Electrical resistivity of graphite electrodes is a physical indicator of their conductivity, influenced by the manufacturing process. National standards specify qualitative values for the electrical resistivity of graphite electrodes of different specifications and types. Generally, when a steel plant selects electrodes of a certain specification, it must choose those within the electrical resistivity range specified by national metallurgical standards. Excessive electrical resistivity can cause the graphite electrodes to heat up and turn red when conducting electricity, leading to increased oxidation and consumption of the electrodes.
The bulk density of graphite electrodes reflects their compactness and is closely related to the manufacturing process. National standards specify values for the bulk density of graphite electrodes of different specifications and types. A low bulk density indicates a higher overall porosity, leading to faster oxidation at high temperatures and increased electrode consumption. Generally, steel plants prefer electrodes with higher bulk density values within the specified range. However, higher bulk density is not always better, as excessively high bulk density can result in poor thermal shock resistance, causing surface peeling, chipping, and cracking during steelmaking, which negatively affects the process.