What problem can an excessively large tungsten cause?

• A. They may result in too low a temperature for a stable arc.
• B. They cause the arc to overheat and burn back into the torch.
• C. They increase the arc stability too much.
• D. They prevent current from flowing at all.

Answer: (A)

In GTAW, electrode size controls how concentrated the heat is at the arc tip. An excessively large tungsten spreads the current over a bigger area, lowering the current density at the tip. With the given welding current, that means the arc temperature is too low to sustain a stable arc. The arc can become weak, unstable, or extinguish, making it hard to maintain good heat input and penetration. To fix this, use a tungsten diameter that matches the current you’re welding with, or increase the current within the electrode’s rating so the arc can reach the proper temperature.