1.Induction melting furnace power density configuration

a, the level of power density configuration of induction melting furnace. High configuration, fast melting speed and good energy saving effect. Whether the electric furnace can maintain a high power factor and send electricity into the furnace is also the difference between high and low energy consumption. Zh

b. The efficiency of the induction melting furnace and the electrical efficiency of the induction coil. (The total efficiency of foreign advanced induction melting furnaces is as high as 75%, the induction coil is as high as 85%, and the domestic is 73% and 80%, respectively). Zh

c. The efficiency of IF power conversion. 97% to 98% in foreign countries and 97% in China, mainly in the efficiency of reactance and capacitance.

d. Arrangement of electric furnace unit. The distance between the power supply and the furnace body, the length of the power supply copper bar, the length of the water-cooled cable, and the power supply voltage. The distance between the high-voltage transformer and the power point is the influencing factor. Zh

2, the impact of the melt

1) The cleanliness of the surface of the charge (if there is 5% sundries and 5% electrical energy to melt these impurities), it will also affect the life of the furnace lining. Zh

2) Whether the length of the furnace block is appropriate or not will affect the electric efficiency and melting quality of the electric furnace. Generally, a block size of 200 to 300 mm is appropriate. Zh

3) Whether there is liquid metal in the furnace during melting. The residual liquid is preferably 15% of the furnace capacity. If it is too small, the overheating of this part of the molten iron will be aggravated. If it is too much, it will reduce the effective use of the molten iron and increase the unit energy consumption. The emptying of molten iron reduces the power factor and the melting speed during use. Zh

3.Refractory materials

1) Reasonable hot surface material thickness. Increasing the melting rate can reduce its thickness, but the service life is reduced, the cost of furnace construction is increased, and the potential safety hazards are increased. Zh

2) The correct bottom thickness also affects electrical efficiency and furnace lining life. When the height of the furnace bottom exceeds 100mm of the effective coil, the bottom refractory will strongly scour the bottom due to the induction stirring force, which drastically reduces the service life. Zh

3) Use the correct furnace lining material. The insulation material is called furnace lining material (such as asbestos cloth, etc.).

The use of asbestos cloth as a furnace lining material harm: people inhaled in the lungs will be carcinogenic tendencies; asbestos cloth is generally high in moisture content, after a period of time with the water into the quartz sand caused by cracking of the board. The function of the furnace lining material is insulation, water resistance and the fire resistance of the inductor coil. The surface of the cement acts as an insulation and facilitates the replacement of the furnace lining. After the quartz sand hot surface furnace, we hope that there is a loose layer so that molten iron will stop here if it passes through the hot surface. The cooling water temperature of the sensor is a necessary condition for the loose layer. If you use asbestos cloth with good heat insulation and moisture, the trace amount of boric acid in the quartz sand will make it harden. Mica paper is the best choice. The surface is treated with high-grade coil cement, and the surface is smooth. There is no need to use furnace lining materials, but it must have the characteristics of easy processing, no cracks after drying, and no reaction with acidic substances.

4. Energy saving during operation

Timing of feeding. For the first time, the solid charge should be added to the furnace capacity of about 1/3, otherwise it will affect the power output, spark (discharge), arcing and power consumption, and may cause cracks on the surface of the furnace lining, which will cause cast steel neutral materials. Destructive. When the first batch of materials reaches the molten state, the solid furnace material sinks, and the material should be renewed immediately at this time, which can melt the softened solid material under pressure so that the melting proceeds at the fastest speed. It is normal that the liquid is not violently tumbling in the furnace (the violent tumbling of the liquid means that the metal liquid is overheating and flushes the furnace wall and consumes the furnace lining material). This requires the power input of the melting time to be less than 20% (first feeding) → 50% (softening) → 65% (feeding) → 100% feeding-a regular change to the temperature required by the process. Then power off the liquid. Zh

5 Avoid high energy consumption due to improper operation

a. The metal liquid is too hot. Zh

b. Non-stop furnace discharge. Not only is it unsafe, it is also wrong in terms of energy consumption and melting process. Generally, the electric furnace inductor is divided into two parts. When the liquid level in the furnace is lower than half of the upper inductor, due to the change in resistance, the upper inductor no longer passes the induction current, and all of it is concentrated in the lower inductor. Overheating, flushing the furnace wall, the life of the furnace lining has decreased sharply. Zh

c. High temperature insulation. High temperature for a long time will change the metallographic phase, C and Si phase change, the white mouth tendency of the casting will be serious, and the machinability will be poor.