GMAW (MIG Welding) -...
Transcript of GMAW (MIG Welding) -...
GMAW
(MIG W
elding)
GMAW Unit Topics
GMAW Unit Topics
•D
uring t
his
overv
iew
, w
e
will
dis
cuss t
he f
ollo
win
g
topic
s:
•Safety
•GMAW Basics
•Equipment Set-Up
2
•Equipment Set-Up
•Welding Variables
•Process Advantages and
Lim
itations
•AWS Connection
•National Academic
Standards Connection
Unit Objectives
Unit Objectives
•U
pon s
uccessfu
l com
ple
tion o
f th
e G
MA
W
Unit o
f S
tudy, you w
ill
have learn
ed a
bout:
–
Properly protecting
yourself and others while
welding
–The AWS electrode
classification system
–Taking the next step to
becoming a certified
welder
3
welding
–Setting up and operating
GMAW equipment
–Striking and m
aintaining
an arc
–Welding in four positions
using various electrodes
–Weld Inspection
GMAW Safety
GMAW Safety
4
GMAW Safety
GMAW Safety
GMAW Safety
GMAW Safety
•‘G
MA
W S
afe
ty’ is
supple
menta
l
and d
oes n
ot
repla
ce t
he
info
rmation f
ound in ‘A
rc W
eld
ing
Basic
s’
•U
nders
tand a
nd f
ollo
w a
ll safe
ty
pre
cautions lis
ted in ‘S
afe
ty in
Weld
ing,
Cutt
ing a
nd A
llied
Pro
cesses’ (A
NS
I Z
49.1
), a
nd A
rc
5
Pro
cesses’ (A
NS
I Z
49.1
), a
nd A
rc
Weld
ing S
afe
ty (
E205)
•U
nders
tand a
nd f
ollo
w a
ll w
arn
ing
labels
found:
–On w
elding equipment
–With all consumable packaging
–Within instruction m
anuals
•R
ead M
ate
rial S
afe
ty D
ata
Sheets
(MS
DS
)
If y
ou e
ver
have a
question a
bout
your
safe
ty o
r th
ose a
round y
ou,
PLE
AS
E A
SK
YO
UR
IN
ST
RU
CT
OR
!
GMAW Safety
GMAW Safety
•Fumes and Gases c
an
be
da
ng
ero
us
–Keep your head out of the fumes
–Use enough ventilation, exhaust at the arc, or both, to keep fumes and gases
from your breathing zone and the general area
–Local exhaust and m
echanical ventilation can be used without reducing weld
quality
•Electric Shock c
an
kill
–to
re
ce
ive
a s
ho
ck y
ou
r b
od
y m
ust
tou
ch
th
e e
lectr
od
e
an
d w
ork
or
gro
un
d a
t th
e s
am
e t
ime
–Do not touch the electrode or metal parts of the electrode holder with skin or wet clothing
–Keep dry insulation between your body and the m
etal being welded or ground
6
–Keep dry insulation between your body and the m
etal being welded or ground
–The coil of wire is ‘electrically hot’ when the trigger is pulled
•Arc Rays c
an
inju
re e
ye
s a
nd
skin
-C
ho
ose
co
rre
ct
filte
r sh
ad
e (
Se
e c
ha
rt b
elo
w)
** Info
rmation taken f
rom
AN
SI
Z49.1
:2005**
GMAW Safety
GMAW Safety
•R
EM
EM
BE
R –
Gas C
ylin
ders
require S
PE
CIA
L
safe
ty p
recautions
–Cylinders m
ust be secured in an upright position
–Cylinders should be located in an area away from arc
welding, cutting, heat, sparks, and flame
–Refer to ‘Safety in W
elding, Cutting, and Allied Processes’
7
–Refer to ‘Safety in W
elding, Cutting, and Allied Processes’
(ANSI Z49.1) or Arc W
elding Safety (E205) for more
inform
ation on the handling of gas cylinders
8
GMAW Principles
GMAW Principles
GMAW Definition
GMAW Definition
•G
MA
W s
tan
ds fo
r G
as M
eta
l A
rc W
eld
ing
•G
MA
W is c
om
mo
nly
re
ferr
ed
to
as M
IG o
r M
eta
l In
ert
Ga
s
we
ldin
g
•D
