INTRO to welding, for technical students
DELMAMILAGROSRODRIGU1
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May 13, 2024
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About This Presentation
excelente informacion para estudiante de soldadura
Slide Content
Intro to Welding 1 - Material Joining Processes
Material Joining
Processes
AS
Material Joining
Processes
AS
Material Joining
Processes
There are three main categories Operation
of material joining processes:
* Mechanical fastening
* Adhesive bonding
* Welding
Processes
There are three main categories Operation
of material joining processes:
* Mechanical fastening
* Adhesive bonding
* Welding
Mechanical Fastening
* Mechanical fastening joins two materials together by
using a clamping force.
* Screws, bolts, nails, and rivets are examples of different
types of mechanical fasteners.
* This method allows for the materials
to be disassembled if necessary.
«
\
* Mechanical fastening joins two materials together by
using a clamping force.
* Screws, bolts, nails, and rivets are examples of different
types of mechanical fasteners.
* This method allows for the materials
to be disassembled if necessary.
«
\
Adhesive Bonding
* Adhesive bonding joins materials together using a
nonmetallic material.
* Adhesives are available in several different forms:
— Gels
— Liquids
— Pastes
— Drops
* This process is especially useful when
joining dissimilar materials.
* Adhesive bonding joins materials together using a
nonmetallic material.
* Adhesives are available in several different forms:
— Gels
— Liquids
— Pastes
— Drops
* This process is especially useful when
joining dissimilar materials.
Welding: a joining process that produces coalescence :
of materials by heating them to the welding temperature, 2
with or without the application of pressure or by the
application of pressure alone, and with or without the use of
filler metal.
Coalescence - the melting together of
filler metal and base metal (substrate),
or of base metal only.
of materials by heating them to the welding temperature, 2
with or without the application of pressure or by the
application of pressure alone, and with or without the use of
filler metal.
Coalescence - the melting together of
filler metal and base metal (substrate),
or of base metal only.
wa J > u ne nt À
* There are as many as 94 different types of welding
processes
* The processes covered in Introduction to Welding
include:
— Shielded Metal Arc Welding (SMAW)
— Gas Tungsten Arc Welding (GTAW)
— Gas Metal Arc Welding (GMAW)
— Flux-Cored Arc Welding (FCAW)
— Submerged Arc Welding (SAW)
~
* There are as many as 94 different types of welding
processes
* The processes covered in Introduction to Welding
include:
— Shielded Metal Arc Welding (SMAW)
— Gas Tungsten Arc Welding (GTAW)
— Gas Metal Arc Welding (GMAW)
— Flux-Cored Arc Welding (FCAW)
— Submerged Arc Welding (SAW)
~
* The puddle of liquid metal created while welding must
be protected from air to keep it from oxidizing
(becoming brittle).
* This can be accomplished through
the use of a flux contained on or
inside the electrode, or by the use
of an external shielding gas.
Non-lonized
Sa Shielding Gas
lonized Gas
— = (4
be protected from air to keep it from oxidizing
(becoming brittle).
* This can be accomplished through
the use of a flux contained on or
inside the electrode, or by the use
of an external shielding gas.
Non-lonized
Sa Shielding Gas
lonized Gas
— = (4
Filler Metals
Melting the pieces of metal together will not create a strong
enough weld. For this reason, filler metal is typically added
to increase the overall strength of the weld.
Melting the pieces of metal together will not create a strong
enough weld. For this reason, filler metal is typically added
to increase the overall strength of the weld.
Success in welding is achieved by:
— The skill of the person performing the welding process
— Careful matching the filler metal
chemistry to the base metal
this insures that the resulting
weld will have the required:
* Physical properties
* Chemical properties
— To meet the service requirements of the part being
welded.
— The skill of the person performing the welding process
— Careful matching the filler metal
chemistry to the base metal
this insures that the resulting
weld will have the required:
* Physical properties
* Chemical properties
— To meet the service requirements of the part being
welded.
Introduction To
Welding
sl
>
>
—
Welding
sl
>
>
—
| Manual Welding a us
Welding with a torch, gun, or electrode holder held N
manipulated by hand," the welder performs the welding
function and maintains continuous control of the welding
operations by hand.
—o
Welding with a torch, gun, or electrode holder held N
manipulated by hand," the welder performs the welding
function and maintains continuous control of the welding
operations by hand.
—o
Semiautomatic Welding water
* Manual welding with equipment that automatically
controls one or more of the welding conditions.
* The wire feeder controls the filler metal
addition and the arc voltage controls the
arc length, hence two parts are being
controlled automatically,
* The operator physically manipulates
the gun or torch angles and travel
speeds while welding.
* Manual welding with equipment that automatically
controls one or more of the welding conditions.
* The wire feeder controls the filler metal
addition and the arc voltage controls the
arc length, hence two parts are being
controlled automatically,
* The operator physically manipulates
the gun or torch angles and travel
speeds while welding.
Automatic Welding
* Welding with equipment that requires only occasional o!
no observation of welding, and no manual adjustment of
the equipment controls. À
— Fixed Automation utilizes a dedicated
machine specifically designed for arc
welding the same specific parts.
— Flexible Automation a variation of
Fixed Automation that allows for some
part variation such as a diameter change
on a circumferential weld or a length
adaptation on a longitudinal weld.
Flexible Automation
* Welding with equipment that requires only occasional o!
no observation of welding, and no manual adjustment of
the equipment controls. À
— Fixed Automation utilizes a dedicated
machine specifically designed for arc
welding the same specific parts.
— Flexible Automation a variation of
Fixed Automation that allows for some
part variation such as a diameter change
on a circumferential weld or a length
adaptation on a longitudinal weld.
Flexible Automation
‘obotic | Velding = ¢//4 Miller
rar
+ Welding that is performed and controlled by robotic equipment,
+ Robotic Welding offers the following advantages:
— Minimizes hazards to the operator.
- Minimizes labor and material waste, through greater
accuracy and consistency.
— Faster part cycle times.
