LAB REPORT
Faculty of Computing,
Engineering and Science
ENGINEERING
MATERIALS LAB
PORTFOLIO – I : TENSILE TEST
NAME – AASHNA SHRIVASTAVA
STUDENT NUMBER - 30070322
INTRODUCTION
Tensile testing is a fundamental and indispensable technique in the field of engineering materials,
providing crucial insights into the mechanical properties and behaviour of materials under various
loading conditions. This method involves subjecting a specimen to axial tension until failure, allowing
engineers and researchers to analyse key parameters such as ultimate tensile strength, yield
strength, and elongation.
The significance of tensile testing lies in its ability to assess the material's response to external forces,
aiding in the design, quality control, and optimization of diverse materials used in engineering
applications. Understanding the mechanical properties of materials is essential for ensuring the
reliability and safety of structures, components, and devices across a wide range of industries,
including aerospace, automotive, construction, and manufacturing.
The testing process typically involves the preparation of carefully machined specimens with
standardized dimensions, ensuring reproducibility and accuracy of results. These specimens undergo
controlled loading using specialized testing machines, allowing for the precise measurement of force
and deformation throughout the test. The resulting stress-strain curves provide a wealth of
information about the material's elastic and plastic behaviour, ductility, and resilience.
Tensile testing is especially valuable in material selection, helping engineers choose materials that
meet specific performance requirements for a given application. It aids in identifying potential
weaknesses, determining load-bearing capacities, and predicting the material's behaviour under
different environmental conditions. Moreover, the data obtained from tensile testing serves as a
foundation for the development and validation of material models used in finite element analysis
and simulation.
The versatility of tensile testing extends to research and development, enabling scientists to
investigate novel materials or modifications to existing ones. This in-depth exploration contributes to
the continuous improvement and innovation in material science and engineering.
In summary, tensile testing stands as a cornerstone in materials engineering, offering a profound
understanding of material behaviour under tension. Its application spans the entire lifecycle of
engineering materials, from initial material selection to quality control and ongoing research for
advancements in material science. This methodological approach ensures the reliability and
durability of materials in diverse engineering applications, underlining its crucial role in the quest for
safer, more efficient, and technologically advanced materials.
TEST METHODS AND ANALYSIS
800
ENGINEERING STRESS(Pa)
STAINLESS STEEL
600
400
355,7043491
Stainless steel
200
0.2% offset
0
0
0,1ENGINEERING STRAIN
0,15
0,05
0,2
HIGH CARBON STEEL
ENGINEERING STRESS(Pa)
600
500
400
358,7897617
300
HIGH CARBON STEEL
200
0.2% offset
100
0
-100
0
0,02
0,04
0,06
0,08
0,1
ENGINEERING STRAIN
S235 - LOW CARBON STEEL
ENGINEERING STRESS (Pa)
400
350
300
250
200
246,8670561
S235 - LOW CARBON STEEL
150
0.2%offset
100
50
0
-50 0
0,05
0,1
0,15
0,2
ENGINEERING STRAIN
Through an approximation plot derived from the engineering stress-strain curves for each specimen,
the obtained yield strength (σy) values for steel A, steel B, and steel C are 355.7043491 MPa,
0,25
358.7897617 MPa, and 246.8670561 MPa, respectively. These values appear lower than the
specified data sheet values for 301, 304, and 310 stainless steels. Despite this, the closest
correspondence is observed with the 304 stainless steel, which typically exhibits a yield strength
ranging from 470 to 1000 MPa (Rowlands, David P., n.d.). The discrepancy may arise from the
approximation data plotting during the conversion from the force-time curve to the engineering
stress-strain curve, potentially introducing errors in the readings.
Regarding tensile strength (σu), steel A demonstrates an engineering tensile strength of
approximately 314.21582 Mpa, steel B exhibits about 351.6763508 Mpa while steel C exhibits about
219.0128375. However, their true stress values align more closely with the tensile strength of 304
stainless steel. These experimental findings suggest a potential similarity in composition between
steel A and steel B with 304 stainless steel.
In evaluating elongation, steel A experiences an elongation of approximately 11.125 mm, while steel
B undergoes 11 mm elongation, both yielding a 31% elongation at break whereas steel C yielding
25%. In contrast, the EN standard indicates a 70% elongation at break for 304 stainless steel under
specific conditions, introducing a divergence possibly attributed to differences in specimen size and
test parameters. British standards for 304 stainless steel, using the BSI standard, specify a minimum
of 40% elongation, aligning more closely with the experimental results. During the tensile test, as the
specimen elongates, the reduction in area (q) is calculated by the formula q = (A0 - Af) / A0, where
A0 is the initial area and Af is the final area.
The Young's Modulus (E) of the steel specimens is determined by the stress-to-strain ratio prior to
reaching yield strength. It signifies the material's elasticity within the engineering range before yield,
encapsulating its deformation behaviour under applied loads.
Ultimate tensile strength
YOUNG'S MODULUS
348.7229
LOW CARBON
683.132
STAINLESS STEEL
207536.9 High carbon steel
522.904
HIGH CARBON
176623.8 Low carbon steel
158351.2 Stainless steel
The fracture morphology of the specimens manifests as a distinctive cup-cone configuration,
characterized by a fracture angle of approximately 45 degrees. This morphology is indicative of
ductile rupture, signifying that the specimens undergo a cohesive and deformable rupture process,
emphasizing the material's capacity for extensive plastic deformation prior to failure.
The Young's Modulus, or modulus of elasticity, serves as a quantification of a material's resistance to
the separation of adjacent atoms, specifically within the context of iron atoms (Fe – Fe bonding) in
the case of steel. In steel, the incorporation of carbon as a solid solution is a minute fraction,
accounting for less than 2% of the material composition. This carbon content is distributed
throughout the interstitial spaces of the steel, effectively manifesting as impurities. The presence of
these carbon impurities exerts a discernible influence on the bonding interactions between Fe
atoms, ultimately determining the Young's Modulus of the steel.
CONCLUSION
Through a tensile test experiment utilizing a specialized machine, the mechanical attributes of a
material are discerned. As the material undergoes elongation, it undergoes both elastic and plastic
deformation, culminating in the strain hardening phenomenon, fortifying the material until reaching
fracture. In this specific experiment, steel specimens A,B & C exhibit divergent mechanical
properties, despite their near-similar characteristics. Notably, they differ in the strength coefficient,
with steel A resembling the properties of the S304 stainless steel, steel B mirroring the behaviour of
S355 and steel C resembling S235. The precision of the obtained values is compromised due to the
inherent approximation in plotting raw data generated by the machine.
APPENDIX
REFRENCES
Callister, W. D. (2009). Material Science and Engineering. USA: John Wiley & Sons, Inc
304 Stainless Steel Technical Data Sheet. (t.thn.). Dambel kembali dari
https://www.metalshims.com/t-304-Stainless-Steel-technical-datasheet.aspx