WELDING ELECTRODE

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Prepared By: Engr: Arfan Ali Dhamraho

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ARC WELDING ELECTRODE

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CONTENTS OF PRESENTATION
 HISTORY OF ARC WELDING COATED
ELECTRODE
 WHAT IS AN ELECTRODE ?
 SIZE OF ELECRODE
 TYPES OF ELECTRODES
 COATING OF ELECTRODES
 TYPES OF ELECTRODE COATING
 STORAGE AND DRYING OF
ELECTRODES
 TESTING OF ELECTRODES

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HISTORY OF ARC WELDING COATED
ELECTRODE
During first stage of work with metal arc
welding a bare electrode was in use which
was producing brittleness in the welded
area and the weld was considerably weak.
overheating effect on weld metal was
noticed as there was no arc stability.
To overcome these difficulties researchers
developed a number of electrodes in 1907
that were covered with organic or mineral
materials which is known as coating or
flux.

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WHAT IS AN ELECTRODE ?
The electrode may be defined as “it is metal of
which the sole purpose to carry the current and
sustain the electric arc between its tip and base
metal as well as in some cases it melts and
supplies filler metal addition in the proposed
joint.”
Electrode can be divided into two groups
depending upon their functions which are given
below. ELECTRODE
COSUMABLE NON CONSUMABLE

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CONSUMABLE AND NON-
CONSUMABLE
 The consumable electrodes refers to
conduct current from electrode
holder to metal and supply filler
metal to the joint, like in SMAW.
 non-consumable electrodes are only
used to work as conductor carrying
the current from electrode holder to
base metal, like in GMAW

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SIZE OF ELECTRODE
THE SIZE OF ELECTRODE REFERS TO THE DIAMETER OF ITS
CORE WIRE. THE SIZE IS AVAILABLE IN METRIC AS WELL AS IN
ENGLISH SYSTEM. LIKE 1/8”, 3/32” AND 2 MM , 4 MM ETC.
STRIKING
END CORE
BARE END FOR GRIPPING
FLUX OR COVERING
D
d
D = COVERING DIA , d= CORE DIA

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Arc welding electrodes are classified
in groups by American Welding
Society (AWS a5.1-91) based upon
their type of coating, mechanical
properties and performance
characteristics as well as weld
metal chemistry. for our discussion
we can categorize the electrode as
under .
TYPES OF ELECTRODE

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ELECTRODES TYPES
ELECTRODE
BASED UPON MATERIALS BASED UPON COATING

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BASED UPON MATERIALS
 MILD STEEL ELECTRODES (AWS A5.1)
 LOW ALLOY STEEL ELECTRODES (AWS A5.5)
 STAINLESS STEEL ELECTRODES (AWS A5.4)
 ELECTRODES FOR CAST IRON (AWS A5.15)
 COPPER AND COPPER ALLOY ELECTRODE
(AWSA5.6)
 NICKEL AND NICKEL ALLOY ELECTRODE
(AWS A5.11)
 ALUMINIUM AND ALUMINIUM ALLOY ELECTRODE
(AWS A5.3)
ONLY FIRST THREE OF THE ABOVE WILL BE
DISCUSSED.

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MILD STEEL ELECTRODES
AMERICAN WELDING SOCIETY SPECIFICATION
AWS 5.1 DESCRIBES THE REQUIREMENTS FOR
MILD STEEL ELECTRODES. AN IDENTIFICATION
SYSTEM HAS ADOPTED IN ORDER TO KNOW THE
PROPERTIES AND CHEMISTRY OF THE
ELECTRODE. THE IDENTIFICATION HAS
EXPLAINED AS UNDER.
EXXXX
“E” DESIGNATES FOR ELECTRODE

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 EXXXX FIRST TWO NUMBERS
REFER TO TENSILE STRENGTH OF
THE DEPOSITED WELD METAL.
FOR EXAMPLE : E6010
“60” MEANS 60, 000 PSI TENSILE
STRENGTH OF THE
DEPOSITED WELD METAL.

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 EXX X X THIRD NUMBER IS DENOTING
THE POSITION IN WHICH THE
ELECTRODE CAN BE USED.
EXAMPLE:
 “1” FOR ALL POSTION (F, V,OH,H)
 “2” FOR FLAT AND H-FILLET POSITION.
 “3” HAS NO DESIGNATION
 “4” FOR F, OH, H AND V-DOWN BUT
MOSTLY SUITABLE FOR V-DOWN
ONLY.

