What polarity is considered ideal for thoriated tungsten?

Thoriated tungsten electrodes are specifically designed for use with direct current, and the ideal polarity for their operation is DCEN, or Direct Current Electrode Negative. In this configuration, the electrode is connected to the negative terminal of the power supply, which leads to several beneficial effects during the welding process.

When using DCEN with thoriated tungsten, approximately 70% of the heat is generated at the workpiece rather than at the electrode. This results in better control of the weld puddle and improved penetration into the base material. The thoriated tungsten itself is designed to withstand high temperatures and to maintain stability, providing a consistent arc and more effective arc starting.

While alternating current (AC) and other polarities can be used in specific scenarios, they do not take full advantage of the benefits provided by thoriated tungsten. AC is typically advantageous for some aluminum welding applications, while DCEP (Direct Current Electrode Positive) can result in excessive heat at the electrode, causing premature wear. Thus, DCEN is the preferred choice for maximizing the effectiveness and longevity of thoriated tungsten electrodes in welding applications.