Figuring out the important mechanical properties of Mild steel through various steps in a small and helpful basic guide for beginners. Being an engineering student we all know that steel has wide amount of applications and for that it is using in his different forms with unique properties. This manual will click your mind that how steel is being used for various purposes and how can we get the wide amount of range through heat treatments.

1. ENGINEERING MATERIALS
FINAL REPORT PREPARED BY SYED RAHEEL ZAFAR
DHA SUFFA UNIVERSITY-

2. ACKNOWLEDGMENT
I express my sincere thanks to Mr. Hamza Shams (Course advisor)
and Mr. Harris (Project advisor) , who guided me through the project
also gave me valuable suggestions and guidance for completing the
project. I’m also very thankful to our Mechanical Engineering
department for providing us the technical support to carry out
the project work.
DHA SUFFA UNIVERSITY 2

3. GRAND ASSIGNMENT
Obtain a 0.75 inch square rod that is 5 ft long of Mild Steel of available grade.
DHA SUFFA UNIVERSITY 3

4. DHA SUFFA UNIVERSITY 4
.Step # 1:- Preparation of Sample
Cutting : Cut sample(s) of 10 mm - 20 mm diameter using hacksaw or band saw and face it. For abrasive
cutting use LABOTOM-5 an extremely user friendly cutting machine in which you have to clamp your piece
and control your cut-off wheel through an ergonomic handle.

5. DHA SUFFA UNIVERSITY 5
Mounting
Mount sample(s) to polish/grind them. The process of compressing and heating bakelite powder around a
piece of metal in order to form a solid disk or puck that can be used to handle the sample easier. Small or
oddly shaped specimen are mounted to facilitate easy handling during examination. CitoPress is offering
ultra-short mounting times and maximum user friendliness. On-screen Hot Mounting Application Guide for
convenient information and a minimum of errors.

6. DHA SUFFA UNIVERSITY 6
Grinding
Grind the sample(s) to max available grit size. To get the surface for metallographic examination as
optically flat, reflective and smooth scratch free. LaboPol is widely use for its friendly use, Increasing the
fineness or lowering the level of abrasiveness of emery papers with the flow of water to produce finer
grooves or scratches.

7. DHA SUFFA UNIVERSITY 7
Polishing
Rubbing the specimen with an abrasive paper with some amount of liquid. Mechanized process are less
time consuming and performed with ease through LaboPol in which you have to clamp your specimen
and then it will rub it in opposite direction from sandpaper with some amount of liquid gel, Polishing is
done automatically in a minute to two minutes time duration automatically.

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Etching
Its purpose is to reveal the microstructures of a specimen under optical microscope . There are so many
ways to etch but the most cheapest way is Chemical Etching in which the head of specimen is dipped in
strong acid, the acid bites into the metal and contrasted the surface, usually we use Nital following are
some of the most commonly used etchants

9. DHA SUFFA UNIVERSITY 9
OBJECT: From the microstructure determined in Engineering Materials Lab, label the following items on the image
obtained and write briefly on their significance.
1. Number of Grains
2. Grain Size Number
3. Average Grain Size
From the figure above we have calculated the Number of grains.
Number of Grains at the boundary of the picture are 62, 62/2 = 31
Number of Grains under the boundary are 250
Total Number of grains = 250+31= 281
Magnification of the above Microstructure is 400
To calculate the real width/Height we use formula
Magnification = Printed Width (or) Height
Real Width(or) Height
Printed width or height is the height of the image you get on A4
Real Width = 274/400 = 0.685
Real Height = 153/400 = 0.3825
Real Area = 0.685*0.3825 = 0.262 mm^2

10. DHA SUFFA UNIVERSITY 10
N100 = {4002
/1002
}* Number of Grains at 400
N100 = 4496
Number of Grains x Actual Area Actual Area = 0.0654 𝑚𝑚2 (ASTM Standard)
True Area
Number of Grains = 1122.3
N=2 𝑛−1
By applying Log
n = 11.13 ≈ 11
Average Grain size length = Total true length / Number of grains intercepted
Total true length = Length of the lines / Magnification
L = 2 x 153 / 400 = 0.765 mm
Number of Grains intercepted = 27 (in both the lines)
Avg Grain Size = 0.765/27
= 0.02833 mm

11. DHA SUFFA UNIVERSITY 11
Step # 2:- Annealing of the rod.
Before anneal the rod , make 4 specimens for further testing of the material.
1. Two Dumbbell shaped specimens for Tensile testing, Lathe or CNC machine is highly preferred in the
manufacturing of dumbbells
2. Two U notch specimens for impact testing using a rectangular rod , Milling or CNC machine is highly
preferred for cavity or adept saw user can easily make a notch.

