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European Journal of Applied Sciences – Vol. 9, No. 5
Publication Date: October 25, 2021
DOI:10.14738/aivp.95.10958. Munkaila, A. (2021). The Relative Tensile Outcome of E60 and E70 Electrodes Deposits on Low Carbon Steel Welded Joints.
European Journal of Applied Sciences, 9(5). 336-342.
Services for Science and Education – United Kingdom
The Relative Tensile Outcome of E60 and E70 Electrodes Deposits
on Low Carbon Steel Welded Joints
Munkaila, Alhassan
Faculty of Engineering; Department of Welding and Fabrication
Tamale Technical University Tamale, Ghana
ABSTRACT
The responsive nature of low carbon steel to various applications such as
fabrication works, construction and maintenance cannot be overemphasized. In
most applications of low carbon steel there is the necessity to provide welding
joints. In the majority of cases, the E6013 and E7018 electrodes are generally used.
This study was designed to examine the influence of these electrodes on the tensile
characteristics of welded low carbon steel of grade, AISI 1018. The test was
conducted after preparing the joints and welding with shielded metal arc welding
(SMAW) process. The results showed that the yield point for E6013 was
392.8N/mm2 and that of E7018 deposits was 443N/mm2, suggesting that E7018
deposit is relatively higher in yield point than the E6013. The results also revealed
that the E7018 electrode has higher tensile deposit in relation to E6013 electrode.
Clearly, the E6013 deposit has lower UTS as compared with E7018. Basically the
E6013 deposit will fracture before the E7018 deposit when a tensile force is applied.
It is therefore recommended that the E7018 electrode be used for when higher
tensile deposit on low carbon steel required. If however a lower tensile deposit is
required on low carbon steel the E6013 electrode could be used.
Keywords: E6013 and E7018 Electrodes; Low Carbon Steel; Shielded Metal Arc Welding;
Tensile Test; Weld Deposits.
INTRODUCTION
Low carbon steel (LCS) is the most common form of material found and used in the steel
industry; it has a carbon percentage between 0.25% and 0.30%, and for that matter not
responsive to heat treatment because of the low carbon content. Obviously plain carbon steel
of this kind does not form martensite when heat is applied and quenched; its microstructure is
chiefly of ferrite and pearlite constituents [1] [2]. As a result, the LCS is relatively soft with
superior mechanical properties such as tensile strength, ductility and toughness. Further, LCS
is less expensive as compared to other steels, and can easily be welded and machined [2]. In the
welding industry, low carbon steel is extensively used for fabrication works, construction and
maintenance. It is interesting to note that steel is produced in various forms with different
mechanical and physical properties. The properties are due to varying chemical compositions
as well as the quantities in which they are found in the steel in question. The AISI 1018 is a
Standard grade Low Carbon Steel which is composed of 0.15-0.20% Carbon (C), 0.60-0.90%
Manganese (Mn), 0.04%(max) Phosphorus (P), 0.05%(max) Sulfur (S), and the base metal
being Iron (Fe), and is responsive to many engineering applications. Clearly, the choice of
electrode in welding LCS to achieve a high quality and strong weld is of paramount importance
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Munkaila, A. (2021). The Relative Tensile Outcome of E60 and E70 Electrodes Deposits on Low Carbon Steel Welded Joints. European Journal of
Applied Sciences, 9(5). 336-342.
URL: http://dx.doi.org/10.14738/aivp.95.10958
to the welding engineer. The commonly used electrodes for welding LCS are the E60 and E70
groups [3]. The E60 and E70 electrodes are very popular for welding applications such as
vehicles, sheet metal works, shipbuilding, fabrication, construction and maintenance [3]. While
both electrodes are mild steel based, they differ in yield and tensile strength where
the E7018 has higher specifications in both. Precisely, the coating on the E6013 is high Titania
potassium whereas that of the E7018 is low hydrogen potassium coating. Two separate
samples welded with these electrodes can be subjected to a tensile pull to examine the extent
to which they can resist a permanent deformation or fracture. The effects of welding current on
tensile strength have not been considered in this study. The empirical results of Rohit and Jha
[4] on the effect of process parameter such as welding current on tensile strength of mild steel
weld metal is quite impressive. The study revealed that welding current of 120A with Shielded
Metal Arc Welding (SMAW) produces a maximum tensile strength. With this current value the
ultimate tensile strength (UTS) of 515.185 MPa was recorded. Evidently, it can be concluded
that with increase in welding current the UTS will increase proportionately until an optimum
value is achieved. However, increasing the current beyond this optimum value will result in
decreased UTS [4].
