Graphite electrodes are classified according to the power (the current passing under a certain voltage): ordinary power graphite electrodes RP, high-power graphite electrodes HP, and ultra-high-power graphite electrodes UHP. The structure of graphite electrode is composed of electrode body and electrode joint.
The working principle of the graphite electrode is also very simple. After being inserted into the electric arc furnace and energized, an arc is generated, and the electric energy is released in the form of an arc to heat and melt the scrap steel in the charge to make steel. The arc can be generated between the graphite electrode and the charge or between the graphite electrode and the graphite electrode. Arcing occurs. AC electric arc furnaces generally require three graphite electrodes to be energized at the same time, and DC electric arc furnaces only need one graphite electrode, but the diameter is larger.
1) Ordinary graphite electrodes are used in general industrial power electric arc furnaces, which allow the current density to be lower than 17A/cm2, and are mainly used for making ordinary steel, silicon and yellow phosphorus, etc.
2) High-power graphite electrodes are used in high-power electric arc furnaces, which allow a current density of 18~25A/cm2, and are mainly used for steelmaking.
3) Ultra-high power graphite electrodes are used in electric arc furnaces of the same power, which allow a current density greater than 25A/cm2, and are mainly used for melting refined steel and special steel.
In addition, in the field of electrolytic metals, graphite electrodes are also used to electrolyze metal magnesium, aluminum, and sodium. The anodes in the electrolytic cell also use graphite electrodes, and the furnace heads used to produce emery in resistance furnaces also use graphite electrodes.