Arc welding is a process used to join metals together by using an electric arc to create heat. This heat melts the base metal and a filler material, allowing them to fuse as they cool. The arc is formed between an electrode and the workpiece, which can be done in various environments, including open air or controlled atmospheres. There are several types of arc welding, including Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW). Each method has its own advantages and is suited for different applications, making arc welding a versatile technique in industries like construction and manufacturing.