A tensile test is one of the most basic types of mechanical testing carried out in a laboratory
with a tensile machine [5]. The tensile test is a commonly used method in industry and in
research to characterize the various steels manufactured in the steel industry. With tensile test,
properties such as yield point, ultimate tensile strength (UTS) and elongation are most
commonly used to determine the applicability of steel for various purposes [6]. The yield point
is an important tensile property, it is at this point it manifests whether or not the structure has
the capability to function where and when yielding occurs. However, the material deformation
becomes plastic or permanent beyond the yield point (thus, plastic region) and the stress is no
longer proportional to the strain [7]. Tensile test involves applying a pulling force to a prepared
steel, referred to as specimen and measuring its response to the stress. This test is carried out
by applying longitudinal or axial load at a specific extension rate to a standard tensile specimen
with known dimensions (gauge length and cross sectional area perpendicular to the load
direction) till failure. The applied tensile load and extension are recorded during the test for the
calculation of stress and strain [8]. These two parameters were then used for the calculation of
stress and strain to give a relationship as illustrated in equations 1 and 2.
� = !
"# .......(1)
ε=%&'%#
%# = (%
%# .......(2)
Where; σ is stress, ε is the strain, P is the external axial tensile load, Ao is the original cross- sectional area of the specimen, Lo is the original length of the specimen, Lf is the final length of
the specimen and �� is change in length. The unit of the stress is Pascal (Pa) or N/m2 according
to the SI Metric Unit whereas the unit of psi (pound per square inch) can also be used. A stress- strain relationship had been established between two specimens; they had been prepared with
equal lengths, one welded with E6013 electrode and the other welded with E7018 electrodes.
The yield stress, σy, was obtained by dividing the load at yielding (Py) by the original cross- sectional area of the specimen (Ao) as shown in equation 3.
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European Journal of Applied Sciences (EJAS) Vol. 9, Issue 5, October-2021
Services for Science and Education – United Kingdom
σy =
!)
"# .......(3)
The purpose of this study was to examine the influence of two different mild steel electrodes,
the E6013 and the E7018 on the tensile characteristics of welded low carbon steel of grade, AISI
1018 under a tensile test using the shielded metal arc welding (SMAW) process. The study
examined the difference in yield strengths and tensile strengths of the two specimens. By
subjecting them to an external tensile loading they underwent elastic and plastic deformation.
Initially, the metals elastically deformed giving a linear relationship of load and extension.
These two parameters were then used for the calculation of stress and strain to give a
relationship.
MATERIALS AND METHODS
An experimental procedure had been designed to produce samples from AISI 1018 low carbon
steel for the tensile test. The AISI 1018 is a Standard grade Carbon Steel. It is composed of (in
weight percentage) 0.15-0.20% Carbon (C), 0.60-0.90% Manganese (Mn), 0.04%(max)
Phosphorus (P), 0.05%(max) Sulfur (S), and the base metal being Iron (Fe). Two samples had
been produced by lathing into a dog-bone format, one being welded with E6013 electrode and
the other by E7018. This move was to compare the tensile values of the two specimens when
weld deposits are made with these electrodes. This test was conducted at Akenten Appiah- Menka-University of skills training and entrepreneurial development (AAM-USTED) with a
universal tensile testing machine as specified in table 1.
Table 1: Tensile Test Machine Specification
UNIVERSAL TENSILE TESTING MACHINE
Voltage 380V/3Phs Model WAW-1000H
Power 5KW Serial No. 011206
Frequency 50Hz Date 2017 08
Capacity 1000KN
A geometrical presentation of the sample had been showed in figure 1 with various
designations of the component.
Figure 1: Structure of the Specimens
The overall length of the specimens was 200mm with grip sections of 80mm and distance
between shoulders being 40mm as shown in figure 2.