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 EXXXX LAST NUMBER REFERS TO
CHEMICAL COMPOSITION
PRESENT IN THE ELECTRODE
COATING. FOR EXAMPLE :
 “0” CELLULOSE- SODIUM
 “1” CELLULOSE- POTASSIUM
 “2” RUTILE –SODIUM
 “3” RUTILE – POTASSIUM
 “4” RUTILE IRON POWDER
 “5,6,8” LOW HYDROGEN

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 EXXXX The last two numbers together
indicate the type of welding current the
electrode can be used with.
For example
EXX10 DC+
EXX11 AC OR DC+ EXX20 AC , DC +,-
EXX12 AC OR DC- EXX24 AC , DC +,-
EXX13 AC , DC+,- EXX27 AC, DC +,-
EXX14 AC , DC+,- EXX28 AC, DC +
EXX15 DC+
EXX16 AC , DC+
EXX18 AC , DC+

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LOW ALLOY STEEL ELECTRODE
THESE ELECTRODES ARE DESIGNED FOR THE
WELDING OF LOW-ALLOY STEELS COMMONLY
USED IN STRUCTURES, PIPING, PRESSURE
VESSEL.
THEY GIVE WELD DEPOSITS OF STEEL
CONTAINING A SMALL AMOUNT OF ALLOYING
ELEMENTS SUCH AS Mo, Cr, Ni, AND V. THESE
ELECTRODES ARE SPECIFIED IN AWS A5.5
SPECIFICATION AND IDENTIFICATION IS SAME
AS FOR MILD STEEL ELECTRODES.THE
ELECTRODES HAS A SUFFIX TO REFER AS LOW
ALLOY STEEL CONTENT. LIKE
A1 0.5 Mo, B3 1.0% Mo,2.25%Mn , G 0.2%
Mo, 0.3%Mn, 0.1% V

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STAINLESS STEEL ELECTRODES
STAINLESS STEEL ELECTRODES ARE USED FOR
THE WELDING OF CORROSION –RESISTING AND
HEAT- RESISTING STEELS. THEY ARE
EXPLIANED IN AWS A5.4 “SPECIFICATION FOR
CORROSION –RESISTING Cr AND Cr-Ni STEEL
COVERED ELECTRODES”.
SOME SS ELECTRODES HAVE GIVEN WITH
THEIR MECHANICAL PROPERTIES IN THE
FOLLOWING TABLE.

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Mechanical Properties As Per AWS A5.4
AWS
Classificatio
n
Tensile
Strength
Ksi
Elongation
in 2” Min
%
Heat Treatment
E209 100 15 None
E308L 75 35 None
E309L 80 30 None
E316 75 30 None
E316H 75 30 None
E316L 70 30 None
E317 80 30 None
E318 80 30 None

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BASED UPON COATING
 CELLULOS TYPE
 RUTILE TYPE
 ACID TYPE
 OXIDIZING TYPE
 BASIC TYPE

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CELLULOS TYPE
THE CELLULOSE IS A ORGANIC MATERIAL
WHICH CONTAIN 30 % IN THE ELECTRODE
COATING BY WEIGHT. IT DECOMPOSES IN THE
ARC AND PRODUCE A GAS SHIELD WHICH
PROTECTS ARC FROM AUTMOSPHERIC OXYGEN
AND NITROGEN. EXX10 IS THE EXAMPLE OF
THIS TYPE ELECTRODE COATING. GENERALLY
THIS COATED ELECTRODE IS SUITABLE FOR ALL
POSITION WITH DC +.

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RUTILE TYPE
RUTILE IS NATURALLY- OCCURING SAND
USALLY CONTAIN AROUND 95% OF TITANIUM
DIOXIDE. THIS TYPE OF ELECTRODE IS GOOD
FOR USE WITH AC AND DC + OR DC - .
GENERALLY USE FOR VERTICAL AND OVERHEAD
POSITIONS AS THE SLAG IS VERY VISCOUS AND
QUICKLY FREEZED. EXX12 AND EXX13 ARE THE
EXAMPLES OF THIS TYPE OF COATING .

