一、 I Choosing Graphite Electrode
Please choose the suitable graphite electrodes grade and diameter according to the capacity of furnace and the matched transformer.(Attch 1)
Nominal Diameter
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Regular Power
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Impregnate (HD)
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High Power
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Ultra High Power
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mm
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Inch
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Current-Carrying Capacity(A)
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Current Density(A/cm2)
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Current-Carrying Capacity (A)
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Current Density(A/cm2)
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Current-Carrying Capacity(A)
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Current Density(A/cm2)
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Current-Carrying Capacity(A)
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Current Density(A/cm2)
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75
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3
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1000~1400
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22-31
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1300-2000
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29-45
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|
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100
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4
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1500~2400
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19-31
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1800-3000
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22-37
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|
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130
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5
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2200~3400
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17-26
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2800-4200
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21-31
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|
|
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150
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6
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3000~4500
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16-25
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4000-5000
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22-28
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175
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7
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3800~5100
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16-21
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3900-6800
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16-28
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|
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200
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8
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5000~6900
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15-21
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4800-9000
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15-28
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5500-9000
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18-25
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|
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225
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9
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6000~8000
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15-20
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6400-9700
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16-24
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6500-10000
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18-25
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|
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250
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10
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7000~10000
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14-20
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8000-12000
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16-24
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8000-13000
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18-25
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|
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300
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12
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10000~13000
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14-18
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11000-16000
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15-22
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13000-17400
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17-24
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15000-22000
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20-30
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350
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14
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13500~18000
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14-18
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15000-22000
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15-22
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17400-24000
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17-24
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20000-30000
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20-30
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400
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16
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18000~23500
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14-18
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20000-28000
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15-22
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21000-31000
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16-24
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25000-40000
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19-30
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450
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18
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22000~27000
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13-17
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24000-34000
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15-21
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25000-40000
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15-24
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32000-45000
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19-27
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500
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20
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25000~32000
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13-16
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28000-42000
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13-20
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30000-48000
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15-24
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38000-55000
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18-27
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Remake: the operating current ranges in table 2 are for AC EAF, DC EAF or LF can run at a reasonable higher current level with the electrode.
二、II、Handling and stacking of the electrode
1、Operate carefully when lift and move the electrodes so as to avoid drop and damage caused by the inclining of the electrode.
2、To keep the end face of the electrode and the thread in the socket in a good status, never hook into the sockets on both side of the electrode with metal hooks when moving the electrodes.
3、Carefully lift up and down when load and unload the case with nipples so as to prevent the nipples from clicking against each other and cause damages to the thread of the nipples thereof.
4、Don’t put the electrodes and nipples directly onto the grand, put them onto wooden bars or metal stands instead, collision or sand contamination must be avoided. Don’t take the packing materials away when the electrode and nipples are not going be used. Dust and contaminations to the threads must be avoided.
5、Electrode must be stacked in order in a warehouse; both ends of an electrode stack must be blocked safely so as to avoid collapsing. The electrodes stacks should be lower than 2 meters high.
6、Electrodes in the stacks must be protected away from rains and heavy humidity, wet electrode must be dried before being loaded onto the furnace so as to reduce the risks of cracking and over high oxidization when operation.
7、Nipples must be away from high temperature to prevent the pitch plugs from melting.
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III Preparation works prior to the connections:
1、Take the protection caps on the sockets of electrode away, check the consistency of the thread in the socket. If any dis-consistency of the thread in the socket being found, please ask the seller’s serviceman to determine whether the electrode can be loaded or not, check the cleanness of the electrode sockets, only an electrode with clean sockets can be loaded.
2、Fit the loft plug into a socket on one end of electrode, and put a soft mat under the other end of the electrode with nipple (see figure 4) to prevent the nipple from being damaged.
3、Blow the dusts and contaminations on the end face and in the socket of the electrode at the top of the column away by compressed air, and of the same to the new electrode. When compressed air is not powerful enough to make it clean enough, a brush can be used for this purples
IV Steps to make a column
1、Before make a column, check whether the sockets of electrode, thread in the socket and the pitch plugs are good or not, any lost or damaged pitch plugs must be replaced.
2、Lift a new electrode above the electrode column to be connected, aline the nipple with the socket, lower down slowly. Be careful not to hurt the thread on the nipple and in the socket
3、Lift the new the electrode a little bit higher, turn the new electrode with the torque ring, now the follower hook turns down together with the electrode until the end face of the two electrode contacted
4、Lock the electrode with a corresponding torque lever (please refer table 1 for the suggested torque level) to specific tightness(see figure 9). The room between electrodes should shorter than or equal to 0.4mm. Oblique column is not allowed when connecting.
Table 1: suggested torque level
Dia. Of electrode mm
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Torque level N.K
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Dia. Of electrode mm
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Torque level N.K
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250
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45
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450
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250
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300
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60
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500
|
320
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350
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100
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550
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380
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400
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200
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600
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430
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V Precautions to he use of electrode
1、Determine the grade and diameter of the electrode suitable to be applied by the capacity of the furnace, and the capacity of the furnace transformer.
2、In order to prevent the electrode column from being hit by the collapsed furnace loads, heavy and big scraps should be loaded onto the bottom of the furnace, don’t put significant quantity of insulating materials such as lime and so on just under the electrode column, otherwise it would be difficult to power on the electrode column, or even break the column for this.
3、When the electrode column moves upward and downward, it should be moved smoothly. After mend the furnace cover, please check the position of it.
When melting, in order to prevent it oxidation, fireproofing material
should be used.
4、To avoid breakage, don’t put an electrode column horizontally.
5、The reason must be find out if a gap appeared between two electrodes after connection, the electrode column can only be loaded after the gap eliminated.
6、The electrode column must be straightly perpendicular to the ground level during operation, oblique column is not allowed during operation.
7、Please refer to figure 10 for right position of electrode and nipple.
8、 The position of the electrode holder of the furnace must be between the two holder marks on the top electrode. The electrode holder should neither hole the electrode out of the two holder marks on the electrode, nor hold on the electrode other then the top one, otherwise, the column may be broken for this.
9、Different electrode producers make their electrode by different raw materials and processes, therefore, the physical and chemical specifications of their electrode are different. Please don’t fit electrode and nipple made by different suppliers together.
10、Lock pins can be applied to the electrode conlumns for the furnace with severe vibration, it helps stopping the unscrewing during operation.
VI Using the guidelines
Special tools for electrode handling
1.lifting plug
The tread of the Lifting plug is made of graphite, it match the material of electrode and therefore eliminate the damage
to the electrode(please refer to figure 1)

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