12. DHA SUFFA UNIVERSITY 12
Annealing Metals are annealed to relieve internal stresses, soften them, make them more ductile, and refine their
grain structures. Metal is annealed by heating it to a prescribed temperature, holding it at that
temperature for the required time, and then cooling it back to room temperature. The rate at which metal
is cooled from the annealing temperature varies greatly. Steel must be cooled very slowly to produce
maximum softness. This can be done by burying the hot part in sand, ashes, or some other substance that
does not conduct heat readily (packing), or by shutting off the furnace and allowing the furnace and part
to cool together (furnace cooling).. Annealed metals are relatively soft and can be cut and shaped more easily. They bend
easily when pressure is applied. As a rule they are heated and allowed to cool slowly.

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Procedure
Heating : Material is exposed to elevated temperature for an
extended time period. The material is austenitized by heating
to 15 to 40 degree Celsius
Soaking : The material is held for an hour at the annealing
temperature.
Cooling : At room temperature it’ll be cooled at the rate of
37.8C/hr.

14. DHA SUFFA UNIVERSITY 14
Results
1. Relieve internal stresses and reduce the chances for cracking and distortions.
2. Increasing softness and Machinability.
3. Refinement of grain structures.
4. Structure will get large-grained Pearlite.
Purpose
Annealing can induce ductility, soften material, relieve internal stresses, refine the structure by making it
homogeneous, and improve cold working properties.

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Tensile Testing of Annealed
Specimen
Tensile testing, also known as tension testing, is a
Fundamental materials science test in which a sample
is subjected to a controlled tension until failure.
ASTM (American Society for testing and materials) standards
for this test are E8/E8M
Universal Tensile testing Machine is widely using for the
Tension and compression tests of material. Specimen is fixed
Between the jaws and bring it in little tension tare it and start
Increasing load till fracture. All your valuable readings and
Graphs has been observed by the system connected.

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As we know annealing yields ductility and softens the materials, Our specimen has shown some corresponding
Results on tensile testing under the ASTM standards E8/E8M. The graph below has been obtained by the
software.

17. DHA SUFFA UNIVERSITY 17
Data from the graph below. These values has been obtained through the sensors and then we scattered
graph on Excel sheet
-50
0
50
100
150
200
250
300
350
400
450
-5 0 5 10 15 20 25 30
STRESS(MPA)
STRAIN
TENSILE TESTING OF ANNEALED SPECIMEN

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Impact Testing of Annealed Specimen
Impact testing is of enormous importance. A collision between two objects can often result
in damage to one or both of them. The damage might be a scratch, crack, fracture or break.
Scientists need to know about how materials and products behave under impact and the
magnitude of forces they can resist. When two objects collide, damage is often done to one or other of
them. How well something resists damage is called its impact resistance. An impact test measures how
much energy is absorbed when an object fractures or breaks under a high speed collision.
It’s an important property. The safety of many consumer products depends on their
resistance to breaking. But impact resistance is difficult to quantify.
Impact testing is about resisting impact. This is often called a material’s toughness.
It’s the amount of energy a material can absorb before fracturing or breaking
and has the unit joules per metre cubed (J m-3). If you plot load against
deflection, this energy is given by the area beneath the curve.

19. DHA SUFFA UNIVERSITY 19
Two of the most popular test conducted for Impact testing is Charpy impact test and Izod impact test. I’ve carried out
my test by Charpy method in which Pendulum is used, The Pendulum Impact Tester IT 30 ASTM is made by the French
company Société DELTALAB. It has a pendulum hammer (mass 21.3 kg) that is 775 mm from the rotation axis.
Antifriction bearings limit loss by friction to 0.75%of maximum energy. The test angle of fall is 140 degrees.
Please refer to ASTM E23 to prepare your specimen or inquire your
Lab Assistant for the actual specimen to take measurements. For ease
of preparation we use the specimen geometry as in Fig.1. You must keep
your specimen geometry constant for all investigations in this lab to
compare results. During the fall from its raised position the
pendulum’s potential energy decreases, changing into kinetic energy.
The kinetic energy is at its greatest just before impact.
This is the impact energy. The energy absorbed by the test specimen
during failure (i.e. fracturing or breaking) is worked out from the height of
the pendulum after impact.
The specimen is placed vertically and the impact hammer strikes the
Specimen above the notch and breaks it, thus this type of loading Can be considered as cantilever beam loading.

