Welding gun is a hand-held tool used for arc welding. It usually consists of a handle, an electrode holder and a nozzle, which is used to heat the welding material to a molten state and form a weld on the surface of the workpiece. The welding gun transfers current to the welding material to generate a high-temperature arc, which melts the welding material and connects it to the surface of the workpiece, thereby achieving the purpose of welding.