Graphite Electrodes Introduction
Graphite electrodes is a kind of high temperature resistant graphite conductive ,graphite electrodes is produced by a series of processes such as petroleum coke and needle coke as aggregate and coal pitch as binder after kneading, molding, roasting, impregnation, graphitization and mechanical processing. The graphite electrodes is an important high temperature conductive material for electric steel making. The graphite electrodes is used to input electric energy to the electric furnace, and the high temperature generated by the arc between the electrode end and the charge is used as a heat source to melt the charge for steel making. Other ore furnaces that smelt materials, such as yellow phosphorus, industrial silicon, and abrasives also use graphite electrodes as conductive materials.
Graphite Electrodes Classification
Graphite electrodes are classified into three types
1.Ordinary Power Graphite Electrodes(RP).
2.High power graphite electrodes (HP).
3.Ultra High Power Graphite Electrode (UHP)..
The Post graphite electrode production plant has increased high density graphite electrodes(HD) and quasi ultra high graphite electrodes (SHP) according to user needs.
1.Ordinary Power Graphite Electrodes
Ordinary power graphite electrodes are produced by ordinary grade petroleum coke. The graphitization temperature is low, the resistivity is high, the coefficient of linear expansion is large, and the thermal shock resistance is poor, so the current density is allowed to be low.
2.High Power Graphite Electrodes
The high power graphite electrode is produced by high quality petroleum coke (or low-level needle coke). Sometimes the electrode body needs to be immersed, and its physical and mechanical properties are higher than ordinary power graphite electrodes, such as low resistivity, allowing a large current. density.
3.Ultra High Power Graphite Electrodes
Ultra high power graphite electrodes must be produced with high grade needle coke, and their graphitization heat treatment is carried out in an internal string graphitization furnace. The graphitization temperature is as high as 2300-3000 °C, so the resistivity is lower, allowing for greater passage. Current density, smaller coefficient of linear expansion, excellent thermal shock resistance
Graphite Electrodes Application
1. Ordinary Power Graphite Electrode
It is allowed to use graphite electrodes with current density lower than 17A/cm2, graphite electrodes arc furnace mainly used for ordinary power such as steel making, silicon refining, and yellowing phosphorus.
2.High Power Graphite Electrodes
Allows the use of graphite electrodes with a current density of 18~25A/cm2, mainly used in high-power electric arc furnaces for steel making
3.Ultra High Power Graphite Electrodes
Allows the use of graphite electrodes with current densities greater than 25A/cm2, ultra high power (UHP) graphite electrodes are mainly used in ultra high power electric furnace and ladle furnace.
Graphite Electrodes Quality and Performance Indicators
1.Bulk Density
The larger the bulk density, the more dense the electrode is and the positive correlation with strength and oxidation resistance.The larger the bulk density of the same type of electrode, the lower the resistivity.
2.Resistivity
Resistivity is a parameter that measures the conductivity of an electrode.The lower the resistivity, the better the conductivity of the electrode in use and the lower the consumption.
3.Flexural Strength
The strength of graphite material is significantly different from other metal non metals. Graphite electrode strength increases with temperature, reaching the highest at 2000-2500 °C, 1.8-2 times normal temperature, and then decreases. High-strength electrodes and joints are less likely to break during using .
2. Elastic Modulus
The greater the modulus of elasticity, the more brittle the material, the smaller the modulus of elasticity, the softer the material.The high modulus of the elastic modulus plays a comprehensive role in the use of the graphite electrodes. The higher the bulk density of the graphite electrode productions, the denser the elastic modulus, but the worse the thermal shock resistance of the product, the more likely the cracking is caused. In the graphite electrodes productions, it is often through the adjustment of the formula size, the volume density of the product to grasp a value of the elastic modulus that is more suitable for use.
5.Thermal Expansion Coefficient
The thermal expansion coefficient of graphite electrodes is a very important thermal parameter. The lower the value, the stronger the thermal stability of the product, and the higher the oxidation resistance, the less the fracture is reflected in the use, and the lower the consumption.
6.Ash A%
Ash refers to the amount of solid elements other graphite electrodes in the product. The ash content in the graphite electrodes is mainly affected by the ash content of the raw materials used. The petroleum coke needle coke ash content is lower, so the graphite electrode ash content generally does not exceed 0.5%, and the ash content within 1% has no significant effect on steel making, but in the ash. Impurity elements reduce the oxidation resistance of the electrode.
