103abB Flashcards
1
Q
What does GMAW stand for?
What’s another name for it?
A
Gas Metal Arc Welding
Mig
2
Q
What does Ferrous mean
A
The metal has Iron
3
Q
What is the GMAW - mig process
A
GMAW heats metals with an electric arc established between a continuously fed filler metal (consumable electrode) and the work piece to join the metals
4
Q
What polarity does GMAW generally use
A
DCEP
5
Q
What 4 factors affects the welding mode you use?
A
position of welding
the current and voltage range
shielding gas
type of metal being welded
6
Q
What 3 types of metals is GMAW used on?
A
Carbon and alloy steels
Stainless steel
several classes of non-ferrous metals
( copper alloys and aluminum )
7
Q
Filler wires must be manufactured for specific mechanical properties. List 3 of those properties
A
tensile strength
ductility
impact strength
8
Q
Who has standards for the manufacturing of GMAW filler wires.
A
AWS - American Welding Society
CSA - Canadian Standards Association
9
Q
True or False
GMAW filler wires are drawn from one solid wire that is continuous in length
A
True
10
Q
Why are some wires copper coated ?
A
To improve the electrical conductivity of the wire as it passes through the contact tube/tip.
11
Q
Does the copper coating on filler wire provide any corrosion or oxidization resistance for the wire
Y/N
A
Yes
12
Q
What CSA # covers filler metals and allied materials for metal Arc Welding
A
CSA W48
CSA-ISO 14341
13
Q
CSA-ISO Categorization System.
State what each of the values below mean. Use the charts on page 9.
B-G 49A 3 C G6
A
B- the electrode was classified by tensile strength & tested with an average 27 joule impact test
G- GMAW process
49A - the min tensile strength of the deposited weld metal once welded in MPa divided by 10 (min 490MPA tensile strength)
3 - Average temp of the Impact Test
C- Designates CO2 as the shielding gas
G6 - the letter/# combo designates variations in the chemical analysis of filler metal
14
Q
With the AWS Specification A5.18 classification system. Explain the following
ER 70 S - XNHZ
A
ER - Filler rod
70 - tensile strength of 70000 psi
S- filler metal is solid
X- Chemical composition of a solid electrode
Y- shielding gas to be used
N- if used it is nuclear
HZ - optional supplemental diffusible hydrogen designator
15
Q
Is GMAW wire considered S (solid) or C (composite)
A
Solid
16
Q
Is MCAW wire considered S (solid) or C (composite)
A
C composite
17
Q
Does GTAW use filler rod or electrode wire?
A
Filler Rod
18
Q
Does GMAW use filler rod or electrode wire?
A
electrode wire
19
Q
Does MCAW use filler rod or electrode wire?
A
electrode wire
20
Q
What is the most common wire designation
A
B-G 49A 3C G6
(ER70S-6)
21
Q
What shielding gas(s) does ER70S-6 wire use?
A
CO2 or Argon-CO2
22
Q
Why is ER70S-6 the most common? (3)
A
- most versatile
- can be used in short circuit or spray transfer modes
- Can be used in & out of position applications when using short circuit metal transfer
23
Q
What are 4 Advantages of GMAW
A
low skill requirements
Less distortion than SMAW
High deposition rates in all positions
Good control of penetration
- leads to better control with poor fit-ups and wide gaps
24
Q
What are 3 disadvantages of GMAW
A
Special equip needed that is complex & $$
Starts cold - risk of lack of fusion (cold lap)
Less practical for outdoors due to the shielding gas needing to remain on the weld (wind would remove it)
25
With GMAW where do you keep the wire in the puddle to prevent lack of fusion
The leading edge of the puddle
26
Define and describe the GMAW process in detail
Uses an arc between a continuous filler metal electrode and the weld pool. Uses a shielding gas from an external source.
27
What type of power source is most often used for GMAW?
CV - Constant Voltage
28
Interpret B-G 49A 3C G2 electrode classification
B - electrode is classified by tensile strength with 27joule impact test
G - designates the use of shielding gas
49A - min tensile strength when welded in MPa divided by 10
3 - min -30*C for impact tests
C - designates CO2 shielding gas
G2 - is a specific chemical analysis of this filler metal
29
Why was FCAW immediately preferred?
due to its high deposition rates
30
Does FCAW have high or low fume emissions?
