According to the classification of electric furnace steelmaking power level and the difference of raw materials used for producing Graphite electrodes as well as the physical and chemical indexes of finished product, graphite electrodes are divided into three types: regular power graphite electrodes (RP), high power graphite electrodes (HP) and ultra high power graphite electrodes (UHP).
Classification of Graphite Electrodes
Regular power graphite electrode (RP): regular power graphite electrodes are produced by ordinary grade petroleum coke. With low graphitization temperature, poor thermal shock resistance and high resistivity, large linear expansion coefficient the allowable current density is low.
High power graphite electrode (HP): High power graphite electrodes are produced by high grade petroleum coke. With low graphitization temperature, poor thermal shock resistance and high resistivity, large linear expansion coefficient the allowable current density is low.
Ultra-high power graphite electrode (UHP): UHP graphite electrode must be produced by high-level needle coke, and its graphitization heat treatment should be carried out in the inner series graphitization furnace. The graphitization temperature is as high as 2800-3000 C. Therefore, the resistivity is low, and the linear expansion coefficient is small. It has excellent thermal shock resistance.
Needle coke is an important standard to distinguish regular power graphite electrodes from high power and ultra-high-power graphite electrodes. All the 600mm diameter UHP graphite electrode produced by HUARO use 100% needle coke to ensure an excellent quality performance in the steelmaking factory.
600mm UHP graphite electrode current load
Nominal diameter | Current carrying capacity/A | Current density A/CM2 |
600MM | 50000-75000 | 18-26 |
Physical and chemical index of Ultra High Power Graphite Electrode
Item | Uni | Nominal diameter mm | ||||
300-400 | 450-500 | 550-650 | 700-800 | |||
Electrical Resistivity ≤ | Electrode | μΩm | 6.0 | 6.0 | 6.0 | 6.0 |
Nipple | 5.0 | 5.0 | 4.3 | 4.0 | ||
Flexural Strength ≥ | Electrode | MPa | 10.5 | 10.5 | 10.0 | 10.0 |
Nipple | 20.0 | 20.0 | 22.0 | 23.0 | ||
Elastic Modulus ≤ | Electrode | GPa | 14.0 | 14.0 | 14.0 | 14.0 |
Nipple | 20.0 | 20.0 | 22.0 | 22.0 | ||
Bulk Density ≥ | Electrode | g/cm3 | 1.70 | 1.70 | 1.70 | 1.70 |
Nipple | 1.75 | 1.75 | 1.80 | 1.80 | ||
CTE≤(100℃-600℃) | Electrode | 10-6/℃ | 1.5 | 1.5 | 1.5 | 1.5 |
Nipple | 1.4 | 1.4 | 1.3 | 1.3 | ||
Ash Content≤ | % | 0.5 | 0.5 | 0.5 | 0.5 |