RP Graphite Electrode

RP Graphite Electrode is mainly made of common Cacined Petroleum Coke, Graphitized in lower temperature. With its higher resistivity, larger CTE value and weaker thermal shock resistance ability, RP graphite electrode allows lower current density that pass through the furnace.

RP graphite electrode can carry current density lower than 17A/cm2 which is mostly used in regular power electric furnace for

  • steelmaking
  • silicon smelting
  • yellow phosphorus smelting
  • other smelting application

Industrial Specification of RP Graphite Electrode

Technical Specification of RP Graphite Electrode

Item Dia 150-225mm Dia 250-300mm Dia 350-450mm Dia 500-800mm
Electrode Nipple Electrode Nipple Electrode Nipple Electrode Nipple
Specific Resistance ≤9-10.5µΩm ≤8µΩm ≤9-10.5µΩm ≤8µΩm ≤9-10.5µΩm ≤8µΩm ≤9-10.5µΩm ≤8µΩm
Bending Strength ≥10Mpa ≥15Mpa ≥8Mpa ≥15Mpa ≥7Mpa ≥15Mpa ≥6.5Mpa ≥15Mpa
Elastic Modulus ≤9.3Gpa ≤14Gpa ≤9.3Gpa ≤14Gpa ≤9.3Gpa ≤14Gpa ≤9.3Gpa ≤14Gpa
Bulk density ≥1.53g/cm³ ≥1.7g/cm³ ≥1.53g/cm³ ≥1.7g/cm³ ≥1.53g/cm³ ≥1.7g/cm³ ≥1.52g/cm³ ≥1.7g/cm³
CTE  (100-600℃) ≤2.9*10^-6/℃ ≤2.7*10^-6/℃ ≤2.9*10^-6/℃ ≤2.7*10^-6/℃ ≤2.9*10^-6/℃ ≤2.7*10^-6/℃ ≤2.9*10^-6/℃ ≤2.7*10^-6/℃
Ash ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3% ≤0.3%

RP Graphite Electrode Sizes & Tolerance

Diameter (mm) Length (mm)
Nominal Diameter Actual Diameter Nominal Length (Options) Tolerance
(inch) (mm) (max.) (min.)
3 75 78 73 1000/1200/1400/1600 ±100
4 100 103 98 1000/1200/1400/1600
6 150 154 149 1000/1200/1400/1600
7 175 179 174 1200/1400/1600/1800
8 200 205 200 1600
9 225 230 225 1600
10 250 256 251 1600/1800
12 300 307 302 1600/1800
14 350 357 352 1600/1800
16 400 409 403 1600/1800/2000/2200
18 450 460 454 1600/1800/2000/2200
20 500 511 505 1800/2000/2200/2400
22 550 562 556 1800/2000/2200/2400
24 600 613 607 2000/2200/2400
26 650 663 659 2000/2200/2400/2700
28 700 714 710 2000/2200/2400/2700
30 750 765 761 2000/2200/2400/2700
32 800 816 812 2000/2200/2400/2700

Suggested Current-Capacities of RP Electrodes

Nominal Diameter Suggested Current-Carrying Capacity (A) Current  Density(A/cm2)
mm inch
150 6 3000-4500 16-25
200 8 5000-6900 15-21
250 10 7000-10000 14-20
300 12 10000-13000 14-18
350 14 13500-18000 14-18
400 16 18000-23500 14-18
450 18 22000-27000 13-17
500 20 25000-32000 13-16
550 22 28000-34000 12-14
600 24 30000-36000 11-13
650 26 32000-39000 10-12
700 28 34000-42000 9-11

Surface Quality

Item Defect Dimension Nominal Diameter of Graphite Electrode
300–400mm 450–600mm
Diameter (mm) 20–40
(< 20 mm should be negligible)		 30–50
(< 30 mm should be negligible)
Depth (mm) 5–10
(< 5 mm should be negligible)		 10–15
(< 10 mm should be negligible)
Remarks:
1. There should be less than two defects or holes on the electrode surface, the max size of which is mentioned in the above chart.
2. 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 in between 0.3-1.0mm.
3. The width of black area on electrode surface should be less than 1/10 of electrode circumference and the length less than 1/3 of electrode.