Graphite Electrodes Manufacturing Process
1. Petroleum coke
2. Calcination
3. Broken, screened, ingredients
4. Kneading (Binder asphalt)
5. Forming
6. Metallurgical coke particle,broken,packing material, calcination
7. Impregnating asphalt
8. Again calcination
9. Graphite change(metallurgical coke powder,quartz sand)
10. Mechanical processing
11. Product testing,package
Graphite Electrodes Specification
Electrode diameter Tolerance Error
Unit: mm
Nominal diameter |
Actual diameter(D) |
Nominal length |
inch |
mm |
Max |
Min |
Black skin diameter(B) |
8'' |
200 |
205 |
201 |
197 |
1600/1800 |
9'' |
225 |
230 |
225 |
222 |
1600/1800 |
10'' |
250 |
256 |
251 |
249 |
1600/1800 |
12'' |
300 |
307 |
302 |
299 |
1600/1800/1900/2000 |
14'' |
350 |
357 |
352 |
349 |
1600/1800/1900/2000/2200 |
16'' |
400 |
409 |
403 |
400 |
1600/1800/1900/2000/2200/2400 |
18'' |
450 |
460 |
454 |
451 |
1600/1800/1900/2000/2200/2400 |
20'' |
500 |
511 |
505 |
502 |
1800/1900/2000/2200/2400 |
22'' |
550 |
562 |
556 |
553 |
1800/2000/2200/2400 |
24'' |
600 |
613 |
607 |
604 |
2000/2200/2400/2700 |
26'' |
650 |
663 |
657 |
654 |
2400/2700/3000 |
28'' |
700 |
714 |
708 |
705 |
2400/2700/3000 |
Electrode length Tolerance Error
Unit: mm
Nominal length |
Standard length error |
Short length error |
Max |
Min |
Max |
Min |
1600 |
+100 |
-100 |
-100 |
-275 |
1800 |
+100 |
-100 |
-100 |
-275 |
1900 |
+100 |
-100 |
-100 |
-275 |
2000 |
+100 |
-100 |
-100 |
-275 |
2200 |
+100 |
-100 |
-100 |
-275 |
2400 |
+100 |
-100 |
-100 |
-275 |
2700 |
+150 |
-150 |
-150 |
-300 |
3000 |
+150 |
-150 |
-150 |
-300 |
Graphite Electrodes Conical Joint Size
Unit:mm
Electrode diameter |
Connector |
Joint hole |
Pitch |
D |
d2 |
L |
l |
d1 |
H |
Deviation |
≤ |
Deviation |
Button type |
Metric |
Imperial |
(-0.30~0) |
(-0.30~0) |
(-1~0) |
(0~0.3) |
(0~7) |
8.47 |
3TPI |
225 |
9″ |
139.70 |
91.22 |
203.20 |
7 |
141.22 |
107.60 |
250 |
10″ |
155.57 |
104.20 |
220.00 |
157.09 |
116.00 |
300 |
12″ |
177.16 |
117.39 |
270.90 |
148.68 |
141.50 |
350 |
14″ |
215.90 |
150.48 |
304.80 |
217.42 |
158.40 |
400 |
16″ |
215.90 |
150.48 |
304.80 |
217.42 |
158.40 |
400 |
16″ |
241.30 |
170.23 |
338.70 |
242.82 |
175.30 |
450 |
18″ |
241.30 |
170.23 |
338.70 |
242.82 |
175.30 |
450 |
18″ |
273.05 |
199.17 |
355.60 |
274.57 |
183.80 |
500 |
20″ |
273.05 |
199.17 |
355.60 |
274.57 |
183.80 |
500 |
20″ |
298.45 |
221.73 |
372.60 |
299.97 |
192.20 |
550 |
22″ |
298.45 |
221.73 |
372.60 |
299.97 |
192.20 |
600 |
24″ |
336.55 |
245.73 |
457.30 |
338.07 |
234.60 |
3TPIL |
350 |
14″ |
215.90 |
144.85 |
338.70 |
217.42 |
175.30 |
400 |
16″ |
241.30 |
167.43 |
355.60 |
242.82 |
183.80 |
450 |
18″ |
273.05 |
182.23 |
457.30 |
274.57 |
234.60 |
4TPI |
200 |
8″ |
122.24 |
81.48 |
177.80 |
7 |
115.92 |
94.90 |
6.35 |
225 |
9″ |
139.70 |
98.94 |
177.80 |
133.38 |
94.90 |
250 |
10″ |
152.40 |
109.52 |
190.50 |
146.08 |
101.30 |
300 |
12″ |
177.80 |
130.69 |
215.90 |
171.48 |
114.00 |
350 |
14″ |
203.20 |
149.74 |
254.00 |
196.88 |
