GMAW Modes of Transfer
What are the 4 modes of transfer in GMAW?
Short-Circuit, Globular, Pulse, and Spray
Name the two methods for striking an arc.
Tapping/Scratching
Adjusting the GMAW drive roll pressure too __________ deforms the wire.
Tightly
Flux must be removed in between passes in SMAW
True
Which GMAW electrode wire is most commonly used and works great with CO2?
ER70S-6
Some of the advantages of short-circuit transfer are:(List 2)
All-position capability,Handles poor fit-up extremely well,Lower heat input reduces weldment distortion,Higher operator appeal and ease of use,Higher electrode efficiencies
Explain how the arc is maintained during stick welding.
The arc is maintained when welding current is forced across a gap between the electrode tip and the base metal.
If the hub tension is too _______________, over-spooling, or de-coiling will occur and you will have a mess of wire.
Loose
The most common difficulty encountered in striking the arc is?
sticking
When using 100 percent CO2 with carbon steel, adding argon __________________ tensile and yield strength.
Increases
What are some limitations of axial spray transfer? (List 2)
• Restricted to the flat and horizontal welding positions.
• Welding fume generation is higher.
• The higher-radiated heat and the generation of a very bright arc require extra
welder and bystander protection.
• The use of axial spray transfer outdoors requires the use of a windscreen(s).
• The shielding used to support axial spray transfer costs more than 100% CO2
How you can tell if too long of an arc is being used?
An increase in spatter and the occurrence of undercut.
What are some symptoms of gun liner problems?(Name 2)
Poor wire feeding, unable to control arc, etc.
What shade is necessary for SMAW?
10-14
What two shielding gases can be used on Aluminum?
Argon and Helium
What are the advantages of axial spray transfer?
• Deposition rates are high.
• Electrode efficiency is high: 98% or more.
• Employs a wide range of filler metal types in an equally wide range of electrode
diameters
• Weld bead appearance is excellent.
• High operator appeal and ease of use.
• Requires little post-weld cleanup.
• Weld spatter is absent.
• Weld fusion is excellent.
• Lends itself to semiautomatic, robotic, and hard automation applications.
Normal arc length is slightly less than the diameter of what item?
The electrode
How does amperage impact arc blow?
Arc blow occurs at higher amperages.
How does the welding industry avoid confusion about various kinds of electrodes?
Uses and electrode classification system.
Which shielding gas produces deeper penetration on Aluminum?
Helium
What are the advantages of globular transfer?
• Uses inexpensive CO2
shielding gas, but is frequently used with argon/CO2 blends.
• Is capable of making welds at very high travel speeds.
• Uses inexpensive solid or metal-cored electrodes.
• Welding equipment is inexpensive.
Explain what will happen if the amperage is set too low
It will be difficult to strike and maintain the arc and to maintain correct arc length. Also, the weld metal will pile up, with excessive overlap and poor penetration.
If you notice an increase in spatter and large wobbly drops of metal melting off the electrode, what needs to be corrected?
Arc Length
In the American Welding Society’s electrode classification system, which digits indicate minimum tensile strength?
First 2 digits
When MIG welding steel, what does carbon dioxide increase?
Penetration