What is the relationship between pulse current and background current in pulsed-current GTAW?

In pulsed-current GTAW, the relationship between pulse current and background current is defined by their differing roles in the welding process. The pulse current is typically set to a higher level, which allows for increased heat input during the short bursts, promoting deeper penetration and faster melting of the filler material. In contrast, the background current operates at a lower level and provides a stable heat input that helps maintain consistent and controlled heating during the periods of lower current output.

This approach allows the welder to use the advantages of high current for penetrating welds while simultaneously avoiding excessive heat that could lead to problems such as warping or burn-through. The higher pulse current is essential for managing the fusion of the materials involved, whereas the lower background current is critical for controlling the weld pool and preventing overheating. This distinction highlights why one is significantly higher than the other in this particular welding technique.