UHP GRAPHITE ELECTRODE – Low Electrical Resistance, High Density

DESCRIPTION

UHP graphite electrode is used for the recycling of steel in the electric arc furnace industry. Its main ingredient is high-value needle coke which is made from either petroleum or coal tar. Graphite electrodes are finished with a cylinder shape and machined with threaded areas at each end. In this way, the graphite electrodes can be assembled into an electrode column using electrode nipple. In order to meet the requirement of higher work efficiency and lower total cost, large capacity ultra-high power arc furnaces are becoming more and more popular. Because of this, UHP graphite electrodes with diameters of over 500 mm will dominate market.

FEATURE

Withstand large currents, high discharge rate. Good dimension stability, not easy to deform. Resistant to cracking & spalling. High resistance to oxidation and thermal shock. High mechanical strength, low electrical resistance. High machining accuracy, good surface finishing.

APPLICATION

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. Ladle furnace.

SPECIFICATION

Table 1: Technical Specification of UHP Graphite Electrode
Dia. Resistance Density Flexure Strength Elastic Modulus Ash Content CTE Current Load Current Density
(inch) (≤, µΩ·m) (≥, g/cm3) (≥, MPa) (≤, GPa) (≤, %) (100 °C – 600 °C) (A) (A/cm2)
(≤, 10-6/°C)
10 5.2 1.67 10.5 14 0.3 1.5 8100–12200 20–30
12 5.2 1.70 10.5 14 0.3 1.5 15000–22000 20–30
14 5.2 1.70 10.5 14 0.3 1.5 20000–30000 20–30
16 5.2 1.70 10.5 14 0.3 1.5 25000–40000 19–30
18 5.2 1.70 10.5 14 0.3 1.5 32000–45000 19–27
20 5.2 1.70 11 14 0.3 1.4 38000–55000 18–27
22 5.2 1.72 11 14 0.3 1.4 42000–66000 17–26
24 4.8 1.72 11 14 0.3 1.4 49000–76000 17–26
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)
10 250 256 251 248 1600/1800 ±100 -275
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 2000/2200/2400/2700

SURFACE QUALITY

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)