International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 6 - Apr 2014
Effects of External Magnetic Field on Mechanical properties of a welded
M.S metal through Metal Shield Arc Welding
*Ajit Senapati¹ Siba brata Mohanty²
*1.Asso.Professor, Department of Mechanical Engineering, G.I.E.T, Gunupur, Rayagada, Odisha, India
2. Research scholar, Department of Industrial Engineering, G.I.E.T, Gunupur. Rayagada, Odisha, India
I. INTRODUCTION
Welding is a process in which materials of the same
characteristic changes obtained by the deflection of
fundamental type or class are brought together and caused to
welding arc in the presence of external magnetic field. The join (and become one) through the formation of primary
chemical bonds under the combined action of heat and
magnetic field has been applied from various orientations
pressure . The definition found in IS0 standard is “Welding is
upon the weld bead. The welding process which has been an operation in which continuity is obtained between parts for
assembly, by various means”. Hence, the welding is the fusion
considered under study is shielded metal arc welding on
of two or more pieces of metal together by using the heat
Mild steel plate. The objective of this paper is to study produced from an electric arc welding machine. Arc welding
dates back to the late 1800’s, when a man was welding with a
effect of magnetic field on the weld quality and geometry
bare metal rod on iron, the sparks from the welding caught a
when the field is applied longitudinal to the electrode stack of newspapers on fire near him and while welding, he
noticed that his welds started looking a lot better. The reason
travel i.e. the field lines are perpendicular to the electrode
for this was the smoke took the oxygen out of its welding
travel. However there is lack of information for optimum environment and decreased porosity. The arc is struck
between the electrode and the metal. It then heats the metal to
parameters, very little work has been reported in this a melting point. The electrode is then removed, breaking the
direction. A magnetic field externally applied to the arc between the electrode and the metal. This allows the
molten metal to “freeze” or solidify. The arc is like a flame of
welding arc, deflects the arc by electromagnetic force in
intense heat that is generated as the electrical current passes
the plane normal to the field lines. The magnetic field through a highly resistant air gap. During welding, magnetic
field is set up in the plane of the parts being joined and
exerts force on the electrons and ions within the arc, which
circumferentially around the electrode and the plate as shown
causes the arc to be deflected away from the normal arc in Fig 1. The field, F1, is set up around the electrode; the field
F2, around the plate plates being joined and the field, F3, in
path. The welding arc can be deflected forward, backward,
the plates adjacent to the arc and in a direction similar to that
or sideways with respect to electrode and welding of field F1. Since it is not possible to remove these fields from
welding operation, it is necessary to use external control as a
direction depending upon the direction of an external
means to overcome these magnetic effects [1]. A magnetic
magnetic field. In this paper various mechanical field externally applied to the welding arc deflects the arc by
electromagnetic force (Lorentz force) in the plane normal to
properties tests such as tensile strength, hardness, impact
the field lines. The magnetic field exerts force on the electrons
test etc. are conducted to see the effect of external and ions within the arc, which causes the arc to be deflected
away from the normal arc path. Deminskii, et al. [3],
magnetic field on it. It is observed that weld pool
conducted experiments using a GMAW process on an
penetration reduces while the weld bead width increases aluminum-magnesium alloy while a longitudinal magnetic
field was applied to the welding arc. The magnetic fields
thereby affecting the parameters of the process. The
applied were alternating and of the order of 40 gauss.
results and conclusions are discussed as per the They reported the arc oscillated across the weld axis.
observations while the tensile strength and hardness of Subjecting the welding arc to transverse magnetic fields has
beneficial effects only when the arc is deflected forward with
parent materials are observed as well.
respect to the direction of electrode travel [4] [5]. Applying an
optimum magnetic field to a welding arc on both
nonmagnetic and magnetic materials increases welding speed
Keywords— Arc Instability, Magnetic Effects, Metal several times at which undercut-free and no porosity welds
shield arc Welding, Weld Beads.
can be made It is known the extent of arc deflection is
Abstract— The aim of this study is to show the
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 6 - Apr 2014
dependent upon the flux density of the applied magnetic field,
the arc current, arc length, and so on [4,6 ,7].
be used as automatically regulating the depth of penetration.
