636
5
2 12 12793.756 0.46154 602.343
6
2 12.5 12297.54 0.48077 578.980
7
2 13 11383.56 0.50000 535.949
8
2 13.2 10870.672 0.50769 511.802
9
3 13.3 8792.643 0.51154 413.966
0

STRESS-STRAIN FOR 10% SAMPLE

STRESS
700

600

500

400 STRESS

300

200

100

0
0 0.1 0.2 0.3 0.4 0.5 0.6

30% SAMPLE READINGS

N Elongation( Force( N) STRAIN STRESS(N/mm2)

O mm)
1 0 0 0 0
2 0.5 52.957 0.01842 2.287
3 1 113.757 0.03683 4.912
4 1.5 201.037 0.05525 8.680
5 2 385.402 0.07366 16.641
6 2.5 602.129 0.09208 25.999
7 3 977.724 0.11050 42.216
8 3.5 1423.926 0.12891 61.482
9 4 1920.143 0.14733 82.908
10 4.5 2531.097 0.16575 109.287
11 5 3150.877 0.18416 136.048
12 5.5 3812.826 0.20258 164.630
13 6 4479.678 0.22099 193.423
14 6.5 5367.18 0.23941 231.744
15 7 6114.447 0.25783 264.009
16 7.5 6983.316 0.27624 301.525
17 8 7814.92 0.29466 337.432
18 8.5 8625.93 0.31308 372.449
19 9 9587.962 0.33149 413.988
20 9.5 10597.066 0.34991 457.559
21 10 11633.629 0.36832 502.316
22 10.5 12671.173 0.38674 547.115
23 11 13811.686 0.40516 596.359
24 11.5 14862.959 0.42357 641.751
25 12 16031.912 0.44199 692.224
26 12.5 16993.944 0.46041 733.763
27 12.8 17266.569 0.47145 745.534
28 13 16656.596 0.47882 719.197
29 13.3 14922.78 0.48987 644.334
30 13.4 11371.792 0.49355 491.010

STRESS-STRAIN FOR 30% SAMPLE

STRESS
800

700

600

500
STRESS
400

300

200

100

0
0 0.1 0.2 0.3 0.4 0.5 0.6

40% SAMPLE READINGS

N Elongation( m Force( N) STRAIN STRESS(N/mm2)

0 m)
1 0 0 0 0
2 0.5 36.285 0.01821 1.533
3 1 103.951 0.03643 4.392
4 1.5 226.534 0.05464 9.571
5 2 402.073 0.07286 16.987
6 2.5 680.582 0.09107 28.753
7 3 1020.873 0.10929 43.129
8 3.5 1427.849 0.12750 60.323
9 4 1920.142 0.14572 81.121
10 4.5 2442.837 0.16393 103.204
11 5 3059.675 0.18215 129.264
12 5.5 3698.089 0.20036 156.235
13 6 4454.181 0.21858 188.178
14 6.5 5173.989 0.23679 218.588
15 7 5864.377 0.25501 247.756
16 7.5 6704.807 0.27322 283.262
17 8 7511.895 0.29144 317.359
18 8.5 8323.885 0.30965 351.664
19 9 9296.705 0.32787 392.763
20 9.5 10281.292 0.34608 434.360
21 10 11363.946 0.36430 480.099
22 10.5 12299.501 0.38251 519.624
23 11 13463.55 0.40073 568.802
24 11.5 14573.663 0.41894 615.702
25 12 15657.298 0.43716 661.483
26 12.5 16814.483 0.45537 710.371
27 13 18242.687 0.47359 770.709
28 13.5 17020.422 0.49180 719.071
29 13.7 16220.2 0.49909 685.264
30 13.8 13699.891 0.50273 578.787
31 13.9 11820.937 0.50638 499.406

