Graphite electrodes are used primarily in Electric Arc Furnace or Ladle Furnace steel manufacturing. So let DanCarbon talk about what are graphite electrodes used for?
Graphite electrodes can provide high levels of electrical conductivity and capability of sustaining the extremely high levels of generated heat. Graphite electrodes are also used in the refinement of steel and similar smelting processes.
► Graphite glectrodes used
1. The electrode holder should be held in the place beyond the security line of the top electrode; otherwise the electrode would be easily broken. The contact surface between the holder and the electrode should be cleaned up regularly to maintain a good contacting. The cooling jacket of the holder shall be avoided from water leakage.
2. Identify the reasons if there is gap in the electrode junction, do not use the muntil the gap is eliminated.
3. If there is falling off of nipple bolt when connecting electrodes, it is necessary to complete the nipple bolt.
4. The application of electrode should avoid of tilting operation, particularly, the group of connected electrodes should not be put horizontally so as to prevent from breaking.
5. When charging materials to the furnace, the bulk materials should be charged to the place of the furnace bottom, so as to minimize the impact of the large furnace materials on the electrodes.
6. The large pieces of insulation materials should be avoided of stacking on the bottom of the electrodes when smelting, so as to prevent from affecting the electrode use, or even broken.
7. Avoid of collapsing the furnace lid when rising or dropping the electrodes, which may result in electrode damage.
8. It is necessary to prevent the steel slag from splashing to the threads of the electrodes or nipple stored in the smelting site, which my damage the precision of the threads.
► The Cause of Electrode Breakage
1. Electrode stress status from downward force on the order of decreasing; the joint of electrodes and nipples under clamping device take maximum force.
2. When electrodes receive external force; Stress concentration of the external force is greater than the electrode can withstand then the strength will lead the electrode breakage.
3. The causes of external force are: melting of bulk charge collapse; scrap non-conductive objects below the electrode: impact of massive steel bulk flow and etc. Clamping device lifting response speed uncoordinated: partial core hole lid electrode; electrodes gap linked with bad connection and nipple strength is not up to compliance.
4. Electrodes and nipples with poor machining accuracy.
► Precautions for using the graphite electrode:
1. Wet graphite electrodes must be dried prior to use.
2. The foam protective caps on the electrodes socket shall be removed to verify the integrity of the internal threads of the electrode socket.
3. The surfaces of the electrodes and the internal threads of the socket shall be cleared by compressed air free of any oil and water. No steel wool or metal sand cloth shall be used in such clearance.
4. The nipple must be screwed carefully into the electrode socket of one end of the electrode without collision with the internal threads t is not suggested to directly put the nipple into the electrode removed from the furnace)
5. The lifting appliance (it' s preferred to adopt graphite lifting appliance) should be screwed into the electrode socket of the other end of the electrode
6. When lifting the electrode, cushion-like materials must be put on the ground under the connecting end of the electrode to avoid any collision. After the lifting hock has been put into the ring of the lifting appliance. The electrode shall be lifted smoothly to prevent it from falling or colliding with any other fixture.
7. The electrode shall be lifted above the head of the working electrode and dropped slowly aiming at the electrode socket. Then the electrode will be screwed to make the helical hook and the electrode declining and tuning together. When the distance between the end faces of two electrodes is 10-20mm, the two end face of the electrodes and the outer part of the nipple must be cleared again by compressed air. Finally the electrode must be laid gently, or the threads of the electrode socket and nipple will be damaged because of the violent collision.
8. Use torque spanner to screw the electrode until the end faces of the two electrodes contact closely(the gap of correct connection between the electrodes is less than 0.05mm).
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