Welding electrodes are classified according to different situations, welding, there are three classification methods: melting characteristics of slag after classification by drug skin electrode use classification, according to the classification of the main chemical components of the drug skin. In accordance with the purpose of the welding rod, welding can be divided into: structural steel welding rod, heat-resisting steel electrodes, stainless steel welding rod, welding electrodes, low temperature steel electrodes, Cast Iron Electrode, nickel and nickel alloy electrode, copper and copper alloys, aluminum and aluminum alloy electrode, and special purpose welding rod. Classified according to the chemical composition of the electrode drug skin, welding can be divided into: type electrode of titanium dioxide, titanium dioxide calcium electrode, ilmenite type electrode, the iron oxide type electrode, cellulose type electrode, low hydrogen type electrode graphite electrode and the base electrode. According to the melting of the electrode drug skin characteristics of the slag to classification, welding can be divided into acid electrode and alkaline welding rod. The main ingredient of the drug skin acid electrode for acidic oxides such as silica, titanium dioxide, ferric oxide, etc.. Alkaline electrode main ingredient of the drug skin as alkaline oxides, such as marble, fluorite.