STRESS-STRAIN FOR 40% SAMPLE

STRESS
900

800

700

600

500 STRESS

400

300

200

100

0
0 0.1 0.2 0.3 0.4 0.5 0.6
 STRESS-STRAIN FOR 50% SAMPLE

STRESS
800

700

600

500
STRESS
400

300

200

100

0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

EXPERIMENTAL READINGS

Gauge Guage Initial Final Neck

Percentage diameter length Overall overall diameter
Reduction (mm) (mm) length length (after break)
(mm) (mm) (mm)
Control(0%) 5.31 26.55 73.48 78.86 3.81
10% 5.20 26.00 73.13 77.42 3.93
20% 5.46 27.30 73.56 76.76 4.44
30% 5.43 27.15 74.07 76.49 4.52
40% 5.59 27.45 74.26 76.25 4.67
50% 5.50 27.50 74.38 75.83 4.82

PRECAUTIONS
1.) Wear clear safety glasses with side shields.
2.) Put on Personal protective equipment.
3.) Inspect work area for debris and ensure proper lighting.
 4.) Turn machine off when done testing.

On the experimental graph The Following Labeled Points.

Specimen a. b. Yield c. Fracture d. Elastic e. Plastic f.

Ultimate Point Point Deformation Deformation Proportional
Strength (N/mm²) (Stress, Point (Stress, Region (Strain) Limit
(N/mm²) Strain) Strain) (Stress,
Strain)
10% 606.636 131.725 (413.966, (8.726, 0.03846) 0.17308–0.51154 (8.726,
0.51154) 0.03846)
20% 660.745 114.949 (467.125, (6.619, 0.03659) 0.16465–0.47567 (6.619,
0.47567) 0.03659)
40% 770.709 103.204 (499.406, (4.392, 0.03643) 0.16393–0.50638 (4.392,
0.50638) 0.03643)

PART A
Using the collected data for the Specimens Compute the average and standard deviation for
the following quantities.

Table Structure:
Specimen Tensile Percentage Percentage Modulus of Tensile
Strength Elongation Reduction in Area Elasticity Yield
(N/mm²) (%) (%) (N/mm²) (N/mm²)
0% 494.737 55.367 48.514 199.468 130.755
10% 606.636 51.154 48.514 189.703 131.725
20% 660.745 47.567 48.514 173.699 114.949
30% 745.534 49.355 48.514 142.532 109.287
40% 770.709 50.638 48.514 156.915 103.204
50% 711.230 41.818 48.514 204.345 152.176

CONCLUSION
. The carbon fiber composite material has a much higher tensile strength and modulus
of elasticity than the other materials. Note they all break in a “brittle” manner, as the
curve is linear until it breaks or fractures with no bending at high of the curve loads.
 HARDNESS TEST
OBJECTIVE
1.) To understand what hardness is, and how it can be used to indicate some properties of
materials.
2.) To conduct typical engineering hardness tests and be able to recognize commonly
used hardness scales and numbers.
3.) To be able to understand the correlation between hardness numbers and the
properties of materials.
4.) To learn the advantages and limitations of the common hardness test methods.

THEORY
Hardness, the opposite of softness, refers to a material’s ability to resist
localized plastic deformation, such as indentations (over a surface area) or scratches
(along a line), caused by mechanical means like pressing or abrasion. Generally,
materials vary in their hardness; for instance, hard metals like titanium and beryllium
exhibit greater resistance. Hardness measures a metal’s resistance to permanent (plastic)
deformation, determined by pressing an indenter into its surface. The indenter, typically
a ball, pyramid, or cone, is made of a material significantly harder than the tested metal.
In standard hardness tests, a predetermined load is applied gradually by pressing the
indenter perpendicularly (at 90 degrees) into the metal surface. Once the indentation is
formed, the indenter is removed, and an empirical hardness value is calculated or
displayed on a dial (or digital screen), derived from the depth or cross-sectional area of
the indentation. The Brinell, Vickers, and Rockwell tests are the most commonly used
and widely accepted methods in engineering applications.

