FCAW and GMAW are welding on DC polarity, but they are never used on which type of current?

FCAW (Flux-Cored Arc Welding) and GMAW (Gas Metal Arc Welding) are processes that typically utilize DC polarity to achieve a stable arc and effective weld quality. When considering the characteristics of each type of current, AC (Alternating Current) is not commonly used with these processes because AC can lead to fluctuations in arc stability, penetration, and heat input, which may adversely impact the overall quality and consistency of the weld.

The nature of AC, where the current periodically reverses direction, is not ideal for the welding processes that benefit from the more stable and controllable characteristics of DC. In contrast, DC current provides a constant flow that helps maintain the necessary heat and penetration during welding, which is crucial for the success of FCAW and GMAW.

While the other types of current mentioned – DC, High Frequency Current, and Low Voltage Current – may have applications in certain welding scenarios or processes, AC is specifically notable for not being compatible with FCAW and GMAW when compared to the advantages offered by DC polarity.