In which current mode does the majority of heat develop at the workpiece?

The correct answer is electrode negative polarity. In gas tungsten arc welding (GTAW), when using electrode negative (also referred to as direct current electrode negative or DCEN), the majority of the heat generated during the welding process is concentrated at the workpiece. This is because the DCEN mode causes electrons to flow from the electrode to the workpiece, resulting in a more efficient transfer of energy and higher heat input at the workpiece compared to other current modes.

This concentrated heat at the workpiece is beneficial for achieving deeper penetration and allowing for better fusion of the materials being welded. Additionally, using electrode negative polarity helps in stabilizing the arc and can result in cleaner welds due to reduced oxidation and contamination.

In contrast, using electrode positive polarity (DCEP) shifts more of the heat to the electrode, which is less desirable for most GTAW applications focusing on effective penetration. Alternating current (AC) also distributes heat between the electrode and the workpiece, but does not offer the same level of focused heat on the workpiece as the DCEN mode. Direct current with constant voltage is a different configuration that does not specifically emphasize the current polarity, which makes it less effective for achieving optimal heat concentration on the workpiece in the context of