POINTS TO NOTE
1. Elastic region: In this region, the material deforms elastically, meaning it returns to its original
shape once the stress is removed. The relationship between stress and strain is linear, described by
Hooke's Law (σ = Eε), where σ is stress, ε is strain, and E is the Young's modulus of the material.
2. Yield point: Beyond a certain point, known as the yield point, the material begins to deform
plastically, meaning it undergoes permanent deformation even after the stress is removed. The stress
required to cause this permanent deformation is known as the yield strength.
3. Plastic region: In this region, the material continues to deform plastically, with an increase in strain
occurring without a proportional increase in stress.
4. Ultimate tensile strength (UTS): The ultimate tensile strength is the maximum stress the material can
withstand before fracturing. It represents the peak of the stress-strain curve and is a crucial parameter in
material selection for structural applications.
5. Fracture point: After reaching its ultimate tensile strength, the material undergoes rapid
deformation until it fractures. The stress at fracture is known as the fracture strength
Rockwell Hardness Test

Hardness, the opposite of softness, refers to a material’s ability to resist localized plastic
deformation, such as indentations (over a surface area) or scratches (along a line),
caused by mechanical means like pressing or abrasion. Generally, materials vary in their
hardness; for instance, hard metals like titanium and beryllium exhibit greater resistance.
Hardness measures a metal’s resistance to permanent (plastic) deformation, determined
by pressing an indenter into its surface. The indenter, typically a ball, pyramid, or cone,
is made of a material significantly harder than the tested metal. In standard hardness
tests, a predetermined load is applied gradually by pressing the indenter perpendicularly
(at 90 degrees) into the metal surface. Once the indentation is formed, the indenter is
removed, and an empirical hardness value is calculated or displayed on a dial (or digital
screen), derived from the depth or cross-sectional area of the indentation. The Brinell,
Vickers, and Rockwell tests are the most commonly used and widely accepted methods
in engineering applications.

PROCEDURES

 The Universal Testing Machine (UTM) was powered on.

 The computer connected to the UTM, used for recording experimental data, was
turned on.
 The diameter and length of the sample were measured with a Vernier caliper.
 The MTS TestWorks software was launched, and the sample dimensions, including
diameter and length of the steel sample, were entered.
 The sample was securely fastened at both ends of the machine (stationary and mobile
grips).
 The “Start” icon was clicked, initiating the test, during which the sample was
stretched under applied force until it broke, and the final length was recorded.
 Steps 4, 5, and 6 were repeated for samples with 10%, 20%, 30%, 40%, and 50%
reductions.

RESULTS
Material of test piece = piece of cast Iron

Hardness Test (HVN)

Test A Test B Test C Average
control 187.6 185.6 189.4 187.5
10% 200.0 186.6 197.9 194.8
20% 223.1 212.0 234.5 223.2
30% 231.2 243.0 237.8 237.3
40% 251.3 257.2 253.5 254.0
50% 258.2 261.2 264.8 261.4

Table 3: Experimental Hardness Values(ALL VALUES IN HRC)

QUESTIONS

(1) Is the Brinell indentation truly spherical? Explain.

Answer: Yes, in the Brinell hardness test, which employs an optical method, the
indentation’s size created by the indenter is measured. Unlike the Vickers method,
which uses a pyramid-shaped indenter pressed into the material, the Brinell test utilizes a
spherical indenter, resulting in a spherical indentation.
(2) In a Brinell test, why is a polished specimen surface more critical for harder
materials?
Answer: In hardness testing, particularly with lower loads used for microhardness, a
polished or electropolished surface is essential. For harder materials, a well-prepared
surface ensures that the edges and corners of the optically assessed indentation are
clearly visible, which is necessary for accurate measurement. Surface preparation can be
achieved through mechanical, chemical, or electrochemical methods.
(3) Why is a minimum specimen thickness of at least ten times the indentation
depth required in the Brinell test? How is the obtained value affected if the
specimen is too thin, assuming it is tested on a heavy anvil?
Answer: A minimum specimen thickness of ten times the indentation depth is required
to prevent deformation or marking on the opposite surface of the specimen. This
requirement can be met more easily by using a lighter load. No visible marks should
appear on the back of the specimen. Various Vickers hardness testers from different
manufacturers are available, but the principle applies similarly ..

PRECAUTIONS:
Calibrate the machine occasionally using standard test blocks.