~ Capable of welding in all positions.
- Capable of quickly adapting to
welding a variety of production
parts as needed and/or parts
changes.
N
rar
+ Welding that is performed and controlled by robotic equipment,
+ Robotic Welding offers the following advantages:
— Minimizes hazards to the operator.
- Minimizes labor and material waste, through greater
accuracy and consistency.
— Faster part cycle times.
~ Capable of welding in all positions.
- Capable of quickly adapting to
welding a variety of production
parts as needed and/or parts
changes.
N
lectrical Terms
for Welding
for Welding
Primary Voltage
Primary voltage is the voltage input to the machine that is supplied
by the power company, or by an auxiliary electrical power generator
unit.
This voltage has a constant voltage or potential at every receptacle.
Typical voltages found in North America include:
— 120 VAC, commonly referred to as (110/115)
208 VAC, sometimes referred to as (200)
230 VAC, (220/240)
460 VAC, (440/480)
575 VAC, (600)
VAC (volts of alternating current)
Frequency of 60 Hz - North America.
(50 Hz in some international countries)
Primary voltage is the voltage input to the machine that is supplied
by the power company, or by an auxiliary electrical power generator
unit.
This voltage has a constant voltage or potential at every receptacle.
Typical voltages found in North America include:
— 120 VAC, commonly referred to as (110/115)
208 VAC, sometimes referred to as (200)
230 VAC, (220/240)
460 VAC, (440/480)
575 VAC, (600)
VAC (volts of alternating current)
Frequency of 60 Hz - North America.
(50 Hz in some international countries)
Primary Voltage
+ Primary voltage may be single or three-phase
* Three-phase is simply three sources of AC power as
identical voltages brought in by three wires.
Single Phase Primary Power (19) Three Phase Primary Power (30)
+ Primary voltage may be single or three-phase
* Three-phase is simply three sources of AC power as
identical voltages brought in by three wires.
Single Phase Primary Power (19) Three Phase Primary Power (30)
Welding Current Types
* Direct current (DC)
* Alternating current (AC)
. AUS
L L
Mn 1 Prune DC Found 3 Prune DC
- Singe Phase er
AP RR
There are two types of Electrical Current:
Direct current is an electrical
current that flows in one
direction and has either a
negative or positive polarity.
Alternating current (AC) is an
electrical current that has both a
positive and a negative half cycle
value (polarities) that alternate.
* Direct current (DC)
* Alternating current (AC)
. AUS
L L
Mn 1 Prune DC Found 3 Prune DC
- Singe Phase er
AP RR
There are two types of Electrical Current:
Direct current is an electrical
current that flows in one
direction and has either a
negative or positive polarity.
Alternating current (AC) is an
electrical current that has both a
positive and a negative half cycle
value (polarities) that alternate.
Direct Current
Welding Power Source
die
* Direct current is an electrical current that flows in one
direction and has either a negative or positive polarity.
+ DC has a positive and a negative terminal (pole).
* Current flows from the negative (-) terminal to the
positive (+) terminal in a single direction.
Welding Power Source
die
* Direct current is an electrical current that flows in one
direction and has either a negative or positive polarity.
+ DC has a positive and a negative terminal (pole).
* Current flows from the negative (-) terminal to the
positive (+) terminal in a single direction.
Polarity of the electrical current (or the direction of
current flow) is selected by connecting the electrode
cable, holder, and electrode to either the positive or
negative terminal.
‘Welding Power Source
ing So
GG
A
Electrode Negative Electrode Positive
or “Straight Polarity!” or “Reverse Polarity?”
* Nonstandard Term for Electrode Negative
2 Nonstandard term for Electrode Positive
current flow) is selected by connecting the electrode
cable, holder, and electrode to either the positive or
negative terminal.
‘Welding Power Source
ing So
GG
A
Electrode Negative Electrode Positive
or “Straight Polarity!” or “Reverse Polarity?”
* Nonstandard Term for Electrode Negative
2 Nonstandard term for Electrode Positive
Electrode Positive is the typical polarity used
when welding with a process that uses a
consumable electrode like GMAW or SMAW.
when welding with a process that uses a
consumable electrode like GMAW or SMAW.
Electrode Negative produces deeper penetration into the
base metal with a non consumable electrode such as the
tungsten used in the GTAW process.
30% Heat
70% Heat
base metal with a non consumable electrode such as the
tungsten used in the GTAW process.
30% Heat
70% Heat
Alternating Current
Alternating current (AC) is an electrical current that has
both a positive and a negative half cycle value (polarities)
that alternate.
+
=
BR re
or
One Hertz N
Alternating current (AC) is an electrical current that has
both a positive and a negative half cycle value (polarities)
that alternate.
+
=
BR re
or
One Hertz N
The number of cycles of
alternating current completed in
one second of time is called the
B Cycle
or
One Hertz
frequency.
The phrase “60 cycles
per second” or “hertz” >.
means that the particular A A
alternating current y : V
completes 60 cycles in 60 Hz 120 Hz 2 kHz
one second.
alternating current completed in
one second of time is called the
B Cycle
or
One Hertz
frequency.
The phrase “60 cycles
per second” or “hertz” >.
means that the particular A A
alternating current y : V
completes 60 cycles in 60 Hz 120 Hz 2 kHz
one second.
Constant Current Powe
Sources
Welding amperage or load current is
adjusted or set on Constant Current
(CC) type welding machines.
GTAW Constant Current
Output Curve
These machines are normally used for
manual Shielded Metal Arc Welding
(SMAW or Stick), Gas Tungsten Arc
Welding (GTAW, TIG or Heliarc), or Air
Carbon Arc Cutting & Gouging.
35 VOLTAGE > $
2
SA AMPERAGE =>
1874
Sources
Welding amperage or load current is
adjusted or set on Constant Current
(CC) type welding machines.
GTAW Constant Current
Output Curve
These machines are normally used for
manual Shielded Metal Arc Welding
(SMAW or Stick), Gas Tungsten Arc
Welding (GTAW, TIG or Heliarc), or Air
Carbon Arc Cutting & Gouging.