High
31
What metals can FCAW weld?
Carbon & alloy steels
SS
hard surfacing applications
32
What does FCAW stand for
Flux Cored Arc Welding
33
What does the designation FCAW-G mean
the shielding gas will be externally supplied
34
What protects the weld when using FCAW
a mix of CO2 and Argon or CO2 alone
35
What is self shielded FCAW
uses an electrode containing a flux that generates the shielding gas required.
36
Where is Self Shielded FCAW a common choice for fabrication repairs & why
In the field - as the shielded electrode tolerate windy conditions
37
Does FCAW use DCEN or DCEP
DCEN
38
Using DCEN do you have lower or higher penetration?
What type of materials work well with FCAW
Lower & thin materials
39
Is there aluminum FCAW wire? Y/N
no
40
With Basic cored wires what type of material transfer is used?
Spray or globular?
Globular
41
Do Basic cored wires have very high or very low levels of diffusible hydrogen?
very low just like those used for SMAW
42
If using Self shielding wire indoors what system should you have in place?
Fume extraction system due to large volumes of smoke produced.
43
What are the 3 main functions of flux.
- provides deoxidizers & scavengers to remove impurities
forms slag to prevent contamination and control the beads shape & appearance.
provides a shielding gas to displace atmospheric air
44
What is the main difference between CSA & AWS specifications?
AWS uses imperial (psig)
CSA uses metric MPa
45
What is the title of the FCAW Wire standards
CSA W48
46
Filler Wire Classifications in CSA W48-20-20 when the
#1 is used what is indicated
#2 is used what is indicated
1 - can be used in all positions
2 - only for flat or horizontal positions
47
AWS A5 20 & 29 uses a different numbering system what does
#0 indicate
#1 indicate
0 - flat or horizontal positions
1 - all positions
48
E491T-6CH is a classification for typical flux core wire - Explain the classification
E
49
1
T
6
CH
E - electrode
49- min tensile strength of 490MPa
1- all positions
T- tubular
6 - slag system, current, polarity, shielding gas
CH - optional controlled hydrogen designator
49
E-XXT-XMJHZ is a classification for filler metal - Explain the classification
E - electrode
X - min tensile strength x 10000 psi
X - position to use
T - tubular
X - usability & performance characteristics
M - designator of type of shielding gas
J- optional improved toughness value
HZ - optional controlled hydrogen designator
50
What shielding gas does E7XT-9 wire use? What performance characteristics does this wire have?
Argon-CO2
or
Argon-O2-CO2 mixes
Rutile flux core - uses globular metal transfer
51
List 5 FCAW Advantages
Smooth Uniform weld
high quality metal deposits
unto 4x greater deposition rates than with SMAW
Using self shielding eliminates the need for flux or gas system.
More tolerant of windy conditions
resistant to underbid cracking
52
Describe the operating principles of FCAW
uses an established arc between a continuously fed consumable electrode and the work piece
Constant burn rate achieved with correct settings
Arc length is maintained automatically
Shielding gas can be external or internal from flux within the electrode core
52
List 4 disadvantages of FCAW
Slag removal is needed
equip is more $$ than SMAW
More smoke/fumes generated
Equip is more complex & needs more maintenance
53
What is the electrode extension range for self shielded FCAW
3/4" to 3 3/4"
54
What are the primary functions of flux in FCAW
Protect the molten weld metal from atmospheric air
provides oxidizers & scavengers to remove impurities
control the bead shape & appearance
acts as a arc stabilizer resulting in less spatter and uniform weld bead
to add alloying elements to provide the required mechanical, metallurgical, and corrosion resistance properties
55
Name 2 FCAW wires that can be used without external gas shielding
Any of the following
EXXXT-3*
-3
-6
-10
-11
-13
-14
56
Explain E491T-9CH FCAW electrode classification.
