Electric Arc Furnace

1. EAF Introduction
2. Developments in EAF Technology
3. Basic Equipment and Operation
4. Furnace Layout
5. Electrical Equipment
6. Melting
7. Burners
8. Raw Materials
9. Raw Materials Preparation
10. Alloy Yield
11. Electrode Breakage
12. Slag Foaming
13. Slag Foamability
14. Slag Reduction
15. Deslagging
16. Tapping
17. Exercise: EAF Operation
18. EAF Simulation

Electrode breakage occurs occasionally in the EAF, predominantly during the melt-down operation. This should be avoided due to the high costs associated with a breakage. Besides the cost for the high density graphite electrode – which is a rather expensive material – the down-time equals loss of production which represents high values. Normally a broken electrode is changed within 10 minutes, but in difficult cases considerably longer down-times can be expected.

Electrode breakage is usually a consequence of mechanical overload on the electrode from the surrounding scrap:

• Scrap is caving in from the side as the electrode penetrates into the scrap pile inside the furnace. If heavy pieces hit directly on the electrode side breakage may occur.
• The electrodes are moving downward without detecting that a non-conducting material is present at the tip of the electrode. As the electrode continues to push downwards, breakage may occur.

The combination of arc length and scrap material is also of importance when considering the probability of an electrode breakage. The furnace operator then needs to balance the tap settings (voltage and current) with the need of highest possible power input and suitable arc length.