Overview: The intermediate frequency induction furnace is also known as the intermediate frequency furnace . It is a power supply device that converts the industrial frequency 50HZ alternating current into the intermediate frequency ( 300HZ or higher to 1000HZ ). The three-phase power frequency alternating current is rectified and turned into direct current. Then, the direct current is changed into an adjustable intermediate frequency current, and the intermediate frequency alternating current flowing through the capacitor and the induction coil is supplied to generate a high-density magnetic line in the induction coil , and the metal material contained in the induction coil is cut in the metal material. A large eddy current is generated. Widely used non-ferrous and ferrous metal melt. Compared to other casting apparatus, medium frequency induction furnace having a high thermal efficiency, short melting times, less burning of alloying elements, wide melt material, on environmental pollution, can accurately control the temperature and composition of the molten metal and the like.

A good way to quickly select the " intermediate frequency furnace "

1 、 Selection of intermediate frequency furnace transformer capacity

The value of the transformer capacity = the value of the power supply of the intermediate frequency furnace x 1.2

Transformer rectifier transformer to reduce the harmonic interference, possible special plane, i.e., a furnace disposed intermediate frequency of a rectifier transformer.

2 , the selection of the intermediate frequency furnace incoming line voltage

For the intermediate frequency power supply for medium frequency furnaces below 1000KW , three-phase five-wire 380V and 50HZ industrial power are generally used . For medium frequency furnaces above 1000KW , the focus is on using 660V incoming voltage .

3 , according to the capacity requirements to determine the selection of large tonnage of the intermediate frequency furnace.

Liquid iron in a weight of each working day and the weight required for a single piece, may determine the capacity of the furnace IF furnace.

4 , the choice of furnace structure

The melting furnace for the aluminum alloy structure with the reducer as the tilting furnace is commonly known as the aluminum shell furnace. The induction melting furnace of the steel structure with the hydraulic cylinder as the tilting furnace is commonly called the steel shell furnace. The steel shell furnace is asteel structure , and the aluminum shell furnace shell material is an aluminum alloy .

5 , medium frequency furnace temperature control method

Generally use red ultraviolet thermometer + closed loop PID control to automatically adjust power and control temperature

The price of the intermediate frequency furnace :

The intermediate frequency furnace is mainly composed of four parts :

1, the power supply and electrical components: power supply apparatus includes a high voltage or low voltage switchgear, wherein there are frequency power supply control circuit chip motherboard i.e., three-phase power rectifier (SCR 6 by the rectified AC power into DC), an inverter section (4 a the SCR or 8 converts the DC voltage into a frequency of about 1000HZ IF) output by the electric capacitance. Power conversion switch, compensation capacitor and intermediate frequency control cabinet (furnace distribution console), etc., the electrical part of the large intermediate frequency furnace also includes the leaking furnace alarm system.  

2 , the furnace body part: the furnace body includes the furnace cover, the sensor, the crucible, the furnace body bracket and the like.

3. Transmission: The transmission includes the movement of the furnace cover and mechanical or hydraulic devices such as tilting and resetting of the furnace body.

4 , water cooling system: water cooling parts are: intermediate frequency power supply, sensors, capacitors and busbars, flexible cables. In order to save water, a method of circulating cooling is usually employed. The cooling water circulation system includes a water pump, a cooling tower, a water tank, and the like.

Medium frequency furnace power, tonnage, power consumption selection method :

Classification of intermediate frequency furnaces :

 medium frequency furnace can be divided into molten metal materials

1 , medium frequency copper melting furnace

2 , medium frequency aluminum melting furnace

3 , medium frequency melting furnace

4 , medium frequency melting iron furnace

5. Noble metal melting furnace,

 Medium frequency furnace can be divided into furnace body structure according to the outer shell material

1, steel shell intermediate frequency furnace

2, aluminum shell intermediate frequency furnace

What is the difference between an aluminum shell intermediate frequency furnace and a steel shell intermediate frequency furnace ?

