Which polarity is most commonly chosen for direct current GTAW welding of steel?

In the context of direct current Gas Tungsten Arc Welding (GTAW), the most commonly chosen polarity for welding steel is Direct Current Electrode Negative (DCEN). Using DCEN means that the electrode, which is typically made of tungsten, is connected to the negative side of the power supply, while the workpiece is connected to the positive side.

The choice of DCEN is beneficial for several reasons. Firstly, it allows for greater heat concentration at the workpiece, as about 70% of the heat generated in the welding arc is transferred to the base material. This concentrated heat helps in achieving better penetration, which is particularly important when welding thicker sections of steel.

Moreover, DCEN minimizes the potential for electrode wear, as the heat generated at the electrode is less compared to when using an electrode connected to the positive side. This prolongs the life of the tungsten electrode, thus reducing downtime and the need for frequent replacement.

In summary, DCEN is favored in steel welding applications due to its efficient heat distribution, better penetration, and reduced electrode wear, making it the preferred choice in GTAW for steel.