EXPERIMENTAL INVESTIGATION OF THE MECHANICAL AND MICROSTRUCTURE PROPERTIES OF S49 RAIL STEEL

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Copyright © European Journal of Technique (EJT) ISSN 2536-5010 | e-ISSN 2536-5134 https://dergipark.org.tr/en/pub/ejt
European Journal of Technique
journal homepage: https://dergipark.org.tr/en/pub/ejt
Vol.11, No.1, 2021
Experimental Investigation of the Mechanical and
Microstructure Properties of S49 Rail Steel
Anıl Rıdvanoğulları1*, Tayfun Çetin2 and Mehmet Akkaş3
1*Muş Alparslan University, Department of Motor Vehicles and Transport Technologies, 49250, Güzeltepe, Muş, Turkey. (e-mail:
a.ridvanogullari@alparslan.edu.tr).
2 Hakkari University, Department of Electricity and Energy, 30000, Hakkari, Turkey. (e-mail: tayfuncetin@hakkari.edu.tr).
3 Kastamonu University, Department of Mechanical Engineering, 37150, Kastamonu, Turkey. (e-mail:
mehmetakkas@kastamonu.edu.tr).
1. INTRODUCTION
Railway transport has an important place in both freight
and passenger transport. Railway transportation, which is in
the safe class in the field of logistics, consists of three main
parameters as railway, vehicles and facilities [1]. Railway is
divided into two main components as infrastructure and
superstructure. Railway infrastructure is known as all kinds of
excavation work (ground consolidation) to be able to build a
superstructure on the railway whose route is determined. The
superstructure, on the other hand, is the part consisting of rails,
sleepers, ballasts and fasteners that enable the movement of
railway vehicles and transfer the loads on them to the platform
[2-4].
The rail, which is one of the elements that make up the railway
superstructure, is a very important element for the
superstructure that enables the railway vehicles to roll (move)
on it and is responsible for transferring the weight and forces
from the vehicles to the ballast and sleeper. The rail is
specially manufactured because it must be resistant to weight
and other forces from railway vehicles. A standard rail; It
consists of three parts: cork, body and base (Figure 1) [5].
Figure 1. Sections of a standard rail
Rails are divided into classes in terms of shape and weight.
S49 (49E1), UIC60 (60E1), which are divided into corrugated,
single mushroom, double mushroom. such as the rail's weight
per kilogram per meter (Figure 2).
ARTICLE INFO
ABSTRACT
Received: Oct., 18. 2020
Revised: May., 19. 2021
Accepted: Jun, 20. 2021
This study was carried out to determine the microstructure and mechanical properties of S49
rail steel. For this purpose, firstly, three samples of S49 rail steel material were prepared by
cutting by wire erosion method for three-point bending test. Microstructural analyses of S49
rail steel were examined by scanning electron microscopy (SEM). Energy dispersion
spectrometer (EDS) analysis was performed to determine the chemical composition of the
S49 rail steel material. Hardness test and three-point bending test were performed to
determine the mechanical properties of the samples. SEM and EDS analyses of fractured
surfaces were performed from the broken samples after the three point bending test.
Keywords:
S49 rail steel
Mechanical properties
Three-point bending
Microstructure
Hardness
Corresponding author: Anıl
Rıdvanoğulları
ISSN: 2536-5010 | e-ISSN: 2536-5134
DOI: https://doi.org/10.17694/ejt.812142
Head
Web
Foot
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EUROPEAN JOURNAL OF TECHNIQUE, Vol.11, No.1, 2021
Copyright © European Journal of Technique (EJT) ISSN 2536-5010 | e-ISSN 2536-5134 https://dergipark.org.tr/en/pub/ejt
Figure 2. Rail shapes
Rails should be rigid enough not to wear but flexible
enough not to break [6]. As the train speed increases, security
problems occur. Therefore, material properties and shape are
important in the railway line [7].
