ARC WELDING ELECTRODE

03/12/14
03/12/14
ARC WELDING ELECTRODES
ARC WELDING ELECTRODES
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1
ARC WELDING
ARC WELDING
ELECTRODE
ELECTRODE
NAFFAA. AL-ANEZI
NAFFAA. AL-ANEZI


MECHANICAL INSPECTOR
MECHANICAL INSPECTOR
OCTOBER 30,2005
OCTOBER 30,2005
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CONTENTS OF PRESENTATION
CONTENTS OF PRESENTATION

HISTORY OF ARC WELDING COATED
HISTORY OF ARC WELDING COATED
ELECTRODE
ELECTRODE

WHAT IS AN ELECTRODE ?

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

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

The electrode may be defined as “it is
The electrode may be defined as “it is
metal of which the sole purpose to carry the
metal of which the sole purpose to carry the
current and sustain the electric arc between
current and sustain the electric arc between
its tip and base metal as well as in some
its tip and base metal as well as in some
cases it melts and supplies filler metal
cases it melts and supplies filler metal
addition in the proposed joint.”
addition in the proposed joint.”


Electrode can be divided into two groups
Electrode can be divided into two groups
depending upon their functions which are
depending upon their functions which are
given below.
given below.


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

THE SIZE OF ELECTRODE REFERS TO THE DIAMETER OF ITS
THE SIZE OF ELECTRODE REFERS TO THE DIAMETER OF ITS
CORE WIRE. THE SIZE IS AVAILABLE IN METRIC AS WELL
CORE WIRE. THE SIZE IS AVAILABLE IN METRIC AS WELL
AS IN ENGLISH SYSTEM. LIKE 1/8”, 3/32” AND 2 MM , 4
AS IN ENGLISH SYSTEM. LIKE 1/8”, 3/32” AND 2 MM , 4
MM ETC.
MM ETC.
STRIKING
END
CORE
BARE END FOR GRIPPING
FLUX OR COVERING
Dd
D = COVERING DIA , d= CORE DIA
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Arc welding electrodes are classified in
Arc welding electrodes are classified in
groups by American Welding Society (AWS
groups by American Welding Society (AWS
a5.1-91) based upon their type of coating,
a5.1-91) based upon their type of coating,
mechanical properties and performance

mechanical properties and performance
characteristics
characteristics


as well as weld metal
as well as weld metal
chemistry. for our discussion we can
chemistry. for our discussion we can
categorize the electrode as under .
categorize the electrode as under .
TYPES OF ELECTRODE
TYPES OF ELECTRODE
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ELECTRODES TYPES
ELECTRODES TYPES


ELECTRODE
ELECTRODE
BASED UPON MATERIALS
BASED UPON COATING
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BASED UPON MATERIALS

BASED UPON MATERIALS

MILD STEEL ELECTRODES (AWS A5.1)
MILD STEEL ELECTRODES (AWS A5.1)

LOW ALLOY STEEL ELECTRODES (AWS A5.5)
LOW ALLOY STEEL ELECTRODES (AWS A5.5)

STAINLESS STEEL ELECTRODES (AWS A5.4)
STAINLESS STEEL ELECTRODES (AWS A5.4)

ELECTRODES FOR CAST IRON (AWS A5.15)
ELECTRODES FOR CAST IRON (AWS A5.15)

COPPER AND COPPER ALLOY ELECTRODE
COPPER AND COPPER ALLOY ELECTRODE


(AWSA5.6
(AWSA5.6
)
)

NICKEL AND NICKEL ALLOY ELECTRODE
NICKEL AND NICKEL ALLOY ELECTRODE




(

(
AWS A5.11)
AWS A5.11)

ALUMINIUM AND ALUMINIUM ALLOY
ALUMINIUM AND ALUMINIUM ALLOY
ELECTRODE
ELECTRODE


(
(
AWS A5.3)
AWS A5.3)


ONLY FIRST THREE OF THE ABOVE WILL BE
ONLY FIRST THREE OF THE ABOVE WILL BE
DISCUSSED.
DISCUSSED.
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MILD STEEL ELECTRODES
MILD STEEL ELECTRODES


AMERICAN WELDING SOCIETY SPECIFICATION
AMERICAN WELDING SOCIETY SPECIFICATION

AWS 5.1 DESCRIBES THE REQUIREMENTS FOR
AWS 5.1 DESCRIBES THE REQUIREMENTS FOR


MILD STEEL ELECTRODES. AN IDENTIFICATION
MILD STEEL ELECTRODES. AN IDENTIFICATION
SYSTEM HAS ADOPTED IN ORDER TO KNOW THE
SYSTEM HAS ADOPTED IN ORDER TO KNOW THE
PROPERTIES AND CHEMISTRY OF THE ELECTRODE.
PROPERTIES AND CHEMISTRY OF THE ELECTRODE.
THE IDENTIFICATION HAS EXPLAINED AS UNDER.
THE IDENTIFICATION HAS EXPLAINED AS UNDER.