1. After applying Major load, wait for sometime to allow the needle to come to rest. The
waiting time vary from 2 to 8 seconds.
2. The surface of the test piece should be smooth and even and free from oxide scale and
foreign matter.
3. Always wear eye protection and Personal Protective Equipment (PPE) when using the
Rockwell hardness tester
4. Specimen Geometry. Avoid irregular shapes.
5. Hardness test specimens should have parallel top and bottom surfaces.

CONCLUSION The Rockwell type C test was performed six times on a steel sample
provided. The sample was cut into 3 parts for easy handling and was reacted with a 5%
NITAL etchant to reveal the microstructures and from the results obtained it was noticed
that the hardness value increased with an increase in reduction/ increase stretch in the
length

COLD WORKING
OBJECTIVES
1.) To obtain an understanding of the effects of mechanical (cold) working on the tensile
strength, hardness and the ductility properties of engineering metals and alloys.

2.) To obtain an understanding of the effects that post-heating treatments will have some
mechanical properties of engineering metals and alloys which have been previously
work-hardened.
3.) To understand the principles of recovery, recrystallization and grain growth
4.) To gain experience in operating a rolling machine

APPARATUS

INTRODUCTION

Cold working is a process performed at room temperature. This includes a variety of

processes, such as forging, rolling, drawing, and extrusion. Although these processes can
be done at elevated temperatures, they must be done at room temperature in order to be
considered a cold working process. There are a few reasons for utilizing cold working. One
of these reasons is to homogenize the material by moving the atoms within the structure.
Secondly, this process aids in controlling grain size. The grain size is maintained through full
annealing when the cold working process is completed. In addition to this, the material is
hardened through this process because the yield strength is increased, and thus lowering
the ductility. In order to restore ductility, a process called annealing is performed. Since cold
working increases the yield stress and lowers the ductility, cold working can only go so far
before the material cannot handle the process anymore. Although some ductility is restored
to the material, some of the yield stress gained from cold working will be lost. Annealing is a
three-step process that recovers the material to move and remove dislocations,
recrystallizes to restore its mechanical properties, and stimulate grain growth.
PROCEDURES
1.) Cut out six (6) samples of the 12mm (half inch) low carbon steel rod.
2.) Measure the initial thickness of the samples with a caliper and record the values in the
appropriate column of the table.
3.) Label the samples 0-6
4.) Take the hardness value of sample labeled zero(0) and record it as the control sample
5.) Deform the samples 1-6 by 10,20,30,40,50,60 percent respectively
6.) Measure the final thickness of the samples after the deformation
7.) Take the hardness readings of the deformed samples and record the values in the
appropriate column of the table
8.) Prepare the controlled sample as well as the deformed samples for microscopic
examinations.

% Reduction Initial Thickness After Hardness(Rc)

Nominal Thickness Rolling(mm) After Rolling
0 0 12 187.5
10 12mm 10.8 194.8
20 12mm 9.6 223.2
30 12mm 8.4 237.3
40 12mm 7.2 254.0
50 12mm 6.0 261.4

DISCUSSION
Each sample tested during cold working started with the same initial thickness, but after
rolling at room temperature, their final thicknesses varied. The percent cold work for
each sample can be calculated using the equation: % Cold Work = [appropriate formula,
not provided]. Due to the differing final thicknesses, each sample exhibited a unique
percent cold work, leading to variations in hardness. Thus, the percent cold work is
correlated with hardness and yield strength, as cold working enhances these properties
while reducing ductility. During annealing, all samples were subjected to identical
conditions in a 400°C furnace for intervals of 5, 10, 15, 30, and 45 minutes, with
hardness tested after each interval. Despite uniform conditions, each sample responded
differently, as evidenced by distinct curves in the graph, due to their varying percent
cold work. The percent cold work influences recrystallization, hardness, and grain size.
Consequently, a specific percent cold work is required for recrystallization to occur
effectively.
Conclusion: Cold working and annealing collaborate to enhance a material’s
mechanical properties. Cold working, performed first through processes like rolling,
forging, extrusion, or drawing at room temperature, aims to increase yield stress and
hardness. This process elevates stress and strain, inducing plastic deformation and work
hardening. Post-cold working, the material exhibits high yield stress and dislocation
density but low ductility. Annealing restores some lost ductility through a three-stage
process: recovery, recrystallization, and grain growth. In recovery, thermal processes
facilitate the movement and removal of dislocations via atomic diffusion, forming cell
structures that serve as nuclei for new grains, with minimal changes to ductility or yield
stress. Recrystallization restores most mechanical properties, requiring an optimal level
of prior cold working to form new grains. During grain growth, small grain sizes are
preferred, achievable only if the material reaches a critical percent cold work; otherwise,
larger grains form.Cold working improves the harness of metals up to a certain point.
Increased harness is a direct result of the phenomenon discussed in the introduction called
strain hardening. The lab confirms that strain hardening occurs and it is expected that other
cold worked metals exhibit similar strain hardening.

