Types of Graphite Electrodes

Today, Graphite Electrode Manufacturer will give you a loan for the variety of graphite electrodes.

According to the different raw materials used and the physical and chemical indicators of the finished product, graphite electrodes are divided into three types: ordinary power graphite electrodes (RP grade), high power graphite electrodes (HP grade) and ultra high power graphite electrodes (UHP grade). This is because graphite electrodes are mainly used to supply electric arc steelmaking furnaces as conductive materials. In the 1980s, the international electric furnace steelmaking industry classified electric arc steelmaking furnaces into three categories according to the transformer input power per ton of furnace capacity: ordinary power electric furnaces (RP Furnace), high power electric furnace (HP furnace) and ultra high power electric furnace (UHP furnace). Transformer input power per ton of furnace capacity of general power electric furnace above 20t is generally about 300kW / t; high power electric furnace is about 400kW / t; input power of electric furnace below 40t is 500 ～ 600kW / t, 50 ～ 80t electric furnace input power 400-500kW / t, 100t or more electric furnace input power 350-450kW / t is called ultra-high power electric furnace.

By the end of the 1980s, economically developed countries eliminated a large number of small and medium-sized ordinary electric furnaces below 50t. Most of the newly built electric furnaces were ultra-high-power large electric furnaces of 80 to 150t, and the input power was increased to 800kW / t. Some ultra-high power electric furnaces have been further increased to 1000-1200kW / t. The graphite electrodes used in high-power and ultra-high-power electric furnaces operate under more severe conditions. Due to the significantly increased current density through the electrodes.

As a result, the following problems arise: 

(1) The temperature of the electrode rises due to resistance heat and hot air flow, which causes the thermal expansion of the electrode and the joint to increase, and the oxidation consumption of the electrode also increases.

(2) The temperature difference between the center part of the electrode and the outer circle of the electrode has increased, and the thermal stress caused by the temperature difference has also increased accordingly. The electrode is prone to cracks and surface peeling.

UHP Graphite Electrode

(3) The electromagnetic force is increased, causing severe vibration. Under severe vibration, the probability of the electrode breaking due to loose connections and trips increases. Therefore, the physical and mechanical properties of high power and UHP Graphite Electrode must be better than ordinary power graphite electrodes, such as lower resistivity, larger bulk density and higher mechanical strength, smaller thermal expansion coefficient, and good thermal shock resistance. Table 1 lists the common standard series of three different power arc steelmaking furnaces and the graphite electrode diameters used in the late 1980s. In order to meet the needs of large-scale development of high-power and ultra-high-power electric furnaces in steelmaking plants, since the 1980s, carbon plants in Europe, America and Japan have mainly produced two quality standards of graphite electrodes, namely high-power graphite electrodes and ultra-high-power graphite electrodes. Graphite electrodes are rarely produced due to their low sales. DC electric arc furnace is a new type of electric furnace steelmaking equipment developed in the early 1980s. The initial DC electric arc furnace is based on the original AC electric arc furnace. Some use 3 graphite electrodes and some use 2 Graphite Electrode.