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ACID TYPE
THIS TYPE OF COATING CONTAIN IRON-OXIDE
AS A MAJOR CONSTITUENT. DURING WELDING
IT PRODUCE A IRON-MANGANESE OXIDE –
SELICA FLUID SLAG WHOSE METALLARGICAL
EFFECT IS ACIDIC. THIS SLAG SOLIDIFIES LIKE
HONEY- COMBSTRUCTURE AND EASLY
DETACHED. ELECTRODE HAVING THIS COATING
IS GOOD FOR FILLET WELD ONLY.
EXX22 IS THE EXAMPLE OF THIS TYPE OF
ELECTRODE.

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OXIDIZING TYPE
IT CONTAIN MAINLY IRON-OXIDE AND
SILICATES WITH OR WITH OUT
MANGANESE OXIDES. IT PRODUCE A
HEAVY SLAG WHICH HAS OXIDISING
PROPERTIES. THIS TYPE ELECTRODE IS
LIMITED IN USE BECAUSE THE
RESULTANT WELD METAL IS SOFT AND
LOW MECHANICAL PROPERTIES.
EXX27 ELECTRODES ARE HAVING THIS
TYPE OF COATING, GENERALLY USING
FOR FLAT POSITION ONLY.

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BASIC TYPE
THIS TYPE OF COATING CONTAINS CALCIUM
CARBONATES (CaCO3), CALCIUM FLOURIDE (CaF2) ,
METAL POWDER AND COMPARATIVELY MORE POWERFUL
DEOXIDISERS.
THIS RESULTS IN A CHEMICALLY BASIC SLAG, WHICH IS
FAIRLY FLUID.THE SOLIDIFIED SLAG, WHICH IS HEAVY
AND FRIABLE HAS BROWN TO DARK- BROWN COLOR AND
GLASSY APPEARANCE.
MOISTURES IS REMOVED FROM THE COATING TO RENDER
IT LOW HYDROGEN ELECTRODES. THE ELECTRODES
HAVING THIS TYPE OF COATING IS PREFERRED TO USE
FOR MINIMISE THE RISK OF HYDROGEN-INDUCED
CRACKING OR COLD CRACKING IN THE BASE METAL.
EXX15,16,18 OR THE EXAMPLES OF THIS TYPE OF
COATING.

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STORAGE AND DRYING OF
ELECTRODE
Arc welding electrodes must be properly stored
in order to deposit quality welds. when
electrodes absorb moistures from the
atmosphere, they must be dried in order to
restore the ability to deposit quality welds.
Electrode with too much moisture may lead to
Cracking and Porosity. Operational characteristics
may be affected as well. If it is experienced
unexplained weld cracking problems, or if the
electrode arc performance may have
deteriorated, it may be due to the storage
methods or re-drying procedures.

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 All electrodes must be
dried to the right level
to perform properly.
Even a small amount
of moisture in low
hydrogen electrodes
can lead to major
weld problems such as
internal porosity, weld
cracking or poor
operating
characteristics.

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 Low Hydrogen Electrodes
Storing and exposure limits
SMAW electrodes with low hydrogen
coatings, such as E7018 and E8018-
C3, must be kept very dry since
hydrogen induced cracking can easily
occur, especially in steels that are
80,000 psi and higher yield
strengths. To keep these electrodes
dry during storage, here are some
suggestions:

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 Purchase these electrodes in
hermetically sealed containers, which
provide excellent protection against
moisture pickup.
 Do not open the hermetically sealed
containers until the electrode is
needed for use.
 When the cans are opened,
electrodes that will not be
immediately used should be placed
in a OVEN at 250 degrees F to 300
degrees F
(120 – 150 degrees C).

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 Electrodes should be supplied to
welders in quantities that can be
consumed within time limits that are
dependent on the electrode type and
strength level. For example,
standard E7018 electrodes can be
safely be exposed to the atmosphere
for 4 hours whereas standard
E11018 electrodes are restricted to
only ½ hour.

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Re-drying Of Low Hydrogen Electrodes
When the electrodes have been exposed to the
atmosphere for period of a four hours , the
electrode can be re-dried. The following re-
drying procedure should be used:
 To re-dry, electrodes should be removed from the
can, and placed in suitable oven. The electrodes
should be spread out in the oven so that all
electrodes will reach the drying temperature. The
can of electrodes should not be put in the oven;
the cardboard liners can char, and the
temperature of the electrodes will not be uniform.