PRECAUTIONS
1.) Do not use bare fingers to push the specimen through the rolling mill.
2.) Do not use the Rockwell hardness tester until you have received the necessary
instructions. Do not test a specimen when it is warm. Make sure that the bottom of the
specimen directly under the indenter is firmly seated on the platen before applying the
major load.
3.) Use the cut-off wheel only with permission of the instructor. Wear face shield while
operating the cut-off wheel. A hack saw may be used instead.
4.) Always use tongs to place and remove specimens from the furnace.

METALLOGRAPHY

OBJECTIVE
To demonstrate a standard procedure for the preparation and subsequent optical examination
of metallographic specimens.

THEORY
Metallography is the preparation of specimens for microscopic examination and the study of
microstructure in relation to the physical and mechanical properties of a particular material.
There are two types of metallography: research and quality control. Of the two, research
metallography is perhaps the more sophisticated in that it requires a knowledge of phase
diagrams, TTT diagrams, among others. Quality control metallography is the most important
to industry and it can answer such questions as: has the heat treatment yielded the correct
hardness or the desired grain size? has the carburization treatment given the desired case
depth? are precipitates forming and to what size? are defects occurring in the finished
product? These are just a few of the questions that can be answered by metallography. All of
which depend on the microstructure and our ability to view it using optical microscope.
In Metallography the preparation should result in the production of a specimen having a
planar surface, which satisfies the following:
The Specimen should be a representative section, which have been ground and polished to
minimize surface damage by mechanical deformation or overheating, so that the true
structure can be revealed by etching. The surface should be free from polishing scratches,
pits and liquid staining.
The prepared surface should be flat enough to permit examination at high
magnification.

INTRODUCTION
Metallography is the study of the microstructure of all types of metallic alloys. It can be more
precisely defined as the scientific discipline of observing and determining the chemical and
atomic structure and spatial distribution of the grains, constituents, inclusions or phases in
metallic alloys. By extension, these same principles can be applied to the characterization of
any material.

Different techniques are used to reveal the microstructural features of metals. Most
investigations are carried out with incident light microscopy in brightfield mode, but other less
common contrasting techniques, like darkfield or differential interference contrast (DIC), and
the use of color (tint) etching are expanding the scope of light microscopy for metallographic
applications.

SECTIONING
A sample to be metallographically examined must be sectioned to a convenient size before
other steps to reveal its microstructures can be performed. The microstructure is more
vulnerable to alteration during sectioning than in any other metallographic preparation step.
An altering of the microstructure commonly called an artifact can occur by extensive heat and
this often prevents correct interpretation of the true microstructure, Abrasive wheel cutting
sawing and shearing are common methods of sectioning.

MOUNTING
Specimens of small section of thin materials are best mounted in plastic materials for easier
handling. Cold mounting may be carried out by placing the specimen(s) in a small plastic
mould and covering with a cold setting plastic which usually involves adding a hardener to a
thermoplastic powder or resir Specimens can also be hot mounted in certain thermoplastic
materials using a mounting press.
GRINDING
Grind the specimen face chosen for examination to a plane surface using the grinder and
remove any sharp corners or edges from the surface by beveling, if this action will not
interfere with subsequent examination. Grind the flat surface using the successively finer
silicon carbide papers on rotary wheels to remove scratches left by the previous grinder.
The specimen should be rotated through approximately at interval after each stage of grinding
i.e. when moving from 220-320 grit papers and subsequently to 400 and 600 microns to
prevent excessive beveling at the specimen edge Move into the next grinding wheel when all
the scratches from the previous grinding stage have been removed. Examination of the
cleaned surface under the microscope will reveal if any scratches will remain.Grinding is a
very important operation in specimen preparation and care taken during this stage will reduce
the time taken for subsequent polishing.