Medium frequency melting furnace with a steel structure into the yoke and the aluminum hydraulic tilting furnace with the furnace tilting gear. usually

Steel shell furnace: It has long service life (normal normal service life is more than 10 years) and good stability. Because of the use of magnetizer, the magnetizer has two functions: first, the top wire of the magnetizer and the induction coil are firmly fixed, so that The coil and the magnetizer form a stable structure. Second, the magnetizer can form a magnetic permeability barrier around the coil; energy saving, because the furnace with the magnetizer saves 3%-5% compared with the aluminum shell furnace ; the casting is stable, and the hydraulic tilting device can well control the casting Angle, speed; good safety performance, due to the characteristics of the leaking alarm device and refractory rubber layer, its good characteristics are steel shell structure when the tonnage is more than 2T .

Aluminum shell furnace: Aluminum shell furnace is a simple structure, the service life is generally about 5-8 years, there is no magnetizer, furnace lining mechanism, refractory clay layer, its safety performance is poor, generally used with capacity below 2T . For example: a 5T medium frequency furnace, when the furnace is full of molten iron, the overall weight of the equipment reaches 8-10T . If the aluminum shell structure is selected, when the reducer rotates the furnace body to 95 degrees, the whole furnace body will lean forward, and the safety performance is very good. difference. The aluminum shell furnace is suitable for small tonnage users who change production in a short time.

 What should I pay attention to in the operation of the intermediate frequency furnace ?

The phase-frequency AC power is converted into DC power, and after the inverter circuit output is converted into a single-phase AC power, the metal is heat-treated according to the principle of electromagnetic induction. However, in order to ensure that the intermediate frequency furnace can operate efficiently, it is necessary to carry out safe operation. The following is a detailed description of how to carry out safe operation.

1 , precautions before opening the furnace

The intermediate frequency electric furnace must check the electrical equipment, the water cooling system, the inductor copper tube, etc. before the furnace is opened. Only when these several equipments are in good condition can the correct method of safe operation of the intermediate frequency furnace be analyzed.

IF forging and casting furnace is a thermal processing apparatus for the inverter unit of several parts, the furnace and furnace control other components of the furnace by three, to ensure the safety of the heat treatment, or prohibiting the opening of the furnace; specifically determining The person responsible for power transmission and opening, and the responsible person shall not leave the post without authorization. During the work, the external condition of the sensor and the cymbal must be supervised to prevent people from touching the sensor and cable after power transmission, which affects the normal operation of the intermediate frequency electric furnace. Work or a safety accident.

2 , precautions after opening the furnace

After the intermediate frequency furnace is opened, during the charging, the inside of the furnace should be inspected to avoid mixing with flammable and explosive materials. In order to prevent the occurrence of the capping phenomenon, it is strictly forbidden to directly add the cold material and the wet material in the molten steel, and after the molten liquid is filled to the upper portion, the bulk material should not be added ; in order to avoid the explosion accident, it is necessary to ensure the pouring place and the furnace. There is no water in the front pit, no obstacles . In the pouring, two people need to cooperate, and the remaining molten steel can only be dumped at the place where it is made, and cannot be dumped anywhere.

3 , precautions during maintenance

When maintaining the medium frequency electric furnace, the internal frequency generator room should be kept clean and the flammable and explosive materials should not be stacked. Repair the furnace with excessive melt loss in time, and avoid the incorporation of iron filings and iron oxide in the furnace to ensure the compaction of the crucible.

What are the main factors that cause the accident in the intermediate frequency furnace ?

The reasons for the intermediate frequency furnace explosion accident are:

1 . The presence of moist materials in the charge causes a steam explosion.

2 . Temperature sampling or lack of operating skills when adding alloys, causing splashes of molten metal.

3 . Injecting large metal materials into the furnace causes the molten iron to splash.

4 . Unreasonable feeding system leads to bridging.

5 . Failure to escape outside the safety line resulted in injury.

6 . Contact with the power conductor, safety interlock control failure or contact with incompletely discharged capacitors, etc., resulting in shock or death.