35 VOLTAGE > $
2
SA AMPERAGE =>
1874
mo>ro<
Load Voltage is set on Constant
Voltage (CV) welding machines.
Maximum
Minimum
AMPERAGE
Load Voltage is set on Constant
Voltage (CV) welding machines.
Maximum
Minimum
AMPERAGE
Constant Voltage Powe
Sources
Constant Voltage (CV) welding power sources are used
for the continuous electrode wire processes such as
— Gas Metal Arc Welding (GMAW)
— Flux Cored Arc Welding (FCAW)
— Submerged Arc Welding (SAW)
Sources
Constant Voltage (CV) welding power sources are used
for the continuous electrode wire processes such as
— Gas Metal Arc Welding (GMAW)
— Flux Cored Arc Welding (FCAW)
— Submerged Arc Welding (SAW)
Electrical Arc
Welding Processes
ey I
Welding Processes
ey I
Shielded Metal Arc Welding
(SMAW) an arc welding
process with an arc
between a covered
electrode and the weld pool.
Penetration Depth
M
La
Electrode Covering
Core Wire
Shielding Ancap. ™
+ Metal and Slag Droplets
Soliditied Sia & Weld Pool
a e nee 3
7/4 Miller
(SMAW) an arc welding
process with an arc
between a covered
electrode and the weld pool.
Penetration Depth
M
La
Electrode Covering
Core Wire
Shielding Ancap. ™
+ Metal and Slag Droplets
Soliditied Sia & Weld Pool
a e nee 3
7/4 Miller
Miller.
Shielded metal arc welding is a
manually operated process. The
electrode is clamped in an electrode
| holder and the welder manipulates the
tip of the electrode in relation to the
metal being welded.
| ,
Wa’
Shielded metal arc welding is a
manually operated process. The
electrode is clamped in an electrode
| holder and the welder manipulates the
tip of the electrode in relation to the
metal being welded.
| ,
Wa’
SMAW Equipment
Welding Power Source
Work Cable
Work Clamp >
SS
Electrode Cable
A
Electrode
Electrode Holder
Welding Power Source
Work Cable
Work Clamp >
SS
Electrode Cable
A
Electrode
Electrode Holder
Welding Power Source (Z iter
The power source for SMAW must be
Constant Current (CC).
Shielded Metal Arc Welding can be
accomplished by using:
— Alternating Current (AC).
— Direct Current (DC)
— When using direct current (DC) the electrode is either
Negative (DCEN) or Positive (DCEP).
The power source for SMAW must be
Constant Current (CC).
Shielded Metal Arc Welding can be
accomplished by using:
— Alternating Current (AC).
— Direct Current (DC)
— When using direct current (DC) the electrode is either
Negative (DCEN) or Positive (DCEP).
Advantages of DC
Advantages of direct current over alternating current
* Direct current is better at low current levels and with
small diameter electrodes.
* Arc starting is generally easier with direct current.
* Maintaining a short arc is easier with direct current.
* Direct current generally produces less weld spatter than
alternating current.
Advantages of direct current over alternating current
* Direct current is better at low current levels and with
small diameter electrodes.
* Arc starting is generally easier with direct current.
* Maintaining a short arc is easier with direct current.
* Direct current generally produces less weld spatter than
alternating current.
Polarity or direction of current flow is
important when direct current is used.
+ Electrode Positive DCEP (aka reverse Polarity)
— Used where deep *
penetration is needed. | 1
A
LI
important when direct current is used.
+ Electrode Positive DCEP (aka reverse Polarity)
— Used where deep *
penetration is needed. | 1
A
LI
Alternating Current
Alternating current is a combination of both
polarities that alternates in regular cycles.
Sinewave AC
Alternating current is a combination of both
polarities that alternates in regular cycles.
Sinewave AC
armatTi To rra mi TP B V//
2 Mal Le | e 4 #4
In each cycle, the current starts at zero, builds toa '
maximum value in one direction, decays back to zero,
then repeats itself in the other direction.
SKIP \
2 Mal Le | e 4 #4
In each cycle, the current starts at zero, builds toa '
maximum value in one direction, decays back to zero,
then repeats itself in the other direction.
SKIP \
Alternating Current
Depths of penetration and deposition rates for
alternating current are generally somewhere between
those for DC electrode positive and DC electrode
negative.
Welding Power Source
Depths of penetration and deposition rates for
alternating current are generally somewhere between
those for DC electrode positive and DC electrode
negative.
Welding Power Source
SMAW Filler Metal
The electrodes for shielded metal arc
welding consist of
+ A core wire (filler metal)
* A flux coating.
Y
LESS EAS
pre)
a
The electrodes for shielded metal arc
welding consist of
+ A core wire (filler metal)
* A flux coating.
Y
LESS EAS
pre)
a
SMAW Filler Metal
The covering on the electrode dictates the
usability of the electrode.
An AWS classification number is printed on each electrode for identification purposes
The covering on the electrode dictates the
usability of the electrode.
An AWS classification number is printed on each electrode for identification purposes
SMAW Filler Metal
Depending on the electrode type, the covering also
provides many or all of the following benefits:
Shielding gas from the decomposition of certain ingredients of the
coating to shield the arc from the atmosphere.
Deoxidizers for scavenging and purifying the deposited weld metal.
Slag formers to protect the deposited weld metal from oxidation.
lonizing elements to make the arc more stable and the electrode
operate more smoothly.
Alloying elements to provide special characteristics to the deposited
weld metal.
Iron powder to improve the productivity of the electrode.
Depending on the electrode type, the covering also
provides many or all of the following benefits:
Shielding gas from the decomposition of certain ingredients of the
coating to shield the arc from the atmosphere.
Deoxidizers for scavenging and purifying the deposited weld metal.
Slag formers to protect the deposited weld metal from oxidation.
lonizing elements to make the arc more stable and the electrode
operate more smoothly.
