What are ordinary power, high power and ultra-high power graphite electrodes

The development of electric furnace steelmaking technology (large-scale electric furnaces, increase in electric power per unit furnace capacity and use of DC electric arc furnaces) has continuously put forward new requirements for the varieties and performance of graphite electrodes. The use of high power and ultra-high power electric furnaces for steelmaking can shorten the melting time of furnace materials, improve production efficiency, reduce electricity consumption and reduce the consumption of graphite electrodes. According to the transformer capacity per ton of furnace capacity, electric arc steelmaking furnaces can be divided into ordinary power electric furnaces (about 300kV, A per ton of furnace capacity), high power electric furnaces (about 400kV.A per ton of furnace capacity) and ultra-high power electric furnaces (500~1200kV/A per ton of furnace capacity).

According to the classification of electric power levels for electric furnace steelmaking, and based on the different raw materials used to produce electrodes and the differences in the physical and chemical indicators of finished electrodes, graphite electrodes are divided into three varieties: ordinary power graphite electrodes (RP), high power graphite electrodes (HP) and ultra-high power graphite electrodes (UHP).

Ordinary power graphite electrodes are produced from ordinary grade petroleum coke, with low graphitization temperature, high resistivity, large linear expansion coefficient, and poor thermal shock resistance, so the permissible current density is low. High power graphite electrodes are produced from petroleum coke (or low-grade needle coke), and sometimes the electrode body needs to be impregnated. Its physical and mechanical properties are higher than those of ordinary power graphite electrodes, such as low resistivity and a larger permissible current density. Ultra-high power graphite electrodes must be produced from needle coke, and their graphitization heat treatment must be carried out in an internal graphitization furnace. The graphitization temperature is as high as 2800 ~ 3000 degree C, so the resistivity is lower, a larger current density is allowed, the linear expansion coefficient is smaller, and it has excellent thermal shock resistance.