What is a "welding arc"?

A welding arc is defined as the electrical discharge that occurs between the electrode and the workpiece during the welding process. This arc generates intense heat, which melts the base materials and allows them to fuse together. In MIG welding, the electrode is a filler wire that is continuously fed into the weld pool, and the arc is crucial for creating that weld pool by providing the necessary thermal energy.

The welding arc is characterized by its brightness, temperature, and stability, which are essential for producing high-quality welds. The parameters that govern the arc, such as voltage and current, can significantly impact the weld's penetration, appearance, and overall strength, making an understanding of the welding arc vital for anyone involved in welding processes.

Other choices do not accurately define a welding arc, as they refer to different aspects of the welding process. One option discusses the physical interaction of metals, another addresses equipment for quality measurement, and the last describes an auditory phenomenon. Each of these concepts is relevant to welding, but they do not encompass the true nature of what a welding arc is.