Which effect is observed when oxygen is added to argon shielding gas in GMAW?

Which effect is observed when oxygen is added to argon shielding gas in GMAW?

• A. Molten metal temperature decreases.
• B. Molten metal temperature increases.
• C. Arc stability is eliminated.
• D. No change to temperature.

Answer: (B)

Adding a small amount of oxygen to argon shielding gas changes the arc chemistry in GMAW, making the arc more conductive and hotter. The oxygen helps ionize and stabilize the plasma, which can raise the arc voltage and deliver more energy to the weld pool. That increase in energy translates to a higher heat input, melting more metal and driving up the molten pool temperature. While too much oxygen can cause oxidation or instability, a modest addition typically boosts heat input and raises the molten metal temperature.

Adding a small amount of oxygen to argon shielding gas changes the arc chemistry in GMAW, making the arc more conductive and hotter. The oxygen helps ionize and stabilize the plasma, which can raise the arc voltage and deliver more energy to the weld pool. That increase in energy translates to a higher heat input, melting more metal and driving up the molten pool temperature. While too much oxygen can cause oxidation or instability, a modest addition typically boosts heat input and raises the molten metal temperature.