Induction furnace's classification

Induction furnace-power frequency 

Power frequency induction furnace is an induction furnace with industrial frequency current (50 or 60 Hz) as the power supply. Power frequency induction furnace has developed into a kind of smelting equipment with wide application. It is mainly used as a melting furnace to smelt gray cast iron, malleable cast iron, nodular cast iron and alloy cast iron. In addition, it is also used as a holding furnace. As before, the power frequency induction furnace has replaced the cupola as a hot spot in casting production.

Compared with cupola, power frequency induction furnace has many advantages, such as easy control of hot metal composition and temperature, low amount of gas and inclusions in castings, no environmental pollution, energy saving and improved working conditions. Therefore, power frequency induction furnace has developed rapidly in recent years.

Power frequency induction furnace-the complete set of equipment of it includes four parts

1. Furnace body

The furnace body of power frequency induction furnace for smelting cast iron is composed of induction furnace (two sets, one for smelting and the other for standby), furnace cover, furnace frame, furnace tilting oil cylinder, furnace cover moving opening and closing device, etc.

2. Electrical part

The electrical part is composed of power transformer, main contactor, balance reactor, balance capacitor, compensation capacitor and electrical console.

3. Water cooling system

The cooling water system includes capacitor cooling, inductor cooling and flexible cable cooling. The cooling water system is composed of water pump, circulating water tank or cooling tower, pipeline valve, etc.

4. Hydraulic system

The hydraulic system includes oil tank, oil pump, oil pump motor, hydraulic system pipeline and valve, hydraulic console, etc.

Induction arc furnace-intermediate frequency

The induction furnace whose power frequency is in the range of 150-10000 Hz is called intermediate frequency induction furnace, and its main frequency is in the range of 150-2500 Hz. The power frequencies of domestic small frequency induction furnace are 150, 1000 and 2500 Hz.

Medium frequency induction furnace is a special smelting equipment suitable for smelting high-quality steel and alloy. Compared with the work induction furnace, it has the following advantages:

1. Fast melting speed and high production efficiency. The power density of medium frequency induction furnace is high, and the power configuration per ton of molten steel is about 20-30% higher than that of power frequency induction furnace. Therefore, under the same conditions, the melting speed of medium frequency induction furnace is fast and the production efficiency is high.

2. Strong adaptability and flexible use. The liquid steel of each furnace of medium frequency induction furnace can be completely discharged, and it is convenient to change the steel grade; The liquid steel of each furnace of the power frequency induction furnace is not allowed to be discharged, and a part of the liquid steel must be reserved for the start-up of the furnace. Therefore, it is inconvenient to change the steel grade, which is only applicable to smelting a single variety of steel.

3. The effect of electromagnetic stirring is good. Because the electromagnetic force borne by liquid steel is inversely proportional to the square root of power frequency, the stirring force of medium frequency power supply is smaller than that of power frequency power supply. For removing impurities in steel, uniform chemical composition and uniform temperature, the stirring effect of medium frequency power supply is better. The excessive stirring force of power frequency power supply increases the scouring force of molten steel on the furnace lining, which will not only reduce the refining effect, but also reduce the service life of the crucible.

4. Easy to start and operate. Since the skin effect of the medium frequency current is much greater than that of the power frequency current, the medium frequency induction furnace has no special requirements for the charge when starting, and can be heated quickly after charging; The power frequency induction furnace requires specially made starting blocks (cast steel or cast iron blocks similar to the size of the crucible and about half the height of the crucible) to start heating, and the heating speed is very slow. Therefore, under the condition of periodic operation, medium frequency induction furnace is mostly used. Another advantage is that it can save power during the starting cycle.

Medium frequency furnace heating device has the advantages of small volume, light weight, high efficiency, excellent thermal processing quality and favorable environment. It is rapidly eliminating coal-fired furnace, gas furnace, oil furnace and ordinary resistance furnace. It is a new generation of metal heating equipment.

Due to the above advantages, medium frequency induction furnace has been widely used not only in the production of steel and alloy, but also in the production of cast iron, especially in the foundry workshop with periodic operation.