20. DHA SUFFA UNIVERSITY 20
Principle of Charpy Testing

21. DHA SUFFA UNIVERSITY 21
Results from Impact testing
The Energy we get is 140 Nm
𝐸 = 𝑃𝑑 𝐶𝑜𝑠𝛽 − 𝐶𝑜𝑠𝛼
Where
𝑃= Load of Hammer (mass of hammer into
𝑑= Distance of the hammer from the center of gravity
𝛽= Angle of Fall
𝛼= Angle of Rise

22. DHA SUFFA UNIVERSITY 22
Hardness Testing
Hardness is the property of a material that enables it to resist plastic deformation, usually by penetration.
However, the term hardness may also refer to resistance to bending, scratching, abrasion or cutting.
Hardness Test methods:
Rockwell Hardness Test
Rockwell Superficial Hardness Test
Brinell Hardness Test
Vickers Hardness Test
Microhardness Test
Moh's Hardness Test
Scleroscope Hardness Test

23. DHA SUFFA UNIVERSITY 23
Vickers Hardness Test
The Vickers hardness test method consists of indenting the test material with a diamond indenter, in the form
of a right pyramid with a square base and an angle of 136 degrees between opposite faces subjected to a load
of 1 to 100 kgf. The full load is normally applied for 10 to 15 seconds. The two diagonals of the indentation left
in the surface of the material after removal of the load are measured using a microscope and their average
calculated. The area of the sloping surface of the indentation is calculated. The Vickers hardness is the quotient
obtained by dividing the kgf load by the square mm area of indentation.
From the above method,
The length of the diagonal of cone shaped dent is 898-298 = 600
The length of the second diagonal is 660-66 = 594
The area is 597 nano meter square = 1.194 milli meter square
The Vickers Hardness number is 39.02HV100

24. DHA SUFFA UNIVERSITY 24
Now the broken specimen of either tensile test (dumbbell shaped) or from Charpy test (U notch) prepare for
microscopy for that object we have to repeat the whole method of mounting, grinding, polishing and etching.
Cut out the piece from broken specimen of the same dimensions as we did earlier and repeat the above same
procedure.

25. DHA SUFFA UNIVERSITY 25
As we did earlier, we’ll calculate the Number of grains, Grains Size Number, Average grain size.

26. DHA SUFFA UNIVERSITY 26
From the figure above we have calculated the Number of grains.
Number of Grains at the boundary of the picture are 53, 53/2 = 26.5
Number of Grains under the boundary are 193
Total Number of grains = 193+26.5 = 219.5
Magnification of the above Microstructure is 400
To calculate the real width/Height we use formula
Magnification = Printed Width (or) Height
Real Width(or) Height
Printed width or height is the height of the image you get on A4
Real Width = 274/400 = 0.685
Real Height = 153/400 = 0.3825
Real Area = 0.685*0.3825 = 0.262 mm^2
N100 = {4002/1002}* Number of Grains at 400
N100 = 3512
Number of Grains = Actual Area Actual Area = 0.0654 𝑚𝑚2
(ASTM Standard)
True Area
Number of Grains = 877
N=2 𝑛−1
By applying Log you can get your desired value

27. DHA SUFFA UNIVERSITY 27
n = 10.8 ≅ 11
Now Draw two lines parallel to each other at some distance
Height of both the lines are 153mm as of the image
Average Grain size length = Total true length / Number of grains intercepted
Total true length = Length of the lines / Magnification
L = 2 x 153 / 400 = 0.765 mm
Number of Grains intercepted = 30 (in both the lines)
Avg Grain Size = 0.765/30
= 0.0255mm

28. DHA SUFFA UNIVERSITY 28
Talking Points
• Steel must be cooled slowly to anneal. In this fashion, the metal is softened and prepared for further
work such as shaping, stamping, or forming.
• Material’s ductility has been increased so its tensile strength increased and it will produce some
elongations as necking

