rp grade graphite electrode
Analysis of the causes of graphitization cracks in rp grade graphite electrode products
Causes of graphitization cracks in rp grade graphite electrode products During the graphitization process, the internal factors that cause the product to produce cracks are poor product quality and poor heat resistance; the external factors are excessive heating during the graphitization process and the temperature difference during the graphitization process , Temperature changes during graphitization, etc. The graphitization process, the temperature change during the graphitization process, the temperature change during the graphitization process, the temperature change during the graphitization process, and the temperature change during the graphitization process. Temperature change during graphitization, temperature change during graphitization, temperature change during graphitization, temperature change during graphitization, temperature change during graphitization, and increase in top and top thermal stress. Corresponding increase at the bottom of the product or around the product is the main cause of product cracking.
The graphitization process system is unreasonable
1. Furnace loading method rp grade graphite electrode manufacturers usually use vertical charging methods, including direct loading and cross loading.
When installing the core product, any product has only one high-density current heating belt. The wider the heating band, the more even the product will be heated. On the contrary, the heating is very uneven. When the packaging is wrong, each product has two high-density current heating belts, which are more uniform than the formal heating belts. Therefore, the charging method of the graphitization furnace product is improper. During the graphitization power transmission process, the temperature rise rate around the product changes greatly, and the thermal stress generated by the product exceeds the thermal stress that the body can withstand, resulting in the graphitization furnace The thermal stress of the product is reduced. The product is prone to cracks.
2. The temperature curve of the unreasonable graphitization furnace core of the electrified system is controlled by the power curve of constant power distribution.
If the electrification system of the graphitization furnace is unreasonable, the starting power of the electrification curve of the graphitization furnace is too large, and the rising power is too fast, so that the temperature gradient inside and outside the product during the electrification process is too large. During the processing, the thermal stress generated greatly exceeds the thermal stress of the product. Resistance causes cracks. Especially when the furnace temperature rises, in order to strictly control the rising stage of the furnace temperature, the physical structure and chemical composition of the product begin to undergo great changes at this stage. Graphitization of amorphous carbon has not yet begun. In fact, the chemical reaction is the main reaction. The combination of hydrogen, oxygen, nitrogen, and sulfur in the microcrystalline structure of amorphous carbon leads to escape. The impurity elements at the edge of the amorphous carbon microcrystalline structure are constantly decreasing, and there are certain lattice defects. At the same time, relatively concentrated thermal stress can easily cause product cracking.
3. Resistance Graphitized furnace core resistance is made up of product resistance and resistance material resistance in series.
When the graphitization furnace is energized, the resistance of the resistive material accounts for about half of the resistance of the furnace core, and after energization, the resistance of the resistive material also accounts for about half of the resistance. It can be seen that during the entire graphitization process, the current is mainly heated by the heat generated by the resistive material. When the resistance of the resistive material differs greatly from the resistance of the product, the heat generated by the resistive material during the graphitization process is far greater than the heat of the product itself. Therefore, if the temperature difference between the inside and outside of the product is too large, excessive thermal stress will be generated, causing the waste product to crack.