The core and the drug electrode by the welding of two parts the skin. Metal welding electrode is external to the core coating (drug skin) evenly to carefully applied pressure on the core welding. Different types of welding rod, Welding Electrode core is different. Welding electrode metal core that is the core, in order to ensure the quality and performance of the weld, butt in the core content of the metal elements, there are stringent requirements, especially for harmful impurities (eg sulfur, phosphorus, etc.) content, there should be strict limitations, better than the base metal. Welding core components directly affect the weld metal composition and performance, so the welding core of the harmful elements to minimize welding carbon steel and low alloy steel welding core, low-carbon steel is generally used as a welding core, and fill up the manganese, silicon, chromium, nickel and other ingredients (see the national standard GB1300 an 77 wire). The reason one is low carbon low carbon steel wire plastic, wire drawing easier, on the other hand reducing gas to reduce CO content to reduce spatter or porosity, and increased the temperature of the weld metal solidification, beneficial to the overhead position welding. Other major alloying elements added to ensure the weld mechanical properties, while the welding performance and to remove impurities, also have a role. High-alloy steel and aluminum, copper, iron and other metal materials, its core components in addition to welding and welded metal similar requirements, but also have control of impurities, according to process requirements often adding certain alloying elements. Electrode is coated with a drug for skin melt welding electrodes used in arc welding, it is a drug and the skin-core solder composed of two parts. Drug in the skin are the front electrode of about 45 ° chamfer, which is to facilitate the arc. In the rear there is a bare core welding, welding rod length of about 1 / 16, to facilitate the welding clamp holding and help conduct electricity. Electrode diameter Chung actually refers to Mig Electrode core diameter) is usually 2,2. 5,3 2 or 4, 5 or 6mm and other types of specifications, used a small 3.2 small 4 small 5 three species, its length "L" is generally between 250 ^ -450 mm.