Alloying elements to provide special characteristics to the deposited
weld metal.
Iron powder to improve the productivity of the electrode.
Gas Tungsten Arc
Welding (GTAW)
R er
Pe
am =
Welding (GTAW)
R er
Pe
am =
Gas Tungsten Arc Welding
(GTAW) is defined by the
American Welding Society
(AWS) as:
An arc welding process that
uses an arc between a tungsten
electrode (nonconsumable) and
the weld pool.
(GTAW) is defined by the
American Welding Society
(AWS) as:
An arc welding process that
uses an arc between a tungsten
electrode (nonconsumable) and
the weld pool.
Used on a wide range of metal thicknesses and in all
welding positions.
Can be used to weld any weldable metal
It is also popular for depositing the root and hot passes
on pipe and tubing.
Since a shielding gas is used, the weld is clearly visible
to the welder
No spatter is produced, post weld cleaning is reduced,
and slag is not present.
welding positions.
Can be used to weld any weldable metal
It is also popular for depositing the root and hot passes
on pipe and tubing.
Since a shielding gas is used, the weld is clearly visible
to the welder
No spatter is produced, post weld cleaning is reduced,
and slag is not present.
Methods of Application
* The Gas Tungsten Arc Welding
process is normally applied manually. , tae
* Arelatively high degree of welding "IT pea
skill is required. eS ETA
— The welder controls the torch with
one hand and feeds filler metal
with the other.
— The operator may also be using a
hand or foot remote control device
to control the amperage and the
initiation and termination of the
arc.
* The Gas Tungsten Arc Welding
process is normally applied manually. , tae
* Arelatively high degree of welding "IT pea
skill is required. eS ETA
— The welder controls the torch with
one hand and feeds filler metal
with the other.
— The operator may also be using a
hand or foot remote control device
to control the amperage and the
initiation and termination of the
arc.
Methods of Application
* The semiautomatic method is
used with limited applications.
* The automatic methods are great
for productivity. However, they
require precise part location and
fit-up.
— The filler metal is fed into the
weld puddle by a wire feeder
similar to that used in Gas A Seam Welding System
Metal Arc Welding.
* The semiautomatic method is
used with limited applications.
* The automatic methods are great
for productivity. However, they
require precise part location and
fit-up.
— The filler metal is fed into the
weld puddle by a wire feeder
similar to that used in Gas A Seam Welding System
Metal Arc Welding.
Major components for Gas Tungsten Arc Welding
4 Miller
Gas Tungsten Arc Welding uses a
Constant Current power source.
Depending on the material being
welded, GTAW can be performed
with either:
* Alternating Current (AC)
* Direct Current (DC)
Gas Tungsten Arc Welding uses a
Constant Current power source.
Depending on the material being
welded, GTAW can be performed
with either:
* Alternating Current (AC)
* Direct Current (DC)
The power source usually incorporates a high
frequency generator in its design.
— High frequency is used to aid arc starting
and to stabilize the welding arc.
— It does not clean the metal as believed by
many welders over the years.
Miller
frequency generator in its design.
— High frequency is used to aid arc starting
and to stabilize the welding arc.
— It does not clean the metal as believed by
many welders over the years.
Miller
Tungsten Electrodes
+ The electrodes used with the Gas
Tungsten Arc Welding process are
made of tungsten or tungsten
alloys.
Tungsten has the highest melting
point of any usable metal at about
6170°F (3410°C).
+ When properly used, the electrode
does not touch the molten weld
puddle, and is considered to be
nonconsumable.
+ The electrodes used with the Gas
Tungsten Arc Welding process are
made of tungsten or tungsten
alloys.
Tungsten has the highest melting
point of any usable metal at about
6170°F (3410°C).
+ When properly used, the electrode
does not touch the molten weld
puddle, and is considered to be
nonconsumable.
Tungsten Electrodes
* Tungsten electrodes are color coded for ease of
recognition.
* The classifications and color codes are listed
HEE EID
* Tungsten electrodes generally come in diameters ranging
from .020 in. (0.5 mm) up through 1/4 in. (6.4 mm).
* Tungsten electrodes are color coded for ease of
recognition.
* The classifications and color codes are listed
HEE EID
* Tungsten electrodes generally come in diameters ranging
from .020 in. (0.5 mm) up through 1/4 in. (6.4 mm).
Shielding Gas
Shielding gas protects the weld puddle and
tungsten electrode from oxidation during welding.
Tungsten Gas Nozzle
Electrode
Filler
S Shielding Gas
I Molten Puddie
OT vu eut
Etched Oxides (AC)
Shielding gas protects the weld puddle and
tungsten electrode from oxidation during welding.
Tungsten Gas Nozzle
Electrode
Filler
S Shielding Gas
I Molten Puddie
OT vu eut
Etched Oxides (AC)
Qniitier
Shielding Gas
Most commonly used shielding gases:
— Argon used more than helium since
it is less expensive.
* Better for arc starting
* Lower arc voltage than helium
(lower heat input)
— Helium is normally used on heavy
weldments where high heat input is
required to produce deeper
penetration.
Shielding Gas
Most commonly used shielding gases:
— Argon used more than helium since
it is less expensive.
* Better for arc starting
* Lower arc voltage than helium
(lower heat input)
— Helium is normally used on heavy
weldments where high heat input is
required to produce deeper
penetration.
GTAW Filler Metal
The filler metal for Gas Tungsten
Arc Welding is solid and bare.
* Filler metals are available in a
wide range of sizes in an
approximate range from .020 in.
(0.5 mm) to 1/4 in. (6.4 mm).
* Filler metals for Gas Tungsten
Arc Welding are classified using
the same system as GMAW
electrodes.
The filler metal for Gas Tungsten
Arc Welding is solid and bare.
* Filler metals are available in a
wide range of sizes in an
approximate range from .020 in.
(0.5 mm) to 1/4 in. (6.4 mm).