EXXXX
EXXXX
“
“
E” DESIGNATES FOR ELECTRODE
E” DESIGNATES FOR ELECTRODE
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
E

E
XX
XX
XX
XX
FIRST TWO NUMBERS REFER TO
FIRST TWO NUMBERS REFER TO
TENSILE STRENGTH
TENSILE STRENGTH
OF THE DEPOSITED
OF THE DEPOSITED
WELD METAL.
WELD METAL.
FOR EXAMPLE : E
FOR EXAMPLE : E
60
60
10
10
“
“
60”
60”


MEANS 60, 000 PSI TENSILE
MEANS 60, 000 PSI TENSILE


STRENGTH OF THE

STRENGTH OF THE
DEPOSITED WELD
DEPOSITED WELD
METAL.
METAL.
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
EXX
EXX
X
X


X
X
THIRD NUMBER IS DENOTING
THIRD NUMBER IS DENOTING


THE
THE


POSITION
POSITION

IN WHICH THE
IN WHICH THE
ELECTRODE CAN BE USED
ELECTRODE CAN BE USED
.
.


EXAMPLE:
EXAMPLE:

“
“
1”
1”
FOR ALL POSTION (F, V,OH,H)
FOR ALL POSTION (F, V,OH,H)

“
“
2”
2”
FOR FLAT AND H-FILLET POSITION
FOR FLAT AND H-FILLET POSITION
.
.

“
“
3”

3”
HAS NO DESIGNATION
HAS NO DESIGNATION

“
“
4”
4”
FOR F, OH, H AND V-DOWN BUT
FOR F, OH, H AND V-DOWN BUT
MOSTLY SUITABLE FOR V-DOWN
MOSTLY SUITABLE FOR V-DOWN
ONLY.
ONLY.
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
EXX
EXX
X
X
X
X


LAST NUMBER REFERS TO
LAST NUMBER REFERS TO
CHEMICAL

CHEMICAL
COMPOSITION
COMPOSITION
PRESENT IN THE ELECTRODE
PRESENT IN THE ELECTRODE
COATING. FOR EXAMPLE :
COATING. FOR EXAMPLE :

“
“
0”
0”


CELLULOSE- SODIUM
CELLULOSE- SODIUM

“
“
1”
1”


CELLULOSE- POTASSIUM
CELLULOSE- POTASSIUM

“
“
2”
2”

RUTILE –SODIUM
RUTILE –SODIUM

“
“
3”
3”


RUTILE – POTASSIUM
RUTILE – POTASSIUM

“
“
4”
4”


RUTILE IRON POWDER
RUTILE IRON POWDER

“
“
5,6,8”
5,6,8”
LOW HYDROGEN
LOW HYDROGEN
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
EXX
EXX
XX
XX
The last two numbers together
The last two numbers together
indicate the type of welding current the
indicate the type of welding current the
electrode can be used with.
electrode can be used with.
For example
For example
EXX
EXX
10
10
DC+
DC+
EXX
EXX
11
11
AC OR DC+
AC OR DC+
EXX
EXX

20
20


AC , DC +,-
AC , DC +,-
EXX
EXX
12
12
AC OR DC-
AC OR DC-
EXX
EXX
24
24
AC , DC +,-
AC , DC +,-
EXX
EXX
13
13
AC , DC+,-
AC , DC+,-
EXX
EXX
27
27
AC, DC +,-
AC, DC +,-

EXX
EXX
14
14
AC , DC+,-
AC , DC+,-
EXX
EXX
28
28
AC, DC +
AC, DC +
EXX
EXX
15
15
DC+
DC+


EXX
EXX
16
16


AC , DC+
AC , DC+
EXX
EXX

18
18


AC , DC+
AC , DC+
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LOW ALLOY STEEL ELECTRODE
LOW ALLOY STEEL ELECTRODE




THESE ELECTRODES ARE DESIGNED FOR THE
THESE ELECTRODES ARE DESIGNED FOR THE
WELDING OF LOW-ALLOY STEELS COMMONLY USED
WELDING OF LOW-ALLOY STEELS COMMONLY USED
IN STRUCTURES, PIPING, PRESSURE VESSEL.
IN STRUCTURES, PIPING, PRESSURE VESSEL.


