103abB 83.33% Flashcards
What does GMAW stand for?
What’s another name for it?
Gas Metal Arc Welding
Mig
What does Ferrous mean
The metal has Iron
What is the GMAW - mig process
GMAW heats metals with an electric arc established between a continuously fed filler metal (consumable electrode) and the work piece to join the metals
What polarity does GMAW generally use
DCEP
What 4 factors affects the welding mode you use?
position of welding
the current and voltage range
shielding gas
type of metal being welded
What 3 types of metals is GMAW used on?
Carbon and alloy steels
Stainless steel
several classes of non-ferrous metals
( copper alloys and aluminum )
Filler wires must be manufactured for specific mechanical properties. List 3 of those properties
tensile strength
ductility
impact strength
Who has standards for the manufacturing of GMAW filler wires.
AWS - American Welding Society
CSA - Canadian Standards Association
True or False
GMAW filler wires are drawn from one solid wire that is continuous in length
True
Why are some wires copper coated ?
To improve the electrical conductivity of the wire as it passes through the contact tube/tip.
Does the copper coating on filler wire provide any corrosion or oxidization resistance for the wire
Y/N
Yes
What CSA # covers filler metals and allied materials for metal Arc Welding
CSA W48
CSA-ISO 14341
CSA-ISO Categorization System.
State what each of the values below mean. Use the charts on page 9.
B-G 49A 3 C G6
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
With the AWS Specification A5.18 classification system. Explain the following
ER 70 S - XNHZ
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
Is GMAW wire considered S (solid) or C (composite)
Solid
Is MCAW wire considered S (solid) or C (composite)
C composite
Does GTAW use filler rod or electrode wire?
Filler Rod
Does GMAW use filler rod or electrode wire?
electrode wire
Does MCAW use filler rod or electrode wire?
electrode wire
What is the most common wire designation
B-G 49A 3C G6
(ER70S-6)
What shielding gas(s) does ER70S-6 wire use?
CO2 or Argon-CO2
Why is ER70S-6 the most common? (3)
- 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
What are 4 Advantages of GMAW
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
What are 3 disadvantages of GMAW
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)
With GMAW where do you keep the wire in the puddle to prevent lack of fusion
The leading edge of the puddle
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.
What type of power source is most often used for GMAW?
CV - Constant Voltage
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
Why was FCAW immediately preferred?
due to its high deposition rates
Does FCAW have high or low fume emissions?
High
What metals can FCAW weld?
Carbon & alloy steels
SS
hard surfacing applications
What does FCAW stand for
Flux Cored Arc Welding
What does the designation FCAW-G mean
the shielding gas will be externally supplied
What protects the weld when using FCAW
a mix of CO2 and Argon or CO2 alone
What is self shielded FCAW
uses an electrode containing a flux that generates the shielding gas required.
Where is Self Shielded FCAW a common choice for fabrication repairs & why
In the field - as the shielded electrode tolerate windy conditions
Does FCAW use DCEN or DCEP
DCEN
Using DCEN do you have lower or higher penetration?
What type of materials work well with FCAW
Lower & thin materials
Is there aluminum FCAW wire? Y/N
no
With Basic cored wires what type of material transfer is used?
Spray or globular?
Globular
Do Basic cored wires have very high or very low levels of diffusible hydrogen?
very low just like those used for SMAW
If using Self shielding wire indoors what system should you have in place?
Fume extraction system due to large volumes of smoke produced.
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