E - electrode
49 - 490KMPa tensile strength
1 - all positions
T- Tubular wire
9 - slag system, current, polarity & shielding gas
CH- controlled hydrogen
57
What does MCAW stand for
Metal Cored Arc Welding
58
Are metal cored electrodes or solid electrodes more cost efficient?
Metal Cored
59
Describe MCAW wire
the wire is tubular with a metal shieth and a core of various powdered materials
60
What does the metal powders in MCAW wire consist of?
metalic powders, alloys, & arc stabilizers
61
with MCAW can you use Spray Transfer in horizontal and flat positions?
Yes it is very common
62
With MCAW what transfer mode is best to use for all positions?
Pulsed Spray Arc transfer
- allows for higher deposition rates & improved puddle control
63
4 Advantages of MCAW
High travel speeds with good root penetration
no slag
almost no spatter
very little post weld or inter pass cleaning
the power source is equipped with modified short circuit capabilities
64
Why does metal cored wire excel in heavy equipment & automobile fabrication?
Because the filler wire can be alloyed for almost every type of steel. from low carbon to SS
65
Using metal core wire would you use it for flat and horizontal applications using spray transfer or vertical & globular
Flat & horizontal with Spray transfer
66
Using E491C-6-CH would you use 85%Argon and 15%CO2
Yes
67
4 advantages of MCAW
High quality metal deposits
no slag or inter pass cleaning
skill requirements are lower than saw
resistance to under bead cracking
68
4 Disadvantages to MCAW
Special equip required & its more complex
More maintenance needed
MCAW less practical to use outside
Pulsed Arc is often used for out of position welding
69
Explain the E491C-6 MCAW electrode
E- electrode
49 - 490MPa tensile strength
1- all positions
C- metal core wire
6- designates shielding gas, slag system, current, polarity
70
What is the recommended mix of shielding gasses for the C-3 and C-6 electrode classifications for MCAW
Both use 85% Argon and 15% CO2
71
What need is increases when using shielding gasses for wire feed processes?
a) good lighting
b) good ventilation
c) heat shielding
d) eye protection
b) good ventilation
72
High UV radiation emissions from an open arc can cause atmospheric O2 in the vicinity of the arc to convert to which of the following?
A) ozone
B) carbon monoxide
c) carbon dioxide
d) argon
A) ozone
73
What is a potential source of poisonous chemical fumes when welding?
a) inert shielding gasses
b) chlorinated degreasing solvents
c) carbon dioxide extinguishers
d) anti spatter nozzle sprays
b) chlorinated degreasing solvents
74
What is the gas metal arc welding process also known as
a) MIG
b) Flux cored arc welding
c) self shielding process
d) shielded metal arc welding
a) MIG
75
GMAW is recommended for use on which of the following metals.
a) SS
b) Aluminum
c) Copper alloys
d) Carbon and low alloy steels
e) all of the above
e) all of the above
76
What is the gas generated from that is used for self shielded FCAW
a) base metal
b) external source
c) the flux
d) a paste flux applied to the base metal before welding
c) the flux
77
The MCAW process uses the same equipment as which process
a) SMAW
b) GTAW
c)FCAW
d) OAW
c) FCAW
78
How are wire feed guns rated?
a) voltage carrying capacity
b) physical size
c) current carrying capacity
d) shielding gas flow rate
c) current carrying capacity
79
What is the major factor required when choosing between an air- cooled or water cooled guns
a) shielding gas
b) current and voltage
c) joint design
d) base metal alloy
b) current and voltage
80
What does constant voltage (CV) machines produce?
a) drooping volt-amp curve
b) rising volt - amp curve
c) relatively flat volt - amp curve
d) constantly changing volt-amp curve
c) relatively flat volt - amp curve
81
Which power source is best suited for short circuit mode of metal transfer?
a) rising are voltage
b) constant voltage
c) constant current
d) constant amperage
b) constant voltage
82
Which type of welding machine produces an almost horizontal output slope?
a) constant current
b) constant voltage
c) rising arc voltage
d) high amperage potential
b) constant voltage
83
What is one of the main advantages of metal core wires
a) lower $ than flux core
b) no external shielding gas required
c) designed for use on conventional CC power supplies
d) high deposition rates
d) high deposition rates
84
What does the powder in a MCAW wire consist mostly of?