S49 (49E1) type rails, which are known to be
approximately 49 kg per meter, are an important type of rail
used in rail superstructure for both freight and passenger
transportation. It is especially preferred in conventional
railway lines. Since conventional lines generally operate
under intense operation, the rails are broken, cracked,
deteriorated over time. such defects occur.
Due to fatigue damage, which is one of the most common
damage to the rails, increase in train operating speeds, higher
axle loads and higher traffic density, train logistics will
continue and will continue to be important. The contact
pressure between the wheel and the rail, which can increase
up to 1 GPa, and the surface shear stresses that can reach MPa
at high levels can cause plastic deformations in the rails [8].
The surface, microstructural and mechanical properties of the
rail have a significant effect on the mechanism of damage that
may occur in the rail material during train operating
conditions and on the wear resistance of the rail [9]. High and
repetitive loads that occur during service conditions cause
micro and macro cracks or rail breaks on the surface where the
rail contacts the wheel [9]. When these defects cannot be
detected within maintenance intervals, they may cause deray
events to occur.
2. EXPERIMENTAL STUDIES
Standard metallographic processes were applied to obtain
images of the samples with scanning electron microscopy
(SEM). These applied metallographic processes were applied
as sanding, polishing and etching respectively. Scanning
electron microscopy (SEM) analysis was taken from the "FEI
QUANTA 250 FEG" brand device in Kastamonu University
Central Research Laboratory. Energy dispersion spectrometer
(EDS) analyzes were taken from the "FEI QUANTA 250
FEG" brand device in Kastamonu University Central
Research Laboratory. Hardness measurements were made to
determine the mechanical properties of the samples. Hardness
measurements were made by DIGIROCK brand macro
hardness tester with Rockwell-C hardness measurement
method. Since the strength of the test specimens is not in the
shape and size of the tensile test specimen, it was measured by
the three-point bending test. The bending tests were carried
out with a SCHIMATZU type universal test machine
according to the ASTM B 528-83 standard. By making a
special apparatus shown in Figure 3, the flexural strength of
the samples was measured using the TRAPEZIUMX
software.
Figure 3. Schematic view of the three-point bending test [10].
In Figure 3, the graphics obtained as a result of the three-
point bending tests for all three sample series are given.
3. EXPERIMENTAL RESULTS AND DISCUSSION
SEM image and EDS analysis results taken from S49 rail
steel are given in Figure 4.
Figure 4. SEM image and EDS analysis of S49 rail steel
When Figure 4 is examined, scattered cementite grains are
observed in martensite blocks. In addition, the microstructure
is thought to be composed of acicular martensite. When the
EDS analysis results given in Figure 4 are examined, it is
understood that the material is S49 rail steel material. In
addition, when the analysis results are examined, the Fe, Mn,
Si and C peaks present in the S49 rail steel material can be
seen clearly [11, 2, 12].
Surface EDS Analysis
Element
Weight (%)
Fe
98.42
Mn
1.23
Si
0.30
C
0.05
Acicular martensite
Flat Bottom Rail Bull Headed Rail Tram Rail
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EUROPEAN JOURNAL OF TECHNIQUE, Vol.11, No.1, 2021
Copyright © European Journal of Technique (EJT) ISSN 2536-5010 | e-ISSN 2536-5134 https://dergipark.org.tr/en/pub/ejt
TABLE I
HARDNESS VALUES OF S49 RAIL STEEL.
1.
Measurem
ent
2.
Measure
ment
3.
Measure
ment
Average
Measurement
Value
HRC
Hardness
Value
22.2
25.4
26.7
24.76
In order to determine the hardness exactly, hardness values
were measured from various parts of the sample and at least
five hardness values were taken from all surfaces of each
sample. By taking the average of the hardness values
measured, the average hardness values of the samples were
found (Table 1). Macro hardness measurement values were
determined by applying HRC test method and diamond cone
tip by applying 10 kgf preload and 150 kgf total load.
In Figure 5, macro images of S49 rail steel after three-point
bending are given.
Figure 5. Macro images of S49 rail steel after the three-point bending test
When the sample images given in Figure 5 are examined,
it is clearly seen that the samples are broken in the same
regions and in the same shapes after the three-point bending
test.
