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Comparison of Power Frequency Induction Furnace and Medium Frequency Induction Furnace

July 09, 2019

Comparison of Power Frequency Induction Furnace and Medium Frequency Induction Furnace 

一. Power frequency induction furnace: power frequency induction furnace is an induction furnace with an electric current of industrial frequency (50 or 60 hz) as the power source.Power frequency induction furnace has been developed into a widely used smelting equipment.It is mainly used as melting furnace for smelting gray cast iron, malleable cast iron, ductile iron and alloy cast iron.In addition, also used as a holding furnace, with the former, power frequency induction furnace has replaced rushed out as one of the main equipment of casting production, compared with cupola, power frequency induction furnace hot metal composition and temperature easy to control, low amount of gases and inclusions in the castings, polluting the environment, save energy and improve the working conditions and many other advantages.Therefore, the power frequency induction furnace has been developed rapidly in recent years.

The whole equipment of power frequency induction furnace includes four parts.

1. Furnace body part: the furnace body part of the power frequency induction furnace for smelting cast iron is composed of two induction furnaces (one for smelting, the other for standby), furnace cover, furnace frame, tilting furnace oil cylinder, and furnace cover moving opening and closing device.

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: cooling water system includes capacitor cooling, inductor cooling and soft cable cooling.The cooling water system consists of pumps and circulating tanks or cooling towers as well as pipes and valves.

4. Hydraulic system: hydraulic system includes oil tank, oil pump, oil pump motor, hydraulic system pipelines and valves and hydraulic operating platform.

二.Medium frequency induction furnace: an induction furnace with a power frequency in the range of 150 to 10,000 Hertz is called an intermediate frequency induction furnace and its main frequency is in the range of 150 to 2500 Hertz.Domestic small frequency induction furnace power frequency of 150, 1000 and 2500 Hertz three.Medium frequency induction furnace is a special equipment for smelting high quality steel and alloy. Compared with power frequency induction furnace, it has the following advantages:

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

2) Strong adaptability and flexible use.Medium frequency induction furnace each furnace liquid steel can be all clean, easy to replace the type of steel;However, the molten steel in each furnace of power frequency induction furnace is not allowed to be cleaned, and part of the molten steel must be reserved for the lower furnace to start, so it is not convenient to replace the steel, which is only suitable for smelting a single type of steel.

3) the electromagnetic stirring effect is better.Since the electromagnetic force of the molten steel is inversely proportional to the square root of the power supply frequency, the stirring force of the medium frequency power supply is smaller than that of the power supply.For the removal of impurities in steel and uniform chemical composition, uniform temperature, if power stirring effect is better.The oversized pulsing force of power frequency power supply increases the scouring force of molten steel on the furnace lining, which not only reduces the refining effect but also reduces the crucible life.

4) easy to start operation.Since the skin effect of intermediate frequency current is much larger than that of power frequency current, there is no special requirement for charge when starting up the intermediate frequency induction furnace.The power frequency induction furnace requires a specially made open burden block (similar to the size of the crucible, about half the height of the crucible or cast steel or iron block) to start heating, and the heating rate is very slow.Read this, in the cycle operating conditions are mostly used in the medium frequency induction furnace.Another advantage of start up convenience is that power can be saved during the cycle.

Due to the above advantages, in recent years, if induction furnace is not only widely used in the field of steel and alloy production, but also in the production of cast iron, especially in the periodic operation of the casting workshop has been rapidly developed.

Auxiliary equipment of intermediate frequency induction furnace: complete equipment of intermediate frequency induction furnace includes: power supply and electrical control part, furnace body part, transmission device and water cooling system.