uri
ng
th
e G
MA
W p
roce
ss, a
so
lid m
eta
l w
ire
is fe
d th
rou
gh
a
we
ldin
g g
un
an
d b
eco
me
s
9
a w
eld
ing
gu
n a
nd
be
co
me
s
the
fill
er
ma
teri
al
•In
ste
ad
of a
flu
x, a
sh
ield
ing
g
as is u
se
d to
pro
tect th
e
mo
lte
n p
ud
dle
fro
m th
e
atm
osp
he
re w
hic
h r
esu
lts in
a
we
ld w
ith
ou
t sla
g
GMAW is the m
ost widely used arc welding process in the
United States
GMAW Circuit
GMAW Circuit
•T
hre
e th
ing
s h
ap
pe
n
wh
en
th
e G
MA
W g
un
trig
ge
r is
pu
lled
:
–The w
ire electrode
begins to feed
10
begins to feed
–The circuit becomes
electrically ‘hot’
•C
urr
en
t flo
ws fro
m th
e p
ow
er
so
urc
e th
rou
gh
th
e g
un
ca
ble
, g
un
, co
nta
ct tip
to
th
e w
ire
an
d a
cro
ss th
e a
rc. O
n th
e o
the
r sid
e o
f th
e a
rc, cu
rre
nt flo
ws th
rou
gh
th
e b
ase
me
tal to
th
e
wo
rk c
ab
le a
nd
ba
ck to
th
e p
ow
er
so
urc
e
–Shielding gas flows through the gun and out the nozzle
GMAW Components
GMAW Components
•Let’s look a
little c
loser
at th
e G
MA
W p
rocess
Travel direction
Ge
ne
rally
, d
rag o
n th
in s
he
et
me
tal a
nd
pu
sh
on
th
icke
r
ma
teria
ls
11
Ele
ctro
de
1A
rc2
Wel
d P
ud
dle
3
Sh
ield
ing
Gas
4
5S
olid
ifie
d W
eld
Met
al
1 -Electrode
1 -Electrode
•A
GM
AW
ele
ctr
od
e is:
–A m
etal wire
–Fed through the gun by
12
the wire feeder
–Measured by its
diameter
GM
AW
ele
ctr
odes a
re c
om
monly
packaged o
n
spools
, re
els
and
coils
rangin
g f
rom
1lb
to 1
000lb
s
2 -Arc
2 -Arc
•A
n e
lectr
ic a
rc
occu
rs in
th
e g
as
fille
d s
pa
ce
be
twe
en
13
fille
d s
pa
ce
be
twe
en
the
ele
ctr
od
e w
ire
an
d th
e w
ork
pie
ce
Ele
ctr
ic a
rcs c
an g
enera
te
tem
pera
ture
s u
p t
o 1
0,0
00
°F
3 -Weld Puddle
3 -Weld Puddle
•A
s th
e w
ire
ele
ctr
od
e
an
d w
ork
pie
ce
he
at
up
an
d m
elt,
the
y
form
a p
oo
l o
f m
olte
n
ma
teri
al ca
lled
a w
eld
14
ma
teri
al ca
lled
a w
eld
pu
dd
le
•T
his
is w
ha
t th
e
we
lde
r w
atc
he
s a
nd
ma
nip
ula
tes w
hile
we
ldin
g.0
45”
ER
70S
-6 a
t 400 ipm
wire f
eed
speed a
nd 2
8.5
Volts w
ith a
90%
Arg
on/ 10%
CO
2 s
hie
ldin
g g
as
4 -Shielding Gas
4 -Shielding Gas
•G
MA
W w
eld
ing
req
uir
es a
sh
ield
ing
ga
s to
pro
tect th
e
we
ld p
ud
dle
15
we
ld p
ud
dle
•S
hie
ldin
g g
as is
usu
ally
CO
2,
arg
on
,
or
a m
ixtu
re o
f b
oth
The g
auges o
n t
he r
egula
tor
show
gas flo
w r
ate
and b
ott
le p
ressure
5 -Solidified Weld Metal
5 -Solidified Weld Metal
•T
he
we
lde
r “l
ays a
be
ad
” o
f m
olte
n m
eta
l
tha
t q
uic
kly
so
lidifie
s
into
a w
eld
16
into
a w
eld
•T
he
re
su
ltin
g w
eld
is
sla
g fre
e
An a
lum
inum
weld
done
with t
he G
MA
W p
rocess
Application Activity
Application Activity
17
Application Activity
Application Activity
GMAW Components
Application Activity
GMAW Components
Application Activity
•1 __________
•2 __________
•3 __________
•4 __________
•Let’s r
evie
w t
he G
MA
W p
rocess
Travel direction
Genera
lly, dra
g o
n thin
sheet
meta
l and p
ush o
n thic
ker
mate
rials
18
•4 __________
•5 __________
12
3
4
5
Equipment Set Up
Equipment Set Up
19
Equipment Set Up
Equipment Set Up
GMAW Equipment Set Up
GMAW Equipment Set Up
1.