133.00 |
400 |
16″ |
222.25 |
160.32 |
304.80 |
215.93 |
158.40 |
450 |
18″ |
241.30 |
179.37 |
304.80 |
234.98 |
158.40 |
500 |
20″ |
269.88 |
199.49 |
355.60 |
263.56 |
183.80 |
550 |
22″ |
298.45 |
228.06 |
355.60 |
292.13 |
183.80 |
600 |
24″ |
317.50 |
247.11 |
355.60 |
311.18 |
183.80 |
650 |
26″ |
355.60 |
268.27 |
457.20 |
349.28 |
234.60 |
700 |
28″ |
374.65 |
287.32 |
457.20 |
368.33 |
234.60 |
4TPIL |
300 |
12″ |
177.80 |
124.34 |
254.00 |
171.48 |
133.00 |
350 |
14″ |
203.20 |
141.27 |
304.80 |
196.88 |
158.40 |
400 |
16″ |
222.25 |
151.86 |
355.60 |
215.93 |
183.80 |
450 |
18″ |
241.30 |
170.91 |
355.60 |
234.98 |
183.80 |
500 |
20″ |
269.88 |
182.55 |
457.20 |
263.56 |
234.60 |
550 |
22″ |
298.45 |
211.12 |
457.20 |
292.13 |
234.60 |
600 |
24″ |
317.50 |
230.17 |
457.20 |
311.18 |
234.60 |
650 |
26″ |
355.64 |
251.38 |
558.80 |
349.28 |
285.40 |
700 |
28″ |
374.65 |
270.39 |
558.80 |
368.33 |
285.40 |
Graphite Electrodes and Joint Specification
Item |
Unit |
Nominal diameter |
UHP |
HP |
RP |
≤Φ400 |
≥Φ450 |
≤Φ400 |
≥Φ450 |
≤Φ300 |
≥Φ350 |
Resistivity |
Electrode |
μΩ·m |
≤5.5 |
≤6.5 |
≤8.5 |
Connect |
≤4.5 |
≤5.5 |
≤6.5 |
Flexural Strength |
Electrode |
MPa |
≥11.0 |
≥10.5 |
≥9.8 |
≥8.5 |
≥7.0 |
Connect |
≥20.0 |
≥16.0 |
≥15.0 |
Elastic Modulus |
Electrode |
GPa |
≤14.0 |
≤12.0 |
≤9.3 |
Connect |
≤18.0 |
≤16.0 |
≤14.0 |
Bulk Density |
Electrode |
g/cm3 |
≥1.66 |
≥1.67 |
≥1.62 |
1.60 |
≥1.53 |
≥1.52 |
Connect |
≥1.75 |
≥1.73 |
≥1.69 |
Thermal Expansion Coefficient |
Electrode |
10-6/℃ |
≤1.5 |
≤2.4 |
≤2.9 |
Connect |
≤1.4 |
≤2.2 |
≤2.8 |
Ash |
% |
≤0.3 |
≤0.3 |
≤0.5
|
Graphite Electrode Allowable Current Load and Current Density
Nominal Diameter |
RP |
HP |
UHP |
mm |
Current load
A |
Current density
A/cm2 |
Current load
A |
Current density
A/cm2 |
Current load
A |
200 |
5000-6900 |
15-21 |
5500-9000 |
18-25 |
|
250 |
7000-10000 |
14-20 |
8000-13000 |
18-25 |
9200-15100 |
300 |
10000-13000 |
14-18 |
13000-17400 |
17-24 |
13000-22000 |
350 |
13500-18000 |
14-18 |
17400-24000 |
17-24 |
20000-30000 |
400 |
18000-23500 |
14-18 |
21000-32000 |
16-24 |
25000-40000 |
450 |
22000-27000 |
13-17 |
25000-40000 |
15-24 |
32000-45000 |
500 |
25000-32000 |
13-16 |
30000-48000 |
15-24 |
38000-55000 |
550 |
32000-40000 |
13-16 |
37000-57000 |
15-23 |
48000-60000 |
600 |
38000-47000 |
13-16 |
44000-67000 |
15-23 |
52000-72000 |
700 |
45000-54000 |
13-16 |
54000-73000 |
15-23 |
62000-95000 |
Graphite Electrodes Supplier from RS Refractory Factory in China
Rongsheng graphite electrodes manufacture factory can provide our customers with professional and personalized products and engineering services according to the actual working condition and requirements of each customer, in order to meet customers’ increasing demand of energy-saving and graphite.
Electrode products quality improving, competition graphite electrodes market price. Rongsheng firebricks factory tenet is quality and credibility is fundamental, technology and service is the life.