Abstract：
Graphite electrodes are widely used in metallurgy, petrochemical, and other industries. The quality of graphite electrodes directly affects the production and quality of steel products and the normal operation of the electric arc furnace. The main influencing factors of the surface quality of graphite electrodes include start-up method, amount of electrode paste, type of electrode paste, electrode column installation and maintenance, and power supply parameters. A comprehensive summary of various measures and technologies to improve the surface quality of graphite electrodes is made in this paper. All of this is applicable to the needs of industrial production.
1. Introduction
Graphite electrodes are widely used in metallurgy, petrochemical and other large-scale industrial fields. The use of graphite electrodes in modern electric arc furnaces is extensive and is an important part of the steelmaking process. The surface quality of graphite electrodes directly affects the normal production, quality and consumption of steel products, and has an important influence on the electrical energy consumption and power consumption of the electric arc furnace. Therefore, a good surface quality is an important indicator for evaluating the quality of graphite electrodes, and it is necessary to ensure the surface quality of graphite electrodes.
At present, the main factors affecting the surface quality of graphite electrodes in industrial production include start-up method, amount of electrode paste, type of electrode paste, electrode column installation and maintenance, and power supply parameters. Therefore, it is necessary to strengthen the understanding of related technologies, study measures to improve the surface quality of graphite electrodes and promote their actual application.
2. Start-up method
The start-up method is an important factor affecting the surface quality of graphite electrodes. The commonly used graphite electrode start-up method includes line start-up, three-phase cross-start-up and line-alignment start-up. The method of cross-startup before turning on the power supply is beneficial to reduce the starting impact current, but it is easy to damage the carbon block or insulation layer of the graphite electrode column due to the high electrical strength at the cross point. The line drive needs to consume more electrode paste and has a large starting impact current, and it will cause less damage to the carbon block and insulation layer. The line-loaded start-up method is the most common start-up method and has no effect on the surface quality of graphite electrodes. Therefore, it should be noted that the start-up of graphite electrodes should be used in combination with different occasions in order to achieve better results.
3. Amount of electrode paste
The amount of electrode paste is one of the important factors affecting the surface quality of graphite electrodes. Obviously, if the amount of electrode paste used is too small, it will be difficult to connect the graphite electrode electrodes. At the same time, the small amount of electrode paste will reduce the cross-sectional area of the graphite electrode, causing a significant increase in the current density of the electrode, which will cause heating on the electrode surface, even burn marks. If the amount of electrode paste used is too large, it will also cause high current density on the electrode surface and affect the surface quality of the graphite electrode.
Therefore, when determining the amount of electrode paste used during graphite electrode connection, it is necessary to pay attention to the properties of the electrode paste, adjust the amount of the electrode paste according to the properties of the electrode paste, and make the current density at the interface between the electrode paste and the graphite electrode uniform. It should be noted that the amount of electrode paste used should not be too large, which will cause waste and increase cost.
4. Electron paste type
The types of electrode paste used in graphite electrode connection include grease-based and humectant-based. The grease-based electrode paste is suitable for high current and long-term connection. The grease-based electrode paste has strong hydrophobicity, high current capacity and good insulation performance, which can reduce the temperature rise, but the surface quality is poor. The humectant-based electrode paste has better surface quality, which is beneficial to improve the surface quality of the graphite electrode during arc output, and can reduce the consumption of electrode paste. The graphite electrode can be selected according to the type of electrode paste according to the working conditions of the furnace and the current-carrying capacity of the electrode paste.
5. Installation and maintenance of electrode column
The installation and maintenance of graphite electrode column is also an important factor influencing the surface quality of graphite electrode. The graphite electrode should be flatly laid in the furnace and firmly fixed. The gap between the electrodes should not be too small to avoid short-circuit. The temperature of the electrode column should be monitored in real time during startup, and the electrode should be opened in time to remove the dust, oxide slag and electrode paste residue on the electrode column to avoid short circuits. In addition, the electrode joint should be inspected regularly to prevent joint faults and short circuits.
6. Control of power supply parameters
The control of power supply parameters is also an important means to improve the surface quality of graphite electrodes. When the furnace body is turned on and the workpiece is put in, a stable power supply should be maintained to keep the current ratio unchanged. In addition, during the melting process, it is necessary to adjust the working power and the voltage in time according to the change of the furnace body and the input of new ingredients to ensure a reasonable power distribution at all times. Otherwise, it will cause local overheating of the electrodes and reduce the surface quality.
7 Conclusion
The surface quality of graphite electrodes directly affects the production and quality of steel products, power consumption and efficiency of electric arc furnace. Start-up methods, electrode paste type and amount, installation and maintenance of graphite electrodes, and control of power supplies all need to be taken into account to improve the surface quality of graphite electrodes. In summary, these measures and technologies are applicable to the needs of industrial production.