Co
nn
ect w
ork
cla
mp
2.
Se
lect e
lectr
od
e
a. Type
b. Diameter
3. S
ele
ct sh
ield
ing
ga
s
4. T
urn
po
we
r su
pp
ly o
n
20
4. T
urn
po
we
r su
pp
ly o
n
5. A
dju
st m
ach
ine
ou
tpu
t
a. Wire feed speed
b. Voltage
6. A
dju
st g
as flo
w r
ate
Why w
ould
GM
AW
be a
bett
er
choic
e t
han S
MA
W f
or
this
job?
GMAW Process Variables
GMAW Process Variables
•W
eld
ing
va
ria
ble
s
–Wire Feed Speed (WFS)
–Voltage
•O
pe
rato
r co
ntr
olle
d v
ari
ab
les
–Travel speed
–Gun angles
–Contact tip to w
ork distance
21
–Contact tip to w
ork distance
(CTWD)
–Gas flow rate
What is
the r
ela
tionship
betw
een W
FS
and a
mpera
ge?
Striking an Arc
and Making a Weld
Striking an Arc
and Making a Weld
22
and Making a Weld
and Making a Weld
Striking an Arc
Striking an Arc
•P
ositio
n th
e g
un
ove
r jo
int
•P
ositio
n th
e fa
ce
sh
ield
to
pro
tect
23
sh
ield
to
pro
tect
eye
s a
nd
fa
ce
•P
ull
the
gu
n t
rig
ge
r
an
d b
eg
in w
eld
ing
What are
som
e t
hin
gs t
o
consid
er
befo
re s
trik
ing a
n a
rc?
Laying a Bead
Laying a Bead
•M
ain
tain
a C
onta
ct
Tip
to W
ork
Dis
tance (
CT
WD
) of
3/8
” to
1/2
”
•U
se a
uniform
tra
vel speed
•M
ost Im
port
antly –
Watc
h the P
uddle
!
24
Th
e a
pp
ea
ran
ce
of
the
pu
dd
le a
nd
rid
ge
wh
ere
mo
lte
n m
eta
l so
lidifie
s
ind
ica
tes c
orr
ect
tra
ve
l sp
ee
d. T
he
rid
ge
sh
ou
ld b
e a
pp
roxim
ate
ly 3
/8”
(10
mm
) b
eh
ind
th
e w
ire
ele
ctr
od
e.
Mo
st
be
gin
ne
rs t
en
d t
o w
eld
to
o f
ast
resu
ltin
g in
a r
op
ey b
ea
d w
hic
h
me
an
s S
LO
W d
ow
n!
Th
e a
pp
ea
ran
ce
of
the
pu
dd
le a
nd
rid
ge
wh
ere
mo
lte
n m
eta
l so
lidifie
s
ind
ica
tes c
orr
ect
tra
ve
l sp
ee
d. T
he
rid
ge
sh
ou
ld b
e a
pp
roxim
ate
ly 3
/8”
(10
mm
) b
eh
ind
th
e w
ire
ele
ctr
od
e.
Mo
st
be
gin
ne
rs t
en
d t
o w
eld
to
o f
ast
resu
ltin
g in
a r
op
ey b
ea
d w
hic
h
me
an
s S
LO
W d
ow
n!
Fill the Crater
Fill the Crater
•F
ill t
he c
rate
r by p
ausin
g
or
usin
g a
slig
ht
back
ste
p
•R
ele
ase g
un t
rigger
and
pull
gun a
way f
rom
the
work
aft
er
the a
rc g
oes
25
work
aft
er
the a
rc g
oes
out
•Larg
e c
rate
rs c
an c
ause
weld
cra
ckin
g
Cra
ter
cra
cks c
annot
be
tole
rate
d o
n N
AS
CA
R r
adia
tors
.
