For 1/4 inch steel in GTAW, what is the proper tungsten diameter?

• A. 1/8 inch
• B. 1/4 inch
• C. 3/16 inch
• D. 1/16 inch

Answer: (A)

When you choose a tungsten diameter for GTAW, you’re matching the electrode’s current-carrying capability to the amperage needed for the metal thickness. For welding 1/4 inch steel, the current used is in a mid-range that an 1/8 inch tungsten handles well. It provides a stable arc, good heat distribution, and longer electrode life at those currents. A smaller diameter like 1/16 inch would struggle at that current level and can overheat or arc unstable; a larger diameter like 3/16 or 1/4 inch would demand more current and reduce arc control, increasing heat input and making it harder to maintain a focused arc. So the proper tungsten diameter for 1/4 inch steel in GTAW is 1/8 inch.