What is the hardness of graphite electrodes?
By:Win Dec 10, 2020
Graphite electrode hardness is the flexural strength, Check the value of Bending strength in its physicochemical index.
Poor quality graphite electrode is easy to break when used in arc furnace, so it is necessary to test the hardness of graphite electrode when leaving the factory, Test its bending strength.
Flexural strength is usually measured by a four-point method, with two pressure heads above and two support points below, pressing down to determine the value of bending or breaking caused by external forces. Figure 1.
The main indexes of graphite electrode quality and property are Bulk density, Resistance, Chengdu Strength, Young's modulus, Thermal expansion coefficient and Ash content.
The electromagnetic force of large electric arc furnace increases and the vibration is violent. Under severe vibration, the probability of the electrode breaking due to loose connections and trips increases. Therefore, the physical and mechanical properties of super high power graphite electrode must be better than ordinary high power graphite electrode.
The bending strength is a parameter of the mechanical properties of graphite material, also known as bending strength. It refers to the ultimate resistance of an object from bending to breaking at the moment when the external force is perpendicular to the axis of the object. The unit is MPa. The strength of graphite material is significantly different from that of other metals and nonmetals. Its strength increases with the increase of temperature and reaches the highest at 2000-2500 ℃, which is 1.8-2 times of normal temperature, and then decreases somewhat. High - strength electrodes and joints, the more difficult to break in use.
The way to improve the flexural strength is to reduce the diameter of coke particles in the formula, improve the strength of carbonaceous raw materials, increase the volume density of products, reduce the internal defects of products, etc.