The development of EAF steel-making technology constantly puts forward new requirements for the variety and performance of graphite electrode. Using high power and ultra-high power EAF steel-making can shorten the melting time, improve the production efficiency, reduce the power consumption and the consumption of graphite electrode.
According to the classification of electric power level in electric furnace steel-making, and according to the difference of raw materials used in electrode production and the difference of physical and chemical indexes of finished electrode, the graphite electrode is divided into three kinds: ordinary power graphite electrode (RP), high power graphite electrode (HP) and ultra-high power graphite electrode (UHP).
Ordinary power graphite electrode is produced with ordinary grade petroleum coke, which has low graphitization temperature, high resistivity, and poor thermal shock resistance, so the allowable current density is low.
The high-power graphite electrode is produced by high-quality petroleum coke or low-grade needle coke. Sometimes, the electrode body needs to be impregnated. Its physical and mechanical properties are higher than that of ordinary power graphite electrode, with low resistivity and large current density.
The ultra-high power graphite electrode must be produced with high-grade needle coke, and its graphitization heat treatment shall be carried out in the inner string graphitization furnace. The graphitization temperature is as high as 2800-3000 ° C, so the resistivity is lower, and it is allowed to pass through higher current density, and has excellent thermal shock resistance.
Ultra high power graphite electrode is mainly used as conductive material of electric arc furnace. Ultra high power graphite electrode refers to a kind of high temperature resistant graphite conductive material, which is made of petroleum coke, needle coke, pitch coke as aggregate, coal pitch as binder, through calcination, crushing and grinding, batching, kneading, molding, roasting, impregnation, graphitization and machining. It is called artificial graphite electrode.