THEY GIVE WELD DEPOSITS OF STEEL
THEY GIVE WELD DEPOSITS OF STEEL
CONTAINING A SMALL AMOUNT OF ALLOYING
CONTAINING A SMALL AMOUNT OF ALLOYING
ELEMENTS SUCH AS Mo, Cr, Ni, AND V. THESE
ELEMENTS SUCH AS Mo, Cr, Ni, AND V. THESE

ELECTRODES ARE SPECIFIED IN AWS A5.5
ELECTRODES ARE SPECIFIED IN AWS A5.5
SPECIFICATION AND IDENTIFICATION IS SAME AS
SPECIFICATION AND IDENTIFICATION IS SAME AS
FOR MILD STEEL ELECTRODES.THE ELECTRODES
FOR MILD STEEL ELECTRODES.THE ELECTRODES
HAS A SUFFIX TO REFER AS LOW ALLOY STEEL
HAS A SUFFIX TO REFER AS LOW ALLOY STEEL
CONTENT. LIKE
CONTENT. LIKE
A1 0.5 Mo, B3 1.0% Mo,2.25%Mn , G 0.2% Mo,
A1 0.5 Mo, B3 1.0% Mo,2.25%Mn , G 0.2% Mo,
0.3%Mn, 0.1% V
0.3%Mn, 0.1% V
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STAINLESS STEEL ELECTRODES
STAINLESS STEEL ELECTRODES


STAINLESS STEEL ELECTRODES ARE USED
STAINLESS STEEL ELECTRODES ARE USED
FOR THE WELDING OF CORROSION –
FOR THE WELDING OF CORROSION –
RESISTING AND HEAT- RESISTING STEELS.
RESISTING AND HEAT- RESISTING STEELS.
THEY ARE EXPLIANED IN AWS A5.4
THEY ARE EXPLIANED IN AWS A5.4

“SPECIFICATION FOR CORROSION –
“SPECIFICATION FOR CORROSION –
RESISTING Cr AND Cr-Ni STEEL COVERED
RESISTING Cr AND Cr-Ni STEEL COVERED
ELECTRODES”.
ELECTRODES”.


SOME SS ELECTRODES HAVE GIVEN WITH
SOME SS ELECTRODES HAVE GIVEN WITH
THEIR MECHANICAL PROPERTIES IN THE
THEIR MECHANICAL PROPERTIES IN THE
FOLLOWING TABLE.
FOLLOWING TABLE.
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Mechanical Properties As Per AWS
Mechanical Properties As Per AWS


A5.4
A5.4
AWS
AWS
Classificatio
Classificatio
n
n

Tensile
Tensile
Strength
Strength
Ksi
Ksi
Elongation
Elongation
in 2” Min
in 2” Min
%
%
Heat Treatment
Heat Treatment
E209
E209
100
100
15
15
None
None
E308L
E308L
75
75
35
35
None
None

E309L
E309L
80
80
30
30
None
None
E316
E316
75
75
30
30
None
None
E316H
E316H
75
75
30
30
None
None
E316L
E316L
70
70
30
30

None
None
E317
E317
80
80
30
30
None
None
E318
E318
80
80
30
30
None
None
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BASED UPON COATING
BASED UPON COATING

CELLULOS TYPE
CELLULOS TYPE

RUTILE TYPE
RUTILE TYPE


ACID TYPE
ACID TYPE

OXIDIZING TYPE
OXIDIZING TYPE

BASIC TYPE
BASIC TYPE
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CELLULOS TYPE
CELLULOS TYPE


THE CELLULOSE IS A ORGANIC MATERIAL
THE CELLULOSE IS A ORGANIC MATERIAL
WHICH CONTAIN 30 % IN THE ELECTRODE
WHICH CONTAIN 30 % IN THE ELECTRODE
COATING BY WEIGHT. IT DECOMPOSES IN
COATING BY WEIGHT. IT DECOMPOSES IN
THE ARC AND PRODUCE A GAS SHIELD
THE ARC AND PRODUCE A GAS SHIELD
WHICH PROTECTS ARC FROM
WHICH PROTECTS ARC FROM
AUTMOSPHERIC OXYGEN AND NITROGEN.
AUTMOSPHERIC OXYGEN AND NITROGEN.
EXX10 IS THE EXAMPLE OF THIS TYPE

