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Report on Tensile, Impact and Hardness Testing of

Mild Steel Submitted to

Dr. Athar Ibrahim

Submitted by

Arif Ali MME-12-01

Sarmad Saeed MME-12-02

Muhammad Faisal Maqsood MME-12-20

Sania MME-12-26

Muhammad Zubair MME-12-29

Gulfam Hussain MME-12-30

Institute of Advanced Materials, BZU Multan

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Abstract The main purpose of this report is to study the mechanical properties and

failure mode of mild steel. Three types of standard tests i.e. tensile test, impact

test, and hardness test were conducted on the standard specimens of mild steel.

From the tests, results were obtained; Tensile strength, Impact strength, and

hardness were calculated. It was observed that Tensile Strength, Impact Strength

and Hardness of MS specimen were 1450.833 N/mm², 29.5 J & 59.25 HRB.

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EXPERIMENT NO. 01

1.1. Objective To conduct a tensile test on a Mild Steel specimen

1.2. APPARATUS I. Universal Testing Machine (UTM)

II. Mild Steel specimens

III. Scale

IV. Vernier Caliper

1.3. DIAGRAM

Figure 1.1. Tensile Testing Machine

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Figure 1.2. Tensile Specimen Dimensions

Figure 1.3. Tensile Testing specimen before testing

Figure 1.4. Tensile Testing specimen after testing

1.4. THEORY

Tensile testing is one of the most basic tests for engineering which provides valuable

information about a material and its associated mechanical properties. These properties can be

used for design and analysis of engineering structures, and for developing new materials that

better suit a specified use.

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 in the solid body

is entirely elastic. This elastically deformed body will return to its original shape when the load

is removed. The initial portion of the S-S curve will show the elastic behavior. The stress below

which the deformation entirely elastic is known as the yield strength of material. As the body

is loaded beyond this limit i.e. yield stress, the body will deform permanently showing that the

body is plastically deformed. In some material the onset of plastic deformation is denoted by a

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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.

Figure 1.5. Tensile Testing Machine (20 KN)

1.5. PROCEDURE

Measure the original length and diameter of the specimen. The length marked was the

total length of the specimen.

Insert the specimen into grips of the test machine and attach Strain-measuring device

to it.

Begin the load application and record load versus elongation data.

Take readings more frequently as yield point is approached.

Measure elongation values with the help of dividers and a ruler.

Continue the test till Fracture occurs

By joining the two broken halves of the specimen together, measure the final length.

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1.6. OBESERVATIONS

Material: Mild Steel

A) Original Dimensions

Gauge Length = 20 mm

Width = 3 mm

Thickness = 0.5 mm

B) Final Dimensions:

Gauge Length = 22 mm

Width = 2.8 mm

Thickness = 0.5 mm

Percentage Elongation: 10%

1.7. RESULTS

The curve given below shows that the specimen fails ultimately after reaching the maximum load

without showing any strain hardening & a little plastic deformation.

Figure 1.6. Stress Strain Curve

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Figure 1.7. Data Sheet

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EXPERIMENT NO. 02

2.1. OBJECTIVE

To determine the impact strength of mild steel by Charpy impact test.

2.2. APPARATUS

Impact testing machine.

A Mild Steel specimen 55 mm X 10mm X 10mm.

2.3. DIAGRAM

Figure 2.1. Impact Testing Specimen

Figure 2.2. Impact Testing Machine

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Figure 2.3. Impact Specimen before testing

Figure 2.4. Impact Specimen after testing

Figure 2.5. Impact Testing Machine (JB-300B)

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2.4. THEORY

An impact test signifies toughness of material that is ability of material to absorb energy

during plastic deformation. Static tension tests of specimens do not always reveal the

susceptibility of a metal to brittle fracture. This important factor is determined by impact test.

Toughness takes into account both the strength and ductility of the material. Several

engineering materials have to withstand impact or suddenly applied loads while in service.

Impact strengths are generally lower as compared to strengths achieved under slowly applied

loads. Of all types of impact tests, the notch bar tests are most extensively used. Therefore, the

impact test measures the energy necessary to fracture a standard notch bar by applying an

sudden load. The test measures the notch toughness of material under shock loading. Values

obtained from these tests are not of much utility to design problems directly and are highly

arbitrary. Still it is important to note that it provides a good way of comparing toughness of

various materials or toughness of the same material under different conditions. This test can

also be used to assess the ductile brittle transition temperature of the material occurring due to

lowering of temperature.

2.5. PROCEDURE

With the striking hammer (pendulum) in safe test position, firmly hold the steel

specimen in impact testing machines vice in such a way that the notch faces the hammer

and is half inside and half above the top surface of the vice.

Bring the striking hammer to its top most striking position unless it is already there,

and lock it at that position.

Bring indicator of the machine to zero, or follow the instructions of the operating

manual supplied with the machine.

The specimen is placed on supports or anvil so that the blow of hammer

is opposite to the notch.

Release the hammer. It will fall due to gravity and break the specimen through its

momentum, the total energy is not absorbed by the specimen. Then it continues to

swing.

At its top most height after breaking the specimen, the indicator stops moving, while

the pendulum falls back. Note the indicator at that top most final position.

2.6. RESULTS

Sample Energy

1 34 J

2 26 J

3 27 J

4 31 J

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Average impact value is 29.5 J.

EXPERIMENT NO. 03

3.1. OBJECTIVE

To determine the hardness of mild steel specimen.

3.2. APPARATUS

Mild steel specimen

Rockwell Hardness Tester

3.3. DIAGRAM

Figure 3.1. Rockwell Testing Machine in the laboratory

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3.4. PROCEDURE

Place the specimen on platform of a machine.

Using the elevating screw raise the platform and bring the specimen just in contact

with the ball.

Apply an initial load until the small pointer shows red mark.

Release the operating valve to apply additional load. Immediately after the additional

load applied.

Repeat this procedure four times & record the values shown on the display each time.

3.5. RESULTS

Sample Hardness(HRB)

1 56.7

2 64.1

3 63.4

4 52.8

Average value of hardness of the MS sample in HRB scale is 59.25.