GMAW Welding
Q: Gas Metal Arc Welding is also known as?
A: GMAW
Q: What do MIG and MAG stand for?
A:
• MIG: Metal Inert Gas Welding
• MAG: Metal Active Gas Welding
Q: What does "Wire Welding" describe?
A: Describes the electrode used
Q: How can GMAW welding be performed?
A: Semiautomatic, machine, automatic
Most common: Semiautomatic welding
Q: What is GMAW-S (Short Circuiting Transfer)?
A: Low currents allow the liquid metal at the electrode tip to be transferred by direct contact
with the molten weld pool. Requires close interaction between wire feeder and power supply.
Most common on:
• Thin or properly prepared thick materials
• Combination of thick to thin materials
• Wide range of electrode diameters and shielding gases
Q: What is Globular Spray Metal Transfer?
A: Used on thin materials at very low current. The arc melts the electrode tip forming a molten
ball that falls into the weld pool. Rarely used alone.
Q: What is the Axial Spray Method?
A: Small drops are projected axially across the arc gap to the molten weld pool at high velocity.
Allows welding in vertical and overhead positions without losing control.
, Q: What three conditions are required for spray transfer process to occur?
A:
• Argon shielding (or argon-rich gas mixtures)
• DCEP Polarity
• Current above the transition current
Q: In what form is metal transferred in the axial spray metal transfer method?
A: Molten metal drops
Q: Why is the term GMAW preferable to MIG?
A: Originally MIG referred to welding aluminum with argon shielding. Introduction of CO2 and
O2 in shielding gases led AWS to prefer GMAW term as it better covers all variations.
Q: What current ranges does the pulsed arc metal transfer shift between?
A:
• High current pulse for axial spray transfer
• Lower pulse current allowing weld pool cooling and contraction
• Total heat input is lower than axial spray transfer
Pulsed arc metal cycle components:
Ramp Up, Overshoot, High Pulse Current, High Pulse Time, Ramp Down, Step off Current,
Background Current, Pulse Width
Q: What is GMAW-P (Pulsed Arc Metal Transfer)?
A: Dual pulsed current with high pulse for axial spray transfer and low pulse for cooling weld
pool, making control easier.
Q: Why add helium to argon in some spray or pulsed-spray welds?
A: Produces a very hot arc for thick section welds; helium increases arc temperature and
penetration.
Q: Gas Metal Arc Welding is also known as?
A: GMAW
Q: What do MIG and MAG stand for?
A:
• MIG: Metal Inert Gas Welding
• MAG: Metal Active Gas Welding
Q: What does "Wire Welding" describe?
A: Describes the electrode used
Q: How can GMAW welding be performed?
A: Semiautomatic, machine, automatic
Most common: Semiautomatic welding
Q: What is GMAW-S (Short Circuiting Transfer)?
A: Low currents allow the liquid metal at the electrode tip to be transferred by direct contact
with the molten weld pool. Requires close interaction between wire feeder and power supply.
Most common on:
• Thin or properly prepared thick materials
• Combination of thick to thin materials
• Wide range of electrode diameters and shielding gases
Q: What is Globular Spray Metal Transfer?
A: Used on thin materials at very low current. The arc melts the electrode tip forming a molten
ball that falls into the weld pool. Rarely used alone.
Q: What is the Axial Spray Method?
A: Small drops are projected axially across the arc gap to the molten weld pool at high velocity.
Allows welding in vertical and overhead positions without losing control.
, Q: What three conditions are required for spray transfer process to occur?
A:
• Argon shielding (or argon-rich gas mixtures)
• DCEP Polarity
• Current above the transition current
Q: In what form is metal transferred in the axial spray metal transfer method?
A: Molten metal drops
Q: Why is the term GMAW preferable to MIG?
A: Originally MIG referred to welding aluminum with argon shielding. Introduction of CO2 and
O2 in shielding gases led AWS to prefer GMAW term as it better covers all variations.
Q: What current ranges does the pulsed arc metal transfer shift between?
A:
• High current pulse for axial spray transfer
• Lower pulse current allowing weld pool cooling and contraction
• Total heat input is lower than axial spray transfer
Pulsed arc metal cycle components:
Ramp Up, Overshoot, High Pulse Current, High Pulse Time, Ramp Down, Step off Current,
Background Current, Pulse Width
Q: What is GMAW-P (Pulsed Arc Metal Transfer)?
A: Dual pulsed current with high pulse for axial spray transfer and low pulse for cooling weld
pool, making control easier.
Q: Why add helium to argon in some spray or pulsed-spray welds?
A: Produces a very hot arc for thick section welds; helium increases arc temperature and
penetration.