Restarting a Bead
Restarting a Bead
•R
esta
rt the w
eld
bead b
y b
ack
ste
ppin
g into
the
last w
eld
’s c
rate
r
and t
hen c
ontinue
movin
g f
orw
ard
26
movin
g f
orw
ard
•T
his
techniq
ue
should
result in a
seam
less
transitio
n f
rom
one
weld
to the n
ext
2
Ba
ck s
tep
1
Modes of Metal
Transfer
Modes of Metal
Transfer
27
Transfer
Transfer
Modes of Metal Transfer
Modes of Metal Transfer
•G
MA
W is a
pro
ce
ss th
at
fea
ture
s s
eve
ral d
istin
ctive
,
ind
ivid
ua
l m
eth
od
s a
nd
typ
es
of m
eta
l tr
an
sfe
r
•T
he
mo
de
of m
eta
l tr
an
sfe
r is
de
term
ine
d b
y a
nu
mb
er
of
we
ldin
g v
ari
ab
les
28
we
ldin
g v
ari
ab
les
–Voltage
–Amperage
–Shielding G
as
•B
y c
ha
ng
ing
on
e o
r m
ore
va
ria
ble
s, yo
u c
an
go
fro
m
on
e m
eta
l tr
an
sfe
r m
od
e to
an
oth
er
Modes of Metal Transfer
Modes of Metal Transfer
•T
wo c
om
mon c
onventional
modes o
f m
eta
l tr
ansfe
r are
:
–Short arc
–Axial spray arc
Typic
al short
arc
applic
ation
29
–Axial spray arc
•T
he a
pplic
ation,
join
t desig
n,
base m
ate
rial th
ickness,
and
pro
pert
ies d
ete
rmin
e t
he
appro
priate
mode t
o u
se
Typic
al axia
l spra
y
arc
applic
ation
Short Arc Transfer
Short Arc Transfer
•In
sh
ort
arc
tra
nsfe
rM
–The arc is initiated
and a droplet is
form
ed on the end of
the wire
30
–The wire touches the
work piece and
produces a short
circuit
–The droplet is then
transferred to the weld
puddle
Axial Spray Arc Transfer
Axial Spray Arc Transfer
•In
axia
l sp
ray a
rc
tra
nsfe
r M
–Very high currents are
used
–A point form
s at the
31
–A point form
s at the
end of the electrode
and the fine droplets
–The puddle is very
fluid m
aking out of
position w
elding
difficult
Troubleshooting
Welds
Troubleshooting
Welds
32
Welds
Welds
Troubleshooting Welds
Troubleshooting Welds
•G
OA
L -
Ma
ke
Go
od
We
lds
•E
limin
ate
Ro
pe
y C
on
ve
x b
ea
d
33
•E
limin
ate
Po
rosity
•E
limin
ate
Exce
ssiv
e S
pa
tte
r
Advantages and
Limitations
Advantages and
Limitations
34
Limitations
Limitations
Advantages of GMAW
Advantages of GMAW
•H
igh o
pera
ting f
acto
r
•E
asy to learn
•Lim
ited c
leanup
•U
se o
n m
any d
iffe
rent
meta
ls: s
tain
less s
teel,
35
mild
(carb
on)
ste
el,
alu
min
um
and m
ore
•A
ll positio
n
•G
reat fo
r hom
e u
se w
ith
115V
and 2
30V
units
Limitations of GMAW
Limitations of GMAW
•Less p
ort
able
with
short
er
gun length
s (
15
foot guns)
•G
MA
W e
quip
ment
is
more
expensiv
e t
han
SM
AW
equip
ment
36
SM
AW
equip
ment
•E
xte
rnal shie
ldin
g g
as
can b
e b
low
n a
way b
y
win
ds
•H
igh r
adia
ted h
eat
•D
ifficult to u
se in o
ut of
positio
n join
ts
AWS Classification of
GMAW Electrodes
AWS Classification of
GMAW Electrodes
37
GMAW Electrodes
GMAW Electrodes
ER70S-X
Electrode
Rod
AWS Classification of
GMAW Electrodes
AWS Classification of
GMAW Electrodes
38
Rod
70,000 psi Min. Tensile Strength
Solid
Chemistry, Amount of Deoxidizers (Silicon,
