The addition of oxygen to argon causes the molten metal temperature to:

The addition of oxygen to argon causes the molten metal temperature to:

• A. decrease.
• B. increase.
• C. stabilize.
• D. oxidize.

Answer: (B)

Adding a little oxygen to argon changes the shielding gas from purely inert to slightly oxidizing, which makes the plasma more conductive and easier to ionize. That extra ionization boosts the energy density of the welding arc, delivering more heat to the weld pool. With more heat input, the molten metal rises to a higher temperature and can penetrate more easily. So the molten metal temperature goes up. The idea isn’t about oxidizing the metal itself as a chemical reaction in this moment; it’s about the arc delivering more heat due to the gas composition.

Adding a little oxygen to argon changes the shielding gas from purely inert to slightly oxidizing, which makes the plasma more conductive and easier to ionize. That extra ionization boosts the energy density of the welding arc, delivering more heat to the weld pool. With more heat input, the molten metal rises to a higher temperature and can penetrate more easily. So the molten metal temperature goes up. The idea isn’t about oxidizing the metal itself as a chemical reaction in this moment; it’s about the arc delivering more heat due to the gas composition.