What is induction furnace

Induction furnace supporting equipment

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

The working principle of induction furnace

When the alternating current passes through the induction coil, an alternating magnetic field is generated around the coil, and the conductive material in the furnace generates an induced potential under the action of the alternating magnetic field. A current (eddy current) is formed at a certain depth on the surface of the charge, and the charge is heated and melted by the eddy current.

Induction furnace features

(1) Fast heating speed, high production efficiency, less oxidative decarbonization, saving material and forging die costs

Crucible Type High Frequency Induction Furnace

Since the principle of intermediate frequency induction heating is electromagnetic induction, its heat is generated in the workpiece itself. Ordinary workers can carry out the continuous work of the forging task ten minutes after going to work with the intermediate frequency electric furnace, and there is no need for professional workers to burn the furnace and seal the furnace in advance. . There is no need to worry about the waste of heated billets due to power outages or equipment failures.

Due to the fast heating rate of this heating method, there is very little oxidation. Compared with coal-fired furnaces, each ton of forgings saves at least 20-50 kilograms of steel raw materials, and its material utilization rate can reach 95%.

Because the heating method heats evenly and the temperature difference between the core surface is extremely small, the life of the forging die is greatly increased in forging, and the surface roughness of the forging is also less than 50um.

(2) Superior working environment, improve workers' labor environment and company image, no pollution, low energy consumption

Compared with the coal furnace, the induction heating furnace is no longer subject to the baking and smoking of the coal furnace under the scorching sun, which meets the requirements of various indicators of the environmental protection department, and at the same time establishes the company's external image and the future development trend of the forging industry.

(3) The heating is uniform, the temperature difference between the core and the surface is extremely small, and the temperature control accuracy is high.

The heat of induction heating is generated in the workpiece itself, so the heating is uniform and the temperature difference between the core surface is extremely small. The application of temperature control system can realize precise control of temperature and improve product quality and qualification rate.

Induction furnace classification

Induction furnace power frequency

The industrial frequency induction furnace is an induction furnace with industrial frequency current (50 or 60 Hz) as the power source. Power frequency induction furnace has developed into a widely used smelting equipment. It is mainly used as a melting furnace to smelt gray cast iron, malleable cast iron, ductile 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 the main equipment in casting production. Compared with the cupola, the power frequency induction furnace has the advantages of easy control of the composition and temperature of molten iron, and the gas in the casting and the It has many advantages such as low content of inclusions, no environmental pollution, energy saving and improved working conditions. Therefore, the power frequency induction furnace has developed rapidly in recent years.

The complete set of power frequency induction furnace equipment includes four parts.

1. Furnace body part

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

2. Electrical parts

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

3. 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 pool or cooling tower, and pipeline valves.

4. Hydraulic system

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

Induction furnace intermediate frequency

An induction furnace with a power frequency in the range of 150-10,000 Hz is called an intermediate-frequency induction furnace, and its main frequency is in the range of 150-2500 Hz. The power frequency of domestic small frequency induction furnace is 150, 1000 and 2500 Hz.

The medium frequency induction furnace is a special metallurgical equipment suitable for smelting high-quality steel and alloys. Compared with the duty induction furnace, it has the following advantages:

(1) The melting speed is fast and the production efficiency is high. The power density of the intermediate frequency induction furnace is large, and the power configuration per ton of molten steel is about 20-30% larger than that of the 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. The liquid steel in each heat of the intermediate frequency induction furnace can be completely discharged, and it is convenient to replace the steel type; while the molten steel in each heat of the power frequency induction furnace is not allowed to be discharged, and a part of the molten steel must be reserved for the start of the next furnace, so it is inconvenient to replace the steel type, only suitable for For smelting a single variety of steel.

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

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

The intermediate frequency furnace heating device has the advantages of small size, light weight, high efficiency, excellent thermal processing quality and favorable environment. It is rapidly eliminating coal-fired furnaces, gas furnaces, oil furnaces and ordinary resistance furnaces.

Due to the above advantages, the intermediate frequency induction furnace has been widely used not only in the field of steel and alloy production in recent years, but also in the production of cast iron, especially in the foundry that operates periodically.