EXX10 IS THE EXAMPLE OF THIS TYPE
ELECTRODE COATING. GENERALLY THIS
ELECTRODE COATING. GENERALLY THIS
COATED ELECTRODE IS SUITABLE FOR ALL
COATED ELECTRODE IS SUITABLE FOR ALL
POSITION WITH DC +.
POSITION WITH DC +.
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RUTILE TYPE
RUTILE TYPE


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

FREEZED. EXX12 AND EXX13 ARE THE
EXAMPLES OF THIS TYPE OF COATING .
EXAMPLES OF THIS TYPE OF COATING .
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ACID TYPE
ACID TYPE


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

EXX22 IS THE EXAMPLE OF THIS TYPE OF
ELECTRODE.
ELECTRODE.
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OXIDIZING TYPE
OXIDIZING TYPE


IT CONTAIN MAINLY IRON-OXIDE AND
IT CONTAIN MAINLY IRON-OXIDE AND
SILICATES WITH OR WITH OUT
SILICATES WITH OR WITH OUT
MANGANESE OXIDES. IT PRODUCE A
MANGANESE OXIDES. IT PRODUCE A
HEAVY SLAG WHICH HAS OXIDISING
HEAVY SLAG WHICH HAS OXIDISING
PROPERTIES. THIS TYPE ELECTRODE IS
PROPERTIES. THIS TYPE ELECTRODE IS
LIMITED IN USE BECAUSE THE
LIMITED IN USE BECAUSE THE
RESULTANT WELD METAL IS SOFT AND
RESULTANT WELD METAL IS SOFT AND
LOW MECHANICAL PROPERTIES.
LOW MECHANICAL PROPERTIES.


EXX27 ELECTRODES ARE HAVING THIS

EXX27 ELECTRODES ARE HAVING THIS
TYPE OF COATING, GENERALLY USING
TYPE OF COATING, GENERALLY USING
FOR FLAT POSITION ONLY.
FOR FLAT POSITION ONLY.
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BASIC TYPE
BASIC TYPE


THIS TYPE OF COATING CONTAINS CALCIUM
THIS TYPE OF COATING CONTAINS CALCIUM
CARBONATES (CaCO3), CALCIUM FLOURIDE (CaF2) ,
CARBONATES (CaCO3), CALCIUM FLOURIDE (CaF2) ,
METAL POWDER AND COMPARATIVELY MORE
METAL POWDER AND COMPARATIVELY MORE
POWERFUL DEOXIDISERS.
POWERFUL DEOXIDISERS.
THIS RESULTS IN A CHEMICALLY BASIC SLAG, WHICH
THIS RESULTS IN A CHEMICALLY BASIC SLAG, WHICH
IS FAIRLY FLUID.THE SOLIDIFIED SLAG, WHICH IS
IS FAIRLY FLUID.THE SOLIDIFIED SLAG, WHICH IS
HEAVY AND FRIABLE HAS BROWN TO DARK- BROWN
HEAVY AND FRIABLE HAS BROWN TO DARK- BROWN
COLOR AND GLASSY APPEARANCE.
COLOR AND GLASSY APPEARANCE.
MOISTURES IS REMOVED FROM THE COATING TO

MOISTURES IS REMOVED FROM THE COATING TO
RENDER IT LOW HYDROGEN ELECTRODES. THE
RENDER IT LOW HYDROGEN ELECTRODES. THE
ELECTRODES HAVING THIS TYPE OF COATING IS
ELECTRODES HAVING THIS TYPE OF COATING IS
PREFERRED TO USE FOR MINIMISE THE RISK OF
PREFERRED TO USE FOR MINIMISE THE RISK OF
HYDROGEN-INDUCED CRACKING OR COLD CRACKING
HYDROGEN-INDUCED CRACKING OR COLD CRACKING
IN THE BASE METAL.
IN THE BASE METAL.


EXX15,16,18 OR THE EXAMPLES OF THIS TYPE OF
EXX15,16,18 OR THE EXAMPLES OF THIS TYPE OF
COATING.
COATING.
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STORAGE AND DRYING OF
STORAGE AND DRYING OF
ELECTRODE
ELECTRODE


Arc welding electrodes must be properly
Arc welding electrodes must be properly
stored in order to deposit quality welds. when

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

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