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BAKING OVEN
TEMPERATURE
REGULATOR

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POTABLE OVEN

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 When the electrodes are initially placed in the
oven, the temperature should not be greater than
half the re-drying temperature. The electrodes
should be held at that temperature for ½ hour
before heating the electrode to the final
temperature.
 For mild steel low hydrogen electrodes governed
by AWS A5.1 (such as E7018), the final re-
drying temperature is typically 500-800 degrees
F(260-430 degrees C). For low alloy electrodes
governed by AWS A5.5, the final re-drying
temperature should be 700-800 degrees F (700 –
430 degrees C). The manufacturer’s
recommendations should be followed.

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 One hour at the listed final
temperature is satisfactory if it is
supplied in the dried condition. Do
not dry electrodes at higher
temperatures. Also, several hours at
a lower temperature is not
equivalent to using the specified
requirements. Moisture becomes
chemically bonded (absorbed) to the
electrode coating and those chemical
bonds must be broken at the proper
temperature for the proper length of
time.

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How Many Times Low Hydrogen
Electrodes Can Be Re-dried?
 Electrodes may be re-dried only
once. Electrodes that have become
wet or moist shall not be used and
shall be discarded.

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Standard Tests For Electrodes
Type Of
Test
ISO
2560
BS639 DIN
1913
AWS
A5.1
TENSILE &
IMPACT
X X X X
TRANSVERSE
BEND
X X X
TRANSVERSE
TENSILE
X X X
DEPOSITION
EFFECIENCY
X
DIFFUSIBLE
HYDROGEN
X
CHEMICAL
COMPOSITIO
N
X

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2/6/2023 ARC WELDING ELECTRODES 39
Arc Stabilizers - Air is not sufficiently conductive to
maintain a stable arc, so it becomes necessary to
add coating ingredients that will provide a conductive
path for the flow of current. This is particularly true
when welding with alternating current. Stabilizing
materials are titanium compounds, potassium
compounds, and calcium compounds
‫سازگار‬ ‫تک‬ ‫حد‬ ‫کافی‬ ‫ہوا‬ ‫لئے‬ ‫کے‬ ‫رکھنے‬ ‫برقرار‬ ‫کو‬ ‫آرک‬ ‫مستحکم‬
‫کیا‬ ‫شامل‬ ‫کو‬ ‫اجزاء‬ ‫کوٹنگ‬ ‫کہ‬ ‫ہے‬ ‫ہوتا‬ ‫ضروری‬ ‫یہ‬ ‫لہذا‬ ، ‫ہے‬ ‫نہیں‬
‫کرے‬ ‫فراہم‬ ‫راستہ‬ ‫کا‬ ‫راہداری‬ ‫لئے‬ ‫کے‬ ‫بہاؤ‬ ‫کے‬ ‫موجودہ‬ ‫جو‬ ‫جائے‬
‫سچ‬ ‫پر‬ ‫طور‬ ‫خاص‬ ‫یہ‬ ‫وقت‬ ‫کرتے‬ ‫ویلڈنگ‬ ‫ساتھ‬ ‫کے‬ ‫باری‬ ‫باری‬ ‫گا۔‬
‫ا‬ ‫مرکبات‬ ‫پوٹاشیم‬ ، ‫مرکبات‬ ‫ٹائٹینیم‬ ‫مواد‬ ‫واال‬ ‫کرنے‬ ‫استحکام‬ ‫ہے۔‬
‫ور‬
‫ہیں‬ ‫مرکبات‬ ‫کیلشیم‬

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A stabilized arc is one that starts easily, burns
smoothly even at low amperages, and can be
maintained using either a long or a short arc length.
‫کم‬ ، ‫ہے‬ ‫ہوتا‬ ‫شروع‬ ‫سے‬ ‫آسانی‬ ‫جو‬ ‫ہے‬ ‫ہوتا‬ ‫وہ‬ ‫آرک‬ ‫مستحکم‬ ‫ایک‬
‫کی‬ ‫قوس‬ ‫مختصر‬ ‫یا‬ ‫لمبی‬ ‫اور‬ ، ‫ہے‬ ‫جلتا‬ ‫سے‬ ‫آسانی‬ ‫بھی‬ ‫پر‬ ‫امپیریج‬
‫ہے۔‬ ‫سکتا‬ ‫رہ‬ ‫برقرار‬ ‫ہوئے‬ ‫کرتے‬ ‫استعمال‬ ‫کا‬ ‫لمبائی‬

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THE END
THANKS