a) flux
b) metal
c) flag formers
d) arc stabilizers
b) metal
85
When is the base metals composition the major factor to consider?
a) when selecting a shielding gas
b) when selecting filler materials
c) when selecting a power source
d) when selecting current settings.
b) when selecting filler materials
86
Which organizations have written specifications for wire feed filler metals
a) WCB & CSA
b) CWB & AWS
c) ASME & CWB
d) AWS & CSA
d) AWS & CSA
87
What is silicon aluminum and manganese used for when added to ER70S-2
a) stabilizers
b)deoxidizers
c) lubricators
d) indicators
b) deoxidizers
88
What does cast refer to ?
a) circle formed by one wrap of wire
b) method of forming the wire
c) natural twisting action of the wire during forming
d) ability of the wire to be pushed through a plastic liner
a) circle formed by one wrap of wire
89
Describe the helix of a wire and the effect that it may have on welding.
The natural twisting of the wire while forming (corkscrew effect)
this can cause the wire to wander, the arc becomes unstable
90
What wires packaged in a sealed container mainly protected from
a) smoke & fumes
B) moisture contamination
c) transportation damage
d) UV radiation
B) moisture contamination
91
What is often the result of welds produced with improperly cleaned wires?
a) wagon tracks
b) cold lapping
c) slag inclusions
d) porosity
d) porosity
92
What are filler metals containing additional deoxidizers intended for use on?
a) moderately rusty low-carbon steels
b) Alloy steels containing chromium
c) non-ferrous metals
d) SS with more than 18% chromium
a) moderately rusty low-carbon steels
93
What does the G stand for in the CSA FCAW electrode classification of E492T-G
a) gas shielded
b) general classification for electrodes not covered under any other classification
c) for use on Class G secondary containment vessels for nuclear service
d) general purpose electrode for use on carbon and low allow steels.
d) general purpose electrode for use on carbon and low allow steels.
94
In GMAW short circuiting transfer mode, metal is transferred during which situation?
a) when the electrode comes in contact with the weld pool
b) as large globules are released from the filler wire
c) as fine droplets moving axially across the open arc
d) when a high current arc pulse ejects metal from the filler wire
a) when the electrode comes in contact with the weld pool
95
Very fine droplets of metal axially transferred across the arc describes what mode of metal - transfer
a) short circuiting
b) globular
c) spray
d) pulsed spray
c) spray
96
Which GMAW mode of metal transfer is best suited for welding thin metals
a) short circuiting arc transfer
b) globular spray arc transfer
c) spray arc transfer
d) pulsed arc transfer
a) short circuiting arc transfer
97
Where are the drive rolls located on a pull type drive system.
on the gun
98
What is a pull type welding gun designed to be used with
a) hard wires
b) soft wires
c) solid core wires
d) tubular wires
b) soft wires
99
What type of wire drive system allows to work at greater distances?
a push pull systems
100
what is the most popular feed system when using GMAW on mild steel
a) pull
b) push
c) push-pull
d) spool on the gun
b) push
101
What is the gun on page40 question 33 primarily used for
Aluminum
102
In addition to maximizing operator comfort what is the purpose of the curved neck on a welding gun?
a) it allows the use of a wider range of wires
b) helps prevent burn back of the electrode to the contact tip
c) ensures proper electrical transfer to the wire electrode
d) allows the use of all wire electrode types
c) ensures proper electrical transfer to the wire electrode
103
What is the welding cable assembly constructed to do?
a) supply current from the machine to the electrode holder
b) supply current , gas and wire to the gun
c) complete an electrical circuit between the machine and the work
d) supply current from the wall reciprocal to the welding machine.
b) supply current , gas and wire to the gun
104
what types of conduit liner are most often used with soft wires? list 3
1. Plastic
2. nylon
3. teflon
105
What is generally the longest practical feed cable with small diameter wire and a push feed system
15'
106
What is the purpose of a gas nozzle.
to direct the shielding gas onto the weld zone
107
