What type of polarity is primarily used for TIG welding to achieve lower heat input?

The correct answer is DCEN, which stands for Direct Current Electrode Negative. This type of polarity is preferred in TIG welding for achieving lower heat input primarily because it allows for greater heat concentration at the workpiece. In DCEN, the majority of the welding current flows to the workpiece, while the tungsten electrode receives less current. This results in less heat being generated at the electrode, thereby keeping it cooler. Ultimately, this promotes better control over the weld pool and minimizes the risk of overheating, which can lead to distortion or burn-through in thin materials.

In contrast, DCEP (Direct Current Electrode Positive) would cause the electrode to heat up more due to a greater amount of current flowing to it, which is not desirable when aiming for lower heat input. AC (Alternating Current) is commonly used for welding materials like aluminum but does not provide the same level of heat control as DCEN. Pulsed DC can help with heat control but is generally utilized in specific applications rather than serving as the primary option for lowering heat input in standard TIG welding situations.