Induction Furnace Power Consumption – Smelting

Induction furnace power consumption, generally speaking is for steel heating.

The power consumption of intermediate frequency furnace is between 360-450 degrees for forging heating;

The power consumption for melting and casting is between 550-750 degrees.

The consumption is lower, and the small tonnage is higher.

The specific power consumption needs to be determined according to the material and specific tonnage.

So what factors are usually closely related to the power consumption of induction furnaces, Hani Metallurgy will take you to understand.

Five major factors of induction furnace power consumption

1. In terms of intermediate frequency power supply

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

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

c. The conversion efficiency of intermediate frequency power supply is high or low. It reaches 97%~98% in foreign countries, and close to 97% in China, mainly in the efficiency of reactance and capacitance.

d. The layout of the electric furnace unit. The distance between the power supply and the furnace body, the length of the power transmission copper bar, the length of the water-cooling cable, and the distance between the power supply input voltage and the high-voltage transformer and the power supply point are all influencing factors.

2.The influence of the melt

a. The cleanliness of the surface of the charge (if there are 5% impurities, 5% of the electric energy will melt these impurities) will also affect the life of the furnace lining.

b. Whether the length of the charge block is appropriate will affect the electrical efficiency and melting quality of the electric furnace. Generally, the block size of 200~300m is appropriate.

c. Whether there is liquid metal liquid in the furnace at the time of melting. The raffinate should account for 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 large, the effective use of molten iron will be reduced and the unit energy consumption will be increased. The emptying of molten iron reduces the power factor and the melting speed during use.

3.Refractory material

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

b. Correct bottom thickness also affects electrical efficiency and lining life. When the furnace bottom height exceeds the effective coil by 100m, the bottom refractory material will strongly wash the bottom due to the induction stirring force, which will drastically reduce the service life.

c. The correct backing material is used. The isolation material is called the backing material (such as asbestos cloth, etc.).

Disadvantages of using asbestos cloth as a backing material: People inhale it and it will remain in the lungs, which has a tendency to cause cancer.

Asbestos cloth generally has high moisture content, and it is easy to harden and crack behind the quartz sand with water entering the quartz sand after a period of use. The function of the backing material is insulation, waterproof and fire resistance of the inductor coil, and the surface of the cement serves as an isolation function and facilitates the replacement of the furnace lining. Behind the hot surface of quartz sand, it is hoped that there will be a loose layer so that the molten iron will stop here if it drills through the hot surface.

The cooling water temperature of the sensor is a necessary condition for creating a loose layer. If you use asbestos cloth with better heat insulation and add water, the microboric acid in the quartz sand will harden it, and mica paper is the best choice. Treated with high-grade coil cement, the surface is smooth, no need to use backing materials, but it must have the properties of easy processing, no cracks after drying, and no reaction with acidic substances.

4.The influence of energy saving in the operation process of the induction furnace power consumption

Timing of feeding, when adding solid charge for the first time, it should reach about 1/3 of the furnace capacity, otherwise it will affect the power output, and it will also spark (discharge) arc and consume power, and may cause cracks on the surface of the furnace lining, which is harmful to cast steel Neutral materials are extremely destructive.

When the first batch of material reaches the molten state, the solid furnace material sinks, and the material should be continued immediately at this time, which can melt the softened solid material under pressure, so that the melting can proceed at the fastest speed.

It is normal to feed the furnace without violent tumbling in the liquid state (violent tumbling in the liquid state means that the molten metal is overheated, and the furnace wall is washed away, and the lining material is consumed).

This requires that the power input of the melting time is less than 20% (first feeding) → 50% (softening) – +65% (feeding) → 100% feeding to reach the temperature required by the process. Then power off the liquid.

5.Avoid high energy consumption caused by improper operation

a. The molten metal is overheated.

b, the liquid is discharged without stopping the furnace. Not only unsafe, but also wrong in terms of energy consumption and melting process.

Generally, the electric furnace inductor is divided into upper and lower parts. When the molten metal level in the furnace is lower than half of the upper inductor, due to the change of resistance, the upper inductor no longer has induced current passing through, and all of them are concentrated in the lower inductor, so that the lower molten metal Overheating, washing the furnace wall, and the service life of the furnace lining will drop sharply.

C, high temperature insulation. Long-term high temperature will change the metallographic phase, C and Si phase transformation, the whitening tendency of the casting is serious, and the machining performance will be deteriorated.

Through the above, we can better understand the problems that should be paid attention to during use, so as to control power consumption.

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