* Filler metals for Gas Tungsten
Arc Welding are classified using
the same system as GMAW
electrodes.
Intro to Welding 5 - Electrical Arc Welding Processes GTAW
Peak
Amperage
Background
Amperage
(% of Peak Amps)
+ Pulsed Gas Tungsten Arc Welding (GTAW-P) is a gas tungsten arc welding
| process variation in which the current is pulsed.
| + Pulsed gas tungsten arc welding provides a system in which the welding
current continuously changes between two levels.
+ During the periods of high pulsed current, heating and fusion takes place.
+ During low pulsed current periods, cooling and solidification take place.
- SKIP VID Se
Peak
Amperage
Background
Amperage
(% of Peak Amps)
+ Pulsed Gas Tungsten Arc Welding (GTAW-P) is a gas tungsten arc welding
| process variation in which the current is pulsed.
| + Pulsed gas tungsten arc welding provides a system in which the welding
current continuously changes between two levels.
+ During the periods of high pulsed current, heating and fusion takes place.
+ During low pulsed current periods, cooling and solidification take place.
- SKIP VID Se
+ The pulsed current process controls the heat input and
the molten pool, increases penetration, controls the
travel speed, and gives a more consistent quality.
+ It also controls distortion on thinner materials.
+ Power sources designed for pulsed current welding are
equipped with controls to adjust the high and low pulse
current and time.
the molten pool, increases penetration, controls the
travel speed, and gives a more consistent quality.
+ It also controls distortion on thinner materials.
+ Power sources designed for pulsed current welding are
equipped with controls to adjust the high and low pulse
current and time.
Gas Metal Arc
Welding (GMAW)
ete Zi: <=
Welding (GMAW)
ete Zi: <=
Gas Metal Arc
Welding (GMAW)
Gas Metal Arc Welding (GMAW) is an arc welding process
that uses an arc between a continuous filler metal electrode
and the weld pool. The process is used with shielding from
an externally supplied gas and without the application of
pressure.
Welding (GMAW)
Gas Metal Arc Welding (GMAW) is an arc welding process
that uses an arc between a continuous filler metal electrode
and the weld pool. The process is used with shielding from
an externally supplied gas and without the application of
pressure.
Regulator/
Flowmet
Welding Power Source
Cooling System
Power tard
Cooling
System
Pranarnd by the Miller Flactrie Mía Co Trainina Nenartmant & 2016 Miller Finctrie Mía Co
Flowmet
Welding Power Source
Cooling System
Power tard
Cooling
System
Pranarnd by the Miller Flactrie Mía Co Trainina Nenartmant & 2016 Miller Finctrie Mía Co
Power Source
AMPERAGE
* The power source for Gas Metal Arc Welding is normally
a constant voltage (CV) power source.
* The output voltage is adjusted at the power source.
* Its output volt-amp curve characteristic is essentially flat
with a small droop. Thus the output voltage is
approximately the same even though the welding current
changes.
AMPERAGE
* The power source for Gas Metal Arc Welding is normally
a constant voltage (CV) power source.
* The output voltage is adjusted at the power source.
* Its output volt-amp curve characteristic is essentially flat
with a small droop. Thus the output voltage is
approximately the same even though the welding current
changes.
Miller.
* The welding current output is
determined by the electrical load
on the machine which depends
on the electrode wire feed speed.
* Direct current electrode positive
polarity is normally used.
* The welding current output is
determined by the electrical load
on the machine which depends
on the electrode wire feed speed.
* Direct current electrode positive
polarity is normally used.
The wire feeder drives the electrode
wire from the wire spool through the
cable and gun to the welding arc.
A constant speed wire feeder is used
with the constant voltage welding
power source.
Since the arc voltage is set by the
welding power source and is
constant, the arc length is
maintained.
Adjusting the wire feed speed affects
the current.
4 Miller.
wire from the wire spool through the
cable and gun to the welding arc.
A constant speed wire feeder is used
with the constant voltage welding
power source.
Since the arc voltage is set by the
welding power source and is
constant, the arc length is
maintained.
Adjusting the wire feed speed affects
the current.
4 Miller.
Power Rotatable
Connection Neck Juno
Liner
Handle
Trigger
8 Spare
Wires
The welding torch or gun and cable rg | are used to
carry the electrode wire, welding current, and shielding gas
to the welding arc.
A contact tube centered in the nozzle of the gun guides the
wire and transfers the welding current to the electrode wire.
The nozzle directs the flow of shielding gas.
Welding guns can be either air or water cooled.
Strain
Relief
Connection Neck Juno
Liner
Handle
Trigger
8 Spare
Wires
The welding torch or gun and cable rg | are used to
carry the electrode wire, welding current, and shielding gas
to the welding arc.
A contact tube centered in the nozzle of the gun guides the
wire and transfers the welding current to the electrode wire.
The nozzle directs the flow of shielding gas.
Welding guns can be either air or water cooled.
Strain
Relief
Shielding Gas
Nozzle
Non-onizee
2, Shelông Gas
\ Ac Column
Joni Gas
The shielding gas system
displaces the air around the arc to
prevent contamination of the
molten pool by oxygen and
nitrogen in the atmosphere.
The shielding gas system
consists of a gas supply, a
regulator, a flow meter and
connecting hoses.
Nozzle
Non-onizee
2, Shelông Gas
\ Ac Column
Joni Gas
The shielding gas system
displaces the air around the arc to
prevent contamination of the
molten pool by oxygen and
nitrogen in the atmosphere.
The shielding gas system
consists of a gas supply, a
regulator, a flow meter and
connecting hoses.
Miller.
Wages
Short Circuit Gas Metal Arc Welding (GMAW-S) is a
process variation in which the consumable electrode is
deposited during repeated short circuits.
|
Short Circuit Transfer
Wages
Short Circuit Gas Metal Arc Welding (GMAW-S) is a
process variation in which the consumable electrode is
deposited during repeated short circuits.
|
Short Circuit Transfer
) Miller.
