Performance and Dimensional Tolerances of Graphite Blocks

Graphite blocks are used as conductive electrodes in industrial processes such as electrolytic magnesium and electrolytic zinc production. Additionally, they are widely utilized in the chemical industry for manufacturing corrosion-resistant heat exchange equipment and for constructing high-temperature furnaces.

Depending on the requirements of the user, the production of graphite blocks may involve impregnation with coal tar pitch under pressure before graphitization. This treatment can extend the service life of graphite blocks used as conductive electrodes in the electrolytic industry. Before leaving the factory, graphite blocks are tested for their specific resistance and compressive strength.

For graphite blocks used as conductive electrodes in electrolytic devices, high-quality standards are required. For those used in making heat exchange equipment and building high-temperature furnaces, higher specific resistance can be tolerated.

The shape of the graphite blocks should meet the following requirements:

1. Edges and Corners: Chipped edges or corners should not exceed a depth of 20 mm (chips less than 10 mm are not counted), with a maximum length of 80 mm, and no more than two instances per block.
2. Cracks: For 220×220 mm and 400×115 mm graphite blocks, surface cracks less than 0.3 mm wide are not counted. Cracks between 0.3 and 1.0 mm wide and up to 100 mm long are limited to two instances per block. For 400×400 mm graphite blocks, cracks less than 0.5 mm wide and 50 mm long are not counted. Cracks between 0.5 and 1.0 mm wide and 50 to 100 mm long are limited to two instances per block.