Manganese and/or Aluminum, Zirconium and
Titanium) X=2,3,4,6,7 or G
39
Lesson Plans
Lesson Plans
GMAW Lesson #1
GMAW Lesson #1
•Objective: To run a stringer (straight) bead using short arc transfer and to fill the
crater
•Equipment:
–Single Process -Constant Voltage Power Source & W
ire Feeder
�P
ow
er
MIG
21
5 o
r P
ow
er
MIG
25
5C
–Multi-Process
�C
om
po
site
: P
ow
er
MIG
35
0 M
P
�C
om
bin
atio
n: V
-35
0/
LF
-72
pa
cka
ge
•Material:
40
•Material:
–Mild
Steel Plate –
3/16” or thicker
�.0
35”
SuperA
rc L
-56 (
ER
70S
-6)
�100%
CO
2 o
r 25%
CO
2/ 75%
Arg
on b
lend s
hie
ldin
g g
as
GMAW Lesson #2
GMAW Lesson #2
•Objective: To make a fillet weld on a lap joint in the horizontal position (AWS
position 2F)
•Equipment:
–Single Process -Constant Voltage Power Source & W
ire Feeder
�P
ow
er
MIG
21
5 o
r P
ow
er
MIG
25
5C
–Multi-Process
�C
om
po
site
: P
ow
er
MIG
35
0 M
P
�C
om
bin
atio
n: V
-35
0/
LF
-72
pa
cka
ge
•Material
41
•Material
–Mild
Steel Plate –
10 gauge
–.035” SuperArc L-56 (ER70S-6)
–100% CO2 or 25% C
O2/ 75% Argon blend shielding gas
2F
GMAW Lesson #3
GMAW Lesson #3
•Objective: To make a fillet weld on a tee joint in the horizontal position
(AWS position 2F)
•Equipment:
–Single Process -Constant Voltage Power Source & W
ire Feeder
�P
ow
er
MIG
215 o
r P
ow
er
MIG
255C
–Multi-Process –
�C
om
posite:
Pow
er
MIG
350 M
P
�C
om
bin
ation:
V-3
50/
LF
-72 p
ackage
42
�C
om
bin
ation:
V-3
50/
LF
-72 p
ackage
•Material:
–Mild Steel Plate –
10 gauge
–.035” SuperA
rc L-56 (ER70S-6)
–100% C
O2 or 25% C
O2/ 75% Argon blend shielding gas
2F
GMAW Lesson #4
GMAW Lesson #4
•Objective: To make a fillet weld on a lap joint in the vertical position welding
down (AWS position 3FD)
•Equipment:
–Single Process -Constant Voltage Power Source & W
ire Feeder
�P
ow
er
MIG
21
5 o
r P
ow
er
MIG
25
5C
–Multi-Process –
�C
om
po
site
: P
ow
er
MIG
35
0 M
P
�C
om
bin
atio
n: V
-35
0/
LF
-72
pa
cka
ge
•Material:
43
•Material:
–Mild
Steel Plate –
10 gauge
–.035” SuperArc L-56 (ER70S-6)
–100% CO2 or 25% C
O2/ 75% Argon blend shielding gas
3F
D
GMAW Lesson #5
GMAW Lesson #5
•Objective: To make a fillet weld on a tee joint in the vertical position welding down (AWS
position 3FD)
•Equipment:
–Single Process -Constant Voltage Power Source & W
ire Feeder
�P
ow
er
MIG
215 o
r P
ow
er
MIG
255C
–Multi-Process –
�C
om
posite: P
ow
er
MIG
350 M
P
�C
om
bin
ation: V
-350/ LF
-72 p
ackage
•Material:
–Mild Steel Plate –
10 gauge
44
–Mild Steel Plate –
10 gauge
–.035” SuperArc L-56 (ER70S-6)
–100% CO2 or 25% CO2/ 75% Argon blend shielding gas
3F
D
GMAW Lesson #6
GMAW Lesson #6
•Objective: To make a butt weld with a gap in the vertical position
welding down
•Equipment:
–Single Process -Constant Voltage Power Source & W
ire Feeder
�P
ow
er
MIG
21
5 o
r P
ow
er
MIG
25
5C
–Multi-Process –
�C
om
po
site
: P
ow
er
MIG
35
0 M
P
�C
om
bin
atio
n: V
-35
0/
LF
-72
pa
cka
ge
45
