Why is control of current important when using tungsten electrodes?

Control of current is crucial when using tungsten electrodes because it directly affects the arc characteristics and the overall weld quality. A stable and consistent arc is necessary for producing high-quality welds, and varying current levels can lead to irregularities in the arc. This can manifest as unstable arc lengths or erratic arc movement, which in turn affects the heat input and penetration of the weld.

When the current is set appropriately, it ensures that the tungsten electrode can perform optimally, maintaining its condition and preventing excessive wear or degradation. High current can lead to overheating of the electrode, causing it to become contaminated or to melt, while too low of a current might not provide sufficient heat to achieve proper fusion in the weld puddle.

Maintaining control of the current thus contributes to the stability and predictability of the welding process, which is essential for achieving the desired mechanical properties and aesthetics of the weld. This decision ultimately impacts the integrity and performance of the weld joint.