The electrode hard-breaking accident mainly occurs during the charging process after the electrode is baked. Electrode hard-breaking accidents are generally concentrated in voltage level 15-17, voltage between 160-175V, electrode current 65-75KA, electric furnace power 16-17.5MW, hard-breaking length is generally 1.3-1.6 meters, which brings about the opening of the furnace. It is very hemp, and it also brings great difficulties to the determination of the time for the first batch of iron. Once the determination is inaccurate, it will cause a full ladle of molten iron or difficulty in tapping the first furnace.
When the electrode paste changes from solid to liquid, the mechanical strength drops to its lowest point when the temperature reaches 400 degrees Celsius. From 400 degrees Celsius to 700 degrees Celsius, the mechanical strength rises sharply, and the volatiles in the electrode paste begin to escape in large quantities from 400 degrees Celsius, and the strongest is at 500 degrees Celsius. When the electrode firing is included in the third stage at about 700 degrees Celsius, the remaining volatiles volatilize again here. When the temperature reaches 750 degrees Celsius, the electrode binder begins to carbonize. When the temperature reaches 800 degrees Celsius, the electrode baking ends and the electrode reaches the final strength. Even if the temperature reaches 1200 degrees Celsius, the electrode strength will not change much.
It can be seen from the above analysis that when the temperature is between 400 and 700 degrees Celsius, the speed of electrode firing determines the final quality of the electrode paste. If the sintering speed is too fast and the volatiles volatilize strongly, the porosity of the electrode itself will increase, and the quality of the electrode after sintering will be greatly reduced, which is one of the most important factors that cause the electrode to hardly break. Even if the electrode does not have a hard breaking accident, it will eventually fall off during the feeding process, which will cause the electrode to consume too fast, and even show that the working end is too short before the first furnace is tapped, and the tapping is difficult. Even if the iron in the first furnace is barely released, the electrodes must be baked immediately, otherwise the electric furnace cannot be operated and iron production is difficult. On the contrary, the roasting speed is too slow, which prolongs the furnace opening time, and the electric furnace cannot perform as quickly as possible. This is also what we do not want to see.