Decrease in the consumption of graphitized electrodes in arc furnaces during their forced cooling

Abstract

The cost of electrodes during steelmaking is a substantial (up to 12.5%) expenditure part of the end product and is sometimes higher than the cost of the consumed electric power. Therefore, it is necessary to perform a set of measures aimed at decreasing the exploitation consumption of graphitized electrodes. In order to enhance the competitive ability of electric steel products, it is necessary to increase the strength and exploitation reliability of graphitized electrodes, which is controlled, to a great extent, by their technical characteristics. Russian industry produces (TU 48-12-52‐93) electrodes with a diameter from 75 to 555 mm operating at a current density from 10 to 25 A/cm 2 . The technical characteristics of electrodes for both ac and dc furnaces depend on the graphite density ( γ = 1.6‐2.2 g/cm 3 ) and porosity ( σ = 1.4‐2) × 10 5 ( Ω m) ‐1 ). The material density exerts a greater effect on the thermal stability of the electrode, and the porosity mostly affects its oxidation. In addition, the density and electrical conductivity of electrodes affect their electrical resistance and, hence, the electric losses during electric-power transmission. Under the formed economical conditions, the quality of graphitized electrodes is a determining factor; therefore, imported rather than Russian electrodes are most frequently used for the exploitation of furnaces, especially high-power furnaces. Although the imported electrodes are more expensive (by a factor of 1.5‐2.0) but have higher technical characteristics.