Common Problems And Solutions Of Graphite Electrodes in Electric Furnace Steelmaking

1.What are the main factors affecting the consumption of graphite electrodes in electric arc furnace steelmaking?

Mainly include: (1) The amount of material and the method of material addition. (2) Feeding time and power-off time. (3) Smelting cycle. (4) Exhaust emission and dust removal system. (5) Electrode conditioning quality. (6) Load regulation quality. (7) Oxygen blowing operation. (8) Electrode connection quality. (9) The mass of the electrode connector body. (10) Electrode joint hole and joint machining accuracy.

2. What matters should be paid attention to in the storage of graphite electrodes in steel plants?

Electrodes and joints should be stored on a clean cement floor to prevent the electrodes from being damaged or sticking to soil; for electrodes that are not used temporarily, do not remove the packaging to prevent dust and debris from falling on the joint threads or the end face of the electrode and the inner thread of the electrode hole superior. Electrodes should be neatly stored in the warehouse, and both ends of the electrode stack should be well padded to prevent anti-slip stacking. The stacking height of electrodes should generally not exceed two meters. The electrodes stored should be protected from rain and moisture to avoid cracks and accelerated oxidation of the electrodes during steelmaking. Do not store the electrode connector near a high temperature to prevent the connector plug from melting and overflowing.

3. How to avoid electrode breakage and tripping during steelmaking?

The following measures are taken during the steelmaking process to effectively avoid electrode breakage and tripping: (1) The electrode phase sequence is correct, counterclockwise. (2) The scrap steel in the steel furnace is evenly distributed, and the large scrap steel material is placed at the bottom of the furnace as much as possible. (3) Avoid the presence of non-conductive materials in the scrap. (4) The electrode column is aligned with the furnace top hole, and the electrode column is parallel. The furnace top hole wall should be cleaned frequently to avoid the accumulation of residual steel slag and the forcing the electrode off. (5) Keep the electric furnace tilting system in good condition and keep the electric furnace tilting smoothly. (6) The electrode holder avoids being clamped at the electrode connection and the electrode connector hole. (7) Select joints with high strength and high machining accuracy. (8) The torque applied during electrode connection should be appropriate. (9) Before and during the electrode connection, prevent the electrode hole thread and the joint thread from being mechanically damaged. (10) Prevent steel slag or foreign matter from inserting into the electrode hole and the joint to affect the screw connection.

4. When steel mills use graphite electrodes, what should be paid attention to in the process of crane hoisting?

Regardless of whether the electrode is transported by a forklift or a crane, it must be handled carefully. During the electrode lifting process, the damage to the electrode end and the thread will cause serious problems in the use of the electrode. In particular, it is important to protect the threaded hole and the thread of the joint. Use pads when lifting the electrode to avoid damage to the electrode end face and connector threads.

5. How to connect the electrodes correctly?

When connecting, use compressed air to blow out the inside of the electrode hole, the end face of the electrode and the joint. There should be no dust deposits or foreign objects embedded. The connection should be kept clean and flat. Blow once with compressed air, and then use torque pliers to tighten the electrode. The torque applied when tightening should be appropriate. If there is a gap in the connection after tightening, it must be withdrawn and reconnected until there is no gap.

6. About the correct gripping position of the electrode holder

The electrode holder cannot be clamped at the connection of the electrode and the threaded hole of the electrode, but should be clamped between the white lines at both ends of the electrode. Blow out to ensure good conduction of current and heat flow between the electrode and the gripper, prevent the damage of the gripper caused by arcing, and prolong the service life of the gripper.

7. What are the measures to reduce the consumption of electrode oxidation in electric arc furnace steelmaking?

The reduction measures mainly include: (1) Reduce the oxidation consumption of the electrode perimeter, strengthen the sealing of the furnace, and reduce the air intrusion into the furnace; minimize the exposure time of the red hot electrode outside the furnace, and standardize the oxygen blowing operation. (2) For the smelting furnace, if conditions permit, the electrode adopts spray cooling technology, which can effectively reduce the oxidation consumption on the side of the electrode. (3) The steel mill sprays anti-oxidant substances on the surface of the electrode, or the electrode manufacturer uses the anti-oxidant impregnation treatment technology before the electrode leaves the factory to improve the anti-oxidation performance of the electrode body.

8. How does the electrode phase sequence affect the use of electrodes?

The positive and negative electrode phase sequence during electric arc furnace steelmaking has a great influence on the tripping and breaking of the electrode during use. If the electrode phase sequence is clockwise, the electrode will loosen after being energized for a period of time during use, which is easy to cause the electrode to loosen. Or the joint is broken, the correct electrode phase sequence should be counterclockwise, so that the electrodes will be more and more closely connected during use.

9. Why is the phase electrode required to be in parallel and centered with the top hole of the furnace cover during electric arc furnace steelmaking?

The electrode column should be in contact with the top hole of the furnace cover. The electrode column should avoid friction with the furnace cover. Otherwise, the friction with the furnace cover will cause the furnace cover to break the electrode. For AC furnaces, the three-phase electrode columns should be kept as parallel as possible.

10. How to apply torque when the electrode is screwed?

The torque applied when the electrode is screwed should be appropriate, and the operation should be continuous. If the torque is too small, the joint will be thermally loosened. If the torque is too large, the electrode joint hole will be cracked. When screwing, use a special electrode screwing tool. Do not screw Too tight and too loose. If there is a gap in the contact of the end face after tightening, it must be withdrawn to clean up and then screwed again.

11. Why is graphite spreader better than metal spreader?

Although the metal spreader is durable and not easy to be damaged, after being heated during use, the thermal expansion of the metal spreader is easy to crack the electrode hole, and at the same time, it is easy to damage the thread in the electrode hole when the metal spreader is received, resulting in a large area of scraping of the thread in the hole. Because the graphite spreader has the same thermal expansion performance and hardness as the electrode, the above-mentioned bad use situation will not occur, but the graphite spreader has a short service life and is easily damaged. If serious damage is found, it should be replaced in time.