L =
03 e
LU
|
Globular Transfer
In Globular Transfer, the molten droplet at the end of the electrode
grows until the force of gravity causes it to detach and transfer across
the arc to the weld puddle.
The arc is less stable and produces more spatter than short circuit
transfer.
Globular transfer is generally considered to be undesirable due to its
erratic arc and higher spatter levels.
Prepsred by the Miller Electric Mía. Co. Trainina Department © 2016 Miller Electric Mia. Co
L =
03 e
LU
|
Globular Transfer
In Globular Transfer, the molten droplet at the end of the electrode
grows until the force of gravity causes it to detach and transfer across
the arc to the weld puddle.
The arc is less stable and produces more spatter than short circuit
transfer.
Globular transfer is generally considered to be undesirable due to its
erratic arc and higher spatter levels.
Prepsred by the Miller Electric Mía. Co. Trainina Department © 2016 Miller Electric Mia. Co
Spray Transfer
+ Spray Transfer is used to weld ferrous and nonferrous metals.
+ There are two types of Spray Transfer
— Conventional spray transfer
— Pulsed spray transfer
+ In spray transfer, fine molten droplets are electromagnetically pinched
from the end of the electrode wire.
+ Spray Transfer is used to weld ferrous and nonferrous metals.
+ There are two types of Spray Transfer
— Conventional spray transfer
— Pulsed spray transfer
+ In spray transfer, fine molten droplets are electromagnetically pinched
from the end of the electrode wire.
Spray Transfer
* Commonly used on materials in the
flat and horizontal fillet positions;
— spray transfer mode cause the
puddle to remain molten for longer
periods making vertical and
overhead positions difficult to
control.
Spray Transfer
* Spray transfer produces little if any
spatter
* Commonly used on materials in the
flat and horizontal fillet positions;
— spray transfer mode cause the
puddle to remain molten for longer
periods making vertical and
overhead positions difficult to
control.
Spray Transfer
* Spray transfer produces little if any
spatter
Miller.
Poise Spray Tranater
Das
f
Pulse Spray Transfer
AT
+ Pulsed Gas Metal Arc Welding (GMAW-P) is a Gas Metal Arc Welding
variation in which the current is pulsed.
+ Pulsed Spray Transfer is a modification of conventional spray transfer.
+ The average power level is below the power level of conventional Spray
Transfer.
+ This allows the welder to weld with less heat input, weld out of position,
and weld with little or no spatter.
Prepared by the Miller Electric Mfg. Co. Training Department © 2016 Miller Electric Mig. Co
Poise Spray Tranater
Das
f
Pulse Spray Transfer
AT
+ Pulsed Gas Metal Arc Welding (GMAW-P) is a Gas Metal Arc Welding
variation in which the current is pulsed.
+ Pulsed Spray Transfer is a modification of conventional spray transfer.
+ The average power level is below the power level of conventional Spray
Transfer.
+ This allows the welder to weld with less heat input, weld out of position,
and weld with little or no spatter.
Prepared by the Miller Electric Mfg. Co. Training Department © 2016 Miller Electric Mig. Co
* The electrode wire for Gas Metal Arc Welding is typically
solid.
* The wire is contained on spools, coils and reels and packed
in special containers for protection against moisture and
contamination.
Preosred by the Miller Electric Mía. Co. Trainina Department © 2016 Miller Electric Mía. Co.
solid.
* The wire is contained on spools, coils and reels and packed
in special containers for protection against moisture and
contamination.
Preosred by the Miller Electric Mía. Co. Trainina Department © 2016 Miller Electric Mía. Co.
Flux Cored Arc
Welding (FCAW)
Flux Cored Arc Welding (FCAW) is an arc welding
process that uses an arc between a continuous filler metal
electrode and the weld pool. The process is used with
shielding gas from a flux contained within the tubular
electrode, with (FCAW-G) or without (FCAW-S) additional
shielding from an externally supplied gas, and without the
application of pressure.
Welding (FCAW)
Flux Cored Arc Welding (FCAW) is an arc welding
process that uses an arc between a continuous filler metal
electrode and the weld pool. The process is used with
shielding gas from a flux contained within the tubular
electrode, with (FCAW-G) or without (FCAW-S) additional
shielding from an externally supplied gas, and without the
application of pressure.
Equipment for Flux Cored Arc-Gas Equipment for the Flux Cored Arc
Shielded variation (FCAW-G): Welding process (FCAW-S):
» Constant Voltage power source + Constant Voltage power source
» Shielding gas, regulator and hoses + Wire Feeder
+ Wire Feeder + Welding gun and welding cables
+ Welding gun and welding cables
Shielded variation (FCAW-G): Welding process (FCAW-S):
» Constant Voltage power source + Constant Voltage power source
» Shielding gas, regulator and hoses + Wire Feeder
+ Wire Feeder + Welding gun and welding cables
+ Welding gun and welding cables
* The power source for Flux Cored Arc
Welding is normally a constant
voltage machine
The voltage is adjusted by a control
on the welding power source.
Direct current electrode positive
polarity (DCEP) is used with most
gas shielded flux cored electrode
wires (FCAW-G).
Direct current electrode negative
(DCEN) is used for most self-shielded
flux cored wires (FCAW-S).
Miller.
Welding is normally a constant
voltage machine
The voltage is adjusted by a control
on the welding power source.
Direct current electrode positive
polarity (DCEP) is used with most
gas shielded flux cored electrode
wires (FCAW-G).
Direct current electrode negative
(DCEN) is used for most self-shielded
flux cored wires (FCAW-S).
Miller.
Wire Feeder (7) Miter
The wire feeding mechanism
feeds the flux cored electrode
wire automatically from a spool
or coil through the cable
assembly and welding gun to
the arc.
Tension
Adjustment
Knob
The wire feed control sets the
speed at which the wire is fed
on to the arc and controls the
|» Connection amperage.
| Wireiniet
1 Guide
Drive Roll
Weld Power Connection
Dranarad hu tha Millar Flartrio Min Ca Traininn Nanartmant @ 9048 Millar Elantrin hin Co
The wire feeding mechanism
feeds the flux cored electrode
wire automatically from a spool
or coil through the cable
assembly and welding gun to
the arc.