29. DHA SUFFA UNIVERSITY 29
Heat Treatment and Quenching

30. DHA SUFFA UNIVERSITY 30
Conventional heat treatment procedures for producing martensitic steels typically involve continuous and rapid
cooling of an austenitized specimen in some type of quenching medium, such as water, oil, or air. The optimum
properties of a steel that has been quenched and then tempered can be realized only if, during the quenching
heat treatment, the specimen has been converted to a high content of martensite; the formation of any pearlite
and/or bainite will result in other than the best combination of mechanical characteristics. During the quenching
treatment, it is impossible to cool the specimen at a uniform rate throughout—the surface always cools more
rapidly than interior regions. Therefore, the austenite transforms over a range of temperatures, yielding a
possible variation of microstructure and properties with position within a specimen. The successful heat treating
of steels to produce a predominantly martensitic microstructure throughout the cross section depends mainly
on three factors:
(1) The composition of the alloy.
(2) The type and character of the quenching medium.
(3) The size and shape of the specimen. The influence of each of these factors is now addressed.

31. DHA SUFFA UNIVERSITY 31
Quenched specimens ready for the Tensile testing.

32. DHA SUFFA UNIVERSITY 32
Tensile Testing of Water
Quenched Specimen

33. DHA SUFFA UNIVERSITY 33
As we did earlier this test had also been carried out in similar way.
Quenching hardened the steel so
It directly affects the tensile test.
Annealed specimen has UTS around
400 MPa and this specimen has
shown strength.

34. DHA SUFFA UNIVERSITY 34
-100
0
100
200
300
400
500
600
700
800
-1 0 1 2 3 4 5 6 7 8 9 10
STRESSMPa
STRAIN
Tensile Test of Quenched Specimen

35. DHA SUFFA UNIVERSITY 35
The failure leads to ductility because the shear angle is still not zero degree but not at 45 degree as well,
quenching hardened the material so the material has lost some of its ductility and gained brittleness. We can
understand this result by comparing both of the the annealed and quenched samples through tensile testing,
We can easily observe the huge variation in Ultimate tensile strengths of both samples and similarly the
shearing angle of both the specimens have some difference. The annealed specimen is pure shear at 45° and
quenched specimen is broken at less than 45°.

36. DHA SUFFA UNIVERSITY 36
Impact Test of Quenched Specimen
We can expect the result of Impact test before conducting it, as quenching yields hardenability so the Value
of hardness will be much more greater than the annealed one.
By going through the similar method as we did above in annealed case.
Energy or Toughness = 161 Nm
Hardness Test of Quenched Specimen
571-205 = 366
535-168 = 367
Area = 366.5 𝑛𝑚2
= 366.5*0.002 = 0.733𝑚𝑚2
Hardness = 104.68 HV100

37. DHA SUFFA UNIVERSITY 37
Microstructure of Quenched Specimen

38. DHA SUFFA UNIVERSITY 38
From the figure above we have calculated the Number of grains.
Number of Grains at the boundary of the picture are 66
Number of Grains under the boundary are 229
Total Number of grains = 229 + 66/2 = 229 + 33 = 262
Magnification of the above Microstructure is 400
To calculate the real width/Height we use formula
Magnification = Printed Width (or) Height
Real Width(or) Height
Printed width or height is the height of the image you get on A4
Real Width = 274/400 = 0.685
Real Height = 153/400 = 0.3825
Real Area = 0.685*0.3825 = 0.262 mm^2
N100 = {4002/1002}* Number of Grains at 400
N100 = 4192
Number of Grains = Actual Area Actual Area = 0.0654 𝑚𝑚2 (ASTM Standard)
True Area
Number of Grains = 1046.4
N=2 𝑛−1
By applying Log the Grain Size number is 11.01 ≈ 11

39. DHA SUFFA UNIVERSITY 39
Average Grain size length = Total true length / Number of grains intercepted
Total true length = Length of the lines / Magnification
L = 2 x 153 / 400 = 0.765 mm
Number of Grains intercepted = 36 (in both the lines)
Avg Grain Size = 0.765/36
= 0.02125mm

40. DHA SUFFA UNIVERSITY 40
Talking Points
• Quenching can reduce the crystal grain size of both metallic and plastic materials, increasing their
hardness.
• Extremely rapid cooling can prevent the formation of all crystal structure, resulting in amorphous
metal or "metallic glass".
• An iron or steel alloy will be excessively hard and brittle due to an overabundance of Martensite after
quenching.