How does the cleaning action of DCEP work?

The cleaning action of Direct Current Electrode Positive (DCEP) works primarily through the movement of electrons during the welding process. In DCEP, the electrode is positively charged, which leads to a higher rate of electron transfer from the workpiece to the electrode. This transfer results in the lifting of the oxide layer from the surface of the base metal.

When the arc forms, the heat generated is sufficient to melt this oxide layer, which may hinder the welding process by contaminating the weld pool. As the electrons move from the workpiece (negatively charged) toward the electrode (positively charged), they effectively dislodge the oxide layer, allowing for a clean surface. This cleaning action is crucial for achieving strong and reliable welds, as it ensures proper fusion between the base metals without the interference of contaminants.

In contrast, applying heat to the workpiece does contribute to melting but does not specifically address the cleaning of the oxide layer. Adding flux can also help with cleaning, but it is a separate technique, and thus does not describe the inherent action of DCEP. Increasing the arc voltage around the workpiece may influence the penetration and arc stability but does not specifically relate to the cleaning mechanism of the oxide layer.