Source of heating during arc welding is a welding arc, which is a stable electrical discharge occurring in the gas between two electrodes or electrode and the workpiece. To maintain discharge the required duration has developed special sources. When powered by alternating current arc welding transformers are used when dc welding – welding generators, or welding rectifiers. The proposed nn Benardos and ng Slavyanov methods arc welding consumable and consumable electrodes formed the basis for developing the most common modern methods of arc welding. Improvement of arc welding proceeded in the following areas: development of the electrode and the filler material to seek remedies and handling of molten metal weld pool; process automation. By nature of the protection of welded metal and the weld pool from the environment, there are ways arc welding slag, and gas gazoshlakovoy protection. By type of electrode material distinguished arc welding consumable and non-consumable electrode. Consumable elec trodes are metal wires and rods of steel, aluminum alloys, titanium, nickel, copper and other metals; nonconsumable – coal, graphite, tungsten rods.
When arcing and melting of the electrode and the weld metal necessary to protect the weld pool from atmospheric gases – oxygen, nitrogen and hydrogen, since they dissolve in the liquid metal and degrade the quality of weld metal. By way of shielding, the arc itself and the end of the heated electrode from atmospheric gas arc welding is divided into the following types: welding with covered electrodes, submerged arc welding, shielding gas; self-shielding flux cored wire; in a vacuum, with a combined protection. On the degree of automation of the process are distinguished by hand, mechanized and automatic welding. The following are the characteristics of and description of the main species arc welding.