�C
om
bin
atio
n: V
-35
0/
LF
-72
pa
cka
ge
•Material:
–Mild
Steel Plate –
10 gauge
–.035” SuperArc L-56 (ER70S-6)
–100% CO2 or 25% C
O2/ 75% Argon blend shielding gas
3G
GMAW Lesson #7
GMAW Lesson #7
•Objective: To make a fillet weld on a tee joint
in the overhead position (AWS position 4F)
•Equipment:
–Single Process -Constant Voltage Power
Source & W
ire Feeder
�P
ow
er
MIG
215 o
r P
ow
er
MIG
255C
–Multi-Process –
�C
om
posite: P
ow
er
MIG
350 M
P
�C
om
bin
ation: V
-350/ LF
-72 p
ackage
•Material:
46
•Material:
–Mild Steel Plate –
10 gauge
–.035” SuperArc L-56 (ER70S-6)
–100% CO2 or 25% CO2/ 75% Argon blend
shielding gas
4F
GMAW Lesson #8
GMAW Lesson #8
•Objective: To make a three pass fillet weld on a tee
joint in the horizontal position (AWS position 2F)
•Equipment:
–Single Process -Constant Voltage Power Source
& W
ire Feeder
�P
ow
er
MIG
215 o
r P
ow
er
MIG
255C
–Multi-Process –
�C
om
posite: P
ow
er
MIG
350 M
P
�C
om
bin
ation: V
-350/ LF
-72 p
ackage
47
�C
om
bin
ation: V
-350/ LF
-72 p
ackage
•Material:
–Mild Steel Plate –
¼”
–.035” SuperArc L-56 (ER70S-6)
–100% CO2 or 25% CO2/ 75% Argon blend shielding gas
2F
GMAW Lesson #9
GMAW Lesson #9
•Objective: To run a horizontal fillet weld on a tee joint using axial
spray transfer (AWS position 2F)
•Equipment:
–Single Process -Constant Voltage Power Source
& W
ire Feeder
�P
ow
er
MIG
22
5C
–Multi-Process –
�C
om
po
site
: P
ow
er
MIG
35
0 M
P
48
�C
om
po
site
: P
ow
er
MIG
35
0 M
P
�C
om
bin
atio
n: V
-35
0/
LF
-72
pa
cka
ge
Material:
–Mild
Steel Plate –
¼”
–.045” SuperArc L-56 (ER70S-6)
–90% Argon/ 10% C
O2 blend shielding gas
2F
49
AWS Connection
AWS Connection
American Welding Society
(AWS) Connection
American Welding Society
(AWS) Connection
•T
he G
MA
W u
nit o
f stu
dy
covere
d info
rmation r
ela
ted
to the follo
win
g A
WS
requirem
ents
for
cert
ific
ation:
–Setting up for GMAW
50
–Setting up for GMAW
operations on carbon steel
–Operating G
MAW equipment
on carbon steel
–Making G
MAW fillet welds on
carbon steel
English, Math, and Science
English, Math, and Science
51
English, Math, and Science
Connection
English, Math, and Science
Connection
National Academic Standards
Crosswalk
National Academic Standards
Crosswalk
•T
his
un
it c
ove
red
aca
de
mic
co
nte
nt
liste
d in
th
e
Na
tio
na
l A
ca
de
mic
Sta
nd
ard
s a
s fo
llow
s:
–NM-M
EA.9-12.1:Understands m
easurable attributes of objects
and the units, systems, and processes of measurement
–NM-PROB.CONN.PK-12.3:Recognizes and applies
mathematics in contexts outside of mathematics.
52
mathematics in contexts outside of mathematics.
–NS-PHYSICAL SCIENCE: (Understands) structure and
property of matter
–NS-PHYSICAL SCIENCE: (Understands) chemical reactions
–NLA-STANDARD 3: U
ses grammatical and m
echanical
conventions in
written compositions
–NLA-STANDARD 10:Understands the characteristics and
components of the m
edia