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Development Of Basic Agglomerated Flux For Submerged arc welding
#1

Development Of Basic Agglomerated Flux For Submerged Arc Welding
Deviprakash K J & Anand Krishnan O K
Department of Mechanical Engineering
Mohandas College of Engineering and Technology

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Abstract
A significant percentage of the flux used in submerged are welding gets converted into very fine particles particles
termed as flux dust due to transportation and handling. If these very fine particles are not removed fromt he flux before
welding, it may results into defect like surface pitting and porosity. At the same time dumping of this flux dust will
create pollution. Therefore to reduce the cost of welding and pollution, in the present study, attempts have been made
to investigate the feasibility of using developed basic agglomerated flux by urilizing wasted flux dust in place of parent
commercial basic flux. The chemical composition, tensile strength, toughness and radiographic examination of the all
weld metal prepared by using the developed basic flux as well as same parent commercially available basic flux were
compared. These properties for the all weld metal prepared by using the developed basic flux were found to be in the
same range as that being prepared from the parent basic flux.
Keywords : Submerged arc welding. Tensile properties, Toughness

Introduction
Submerged arc welding (SAW) produces
coalescence of the metals by heating them with an arc
between a basic metal electrode and the work. The arc
and molten metal are submerged in blanket of granular
fusible flux on the work. Submerged arc welding
contributes to approximately 10% of the total welding. It
is one of the most widely used processes for fabrication of
thick plates, pipes, pressure vessels, rail tanks, ships, heat
exchangers etc. Submerged arc welding process is
characterized by higher metal deposition rate, deep weld
penetration, high speed welding of plates at over 2.5
m/min and minimum emission of welding fume or arc
light [I). Deposition rates approaching 45kglh have been
reported[2]. This process is commercially suitable for
welding of low carbon steel, high strength low alloy steel,
nickel base alloys and stainless steel [3]. Shielding is
obtained from a blanket of granular flux, which is laid
directly over the weld area.
Flux plays an important role in deciding the weld
metal quality [4]. It may cost 50% of the total welding
cost in submerged arc welding. It influences the weld
metal physically, chemically and metallurgically.
Physically, it influences the bead geometry and shape
relationships, which in turn affects the load carrying
capacity of the weld metal [5]. Chemically it affects the
chemistry of weld metal, which in turn influences the
mechanical properties of the weld metal [6].
Metallurgically, it influences the microstructure and
hence again affects the mechanical properties of the weld
metal [7]. It has been reported that agglomerated fluxes
produce weld deposits of better ductility and impact
strength as compared with fused fluxes [8]. Alloy
transfer efficiency is also better in case of agglomerated
fluxes. These f1uxes are hygroscopic in nature, therefore
baking is essential for good weld metal integrity [9].
Prashad and Dwivedi [10] investigated the
influence of submerged arc welding process parameters
on microstructure, hardness and toughness of HSLA steel
weld joints. Datta and Band)'opadhyay [11] has recycled
slag generated during conventional submerged arc:
welding (SAW) by mixing varying percentages of
crushed slag with fresh flux to use in subsequent runs. In
the work of Datta [12] application of the Taguchi method
in combination with grey relational analysis has been
applied for solving multiple criteria (objective)
optimization problem in submerged arc welding (SA W).
No work so far has been performed to develop
the flux by using waste flux dust. Approximately i 015%
of the flux used in submerged arc welding gets converted
into very fine particles termed as flux dust due to
transportation and handling. At the same time dumping of
this flux dust will create pollution.
In the present study an attempt has been made to
investigate the influence of the developed basic flux
prepared by utilizing wasted flux dust on the tensile
properties and toughness of the welded joints. The
chemical composition and properties viz. tensile strength
and toughness of the all weld metal using basic developed
flux as well as commercially available flux of the same type were
compared. The radiographic examinations of all the welded joints
were conducted to check weld metal integrity. Therefore the
developed flux prepared from the waste flux dust can be used
without any compromise in mechanical properties and quality of
the welded joint. It will reduce the cost of welding and pollution.

Experimental Work
In the present study one agglomerated cost effective basic flux
was developed by using the flux dust of parent flux with addition
of potassium silicate as binder and aluminum powder as
deoxidizer. The solution of potassium silicate binder (90 ml in
550 grams of flux dust) was added to the dry mixed powder of
he flux dust and aluminum powder (4%of the weight of the flux
dust) and it was wet mixed for 10 minutes and then passed
through a 10 mesh screen to form small pellets. Potassium
silicate was added as binder because of better are stability . The
pallets of the flux were dried in air for 24 hours and then baked in
the muffle furnace between 650-750 C for nearly 3 hours. After
cooling these pallets were crushed and subsequently sieved. After
sieving, fluxes were kept in air tight bags and baked again at
300 C before welding.
A constant voltage D.C submerged arc 'welding power source
was used for preparing the joints of mild steel plates of the
dimensions 300 x 125 x 25 nm using 4 mm diameter wire
electrode of grade C (AWS-5.17-S0 EH-14). DCEP polarity was
used throughout the experimentation. The plates were cleaned
mechanically and chemically to remove the rust, oil and grease
from the fusion faces before welding. The surfaces bf the backing
plates were also made free from rust and scale. The backing
plates of 12 mm thick were tack welded to the base plates.The
plates were preset so that they remain approximately flat after
the welding operation has been complete, The inter-pass
temperature was maintained in the range 200-225 C.
Four layer high weld pads were made for the basic developed
agglomerated flux and parent flux as per AWS AS.23 90
standard with the same welding conditions. The chemical
compositions of all weld metal were evaluated by using
spectrometer. The. two. butt weld joints were made with mild
steel as base. plate and backing strip. The welded assembly was,
subjected to radiographic examination to ascertain weld integrity
prior to mechanical testing. The backing' plate was removed by
machining before conducting radiographic examination. Three all
weld metal tensile test pieces were cut from each welded plate
and machined. The tensile tests were carried out on a universal
testing machine (Make FIE-India). Scanning electron microscopy
of the fractured surfaces of tensile test specimens were carried
out at 20kV and 1500 X on microscope (Make J0EL Japan, JSM-
6100).
Charpy V notch impact test was carried (lut to evaluate the
toughness 'of the welded joints at 0 C. Charpy impact tests were
performed on standard notched specimens obtained from the
welded joint. The notch was positioned in the centre of the weId
and was cut in the face of the test specimen perpendicular to the
surface of the plates. Five all weld metal impact test samples
were cut from welded joint of plates.
These samples were then fine polished by the surface
grinder . Among the five values
Of the impact strength the lowest and highest values were
discarded and average of the 3 values was taken for the
evaluation of impact strength of the groove welds.The
charpy impact tests results obtained from the weld metal
showed rather good repeatability.The same procedure was
applied to the developed flux and commercially available
parent flux to investigate the compatibility of the

Results and Discussions
The flux behavior of the basic developed fluxes was
found to be satisfactory. The bead service appearance was
observed to be excellent and free from any visual defects
and is comparable with the parent
As shown in Table 3. the compositions of all weld metal
of the developed and parent flux are found to be in the
same range. However manganese content of the weld
metal laid by using the developed flux is slightly lower
than the weld metal laid by using the parent flux. The
silicon content of the weld metal laid by using the

Reference
1. Kalpakjian, Serope, and Steven Schmid.
Manufacturing Engineering and Technology.
'5th ed'. Upper Saddle river, NJ: Pearson
Prentice Hall, 2006.
2. Jeffus, Larry. Welding: Principles and
Applications. Florence, KY: Thomson
Delmar Learning, 2002
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