Hicken and Jackson found beneficial effects of constant
transverse magnetic field when the arc was deflected forward
with respect to the electrode travel speed. It was possible to
increase the welding speed four times and steel obtains the
welds free from undercuts. Weld width was found to reduce
with increase in magnetic field. Sheinkin found the
application of transverse magnetic field to increase the
productivity of the submerged arc welding process used for
making butt joints between prepared edges
Fig 1.Shows Planes of Magnetic Field Set-up
2. Application of magnetic field
2.1 Longitudinal magnetic field:
A magnetic force acts on the arc, in this system when the
angle between the direction of the electron stream and
magnetic lines of force are not zero. As the arc has a
conical shape and the current carrying electrons also
moves along the surface of the arc, their motions can be
resolved in two components, one along the axis of the
arc and other perpendicular to it. The component along
the arc does not contribute to the magnetic movement.
The component perpendicular to arc exerts a force on the
arc causing the arc to rotate clockwise or anticlockwise
depending upon the direction of the magnetic field and
polarity used.
Fig. 3 Image for Transverse magnetic field set-up
3. Experimental procedure
3.1 Preparation of Specimens:
The mild steel pieces of the dimension 200 mm X 20
mm X 6 mm are used as a work-piece for the welding.
Each metal piece first cleaned for dust and rust. Before
the actual welding process the space between the
specimens is fixed with a support. The space between the
specimens for the butt welding is depends upon the
thickness of the work-piece. For a 6 mm thickness there
is no requirement of making groove, so a 3 mm gap is
maintained during the whole process of welding. The
quality and geometry of weld is much depends on
correct and same gap throughout length of the specimen.
Fig.2-Image for Longitudinal magnetic field
set-up
2.2 Transverse magnetic field:According to the Flemings left hand rule the arc in the
influence of transverse magnetic field will be deflected
forward or backward depending upon the direction of
magnetic field lines force and the polarity of welding system.
Work of earlier investigation can be analyzed keeping this in
mind .Kovalev showed that the transverse magnetic field can
ISSN: 2231-5381
Figure:-4 Image for removing bend from M.S flat set-up
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 6 - Apr 2014
the magnetic field arrangement is removed. The range of
current and voltage are remained similar to the magnetic field
welding. The weld-pieces obtained after the process is shown
in fig. different welding parameters readings associated with
the process are tabulated and it is shown in the table no.2.
WOR
KPIEC
E NO.
CURREN
T
(A)
VOLTAG
E
(V)
M1.
M2.
M3.
90
90
90
25
25
25
Figure:-5 Image for cleaning of Specimen
3.2 Welding In Magnetic Field (M):
The magnetic field is applied as per the set-up
and then the arc welding machine and
electrodes are fixed at their respective places.
Multi-meter, clamp-meter and gauss-meter are
placed and connected to take the readings. As
per the semi-automation to the process feed rod
is connected with the work-piece motion. The
weld-pieces obtained after the process is shown
in fig. different welding parameters readings
associated with the process are tabulated and it
is shown in the table no.1.
MAGN
ETICFIELD
INTENS
ITY
(GAUSS
)
70
70
70
WELDIN
G SPEED
(mm/min
)
60
60
60
Fig:-7 Image for welding of specimen without magnetic
field
WORKPIECE
CURRENT(A)
VOLTAGE
NO.
WM1, WM2, WM3
(V)
90
25
Table-2 Shows operating parameters for welding (without
magnetic field)
Fig:-6 Image shows welding of specimen with magnetic
field magnetic field
Table-1 Shows operating parameters for welding (with
magnetic field)
WORKPIECE
M1, M2, M3
CURRENT
(A)
90-100
VOLTAG
E (V)
27-30
3.3 Welding Without Magnetic Field (WM):
The similar setting as with magnetic welding is used in
without magnetic field process of welding. Only change is that
3.4 Grouping and cutting of weld-pieces:
Each weld-piece (with and without magnetic field) cut
into three pieces and grouped according to the range of
current and voltage and provided a specific code. Now,
the total no. of weld-pieces is 9 and their corresponding
parametric readings are tabulated as below. Each weld
specimen has a code which shows its specifications. The
letter shows the weld-piece is from the category of
magnetic field or without magnetic field. The letter M
shows magnetic field and WM shows without magnetic
field. The number provided to the code shows its range
of current and voltage. The number 1, 2, 3 shows the
range of current 110-120 Ampere and voltage 23-26
volts.
Weld-pieces with magnetic field:Table-3 Shows experimental value for current,
voltage, magnetic field intensity and welding speed
at various stage of experiment.