After the surface has been suitably ground on the finest grit paper, wash the specimen with
water to remove ground particles and polishing the surface on the rotary wheel with finest
particle grit paper.

POLISHING
Polishing could be carried out in two stages: The first stage could be referred to as rough
polishing using 6 micron metadi paste applied to the surface of the sample as polishing
abrasive and nylon cloth as the lap or wheel covering, while the last stage is referred to as
final polishing In this stage Gamma Alumina could be used as abrasive and micro cloth as the
wheel covering cloth for ferrous and copper based materials, aluminium magnesium and their
alloys. Aluminium, Magnesium and their alloys.
Rotate the specimen occasionally during polishing stage and taking care not to exert too
much pressure, this can lead to specimen overheating, which in case of some non-ferrous
materials can result in changes in microstructure. Use the microscope to determine when all
the scratches from the grinding operation have been removed.
To prevent contamination of the polishing wheels, the following rules must be adhered to:
1. Replace the cover over the wheels when not in use.

2. Wash the specimen in water to remove grinding debris before starting each polishing
stage.

Ensure the specimen is thoroughly washed in running water and alcohol after the polishing
stage and dried with the aid of drier by blowing warm air across the specimen.

ETCHING
This is carried out by immersing the specimen in a suitable chemical reagent using plastic
tongs or, alternatively, a swabbing technique may be used. The etching reagent gradually
dissolves the surface layer of the specimen and preferentially attacks the grain boundaries.
The progress of the etching is observed and, when the specimen surface appears dull the
specimen is quickly removed to be rinsed with alcohol water. The time required for etching
varies from a few seconds to several minute.

DISCUSSION
The Microscope used in the experiment was of a lower magnification that the regular micro
scope it was about (x100).
The Sample that was put under the microscope has a 0.2% carbon content, which is known
to contain pearlite and ferrite at room temperature. Its is very important to note that no matt
er whatechanical properites that is changed, the structure is constant, rolling, hammering a
nd staping, cannot change the stucture but the (direction of
pointing) of the micro structures will be changed, their direction.The whitish material are call
ed the ferrite and the black is called the pearlite.

OBSERVATIONS
1.) 10%-the cold work treated metal is watched to be only little compacted.
2.) 20%-the cold work treated material is watched/followed to be compacted and flowing i
n the direction of roll.
3.) 30%-the higher the malformation, the grains become much more compacted and rate
of flow is increased.
4.) 40%-distortion of material grain is almost complete.
5.) 50%-complete distortion of material grain and the ferrites are almost unable to be
separated.

CONCLUSIONS

The grain structure of metals significantly influences their properties, such as

malleability, ductility, strength, density, and hardness. These properties can be assessed
by examining the arrangement of spots, the approximate composition of metal mixtures,
and the presence of grain boundaries. Light microscopes offer a cost-effective method
for observing metal and alloy microstructures, while X-ray diffraction provides a faster
alternative, bypassing the need for extensive sample polishing.
Additionally, the type of deformation affects the microstructure. Hot-deformed and cold-
deformed steel exhibit distinct structures, and brass alloys display a single phase with
two different microstructural forms. These variations in microstructure, driven by
material properties and processing methods, are critical. Metallography plays a vital role
in material science by enabling the study of microstructures and facilitating
modifications that impact the physical properties of materials.

PRECAUTIONS
1.) I used the fine adjustment for focusing. Do not use the adjustment
when looking through the eyepiece onto the sample.
 2.) Lenses for microscope must be maintained free from fingerprints dust, oil and
corrosion
atmosphere. The polished surface of the sample should be kept free from dust.

