Graphite electrodes are electrical conductors, which are electrical conductors under high temperature conditions. The quality of graphite electrodes is electrically conductive around high temperature. Therefore, it is necessary to investigate the current density of graphite electrodes when investigating the use of graphite electrodes.
Having a large allowable current density is one of the basic requirements for the electrode of an electric steelmaking. The current density is the ratio of the current intensity to the cross section of the electrode. The larger allowable current density means that the electrode of the same cross section can be reduced by the heat transfer loss of the electrode. The arc rate is increased and the oxidation consumption is reduced, providing potential for enhanced smelting.
If the actual current density through the electrode during steelmaking exceeds the allowable current density, it will cause oxidation of the electrode outside the furnace, especially causing overheating of the electrode joint and burnout of the joint, and even some of the joints will be broken together with the electrode. In the furnace, the result is to stop the furnace.
- The electrode diameter used in the steelmaking process should generally be selected in accordance with parameters that allow the current load and the allowable current density. Therefore, this is preferable from the viewpoint of heat transfer loss of the electrode and arc efficiency.
- The main way to increase the allowable current load and allow current density of the electrode is to lower the specific resistance, reduce the contact resistance at the electrode junction, and lower the specific resistance of the electrode joint.
- The joint and joint holes shall be closely machined, the diameter tolerance shall be reduced from 0.5 mm to 0.3 mm or even 0.2 mm, the joint hole shall be concentric with the center line of the electrode, and the end face of the electrode shall be perpendicular to the center line, so that the gap between the end faces of the two electrodes is less than 0.5 mm, the center The line deviation is no more than 3 mm.
Here, we only discuss the current density of graphite electrodes in steelmaking. The use of graphite electrodes in other smelting is similar. Of course, different smelting has different situations. Specific circumstances, specific analysis, specific treatment.