Popular Science on Consumption Mechanism of Graphite Electrodes

The consumption of graphite electrodes in electric furnace steelmaking is mainly related to the quality of the electrode itself, and is also closely related to the furnace conditions (such as the age of the furnace, whether there are mechanical failures, whether it is continuous production, etc.) and steelmaking operations (such as smelting steel type, oxygen blowing time, furnace charge conditions, etc.). Here we only discuss the consumption of graphite electrodes themselves, and its consumption mechanism has the following aspects:
1. End consumption: including the sublimation of graphite materials caused by the high temperature of the arc and the loss of chemical reactions between the electrode end and molten steel and slag. The high-temperature sublimation rate of the end mainly depends on the current density passing through the electrode, and secondly on the diameter of the electrode side after oxidation. The end consumption is also related to whether the electrode is inserted into the molten steel to increase carbon.
2. Side oxidation: The chemical composition of the electrode is carbon. Carbon will undergo oxidation reactions with air, water vapor, and carbon dioxide under certain conditions. The amount of electrode side oxidation is related to the unit oxidation rate and exposure area. Under normal circumstances, the amount of electrode side oxidation accounts for about 50% of the total electrode consumption. In recent years, in order to increase the speed of electric furnace smelting, the frequency of oxygen blowing operation has been increased, resulting in increased oxidation loss of electrodes. Frequently observing the redness of the electrode trunk and the taper of the lower end during the steelmaking process is an intuitive way to measure the electrode's antioxidant capacity.
3. Residual loss: When the electrode is used continuously to the connection between the upper and lower electrodes, a small section of the electrode or joint (i.e., the residual body) is detached due to oxidation and thinning of the body or penetration of cracks. The size of the residual loss is related to the shape of the joint, the internal structure of the electrode, and the vibration and impact of the electrode column.
4. Surface peeling and falling off: The result of rapid cooling and heating during the smelting process, and the poor thermal vibration resistance of the electrode itself.
5. Electrode breakage: including electrode trunk breakage and joint breakage. Electrode breakage is related to the quality and processing coordination of the graphite electrode and the joint itself, as well as the steelmaking operation. The cause is often the focus of dispute between steel mills and electrode manufacturers.