In pulse GTAW, two currents are used; one is called peak current and the other is called ____.

In pulse gas tungsten arc welding (GTAW), the process utilizes two distinct current levels: the peak current and the background current. The peak current is responsible for providing the necessary heat input for melting the base metal and adding filler material, while the background current is lower in intensity and serves to maintain the weld pool without overheating the base metal.

The background current plays a crucial role in controlling the heat distribution during the welding process. By using a lower current during the background phase, the welder can prevent excessive heat buildup, allowing for better control over the weld pool and resulting in improved weld quality. This technique helps reduce the risk of issues such as burn-through, warping, or distortion of the workpieces.

The terms related to currents such as DCEP (Direct Current Electrode Positive) and DCEN (Direct Current Electrode Negative) specifically refer to the polarity of the welding circuit rather than being types of currents in the context of pulse GTAW. Valley current is not a recognized term within the pulse GTAW process. Therefore, the background current is the correct answer as it directly describes the second current used in pulse GTAW alongside the peak current.