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RP Graphite Electrode for Ladle Furnace

The Classification of Graphite Electrodes

Electric arc steel making furnace could be divided into regular power electric furnace (about 300KVA per ton), high-power electric furnace (about 400kVA per ton) and ultra-high-power electric furnace (500 ~ 1200KV/A per ton) according to transformer capacity per ton of furnace capacity.

According to the classification of electric power level of electric furnace steel making, and according to the differences of raw materials used in electrode production and physical and chemical indexes of finished electrode, graphite electrode is divided into three varieties: regular power graphite electrode (RP), high power graphite electrode (HP) and ultra-high power graphite electrode (UHP).

The Introduction of RP Graphite Electrode

RP graphite electrode is mainly made of petroleum coke as raw materials and coal asphalt as binder through calcination, batching, kneading, molding, baking, graphitization and machining.

Graphite Electrode is a conductor that releases electric energy in the electric arc furnace to heat and melt the steel scrap.

Features

RP graphite electrode is produced with petroleum coke, with low graphitization temperature. it has the following features:
1.High resistivity
2.Large linear expansion coefficient
3.Poor thermal shock resistance
4.The allowable current density is low

The Application of RP Graphite Electrode

(1) For steel making in Electric Arc Furnace (EAF) and Ladle Furnace (LF)
RP Graphite electrode is mainly used in LF/EAF for steel making. When graphite electrode is working in LF, the current will be introduced by graphite electrode into the furnace, and there will be heat source which is generated by electric arc between electrode end and furnace charge for smelting.

(2) For producing metallic silicon and yellow phosphorus in submerged arc furnace
Some carbon electrode with large size (eg.700mm-1400mm) is used for producing metallic silicon and yellow phosphorus in submerged arc furnace. The lower part of the carbon electrode is buried in the charge, forms an arc in the charge layer, the material will be smelted by the heat energy generated by the resistance of the charge. For example, about 100kg of graphite electrode is consumed for 1 ton of metallic silicon.

(3)For producing corundum in electric furnace

(4)Used for processing special-shaped graphite products
The blank of graphite electrode is also used to process various special-shaped graphite prod

The Production Processes of Graphite Electrode

The Chemical and Physical Indexes of HP Graphite Electrode

Item Unit RP
φ75-φ800mm
Resistivity Electrode μΩm 7.0-10.0
Nipple 4.0-4.5
Modulus of Rupture Electrode Mpa 8.0-10.0
Nipple 19.0-22.0
Young's Modulus Electrode GPa 7.0-9.3
Nipple 12.0-14.0
Bulk Density Electrode g/cm3 1.53-1.56
Nipple 1.70-1.74
CTE (100-600℃) Electrode 10-6/℃ 2.2-2.6
Nipple 2.0-2.5
Ash % 0.5

The Current Carrying Capacity of Graphite Electrode

Item

Nominal Diameter mm

Current Carrying Capacity

A

Current Density

A/cm2

RP Graphite Electrode

200

5000-6900

15-21

250

7000-10000

14-20

300

10000-13000

14-18

350

13500-18000

14-18

400

18000-23500

14-18

450

22000-27000

13-17

500

25000-32000

13-16

550

30000-42000

13-16

600

40000-53000

13-16

Dimension of 4TPI Nipples and Socket

Nominal Diameter

Nipple Type

Sizes of Nipple (mm)

Sizes of Socket

Thread

mm

inch

D

L

d2

l

d1

H

mm

Deviation

(-0.5-0)

Deviation

(-1-0)

Deviation

(-5-0)

Deviation

(0-0.5)

Deviation

(0-7)

200

8’’

122T4N

122.24

177.80

80

<7

115.92

94.90

6.35

250

10’’

152T4N

152.40

190.50

108.00

146.08

101.30

300

12’’

177T4N

177.80

215.90

129.20

171.48

114.00

350

14’’

203T4N

203.20

254.00

148.20

196.88

133.00

400

16’’

222T4N

222.25

304.80

158.80

215.93

158.40

400

16’’

222T4L

222.25

355.60

150.00

215.93

183.80

450

18’’

241T4N

241.30

304.80

177.90

234.98

158.40

450

18’’

241T4L

241.30

355.60

169.42

234.98

183.80

500

20’’

269T4N

269.88

355.60

198.00

263.56

183.80

500

20’’

269T4L

269.88

457.20

181.08

263.56

234.60

550

22’’

298T4N

298.45

355.60

226.58

292.13

183.80

550

22’’

298T4L

298.45

457.20

209.65

292.13

234.60

600

24’’

317T4N

317.5

355.60

245.63

311.18

183.80

600

24’’

317T4L

317.5

457.20

228.70

311.18

234.60

650

26’’

355T4N

355.60

457.20

266.79

349.28

234.60

650

26’’

355T4L

355.60

558.80

249.86

349.28

285.40

700

28’’

374T4N

374.65

457.20

285.84

368.33

234.60

700

28’’

374T4L

374.65

558.80

268.91

368.33

285.40

750

30’’

406T4N

406.4

584.20

296.42

400.08

298.10

750

30’’

406T4L

406.4

609.60

292.19

400.08

310.80

800

32’’

431T4N

431.8

635.00

313.36

425.48

325.50

800

32’’

431T4L

431.8

685.80

304.89

425.48

348.90

Dimension of 3TPI Nipples and Socket

Nominal Diameter

Nipple Type

Sizes of Nipple (mm)

Sizes of Socket

Thread

mm

inch

D

L

d2

l

d1

H

mm

Deviation

(-0.5-0)

Deviation

(-1-0)

Deviation

(-5-0)

Deviation

(0-0.5)

Deviation

(0-7)

250

10’’

155T3N

155.57

220.00

103.80

<7

147.14

116.00

6.35

300

12’’

177T3N

177.16

270.90

116.90

168.73

141.50

350

14’’

215T3N

215.90

304.80

150.00

207.47

158.40

400

16’’

215T3L

215.90

304.80

150.00

207.47

158.40

400

16’’

241T3N

241.30

338.70

169.80

232.87

175.30

450

18’’

241T3L

241.30

338.70

169.80

232.87

175.30

450

18’’

273T3N

273.05

355.60

198.70

264.62

183.80

500

20’’

273T3L

273.05

355.60

198.70

264.62

183.80

500

20’’

298T3N

298.45

372.60

221.30

290.02

192.20

550

22’’

298T3N

298.45

372.60

221.30

290.02

192.20

3TPI Thread Detail

4TPI Thread Detail

Reference of Torque

Diameter

mm

250

300

350

400

450

500

550

600

650

700

inch

10’’

12

14

16

18

20

22

24

26

28

Torque (N.m)

400-450

500-650

700-950

850-1150

1050-1400

1300-1700

1850-2400

2300-3000

3900-4300

4400-5200