1. What are the characteristics of needle coke?

Needle coke is a kind of high-quality carbon raw material. It is divided into two types: coal series and oil series. The surface of needle coke has obvious stripe patterns. When broken, most of them are long needle-shaped fragments. Hence it is called needle coke. Needle coke is easy to graphitize at high temperature above 2000 degrees, and the graphite electrode produced by it not only has low resistivity, high bulk density, but also small thermal expansion coefficient, which is the best choice for the production of ultra-high-power electrodes and high-power electrodes. Necessary raw materials for electrodes. The price of needle coke is much more expensive than that of ordinary coke, currently about 5-8 times higher.

2. Will the vacuuming system on the electric arc furnace affect the use and consumption of the electrodes?

The fan used in the dust collection system generates a certain negative pressure during operation, which increases the air flow rate around the red hot electrode during steelmaking, thereby increasing the oxidation consumption of the electrode. When steelmaking, a well-adjusted dust collection system is It maintains a good working environment and stabilizes the consumption of electrodes.

3. How to avoid the increase of electrode consumption during steelmaking?

To avoid the increase of electrode consumption during steelmaking, the following should be done: 

(1) Maintain a good power supply state, and transmit electricity within the allowable current intensity range of the electrode according to the design requirements of the electric furnace. 

(2) Prevent the arc starting point from immersing in the molten pool. 

(3) Prevent the electrode from being immersed in molten steel to increase carbon. 

(4) If conditions permit, the electrode adopts spray cooling technology. 

(5) Set up the correct exhaust emission system. 

(6) Adopt the correct oxygen blowing system.

4. Why does the quality of electrode joints play an important role in electric arc furnace steelmaking?

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

5. What quality indicators of graphite electrode (joint) 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 joint. 

(3) Machining accuracy of electrodes and joints, no matter how good the quality of electrodes and joints is, without good machining accuracy (mainly refers to the cooperation between electrodes and joints), the use effect is not good. 

(4) The quality of the internal structure of electrodes and joints requires that there are no internal cracks that may cause hidden dangers in use.

6. What are the consequences of severe oxidation of the electrode end face at the upper end of the electrode holder?

When making steel in a smelting furnace, scrap steel 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 face at the upper end of the holder, which is easy to oxidize the electrode end face. If the oxidation is serious, the electrode end face will be deformed by The plane becomes an inclined plane. When a new electrode is connected to the upper end, the oxidation deformation of the end face of the lower electrode cannot make good contact with the new electrode, and the electrode gap is large, which is easy to cause oxidation and breakage of the internal joint. Without changing the steelmaking conditions, the best preventive measure is to add a protective cover to the electrode end face at the upper end of the holder to block the flame and air, so as to achieve the purpose of protecting the electrode end face.

What are the main factors affecting graphite electrode consumption in electric arc furnace steelmaking?