If the workpiece is positive, what polarity is used?

When the workpiece is positive, the correct polarity used is DCEN (Direct Current Electrode Negative) or DCSP (Direct Current Straight Polarity). This choice highlights the relationship between the polarity of the weld and the characteristics of the welding process. In DCEN, the workpiece is connected to the positive terminal of the power source, while the electrode is connected to the negative terminal.

Using DCEN is particularly advantageous for achieving deeper penetration in the weld due to the higher heat concentration at the workpiece. This polarity is commonly used in processes like shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW), providing optimal conditions for welding ferrous materials effectively.

On the other hand, the other options listed involve either alternating current (AC) or polarities that do not align with traditional definitions and practices in welding. For instance, while AC can be suitable for certain applications, it does not have the same penetration characteristics as DCEN when the workpiece is positive. Understanding these principles is crucial for selecting the right polarity in various welding scenarios.