Graphitized electrodes are used as conductive materials in electric arc furnaces to smelt various steel alloys, ferroalloys, nonferrous metals, and rare metals. Graphite tubes and crucibles, machined from graphitized electrode blanks, are also used in the smelting of cemented carbide and the production of quartz glass.
Graphitized electrodes are made from petroleum coke and pitch coke, with coal tar as a binder. They have very low ash and impurity content, excellent conductivity, and excellent heat and corrosion resistance. They do not melt or deform at high temperatures, making them suitable conductive materials for use in electric arc furnaces.
It is well known that melting metals and alloys in electric furnaces requires a large amount of heat generated by electric current. This current must be introduced into the furnace through a conductor. In addition to the aforementioned reasons, carbon graphite is chosen as an electrode material for electric arc furnaces because the carbon arc has a very high temperature. Besides the atomic hydrogen arc, the carbon arc is the hottest electric arc.
The arc between electrodes of different materials reaches the point where the electrodes are inserted into the furnace through a circular hole in the furnace roof and secured with a water-cooled electrode holder. To adjust the arc, the height of each electrode can be adjusted individually using an automatic adjustment device. Graphite electrodes are divided into ordinary graphite electrodes and special graphite electrodes. Ordinary graphite electrodes are made from petroleum coke, pitch coke, and coal tar pitch; special graphite electrodes are made primarily from high-quality petroleum coke and are used as conductive electrodes in higher-power electric arc furnaces.