Investigation of Mechanical Properties of Steel - Construction Tech 2

This report details an experiment conducted to determine the mechanical properties of mild steel, a fundamental material in construction. The experiment utilized an Instron universal testing machine to analyze the steel's behavior under stress, focusing on the stress-strain relationship to identify elastic, plastic, and fracture behavior. Key properties such as the modulus of elasticity, yield point, and ultimate tensile strength were determined and discussed in relation to theoretical values and observed phenomena like necking. The results indicated that steel responds positively to applied forces, with changes in dimensions attributed to particle distribution within the metal's structure. The report includes a detailed procedure, results with statistical analysis, graphical illustrations, and a discussion of the material's behavior under tensile stress, emphasizing the importance of understanding these properties for engineering applications. Desklib offers a platform for students to access similar solved assignments and past papers for academic support.

CONSTRUCTION TECHNOLOGY 2
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ABSTRACT
The analysis was directed to assist through establishing functional characteristics of the chosen
objects sample also known as Mild Steel. The basic requirement of this particular task was to use
the standard machine that is recommended for testing to carry out the property determination
exercise. This particular machine can effectively help in the determination of the characteristics
of the material including yield strength and ultimate strength. The construction engineers will
and also experts of the material science normally study the behaviour of the materials before a
suggestion is given for a particular use.
The establishment of the behaviour and also general characteristics of the material will depend
on the experimental tests that have been performed. In such experiments, the relationship
between force and extension are normally looked into. The engineering property of the sample
that has been properly studied in this particular project is the quality of the yield. This particular
material property was found to change from one metal to another. The sample used for the study
was mild steel. Although different metals have different response to the force- extension tests,
the metal that was chosen for the study is called the mild steel. From the experiment that was
carried out, it was established that steel has perfect characteristics in its engineering applications.
This could be the reason why this particular metal is highly preferred for the engineering use.

Contents
ABSTRACT....................................................................................................................................................2
INTRODUCTION...........................................................................................................................................3
AIM..............................................................................................................................................................4
THEORY........................................................................................................................................................4
Stress-Strain relationship.........................................................................................................................4
Materials and Equipment’s..........................................................................................................................7
The procedure of the Experiment...............................................................................................................7
Differences between the point of deformation and the maximum axial force..........................................12
CONCLUSION.............................................................................................................................................13
REFERENCES..............................................................................................................................................15

INTRODUCTION
The material use within various engineering places requires that their properties that are related
to the mechanical work are known. This is very crucial in the cases where the forces are involved
and there are no expected failures on the components. The measurements in engineering
normally value these properties to assist in the generation of the exact dimensions. The
commonly known properties of the materials include the following. The modulus versatile which
is normally designated letter E as well as the strain (Aghaie, Honarvar and Zanganeh 2012.).
The point of failure in the material, as well as the quality of the definitive, is very important. The
piece of the literature that has been provided here illustrates the finding of the experiment that
was carried out in the laboratory to determine these characteristics. The experiment focused on
the determination of the modulus flexibility, the point of the yield and other extreme qualities of
the material sample. The chosen material was mild steel. The properties became of interest of the
study since they affect directly the safety requirements in the engineering applications. This has

been very crucial especially in the cases where the failures are not needed or the failure is just
not accepted.
Outline of auxiliary segments in extensions, railroad lines, marine’s ships, airplanes, weight
vessels and so forth are just but the selected few areas where the malleable properties of
materials utilized should be analyzed. "Hence the rigidity of the materials should meet the
quality requirements of the basic applications. The mechanical properties of the metals decide
the kind of designing application to be utilized in any component. The applications of the
longitudinal forces that are normally positioned axially assist in establishment of the load bearing
characteristics of the metal. Such examples are used to examine the material before they are used
especially where safety is properly needed. When a material under the test is subjected to very
strong forces, the key point under observation will be deformation point. The point of the
deformation will clearly show how the material is likely to fail when put into proper engineering
use. Its original dimensions as the sample under investigation were taken as of the mild steel.
The diameter of the sample was taken as D. The area of the cross-section that was used in the
experiment was recorded as well.
AIM
The main objective of this particular experiment was to establish the behaviour of the steel metal
when it is exposed to the variation of forces of different magnitude .The relationship between
these forces and the change in the dimensions was given perfect consideration.

THEORY
Stress-Strain relationship
The loading type of tensile normally causes the object under study to undergo deformations.
The change in the dimensions of the material under test or just the extension process will take
place in different forms. Some of the changes are known to be very much slow. This implies
that they cannot be detected easily. Some of the changes are very obvious and they give
instant results.
=Applied load/area
Such practical forces that results from such pressures are given by deviation of the
dimension/original length
It follows that;
…………………………………………………………………………. (1)
………………………………………………………………………… (2)
In which
Refers to the engineering stress
, refers to injected axial force
Represents known area of cross section

Represents t change within dimension or the extension,
Represents the engineering strain.
Represents the original length.
Young’s modulus
The Young’s Modulus E is given by the formula;
………………………………………………………………………….. (3)
A scientist by the name Hooke came up with the law that assists in the prediction of the
connection between the applied force and the extension. Such relationship between these two
parameters is very important considering that they normally work together. According to this
individual, the two quantities are normally related directly that is to say when one value increases
the other value too increases. This kind of relationship will continue up to the point when the
elastic limit is exceeded. After the elastic limit is exceeded any further increase in the applied
force does not produce an extension. This leads to the occurrence of a failure in the components.
Most of the metals are known to obey this law apart from the few cases that do not follow the
specifics of the same law. Since this law affects nearly all the mechanical behavior of any
material, its study is very crucial ((Frazier 2014 (Frazier 2014).