Three-point bending strengths of the samples are given in
Figure 6 graphically.
Figure 6. Three-point bending strength graphs of the samples
When the graphic given in Figure 6 is examined, the
bending strength of S49 rail steel can be seen clearly. Three-
point bending tests were carried out with three samples. It was
measured as 1776 MPa in the first measurement, 2251 MPa in
the second measurement and 1301 MPa in the last
measurement. The average of three measurements was
calculated as 1776 MPa [8,13].
In Figure 7, broken surface SEM and EDS analysis images
and results are given after the three-point bending test of S49
rail steel.
Figure 7. Broken surface SEM and EDS analysis of S49 rail steel after three-
point bending test
When the SEM images given in Figure 7 are examined, it
is seen that the S49 rail steel material is broken in a brittle
way. Because, when looking at the SEM images of the sample,
it is seen that there is too much roughness on the surface and
the materials that make up the composition are broken from
the grain boundaries. In addition, Fe, Mn and C peaks were
detected in the internal structure of the sample as a result of
the broken surface EDS analysis [10,14].
4. CONCLUSION
In this study, the microstructure and mechanical properties
of S49 rail steel were successfully performed. Scanning
electron microscopy (SEM), Energy dispersion spectrometer
(EDS), hardness, three-point bending test and SEM and EDS
analyzes of fractured surfaces were successfully applied to the
samples. The report of the experimental results can be
summarized as below:
 Fe, Mn, Si and C peaks present in S49 rail steel
material were determined.
Sample 1
Sample 2
Sample 3
(4000 x)
(2000 x)
(1000 x)
Surface EDS Analysis
Element
Weight
(%)
Fe
98.74
Mn
1.10
C
0.16
(500 x)
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EUROPEAN JOURNAL OF TECHNIQUE, Vol.11, No.1, 2021
Copyright © European Journal of Technique (EJT) ISSN 2536-5010 | e-ISSN 2536-5134 https://dergipark.org.tr/en/pub/ejt
In the inner structure, scattered cementite grains were
found in martensite blocks.
Macro hardness measurement values were measured
by HRC test method using a diamond cone tip by
applying 10 kgf preload and 150 kgf total load and
the hardness value was measured as 24.76.
The average of the three-point bending test
measurement was calculated as 1776 MPa.
It was found that the S49 rail steel material broke
brittle after the broken surface.
As a result of the broken surface EDS analysis, Fe,
Mn and C peaks were detected in the internal
structure of the sample.
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BIOGRAPHIES
Anıl Rıdvanoğulları obtained his BSc degree in railway system engineering
from Karabük University (KBU) in 2016. He received his MSc from the
Mechanical Engineering Department of the same university, Institute of
Science, Department of Mechanical Engineering in 2018. Research areas,
railway vehicles and equipment. Recently, he focused on rail system
superstructure construction and materials. Between 2016 and 2019, he
worked as a part-time instructor at Karabük University Railway Systems
Engineering. In 2019, he joined Muş Alparslan University Vocational School
of Technical Sciences Rail Systems Road Technology program as a lecturer
and is still working as a lecturer.
Tayfun Çetin obtained his B.Sc. degree from Fırat University in 2010. In
2010, He received his M.Sc. and Ph.D. degrees from Fırat University and
Karabuk University in 2014 and 2019 respectively. He started to work as a
lecturer at Hakkari University in 2019. He has been workingat Hakkari
University since 2019. He works in the fields of powder metallurgy and
material science.
Mehmet Akkaş obtained his BSc degree in Metal Teaching Program from
Fırat University in 2010. He received the MSc. Diploma in Metallurgy
Education from Fırat University in 2013. He received the Ph.D. diploma in
Manufacturing Engineering Department from the Karabük University in
2017. His research interests are powder metallurgy, powder production, gas
atomization and composite materials. In 2018 he joined the Department of
Mechanical Engineering, Faculty of Engineering and Architecture,
Kastamonu University as an assistant professor, where he is presently an
assistant professor.
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