Los Angeles City Structural Welding Code – Steel (D1.1) Certification Practice Test 2026 - Free Welding Certification Practice Questions and Study Guide

In the Gas Metal Arc Welding (GMAW) process, the power supply operates under a constant voltage characteristic. This is essential for maintaining arc stability and ensuring a smooth and consistent welding process. The constant voltage setting helps regulate the arc length which is critical in GMAW, as any variation in wire feed speed can affect the arc length and, subsequently, the weld quality.

A constant voltage power supply adjusts the output accordingly to maintain the set voltage, even when changes occur in the load, such as when the welder moves the torch or experiences variations in material characteristics. This adaptability is key for achieving uniform bead appearance and penetration, which are crucial in high-quality welds.

In contrast, other power supply types, like constant current, are better suited for processes such as Shielded Metal Arc Welding (SMAW) or Gas Tungsten Arc Welding (GTAW), where the arc length is more variable based on the weld conditions. In summary, the constant voltage power supply is integral to the effectiveness of the GMAW process.