HP graphite electrode is the conducting element for electric arc furnaces steelmaking. It is made of petroleum coke, needle coke, coal pitch and produced by a series of strict production processes. High-current lines insert through the graphite electrode port inside the furnace body. This will releases electric energy in the arc furnace to heat the furnace.
The demand for the larger diameter electrodes has been increasing as EAF furnace sizes become larger. Graphite electrodes with diameter of 500 mm or 600 mm have become increasingly popular in recent years.
Anti-oxidation treatment for longevity.
High-purity, high-density, strong chemical stability.
High machining accuracy, good surface finishing.
High mechanical strength, low electrical resistance.
Resistant to cracking & spalling.
High resistance to oxidation and thermal shock.
Graphite electrodes are widely used for production of alloy steels, metal and other nonmetallic materials, etc.
DC electric arc furnace.
AC electric arc furnace.
Submerged arc furnace.
Table 1: Technical Specification of HP Graphite Electrode
| Diameter | Resistance | Density | Flexure Strength | Elastic Modulus | Ash Content | CTE | Current Load | Current Density | |
| (≤, µΩ·m) | (≥, g/cm3) | (≥, MPa) | (≤, GPa) | (≤, %) | (100 °C – 600 °C) | (A) | (A/cm2) | ||
| inch | mm | (≤, 10-6/°C) | |||||||
| 8 | 200 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 5500–9000 | 18–25 |
| 9 | 225 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 6500–10000 | 18–25 |
| 10 | 250 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 8000–13000 | 18–25 |
| 12 | 300 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 13000–17400 | 17–24 |
| 14 | 350 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 17400–24000 | 17–24 |
| 16 | 400 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 21000–31000 | 16–24 |
| 18 | 450 | 6.0 | 1.65 | 10.5 | 12 | 0.3 | 2.4 | 25000–40000 | 15–24 |
| 20 | 500 | 6.0 | 1.65 | 10.5 | 14 | 0.3 | 2.2 | 30000–48000 | 15–24 |
| 22 | 550 | 6.0 | 1.64 | 10.5 | 14 | 0.3 | 2.2 | 37000–57000 | 15–23 |
| 24 | 600 | 6.0 | 1.64 | 10.5 | 14 | 0.3 | 2.2 | 44000–67000 | 15–23 |
Table 2: Graphite Electrode Size & Tolerance
| Diameter (mm) | Length (mm) | ||||||
| Nominal Diameter | Actual Diameter | Nominal Length | Tolerance | Short Length | |||
| (inch) | (mm) | (max.) | (min.) | (rough spot) | |||
| 8 | 200 | 205 | 200 | 197 | 1600 | ±100 | -275 |
| 9 | 225 | 230 | 225 | 222 | 1600 | ||
| 10 | 250 | 256 | 251 | 248 | 1600/1800 | ||
| 12 | 300 | 307 | 302 | 299 | 1600/1800 | ||
| 14 | 350 | 357 | 352 | 349 | 1600/1800 | ||
| 16 | 400 | 409 | 403 | 400 | 1600/1800/2000/2200 | ||
| 18 | 450 | 460 | 454 | 451 | 1600/1800/2000/2200 | ||
| 20 | 500 | 511 | 505 | 502 | 1800/2000/2200/2400 | ||
| 22 | 550 | 562 | 556 | 553 | 1800/2000/2200/2400 | ||
| 24 | 600 | 613 | 607 | 604 | 2000/2200/2400 | ||
There should be less than two defects or holes on the electrode surface, the maximum size of which is mentioned in the below chart.
There should be no transverse crack on the electrode surface. For the longitudinal crack, the length should be less than 5% of the electrode circumference and the width should be 0.3 to 1.0 mm.
The width of black area on electrode surface should be less than 1/10 of the electrode circumference and the length should be less than 1/3 of the electrode.
| SpecificationDefect Dimension | Nominal Diameter of Graphite Electrode (mm) | |
| 300–400 | 450–600 | |
| Diameter (mm) | 20–40 | 30–50 |
| (< 20 mm should be negligible) | (< 30 mm should be negligible) | |
| Depth (mm) | 5–10 | 10–15 |
| (< 5 mm should be negligible) | (< 10 mm should be negligible) | |