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3.5 Hardness test:
Vickers hardness test
The Vickers hardness is as an alternative to
the Brinell method to measure the hardness of materials. The
Vickers test is often easier to use than other hardness tests
since the required calculations are independent of the size of
the indenter, and the indenter can be used for all materials
irrespective of hardness. It is ability to resist plastic
deformation from a standard source. The unit of hardness
given by the test is known as the Vickers Pyramid
Number (HV) or Diamond Pyramid Hardness (DPH). The
hardness number can be converted into units of pascals, but
should not be confused with a pressure, which also has units
of pascals. The hardness number is determined by the load
over the surface area of the indentation and not the area
normal to the force, and is therefore not a pressure.
Fig.9-Image for Vickers Hardness Tester
3.6 Tensile strength test:
This test is used to measure the tensile strength of a welded
joint. The tensile strength, which is defined as stress in kgf per
square meter. It is calculated by dividing the breaking load of
the test piece by the original cross section area of the
specimen. The test result which is conducted on universal
testing machine (UTM) is given in the table. The width
thickness of the test specimen are measured before testing,
and the area in square inches is calculated by multiplying
these before testing , and the area in square inches is
calculated by multiplying these two figures.
Fig-8:- Image for an indentation left in case-hardened steel after a
Vickers hardness test.
A diamond in the form of a square-based pyramid of ideal
size of a Brinell impression was 3/8 of the ball diameter. As
two tangents to the circle at the ends of a chord 3d/8 long
intersect at 136°, it was decided to use this as the included
angle of the indenter, giving an angle to the horizontal plane
of 22° on each side. The angle was varied experimentally and
it was found that the hardness value obtained on a
homogeneous piece of material remained constant,
irrespective of load. Accordingly, loads of various magnitudes
are applied to a flat surface, depending on the hardness of the
material to be measured. The HV number is then determined
by the ratio F/A, where F is the force applied to the diamond
in kilograms-force and A is the surface area of the resulting
indentation in square millimetres
ISSN: 2231-5381
Fig.10-Shows Tensile Testing Process
The shearing strength of the weld in pounds per linear inch
is determined by dividing the maximum load by the length of
fillet weld that ruptured. The shearing strength in pounds per
square inch is obtained by dividing the shearing strength in
pounds per linear inch by the average throat dimension of the
weld in inches. The test specimens are made wider than
required and machined down to size.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 6 - Apr 2014
field applied on vertical the hardness of metal is gradually
increases up to 262.11
Table-5 Shows Experimental values for Hardness carried out
at various conditions
WORK-PIECE NO.
PARENT METAL
WELD
(HV)
METAL (HV)
154.754
194.0125
154.754
176.68
154.754
262.11
MILD STEEL(WITHOUT
MAGNETIC FIELD)
WITH MAGNETIC
FIELD. (HORIZONTAL)
Fig.11-Image for UTM Used for tensile test
WITH MAGNETIC
FIELD. (VERTICAL)
3.7
Impact Test:
The two kinds of specimens used for impact testing are known
as Charpy and Izod. Both test pieces are broken in an impact
testing machine. The only difference is in the manner that they
are anchored. The Charpy piece is supported horizontally
between two anvils and the pendulum strikes opposite the
notch. The Izod piece is supported as a vertical cantilever
beam and is struck on the free end projecting over the holding
vise A Charpy test measures the welds ability to withstand an
Impact force
4.2 Effect of external magnetic field on tensile strength
In the presence of external magnetic field welding is
performed. After that tensile test is carried out by UTM. Three
specimens M1, M2&M3 are taken for tensile test. It was
observed that tensile strength of weld joints is much more
improved. Detail observation datas are shown in the test
report-1, 2&3.
Fig12-Image for Weld specimen for Charpy test
4. Results and discussion
4.1 Effect of external magnetic field on Hardness
The determination of the Rockwell hardness of a material
involves the application of a minor load followed by a major
load, and then noting the depth of penetration from a dial, on
which a harder material gives a higher number. The test result
of the hardness test was conducted on both type of weldpieces (with magnetic field and without magnetic field) are
shown in the table-5 below. From experimental data the
hardness increases within the magnetic field. When magnetic
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 6 - Apr 2014
4.3 Effect of external magnetic field on impact test
The toughness values of the weld-pieces are tabulated below.
Weld-pieces are placed at the impact testing machine as
simply supported
Table-6 Shows Experimental values for Toughness (J) carried
out at various conditions
WORK-PIECE NO.
TOUGHNESS (J)
WITHOUT
MAGNETIC FIELD
20.5
WITH MAGNETIC
FIELD (VERTICAL)
36.0
WITH MAGNETIC
FIELD
(HORIZONTAL)
12.5
4.4 Comparison of all the mechanical properties with
and without application of external magnetic field
The effect of magnetic field on the tensile strength is
increased. The change in the properties is calculated in terms
of percentage and there is an increase of 6.6% on an average.
