The joint of the graphite electrode must be superior to the electrode body, therefore, the joint has a lower Coefficient of thermal expansion and a higher Coefficient of thermal expansion than the electrode.
The tight or loose connection between the connector and the electrode screw hole is influenced by the difference of thermal expansion between the connector and the electrode. If the joint axial Coefficient of thermal expansion exceeds the electrode Coefficient of thermal expansion, the connection will be loosened or loosened. If the Joint Meridional Coefficient of thermal expansion greatly exceeds the Coefficient of thermal expansion of the electrode screw hole, the electrode screw hole will be subjected to expansion stress. The different thermal expansion of the joint and the electrode holes is influenced by the temperature distribution of the inherent (CTE) and cross-section of the two graphite materials, and this temperature gradient is a function of the degree of tightness. If the interface contact resistance is high at the beginning, this is due to the contact surface with lime powder (dust) , end damage, bad connection, or due to processing defects, which will make the joint through more current, resulting in overheating of the joint, the interface pressure at the joint depends on the frictional pressure between the two components, but the Coefficient of thermal expansion is also a factor that should not be underestimated.
In practical use, the temperature of the joint is always higher than that of the electrode at the same horizontal position. With the increase of temperature, both the electrode and the joint produce linear expansion. Whether the electrode and the joint match or not often depends on whether the thermal expansion coefficient of the electrode joint matches or not.
Although there is no perfect thing in the world, Hexi carbon company tries its best to consider various factors when producing graphite electrode joints, so as to achieve perfection as far as possible and improve product quality as far as possible.
Post time: Apr-26-2021