Lab Report: Tensile Testing of Mild Steel and Aluminium

Categories: Engineering

Report, Pages 3 (653 words)

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I. INTRODUCTION

Tensile testing is a fundamental experiment in materials science and engineering. It involves subjecting a material
to increasing tensile forces to measure properties such as tensile strength, breaking point, and elongation. These
properties are used to calculate stress, strain, and Young's Modulus, allowing for a comparison of materials.
In this experiment, we utilized a Universal Testing Machine to test two materials: Mild Steel and Aluminium.
Our goal is to compare their mechanical properties and behavior by plotting stress-strain curves and
determine their suitability for various applications.

Aim

To compare and contrast the tensile strengths of Mild Steel and Aluminium.

II. METHODS

A. Required Equipment and Materials

Universal Testing Machine (Fig-1): Used to measure the tensile strength of the specimens.
Specimens: Mild Steel and Aluminium, with known dimensions (width, depth, and gauge length).

Fig-1: Universal testing machine

B. Experimental Procedure

Measure the width, depth, and gauge length of the specimens using Vernier Calipers.
Set the load frame to zero using the load cell.
Attach the specimen to the machine and an Extensometer to measure strain.
Conduct the experiment until the specimen reaches its breaking point, recording time, displacement, and force.
Calculate stress and strain using the obtained data.
Repeat the experiment for multiple samples of each material.
Plot stress-strain graphs for comparison.

III. RESULTS

The table below presents the displacement, force, stress, and strain data for three samples of Mild Steel and
Aluminium. The measurements were recorded over time during the tensile testing experiment.

Time (s)	Displacement (mm)	Force/Load (kN)	Stress (MPa)	Strain (mm/mm)
0	0	0.0021	5.7377E-08	0
20	2.6575	11.8806	0.000324607	0.03321875
40	5.3243	13.4878	0.000368519	0.06655375
60	7.9913	14.1189	0.000385762	0.09989125
70	9.3242	14.2895	0.000390423	0.1165525
77.515	10.3244	14.3765	0.000392801	0.129055
100.015	13.3245	14.513	0.00039653	0.16655625
120.015	15.9908	14.5292	0.000396973	0.199885
140.015	18.6577	14.4557	0.000394964	0.23322125
160.015	21.3238	14.0681	0.000384374	0.2665475
178.481	23.7882	0.0367	1.00273E-06	0.2973525

A. Equations and Calculations

We can calculate stress and strain using the following formulas:

Stress = (Load(kN) / Area(mm²)) * 10⁹ (measured in Pascals (Pa))
Strain = Displacement (mm) / Original Gauge Length (mm)
Young's modulus = Stress / Strain

Refer to Fig-3 for the stress-strain relationship graph.

B. Errors

Check units when calculating stress and strain.
Ensure the scale on the graph axes is correct for accurate representation.

C. Graph

Plot the stress-strain relationship of Mild Steel and Aluminium using the data obtained from the experiment. See
Fig-4 for reference.

IV. DESCRIPTION

The stress-strain graph clearly shows that Mild Steel has a significantly higher tensile strength than Aluminium.
Yield strength for Mild Steel is around 300 MPa, whereas Aluminium's yield strength is approximately 100-150 MPa.
Young's modulus is also higher for Mild Steel. Beyond the yield strength, both materials experience fracture.
Mild Steel fractures at around 300-350 MPa, while Aluminium fractures at 200-250 MPa. These differences are
attributed to the atomic structure of the materials, with Mild Steel having a Body-Centered Cubic (BCC) structure
and Aluminium having a Face-Centered Cubic (FCC) structure. Additionally, Aluminium exhibits higher ductility
and is corrosion-resistant, making it suitable for various applications despite being more expensive than Mild
Steel. However, Mild Steel's higher strength-to-weight ratio is advantageous in certain scenarios.

V. CONCLUSION

Tensile testing is a crucial method for comparing and selecting materials based on their mechanical properties.
In this experiment, we found that Mild Steel has a higher tensile strength, yield strength, and Young's modulus
compared to Aluminium. The distinct characteristics of each material, such as ductility and atomic structure,
influence their behavior under tensile forces. Mild Steel is suitable for applications requiring high strength and
durability, while Aluminium is preferred for lightweight and flexible applications. The choice of material depends
on specific project requirements and goals, emphasizing the importance of material selection for optimal
performance.

VI. REFERENCES

Davis. J.R., Tensile Testing, 2nd Edition, ISBN 9781615030958, ASM International, 2004. [Online]
Available: https://books.google.com.au/books?hl=en&lr=&id=5uRIb3emLY8C&oi=fnd&pg=PR7&dq=tensile+testing+&ots=Ot0bYQ5r3I&sig=b7tWtn3_k0hBjwgI6TEKhSjf1hY [Accessed: 18-05-2019]
Royal Society of Chemistry, 2018. [Online]. Available: RSC - Aluminium [Accessed: 18-05-2019]
Wenzel Metal Spinning Web, "Steel versus Aluminum Weight, Strength, Cost, Malleability Comparison," 18 May 2019. [Online]. Available: Wenzel Metal Spinning [Accessed: 18-05-2019]

Lab Report: Tensile Testing of Mild Steel and Aluminium. (2024, Jan 04). Retrieved from https://studymoose.com/document/lab-report-tensile-testing-of-mild-steel-and-aluminium