In the practical consideration, the yield point refers to the point in which the law of Hooke does
not apply anymore. This simply means that an increase in the stress or the force does not produce
any corresponding extension. The most common value of the extension that has been recorded in
most of the literature work is just 0.2%. Within this specific value of the percentage, the line that
is obtained is normally straight from the origin. Any slight variation in this value amounts to
permanent failure or the permanent deformation. The manuals used in the explanation of the
properties of various components of the machine will always make reference to this particular
point. The exercise of distortion will take place immediately after the value has been exceeded.
The reduction in size at the cross section point is called necking. It is of advantage to know the
stress value considering that it is affected just before the process of necking starts.
Figure1: Region of elongation (Bassis and Walker 2012)
Materials and Equipment’s
 Universal Testing Machine
 Three rods of Mild steel
 A ruler

 Venire Caller
The procedure of the Experiment
The thickness of the rod samples of Mild steels was measured. The width was also taken in
dimension. An original dimension of the material sample valued at the length of 80mm. The
measurement was taken using a ruler in the confirmation as well as measurement of gauge
dimension of the material. The data acquisition software was activated and the selection of the
material corresponding or connecting with the material was done within this software. Through
starting the cell of the load, the frame of the machine would only be directed to give dimensions
of the tensile load in the inserted material. (Toda, Galindo and Rivera 2014).
There was an adjustment of the jaws to fit the specimen’s size. This particular practice was
followed by attaching the actual extensometer on the lowered section of the specimen in the
gauge. The scroll wheel was used in the preloading of the machine so as to avoid slipping of the
specimen
After the removal of the specimen, the extensometers were again adjusted to zero values and the
test started for the measurements of the strain of the mild steel rod or sample.
The record of the data was achieved using the software on the spreadsheet. The tensile test was
conducted through putting the material in the testing machine at as directed by the technician.
Some of the obtained results needed analysis within the computer (Zare 2015). This data was
later recovered for further analysis as well as the plotting of the graphs. In order to verify the
results, a second procedure was carried out.

During the testing process, the sample was machined using normal operations including turning.
The finished product was then introduced onto the machine using the right geometry. A standard
machine for testing was used. The results that were obtained from the machine were considered
to be very accurate. The substantial measure of the characteristics of the material was achieved
through proper positioning of the sample. This is done by holding one of the end samples on a
fixed position while on end is displaced at a constant rate. (Wang, Mattern, Bednarčík, Li,
Zhang and Eckert 2012).
In order to determine the maximum forces required to cause failure, there was an application of
the model. The model established the variation in the extension at relatively slow rate. The
equations were used to establish such perfect connections. From the information that was
gathered, it was possible to predict the changes in relation to the applied effort. Results and
Discussion
Characteristics Mean Standard Deviation
Modulus of Elasticity 197.7Gpa 2.0Gpa
Yield point=7211N 357.1Mpa 3.6Mpa
Ultimate strength=7788N 487.6Mpa 6.7Mpa
Stress Range From 50 to300Mpa
The force outline dislodging diagram for the 1018 steel inspected is as shown below. The
information was changed over to a comparing pressure strain diagram. The diagram obviously
demonstrates two areas of direct conduct in low strain position of pressure strain diagram(This,
Sistiaga, Wauthle, Xie, Kruth and Van 2013). This conduct proposes that the example was

extremely agreeable at low feelings of anxiety, as well as firm at high feelings of anxiety.
Tragically, there is no basic or concoction motivation behind why steel should show an
expanding modulus with expanding pressure.
Figure 2: Graphical illustration(Bassis and Walker 2012)
Consequently, a more plausible clarification was required in realignment and pivot test
installation within low pressure (low force) region. Keep in mind that this content installation, as
well as the example, is under the equivalent force connected. As these trial conditions concerned,
the most agreeable part, therefore, overwhelm the strain conduct pressure.
This data that has been gathered from the experiment that was carried out on the determination of
the property of the material was very comprehensive. Proper evaluation of the results indicated
that steel will always respond very positively to the forces that it is subjected to. The significant
change in the dimensions can be explained by the nature of the distribution of the particles within
the structure the metal itself .The large values that are obtained in the variation of the dimensions
of the steel sample when subjected to extensional forces speaks volume of the particle
distribution within its structure. The magnitude of the forces that was needed to produce

extension was almost 605MPa.It is important to note that such magnitude forces apply to those
materials with fixed particle distribution. The necking process in the steel metal was the evidence
on its characteristics. There was a lot of necking saw in Mild steel.
Figure 3: Necking points(Bassis and Walker 2012)
The changes that have been witnessed in the dimensions of the material that was under the test
could not just be wished away. It was the starting point of the evaluation process. The theoretical
value of the changes in the dimensions were very much compatible to the actual results that were
obtained .The relationship between the force and the extension within the material translated to a
property called pressure strain bends. The compact nature of steel was responsible for the high
values in the parameter that were obtained. Creation of space within such structures was found to
consume much of the energy. If other materials like aluminum would have been considered for
the same experimental tests, the value of the forces in the final results would have been slightly
low. The value would have been lower than the indicated possible theoretical digits. This
observation therefore implies that the sources of error within the set-up have been greatly
minimized. In the diagram, it is very well visible that for designing pressure strain bends, the
bends drop downwards subsequent to the necking process (Bassis and Walker 2012).