The operating induction melting electric furnace must comply with 18 habits

1. Observe the cooling water (temperature, water pressure, flow) on the internal and external circulating water systems at any time.

If it is found that a branch has small water flow, leakage, blockage or excessive temperature, it should reduce power operation or shutdown; if it is found that the furnace cooling system is out of power or the pump is stopped, the furnace cooling water should be stopped, then stop immediately. Melt and start the water pump with the backup power supply or start the emergency diesel generator to start the emergency circulation cooling system or turn on the tap water to directly enter the cooling. The water cooled by the ginger after the furnace body is directly discharged; if it can not be processed in a short time, the water cycle is difficult to recover, it should be Who is emptied in the furnace to avoid turning the iron into a piece of iron due to the long-term cooling of the molten iron, which is difficult to remove from the furnace.

2. Observe the various indicator instruments on the power cabinet door of the intermediate frequency furnace at any time, and adjust the input of the intermediate frequency power in time to obtain the best melting effect and avoid long-term low-power operation.

3. Pay close attention to the current indication value of the leakage current indicator to grasp the change of the thickness of the lining. When the indicator needle reaches the police value, it should be rebuilt.

4. If the protection indication suddenly appears during normal operation, first turn the power knob to the minimum position, and immediately press “inverter stop” to find out the cause and then start it after elimination.

5. If there is an emergency or abnormal situation, such as abnormal sound, smell, smoke, fire or a sharp drop in output voltage, the output current rises sharply, and the intermediate frequency is higher than normal operation, and the leakage current value fluctuates greatly. It may be that the furnace lining is thin, leaking molten iron, and the induction ring gate is short-circuited by arc. It should be stopped immediately by pressing the “inverter stop” button and deal with it in time to prevent the accident from expanding.

6. When adding and slag, the power should be adjusted first. When the iron is discharged from the furnace, the variable frequency power supply must be placed in the “inverter stop” position.

7. When the hot lining cold material melts, the charging can only be loaded to 50% of the height of the crucible. When the current drops to the rated value, the material is continuously fed into the crucible. (This is because the cold resistance of the cold charge is small, the current is large, and the regulated voltage is limited by the current and affects the power input)

8. During the production process, it is not allowed to overfill or even exceed the furnace mouth. Because the magnetic field of the furnace above the upper end of the induction coil is weak, the heat is mainly transferred by the iron below, so the melting speed is slow. At the same time, because the furnace cannot be covered, a large amount of heat is dissipated through the furnace mouth, reducing productivity.

In addition, the upper end of the induction coil and the lining of the joint with the nozzle are not easy to be compacted, the oven is not perfect, and the sintering is not good, but the mechanical vibration stress is the largest, so the furnace is likely to leak. Therefore, the surface of the solution in the crucible should be controlled to be flush with the upper end surface of the induction coil.

9. Although the induction melting  electric furnace can be emptied, it is good for melting different materials. However, if the material is not replaced, it is better to leave a residual liquid in the furnace. This is because, due to the presence of molten iron in the furnace, the added charge is easily connected into a large number of pieces, and the individual pieces of the charge are arc-bridged together to form a large piece, thereby increasing the melting rate. The speed at which the arc bridges between a single small charge depends on the frequency. The frequency is low and the lap welding speed is low (the power frequency furnace must leave the residual liquid melting).

If it is not emptied, a small portion of the molten iron is left at the bottom of the furnace, which can be easily overcome by using the disadvantages of lower frequencies (the frequency of the intermediate frequency furnace is relatively low). In addition, the residual liquid has a small change in load at the initial stage of energization, and high power can be input from the beginning, and at least the melting time of the metal charge can be shortened.

10. When feeding, avoid the upper limit of the molten iron surface exceeding the 80% capacity limit, and do not cause accidents when the molten iron overflows the furnace mouth during feeding.

11, the feed should first add a small piece of charge and then increase the charge.

12. Frequently observe the melting condition in the furnace. Before the furnace material has not completely melted, it should be replenished in time. It is found that the scaffold should be treated in time to avoid the shed under the temperature of the molten iron, which exceeds the melting point of the furnace material (silica sand 1704 °C).

13. After the molten iron is melted, it should be slag and temperature measured in time, and the temperature of the furnace should be released in time.

14. Under normal circumstances, when the wall of the original lining is 1/3 thickness, the furnace should be rebuilt.

15. The iron lining should be emptied once a week to measure the size of the lining and observe the surface condition. The actual situation of the lining should be grasped in time, and the problem should be dealt with in time.

16. It is preferable to add the C agent a little bit in the process of adding the metal charge. If it is added too early, it will adhere to the bottom of the furnace and will not dissolve easily into the molten iron. If it is added too late, it will prolong the melting and heating time, which will not only cause delay in composition adjustment, but also may cause excessive high temperature. The addition of ferrosilicon (increased Si), for the intermediate frequency furnace with weaker stirring force, because the high content of Si in the molten iron will increase the C property, so the Si iron is added later, but the iron in the furnace will be caused. Delay in composition analysis and adjustment.

17. The liquid metal liquid left in the furnace during melting helps to improve the electrical efficiency of some electric furnaces and improve the power factor of the melting stage. However, these molten iron may endanger the metal quality due to overheating in the furnace for a long time, so the residual metal liquid is preferably 15% of the furnace capacity. Too little molten iron is overheated, and too much reduces the effective use of molten iron and increases unit energy consumption.

18, the thickness of the charge is 200 ~ 300mm is appropriate. The greater the thickness, the slower the melting.