Compare 100% CO2 shielding gas with a mixed Argon/CO2 (e.g., 75/25) for GMAW of carbon steel, including effects on spatter, penetration, and arc stability.

• A. 100% CO2 yields deeper penetration and robust arc but more spatter and rough bead; 75/25 Argon/CO2 reduces spatter and improves bead appearance and arc stability, with slightly less penetration.
• B. 100% CO2 yields shallower penetration and less spatter, while 75/25 yields deeper penetration.
• C. Gas type has no effect on welding.
• D. Using argon reduces cost.

Answer: (A)