23 FAQ About Graphite Electrodes In Electric Furnace Steelmaking(6)

21. Why does the quality of electrode nipples play an important role in EAF steelmaking? 

The nipple plays a key role in the connection of the electrode in steelmaking. The quality of the nipple is directly affect the use of the electrode in the electric furnace steelmaking. No matter how good the electrode is, if there is no high-quality nipple with it, problems can also arise in steelmaking. According to relevant data, in electric furnace steelmaking, more than 80% of electrode accidents are caused by broken nipples and loose tripping. Therefore, the selection of high-quality electrode nipples is a guarantee condition for the normal use of electric furnace steelmaking electrodes. 

22. Which quality indicators of graphite electrode (nipple) products have an impact on electric furnace steelmaking? 

(1) Quality indicators such as bulk density, resistivity, strength, elastic modulus and thermal expansion coefficient of the electrode. (2) Quality indicators such as bulk density, resistivity, strength, elastic modulus and thermal expansion coefficient of the nipple. (3) The machining accuracy of electrodes and nipples. No matter how good the quality of electrodes and nipples is, the use effect couldn’t be ideal without good machining accuracy (mainly refers to the cooperation of electrodes and nipples). (4) The internal structural quality of electrodes and nipples requires that there are no cracks which might cause potential dangers in use. 

23. What are the consequences of severe oxidation of the electrode end surface at the upper end of the electrode holder? 

When making steel in a smelting furnace, scrap is burned in the furnace. At the same time, due to the oxygen blowing in the furnace, the height of the flame column is often higher than the electrode end surface at the upper end of the holder, which is easy to oxidize the electrode end surface. If the oxidation is serious, the end face of the electrode will be deformed from the plane to the inclined plane. When a new electrode is connected to the upper end, the end surface of the lower part of the electrode is oxidized and deformed and cannot make good contact with the new electrode. The electrode gap is large, which may easily cause oxidation and breakage of the internal nipple. Without changing the steelmaking conditions, the best precaution is to install a protective cover on the electrical extreme surface of the upper end of the holder to block the flame and air, so as to achieve the purpose of protecting the end face of the electrode.