What is the role of the arc in SMAW?

In Shielded Metal Arc Welding (SMAW), the primary role of the arc is to melt both the electrode and the base metal. This melting occurs due to the extremely high temperatures generated by the electric arc, which forms when a current flows between the electrode and the workpiece. The heat produced by this arc enables the fusion of metal, allowing the molten electrode to become part of the weld pool, which combines with the molten base metal to create a strong bond upon cooling.

While the arc does emit light, which can enhance visibility during the welding process, this is a secondary effect and not its primary function. Furthermore, while it does provide some heat, the arc is essential for melting metals, and it does not heat solely for the purpose of pre-heating the workpiece or maintaining temperature. Therefore, the critical aspect of the arc in SMAW is its ability to melt both the electrode and the base material, facilitating the welding process effectively.