Which statement describes tungsten suitability for welding materials?

• A. Not suitable for aluminum and magnesium.
• B. Not suitable for steel or nickel alloys.
• C. Very suitable for welding on steel, steel alloys, nickel alloys, and most metals other than aluminum and magnesium.
• D. Only suitable for aluminum.

Answer: (C)

Tungsten electrodes in GTAW provide a stable, non‑consumable arc with excellent heat control, which makes them effective for welding a wide range of metals. For steel and steel alloys, the arc stability and low contamination of the tungsten tip allow clean, reliable welds with precise control. The same stability and broad applicability extend to nickel alloys and many other metals, so tungsten is considered very suitable across those materials.

Aluminum and magnesium present additional challenges due to their surface oxide layers, which require proper AC operation and sometimes different tungsten types or preparations to maintain a clean arc. In a general sense, tungsten is not as straightforward for aluminum and magnesium as it is for steel and nickel alloys, so statements that lump those two metals as universally unsuitable reflect that practical nuance.

Therefore, describing tungsten as very suitable for welding on steel, steel alloys, nickel alloys, and most metals other than aluminum and magnesium best captures its broad usefulness while acknowledging the extra care aluminum and magnesium require.