Causes of cracks in graphite products

1. The quality of charging is not high

The charging operation of graphite furnace does not conform to the standard. When the furnace cores of articles are arranged irregularly, the spacing of the product groups is inconsistent. The uneven filling materials and even the resistance materials appear The phenomenon of "material expansion" occurs in the graphitization furnace. The whole process of the current emission power distribution in the graphitization furnace is very uneven, which leads to uneven heating products and heating rate. The internal product temperature is too high, and the thermal stress makes the products produce crack waste products.

2. Uneven quality of resistance material

Graphitization When different mixed coke is used as resistance material, the resistivity of metallurgical coke is 5-8 times higher than that of graphitized coke. If the mixed structure of metallurgical coke and graphitized coke is not evenly mixed, the main distribution of resistance in the furnace core will be uneven, resulting in the uneven development of temperature rise speed in various parts of the furnace core when the system is powered on, and the temperature difference between the upper and lower parts of the product enterprise and the surrounding environment is too large, and the thermal stress also changes with the increase of temperature It is easy to produce a large number of cracks in the products.

3. Bias flow in graphitization furnace core

According to the traditional heating method of graphitization furnace, not only the temperature distribution related to the resistance of furnace core, but also the current passing through the furnace core is closely related. When the bias current occurs due to various reasons, the current passing through the furnace core is greatly different, and the temperature distribution of the furnace core is very different. As a result, the temperature difference inside the product is also large, and the thermal stress generated is correspondingly increased, which makes the products produce crack waste products.