High power and ultra high power electrodes
The characteristics of high-power and ultra-high-power electrodes are low electrical resistivity, allowing current load to be 25%-40% higher than ordinary electrodes; allowable current density is more than doubled; thermal expansion coefficient is small; flexural strength is high; and oxidation loss is small. The production of high-power and ultra-high-power electrodes uses needle coke as raw material, and uses multiple impregnations in the production process to increase the graphitization temperature, and correspondingly improve the bonding agent and impregnating agent.
The requirements for ultra-high-power graphite electrodes are relatively strict. The volume density of the electrode reaches 1.72g/cm3; the resistivity drops to 5-7Ω.mX10-6. Because the allowable current density of ultra-high power is more than twice that of ordinary electrodes, the thermal stress and thermal shock it bears increases. Correspondingly, the thermal expansion coefficient of the electrode is required to be low, and sufficient mechanical strength, such as compressive strength, is required. Then about 26.8Mpa. The ultra-high-power electrode introduces a large current intensity and a large voltage fluctuation, which is prone to intermittent arcing. Therefore, it is also required to have good "arc stabilization" performance.
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