【Graphite Electrode】Usage Precautions in electric arc furnace Steelmaking

Currently, electric arc furnace (EAF) steel accounts for about 30% of steel production, alongside open-hearth and converter methods. In electric arc furnace steelmaking, graphite electrodes serve as the conductive material. The consumption of graphite electrodes in EAF steelmaking is related to both the quality of the electrodes and the level of steelmaking operation and management.

Ⅰ. Main Factors Affecting Graphite Electrode Consumption in EAF Steelmaking

1. Charging amount, method, timing, and power-off time.

2. Melting cycle, waste gas emission, and dedusting system.

3. Electrode adjustment quality and load adjustment quality.

4. Oxygen blowing operation.

5. Electrode connection quality and nipple itself quality.

6. Electrode nipple hole and nipple machining accuracy.

Ⅱ. Graphite Electrode Storage Precautions in Steel Mills

Electrodes and nipples should be stored on clean cement floors to prevent damage or soil contamination; unneeded electrodes should retain their packaging to avoid dust and debris on the threads or electrode surfaces. Electrodes should be neatly stored in warehouses, with supports on both ends to prevent slippage, and should not be stacked higher than two meters. Stored electrodes must be protected from rain and moisture to prevent cracks and oxidation. Electrode nipples should be stored away from high temperatures to prevent the nipple bolts from melting.

Ⅲ. How to Avoid Electrode Breakage and Detachment During Steelmaking

To effectively prevent electrode breakage and detachment during steelmaking:

1. Ensure correct electrode phase sequence, counterclockwise.

2. Distribute scrap steel evenly in the furnace, placing large scrap at the bottom.

3. Avoid non-conductive materials in scrap steel.

4. Align electrode columns with furnace top holes and maintain parallelism; regularly clean top hole walls to prevent slag accumulation from breaking electrodes.

5. Maintain a good condition of the furnace tilting system for stable operation.

6. Avoid clamping the electrode holder at the electrode connection and nipple hole.

7. Use high-strength, high-precision joints.

8. Apply appropriate torque when connecting electrodes.

9. Prevent mechanical damage to electrode hole threads and nipple threads before and during connection.

10. Prevent steel slag or foreign objects from embedding in the electrode hole and nipple, affecting the screw connection.

Ⅳ. Correct Method of Connecting Electrodes

When connecting, use compressed air to clean inside the electrode holes, ends, and nipples, ensuring no ash or foreign objects are embedded. The connection area must be kept clean and flat. After screwing the electrodes to a certain extent (about a 10mm gap), blow it clean again with compressed air, then tighten with a torque wrench. The applied torque must be appropriate. If a gap is found after tightening, the connection must be redone until there is no gap.

Ⅴ. Impact of Electrode Phase Sequence on Usage

The direction of the electrode phase sequence in EAF steelmaking significantly affects the occurrence of detachment and breakage. If the phase sequence is clockwise, the electrodes may loosen over time, leading to detachment or nipple breakage. The correct phase sequence is counterclockwise, ensuring tighter electrode connections during use.

Ⅵ. Torque Application Precautions

When Screw-Connecting Electrodes: The applied torque should be appropriate and continuous. Too little torque can cause nipple thermal loosening, while too much can crack the electrode nipple hole. Use specialized electrode screwing tools and avoid over-tightening or under-tightening. If a gap is found after tightening, clean and re-screw the connection. Contact us for further guidance on electrode installation.