This shows that a magnetic field applied longitudinal to weld
bead, deflected the arc such that the tensile properties of the
weld-pieces increases
Table-7 Shows Percentage change in value for without
magnetic field and Magnetic field vertical for various
mechanical properties
PROPERTIES
TENSILE
STRENGTH
HARDNESS
TOUGHNESS
WITHOUT
MAGNETIC
FIELD
399
MAGNETIC
FIELD
(VERTICAL)
442
CHANGE
194.012
262.11
20.5
36.0
25.98%
INCREASE
43.05%
INCREASE
9.72% INCREASE
Table-8 Shows Percentage change in value for without
magnetic field and Magnetic field Horizontal for various
mechanical properties
PROPERTI
ES
WITHOUT
MAGNETI
C FIELD
MAGNET
IC FIELD
(HORIZO
CHANGE
NTAL)
TENSILE
STRENGTH
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399
357
10.52% DECRESES
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 6 - Apr 2014
HARDNESS
194.012
176.68
8.93% DECRESES
[8] M. S. U. R. Mahadi, N. A. and M. S. I. Rasel (ICME2011) 18-20
TOUGHNESS
20.5
12.5
39.02% DECRESES
December 2011, Dhaka, Bangladesh.
[9]Yunia Ahmad dar,charanjeet singh,Younish Farooq,Indian journal of
applied ,research,vol;4,issue vol-4 April 2014,ISSN-2249-555X
5. CONCLUSIONS
[10]R.P singh et al. RESEARCH INVENTY: International Journal of
On the basis of different experiments welding process
and effect of magnetic field in the longitudinal direction
the following conclusions are derived:









Effect of magnetic field applied longitudinal to
welding direction affects the bead
width of joint and decreases it.
Undercuts, spatter etc. welding defects are reduced.
The tensile strength of the weld joint is on
improvement side due the refinement of grains.
Hardness of the weld Increases as compared with the
weld-pieces which are welded without magnetic
field.
Reinforcement height of weld reduces as the weld
bead width is increasing.
Toughness of the weld metal increases.
When solenoid is introduce in the transverse
direction then the mechanical properties such as
Hardness, Toughness and Tensile strength are
decreases.
If travel speed is increased, tensile strength of weld
generally increases.
If magnetic field is increased, tensile strength of
weld generally increases.
Engineering and Science ISBN: 2319 6483, ISSN: 2278 4721, Vol. 2, Issue
1(January2013), PP 53-57 Application of Artificial Neural Network to
Analyze and Predict the Tensile Strength of Shielded Metal Arc Welded
Joints under the Influence of External Magnetic Field
[11]Basic Manufacturing Process by P.N.Rao.
[12] A Course In Workshop Technology by B.S.Raghuwanshi.
[13] Engineering Principles of Welding- processes, physics, chemistry and
metallurgy by Robert, Wissler 2004, and welding journal.
[14] Manufacturing Technology by P.C.Sharma.
[15]Principles of Magnetism and Stray Currents in Rotating Machinery
By Paul I. Nippes, P.E., President of Magnetic Products
and Services,
Inc.
Hence, we can say that the use of external magnetic
field longitudinal to the welding direction is helping in
improvement of weld quality and weld geometry. It can
also affect the weld quality.
6. REFERENCES
[1] Rossi, BE, 1954, “Welding Engineering”, McGraw-Hill Book Co. Inc.,
New York, USA.
[2] Hughes, R. V., and Walduck, R. P. 1987. “Electromagnetic arc path
control in robot plasma welding.” Robotic Welding. IFS Publication and
Springer-Verlag, pp. 243–263.
[3] Deminskii, Y. A., and Dyatlov, V. I. 1963. “Magnetic control during gas
shielded arc welding with a consumable
electrode.” Automatic
Welding (4): 67–68.
[4] Hicken, G. K., and Jackson, C. E. 1966. “The effect of applied magnetic
fields on welding arcs.” Welding Journal 45(11): 515-s to 524-s.
[5] Jayarajan, T. N., and Jackson, C. E. 1972. “Magnetic control of gas
tungsten arc welding process.” Welding Journal
51(8): 377-s to 385-s.
[6] 8. Ecer, G. M. 1980. “Magnetic deflection of the pulsed current welding
arc.” Welding Journal 59(6): 183-s to 191-s.
[7] 9. Lancaster, J. F. 1986. “The Physics of Welding”. Oxford, Pergamon.
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