Consumption of graphite electrodes in steelmaking

In the cost of electric arc furnace steelmaking, the consumption of graphite electrodes accounts for about 10%. The consumption of electrodes in steelmaking includes normal consumption (such as arc consumption, chemical consumption and oxidation consumption) and abnormal consumption.

(1) Arc consumption is also called evaporation consumption. This is because an arc is generated between the electrode and the charge, and the temperature is as high as 3000°C, so there is continuous graphite consumption at the electrode end. This consumption accounts for about 40% of normal consumption. It has nothing to do with electrode diameter. It is proportional to the square of the passing current.

(2) Chemical consumption means that the electrode reacts with iron, calcium, manganese and other oxides in the steel slag or reacts with iron in the molten steel to be consumed. It is related to scrap quality, smelted steel grade and electrode diameter.

(3) Oxidation consumption refers to the consumption caused by the reaction of electrodes with oxygen and moisture in the steelmaking process. Oxidative consumption mainly occurs on the side of the electrode. Oxidation consumption plus the exfoliation of carbon particles on the side of the electrode accounts for 50% to 60% of normal consumption. It is related to the furnace atmosphere, gas temperature, flow rate and other factors, and the gas flow rate has the greatest influence.

(4) Abnormal consumption includes mechanical or artificial electrode breakage, joint tripping, serious oxidation in the buckle, and joint expansion that will cause the electrode to burst and crack.