In submerged arc welding, the ignition arc, wire feed, arc movement along the welding direction, and the welding tail are completely performed by the machine. The flux 2 flows out from the hopper 3 and is evenly piled on the assembled workpiece 1. The welding wire 4 is fed into the welding arc zone by the wire feeding mechanism via the wire feeding roller 5 and the contact tip 6. The two ends of the welding power source are respectively connected to the contact tip and the workpiece. Wire feeders, flux hoppers, and control disks are usually mounted on a small cart to move the welding arc. The welding process is automatically controlled by operating a button switch on the control panel. During the welding process, a layer of 30-50mm thick granular flux is covered by the workpiece where the workpiece is welded. The continuous feeding wire produces an arc between the welding layer and the weldment. The heat of the arc dissolves the wire, the workpiece and the flux and forms metal. The baths keep them from the air. As the welder automatically moves forward, the arc continues to melt the weld metal, wire, and flux in front of it, and the edge behind the bath begins to cool and solidify to form the weld. The liquid slag then condenses to form a hard slag shell.