Electric arc furnace steelmaking is on the rise in steel production enterprises. Currently, among the three steelmaking methods of open hearth furnace, converter furnace and electric arc furnace, the proportion of electric furnace steel has reached about 30%. Graphite electrodes are used as conductive materials in electric arc furnace steelmaking. The consumption of graphite electrodes in electric arc furnace steelmaking depends not only on the quality of the electrodes but also on the level of steelmaking operation and management. The problems of the use of graphite electrodes over the years are analyzed one by one now, with the expectation of being beneficial to the operation of the use of graphite electrodes in electric arc furnace steelmaking.
What are the main factors affecting the consumption of graphite electrodes in electric arc furnace steelmaking?
The main ones are: (1) The loading quantity and the feeding method. (2) Feeding time and power-off time. (3) Smelting cycle. (4) Exhaust gas emission and dust removal system. (5) Electrode adjustment quality. (6) Load regulation quality. (7) Oxygen blowing operation. (8) Electrode connection quality. (9) The mass of the electrode connector body. (10) Electrode joint holes and joint processing accuracy.
02. What matters should be noted when storing graphite electrodes in steel mills?
The electrodes and connectors should be stored on a clean cement floor to prevent the electrodes from being damaged or adhering to soil. For electrodes that are not in use for the time being, do not remove the packaging to prevent dust and debris from falling onto the threads of the joint or the inner threads of the electrode end face and the electrode hole. Electrodes should be neatly arranged in the warehouse. Both ends of the electrode stacks should be properly padded to prevent slipping. The stacking height of electrodes generally should not exceed two meters. The stored electrodes should be protected from rain and moisture to prevent cracks and accelerated oxidation during steelmaking. When storing electrode connectors, do not place them near high-temperature areas to prevent the connector bolts from melting and overflowing.
03. How can electrode breakage and disengagement be avoided during the steelmaking process?
The following measures can be taken during the steelmaking process to effectively prevent electrode breakage and disengagement: (1) The electrode phase sequence is correct, in the counterclockwise direction. (2) The scrap steel in the steel furnace should be evenly distributed, and large pieces of scrap steel should be placed at the bottom of the furnace as much as possible. (3) Avoid the presence of non-conductive materials in scrap steel. (4) The electrode column should be centered with the top hole of the furnace and kept parallel. The wall of the top hole of the furnace should be cleaned frequently to prevent the accumulation of residual steel slag and the breaking of the electrode. (5) Keep the electric furnace tilting system in good condition to ensure smooth tilting of the electric furnace. (6) The electrode clamps should be kept away from the electrode connection points and the electrode joint holes. (7) Select joints with high strength and excellent processing accuracy. (8) The torque applied when connecting the electrodes should be appropriate. (9) Before and during the electrode connection, prevent the electrode hole threads and joint threads from being mechanically damaged. (10) Prevent steel slag or foreign objects from getting embedded in the electrode holes and joints to avoid affecting the screwing.
04. What should be noted during the crane hoisting process when using graphite electrodes in steel mills?
Whether forklifts or cranes are used to transport electrodes, meticulous operation is essential. During the lifting process of the electrodes, damage to the electrode ends and threads can cause serious problems for the use of the electrodes. It is particularly important to protect the threaded holes and the threads of the joints. When lifting the electrode, a protective pad should be used to avoid damaging the end face of the electrode and the thread of the joint.
05. How to connect electrodes correctly?
When connecting, use compressed air to blow clean the electrode holes, electrode end faces and joints. There should be no accumulated dust or foreign objects embedded. The connection area should be kept clean and flat. After the two electrodes are screwed in to a certain extent (with a gap of about 10mm), blow it clean again with compressed air, and then tighten the electrodes with a torque wrench. The torque applied during tightening should be appropriate. If a gap is found at the connection area after tightening, Exit and reconnect until there is no gap.
Picture
06. Regarding the correct clamping position of the electrode gripper
The electrode gripper should not be clamped at the connection point of the electrode or the threaded hole of the electrode. It should be clamped between the white wires at both ends of the electrode. Meanwhile, before the gripper clamps the electrode, the surface of the electrode and the gripper should be blown clean with compressed air to ensure good conduction of current and heat flow between the electrode and the gripper, prevent arc damage to the gripper, and thus extend the service life of the gripper.
07. Different power electric furnaces should use graphite electrodes of different powers. graphite electrodes are classified by grade into (regular power)RP graphite electrode,( 68336742,high power)HP graphite electrode, and (ultra high power)UHP graphite electrode.