Tension
Adjustment
Knob
The wire feed control sets the
speed at which the wire is fed
on to the arc and controls the
|» Connection amperage.
| Wireiniet
1 Guide
Drive Roll
Weld Power Connection
Dranarad hu tha Millar Flartrio Min Ca Traininn Nanartmant @ 9048 Millar Elantrin hin Co
FCAW Electrode Wire
The electrode wire for Flux Cored Arc Welding is tubular and filled with
various chemicals and powders.
+ The flux provides shielding, deoxidation, arc stabilization and slag
formation.
Sometimes alloying elements can be added to the ingredients within the
core.
+ Flux cored arc welding electrodes are available in a variety of sizes from
.035 in. (1.1 mm) to 5/32 in. (4.0 mm).
The wire is contained on spools, coils or in drums.
.
Pranarad by the Miller Flectrie Mía Co Trainina Denartmant O 2016 Miller Flectrie Mía Co
The electrode wire for Flux Cored Arc Welding is tubular and filled with
various chemicals and powders.
+ The flux provides shielding, deoxidation, arc stabilization and slag
formation.
Sometimes alloying elements can be added to the ingredients within the
core.
+ Flux cored arc welding electrodes are available in a variety of sizes from
.035 in. (1.1 mm) to 5/32 in. (4.0 mm).
The wire is contained on spools, coils or in drums.
.
Pranarad by the Miller Flectrie Mía Co Trainina Denartmant O 2016 Miller Flectrie Mía Co
Weld Types and
Positions and Symbols
Prepared by ho Electric'Mfg. Co. Training Department
2016 Miller Electric Mfg. Co.
Positions and Symbols
Prepared by ho Electric'Mfg. Co. Training Department
2016 Miller Electric Mfg. Co.
Welding Joint Types
Edge Joints - Members to be welded will not be subjected to any
great stresses. Not recommended where impact or other great
stresses may occur
0. #
FA A
“Hôrooe
Figare 99 - Various Edge Joints
Edge Joints - Members to be welded will not be subjected to any
great stresses. Not recommended where impact or other great
stresses may occur
0. #
FA A
“Hôrooe
Figare 99 - Various Edge Joints
Butt Joints -surfaces of members to be welded are in same
plane with their edges meeting.
plane with their edges meeting.
Welding Joint Types
Lap Joints -surfaces of joined members overlap one another; generally a
fillet weld
Lap
Lap Joints -surfaces of joined members overlap one another; generally a
fillet weld
Lap
Corner Joints — pieces to be welded come together at about 90
degrees; two types: open and closed
V-Groove Comer
3
Pranared fw the Miller Flertrie Mía Co Trainin Nenartment @ MR Millar Electric Mín Ca
degrees; two types: open and closed
V-Groove Comer
3
Pranared fw the Miller Flertrie Mía Co Trainin Nenartment @ MR Millar Electric Mín Ca
Welding Joint Types
T-Joints -surfaces of two members come together at approximately
right angles, or 90 degrees; fillet weld is usually made
Fillet T-Joint J-Groove
T-Joints -surfaces of two members come together at approximately
right angles, or 90 degrees; fillet weld is usually made
Fillet T-Joint J-Groove
Fillet Weld ID
Fillet welds are approximately triangular in cross sectional shape and
are made on members whose surfaces or edges are approximately 90
degrees to each other.
Be en
me ee
Prepared by the Miller Electric Mfg. Co. Training Department © 2016 Miller Electric Mfg. Co.
Fillet welds are approximately triangular in cross sectional shape and
are made on members whose surfaces or edges are approximately 90
degrees to each other.
Be en
me ee
Prepared by the Miller Electric Mfg. Co. Training Department © 2016 Miller Electric Mfg. Co.
Weld Positions (7) Miter.
In order to help the welder understand the location of the weld to be made,
number and letter system is used to indicate the type and position of the weld.
Flat Position Horizontal Position Vertical Position Overhead Position
1F 2 3 4F
Flat Position Horizontal Position
16 26
In order to help the welder understand the location of the weld to be made,
number and letter system is used to indicate the type and position of the weld.
Flat Position Horizontal Position Vertical Position Overhead Position
1F 2 3 4F
Flat Position Horizontal Position
16 26
Welding Symbol
Brazing, and Nondestructive Examination.
Location of Elements of a Welding Symbol
FINISH SYMBOL— — GROOVE ANGLE: INCLUDED ANGLE
CONT MBOL— OF COUNTERSINK FOR PLUG WELDS
Leg F — ROOT OPENING: DEPTH OF FILLING
GROOVE WELD SIZE — 3 / 7 FORPLUG AND SLOT WELDS
DEPTH OF BEVEL: SIZE OR K — LENGTH OF WEI
STRENGTH FOR CERTAIN WELDS +) / PITCH (CENTER-TO-CENTER
R SPACING) OF WELDS
een g — anne
OTHER REFERENCE AE YMBOL
— WELD-ALL.
AROUND
SYMBOL
TAIL (OMITTED
WHEN REFERENCE —
IS NOT USED) N) £ REFERENCE
UNE ARROW CONNECTING
ne L NUMBER OF SPOT, SEAM REFERENCE LINE
‘STUD, PLUG, SLOT, TO ARROW SIDE
OR PROJECTION WELOS MEMBER OF JOINT
OR ARROW SIDE OF
ELEMENTS IN THIS AREA SORT
REMAIN AS SHOWN WHEN TAIL +
AND ARROW ARE REVERSED
Welding symbols are defined by the American Welding
Society in ANSI/AWS A2.4 Standard Symbols for Welding,
Brazing, and Nondestructive Examination.