PHOTOGRAPHS OF RESULTS
UNETCHED SAMPLE

10% SAMPLE
20% SAMPLE

30% SAMPLE
40% SAMPLE

50% SAMPLE
 IRON-CARBON PHASE DIAGRAM
The Fe - C diagram (also called the iron - carbon phase or equilibrium diagram) is a
graphic representation of the respective microstructure states of the alloy iron - carbon (Fe-C)
depending on temperature and carbon content

OBJECTIVES
The Iron Carbon Phase Diagram provides a foundation for understanding both carbon steels
and alloy steels. It also provides knowledge of various heat treatment processes such as
hardening or annealing.
The iron-carbon phase diagram is a critical tool in materials science and metallurgy,
illustrating the phases formed in iron-carbon alloys at different temperatures and carbon
contents. This diagram is essential for understanding steel and cast iron's properties and
heat treatments.

Key Features of the Iron-Carbon Phase Diagram:

1. Carbon Content: The horizontal axis represents the carbon content, ranging from
0% to 6.67%. Steels have carbon content up to 2.14%, while cast irons have higher
carbon content.
2. Temperature: The vertical axis represents the temperature, ranging from room
temperature up to about 1600°C.

Important Points:
Eutectic Point).(0.76% C, 727°C):
Eutectic point is a point where multiple phases meet. For the iron-carbon alloy diagram, the
eutectic point is where the lines A1, A3 and ACM meet. The formation of these points is
coincidental. At these points, eutectic reactions take place where a liquid phase freezes into a
mixture of two solid phases. This happens when cooling a liquid alloy of eutectic composition all
the way to its eutectic temperature.
The alloys formed at this point are known as eutectic alloys. On the left and right side of this point,
alloys are known as hypoeutectic and hypereutectic alloys respectively (‘hypo’ in Greek means
less than, ‘hyper’ means greater than). The temperature and composition at which
austenite transforms into pearlite.

Eutectic Point (4.3% C, 1147°C): The temperature and composition at which

liquid iron solidifies into a mixture of austenite and cementite (ledeburite).

Different Phases
α-ferrite
Existing at low temperatures. body-centered cubic (BCC) structure and low carbon content,
α-ferrite is a solid solution of carbon. This phase is stable at room temperature. In the graph, it can
be seen as a sliver on the left edge with Y-axis on the left side and A2 on the right. This phase
is magnetic below 768°C.
It has a maximum carbon content of 0.022 % C at 727°C and it will transform to γ-austenite at
912°C as shown in the graph. Ferrite is soft and ductile.

γ-austenite
This phase is a solid solution of carbon in FCC Fe with a maximum solubility of 2.14% C. On
further heating, it converts into BCC δ-ferrite at 1395°C. γ-austenite is unstable at temperatures
below eutectic temperature (727°C) unless cooled rapidly. It Is stable at higher
temperatures and capable of dissolving more carbon (up to 2.14% C at 1147°C).
Austenite is non-magnetic and ductile.

δ-ferrite
This phase has a similar structure as that of α-ferrite but exists only at high temperatures. The
phase can be spotted at the top left corner in the graph. It has a melting point of 1538°C.
Fe3C or cementite
Cementite is a metastable phase of this alloy with a fixed composition of Fe3C. It decomposes
extremely slowly at room temperature into Iron and carbon (graphite).
This decomposition time is long and it will take much longer than the service life of the application
at room temperature. Some other factors (high temperatures and addition of certain alloying
elements for instance) can affect this decomposition as they promote graphite formation.
Cementite is hard and brittle which makes it suitable for strengthening steels. Its mechanical
properties are a function of its microstructure, which depends upon how it is mixed with ferrite.

Fe-C liquid solution

Marked on the diagram as ‘L’, it can be seen in the upper region in the diagram. As the name
suggests, it is a liquid solution of carbon in iron. As we know that δ-ferrite melts at 1538°C, it is
evident that melting temperature of iron decreases with increasing carbon content.

. Applications:
1. Heat Treatment: The diagram helps in designing heat treatment processes
like annealing, normalizing, quenching, and tempering to achieve desired
mechanical properties.
2. Material Selection: Guides the selection of steel and cast iron grades for
specific applications based on their carbon content and resulting microstructures.
3. Predicting Microstructure: Allows prediction of microstructure and phase
transformations during cooling and heating, which is crucial for manufacturing
processes.