The consumption of graphite electrode in electric furnace steelmaking is mainly related to the quality of electrode itself and the condition of steelmaking furnace (such as new or old furnace, mechanical failure, continuous production, etc.) is closely related to steelmaking operation (such as steel grades, oxygen blowing time, furnace charge, etc.). Here, only the consumption of graphite electrode itself is discussed, and its consumption mechanism is as follows:
1.End consumption of graphite electrode
It includes the sublimation of graphite material caused by arc in high temperature and the loss of biochemical reaction between graphite electrode end, molten steel and slag. The high temperature sublimation rate at the electrode end mainly depends on the current density passing through graphite electrode, Secondly, it is related to the diameter of the oxidized side of the electrode. Besides, the end consumption is also related to whether the electrode is put into the molten steel to increase carbon.
2.Side oxidation of graphite electrode
The chemical composition of the electrode is carbon, Oxidation reaction will be occurred when carbon mixed with air, water vapor and carbon dioxide under certain conditions. and the amount of oxidation on the side of graphite electrode is related to the unit oxidation rate and exposure area. In general, the consumption of graphite electrode side accounts for around 50% of the total consumption of the electrode.
In recent years, in order to improve the smelting speed of electric arc furnace, the frequency of oxygen blowing operation has been increased, resulting in increased oxidation loss of electrode. In the process of steel making, the redness of the electrode trunk and the taper of the lower end are often observed, which is an intuitive method to measure the oxidation resistance of the electrode.
When the electrode is continuously used at the connection between the upper and lower electrodes, a small section of electrode or nipple ( residue) Separation occurs due to the oxidation thinning of the body or the penetration of cracks. The size of the residual end loss is related to the shape of the nipple, the buckle type, the internal structure of the electrode, the vibration and impact of the electrode column.
4.Surface peeling and block falling
In the smelting process, it is caused by the rapid cooling and heating, and the poor thermal vibration resistance of the electrode itself.
Including the fracture of electrode body and nipple, Electrode breaking is related to the intrinsic quality of graphite electrode and nipple, Processing coordination and steel making operation. The reasons are often the focus of disputes between steel mills and graphite electrode manufacturers.
Post time: Mar-10-2022