Location of Elements of a Welding Symbol
FINISH SYMBOL— — GROOVE ANGLE: INCLUDED ANGLE
CONT MBOL— OF COUNTERSINK FOR PLUG WELDS
Leg F — ROOT OPENING: DEPTH OF FILLING
GROOVE WELD SIZE — 3 / 7 FORPLUG AND SLOT WELDS
DEPTH OF BEVEL: SIZE OR K — LENGTH OF WEI
STRENGTH FOR CERTAIN WELDS +) / PITCH (CENTER-TO-CENTER
R SPACING) OF WELDS
een g — anne
OTHER REFERENCE AE YMBOL
— WELD-ALL.
AROUND
SYMBOL
TAIL (OMITTED
WHEN REFERENCE —
IS NOT USED) N) £ REFERENCE
UNE ARROW CONNECTING
ne L NUMBER OF SPOT, SEAM REFERENCE LINE
‘STUD, PLUG, SLOT, TO ARROW SIDE
OR PROJECTION WELOS MEMBER OF JOINT
OR ARROW SIDE OF
ELEMENTS IN THIS AREA SORT
REMAIN AS SHOWN WHEN TAIL +
AND ARROW ARE REVERSED
Welding symbols are defined by the American Welding
Society in ANSI/AWS A2.4 Standard Symbols for Welding,
Selecting Filler
ae or Electrodes
AA
ae or Electrodes
AA
Selecting Filler Metal
or Electrodes
To ensure that you deposit the best weld possible for strength, integrity,
and to be sure that the weld will meet the requirements of the part,
material, and code when applicable.
or Electrodes
To ensure that you deposit the best weld possible for strength, integrity,
and to be sure that the weld will meet the requirements of the part,
material, and code when applicable.
Selecting Filler Metal
or Electrodes
+ The following are some of the considerations to ensure that you
select the correct electrode.
— Base Metal Strength Properties
— Base Metal Composition
— Welding Position
— Welding Current
— Joint Design and Fit-up
— Thickness and Shape of Base Metal
— Service Condition And/or Specifications
— Production Efficiency and Job Conditions
or Electrodes
+ The following are some of the considerations to ensure that you
select the correct electrode.
— Base Metal Strength Properties
— Base Metal Composition
— Welding Position
— Welding Current
— Joint Design and Fit-up
— Thickness and Shape of Base Metal
— Service Condition And/or Specifications
— Production Efficiency and Job Conditions
Base Metal Strength
Properties
+ Match the filler metal mechanical properties with those of
the base metal.
— These properties include the following:
+ Tensile Strength
+ Elongation
« Yield Strength
+ Charpy V-notch (CVN)
Properties
+ Match the filler metal mechanical properties with those of
the base metal.
— These properties include the following:
+ Tensile Strength
+ Elongation
« Yield Strength
+ Charpy V-notch (CVN)
Tensile Strength
Tensile Strength
* The tensile strength of a material is the ability of the
material to withstand the forces to pull it apart.
* When a material hits its tensile strength it breaks apart.
Tensile Strength
* The tensile strength of a material is the ability of the
material to withstand the forces to pull it apart.
* When a material hits its tensile strength it breaks apart.
Elongation
Elongation
+ A mechanical property of metal that is the degree to
which a material may be bent, stretched, or compressed
before it ruptures.
Elongation
+ A mechanical property of metal that is the degree to
which a material may be bent, stretched, or compressed
before it ruptures.
Yield Strength
Yield Strength
* The yield strength is the
point where the material is
permanently deformed.
Yield Strength
* The yield strength is the
point where the material is
permanently deformed.
Charpy V-notch (CVN) Qniiter
Charpy V-notch (CVN)
This indicates the toughness or resistance to an impact at
determined temperatures.
m
ical Impact Value
Avg. at -20°F (29°C) 20 ftibs (min)
Charpy V-notch (CVN)
This indicates the toughness or resistance to an impact at
determined temperatures.
m
ical Impact Value
Avg. at -20°F (29°C) 20 ftibs (min)
Base Metal Compositio
* Match the weld metal chemistry with the base metal.
* Just as base metal chemistry is analyzed, weld metal
chemistry also looks at the percentages of the deposited
and undiluted weld metal elements that make up the
weld.
* Match the weld metal chemistry with the base metal.
* Just as base metal chemistry is analyzed, weld metal
chemistry also looks at the percentages of the deposited
and undiluted weld metal elements that make up the
weld.
Welding Position
+ Match the electrode to the welding position encountered.
+ Filler metals are manufactured to weld with certain
characteristics.
* Some are more fluid and allow high deposition rates but
a more fluid puddle can deform when welded out of
position.
+ Match the electrode to the welding position encountered.
+ Filler metals are manufactured to weld with certain
characteristics.
* Some are more fluid and allow high deposition rates but
a more fluid puddle can deform when welded out of
position.
Welding Current
Some electrodes are designed for direct current (DC) and others
are designed for use with alternating current (AC).
Some electrodes allow either AC or DC to be used.
You need to ensure that you know on what polarity the electrode
is designed to operate.
It is also important to use the electrode within the designed
operating range that the manufacturer has designed and tested
the filler metal to operate.
14
Some electrodes are designed for direct current (DC) and others
are designed for use with alternating current (AC).
Some electrodes allow either AC or DC to be used.
You need to ensure that you know on what polarity the electrode
is designed to operate.
It is also important to use the electrode within the designed
operating range that the manufacturer has designed and tested
the filler metal to operate.
14
Production Efficiency
And Job Conditions
* The job condition will have influence on what filler metal
to select as well.
+ Filler metals with the highest deposition rates are
preferred to ensure we make a sound weld in the least
amount of time.
* Generally, the most productive filler metals and welding
processes will occur “in position (flat and horizontal fillet
welds or flat groove welds).
And Job Conditions
* The job condition will have influence on what filler metal
to select as well.
+ Filler metals with the highest deposition rates are
preferred to ensure we make a sound weld in the least
amount of time.
* Generally, the most productive filler metals and welding
processes will occur “in position (flat and horizontal fillet
welds or flat groove welds).
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