Which of the following is an inert shielding gas commonly used in GTAW?

Which of the following is an inert shielding gas commonly used in GTAW?

• A. Helium
• B. Hydrogen
• C. Nitrogen
• D. Oxygen

Answer: (A)

Shielding gas used in GTAW must protect the weld from reacting with air, so it needs to be inert. Helium is inert under welding conditions, meaning it won’t chemically contaminate the molten metal. It also provides a hotter arc due to its higher thermal conductivity, which can be beneficial for certain materials or thicker sections. The other gases listed aren’t inert in this context: hydrogen is reactive and can cause porosity or embrittlement; nitrogen and oxygen would readily react with the weld pool and degrade weld quality. So helium is the inert shielding gas commonly used in GTAW.

Shielding gas used in GTAW must protect the weld from reacting with air, so it needs to be inert. Helium is inert under welding conditions, meaning it won’t chemically contaminate the molten metal. It also provides a hotter arc due to its higher thermal conductivity, which can be beneficial for certain materials or thicker sections. The other gases listed aren’t inert in this context: hydrogen is reactive and can cause porosity or embrittlement; nitrogen and oxygen would readily react with the weld pool and degrade weld quality. So helium is the inert shielding gas commonly used in GTAW.