Compared to CO2, argon is an excellent shielding gas for GMAW because it promotes the use of:

Compared to CO2, argon is an excellent shielding gas for GMAW because it promotes the use of:

• A. spray metal transfer.
• B. globular metal transfer.
• C. short-circuit metal transfer.
• D. low gas flow rates in globular transfer.

Answer: (A)

The key idea here is how shielding gas influences the metal transfer mode in GMAW. Argon-friendly shielding stabilizes the arc and supports spray transfer, where many fine droplets are continuously transferred across the arc to the weld pool. This mode requires a stable, high-energy arc and good shielding, and it produces smooth, uniform beads with high deposition efficiency and less spatter compared with other transfer modes. CO2, on the other hand, tends to destabilize the arc and promote globular transfer, which creates larger droplets, more spatter, and a rougher bead. Short-circuit transfer is a different mode that occurs at lower currents and is not what argon-rich shielding is best at promoting. So argon is preferred for GMAW because it enables spray transfer, delivering better weld quality and efficiency.

The key idea here is how shielding gas influences the metal transfer mode in GMAW. Argon-friendly shielding stabilizes the arc and supports spray transfer, where many fine droplets are continuously transferred across the arc to the weld pool. This mode requires a stable, high-energy arc and good shielding, and it produces smooth, uniform beads with high deposition efficiency and less spatter compared with other transfer modes. CO2, on the other hand, tends to destabilize the arc and promote globular transfer, which creates larger droplets, more spatter, and a rougher bead. Short-circuit transfer is a different mode that occurs at lower currents and is not what argon-rich shielding is best at promoting. So argon is preferred for GMAW because it enables spray transfer, delivering better weld quality and efficiency.