High frequency machine and induction heating technology

High frequency machine and induction heating technology Lv Jian (total)

Can you imagine that an iron rod can be heated and burned in a second or two? Can any metal be heated quickly to its melting?

This is the fastest heating method for metal materials that humans can currently achieve and master - high-frequency induction heating.

Usually, people use the energy of coal, oil, gas and other energy to generate heat. Second, they use electrical appliances such as electric furnaces to convert electrical energy into heat. Only by means of heat transfer (heat conduction, heat convection, heat radiation) can this heat be transferred to the object to be heated, and the purpose of heating the object can be achieved. Due to these heating methods, the heated object is heated by absorbing external heat. Therefore, they all belong to the indirect heating method.

We know that the natural law of heat transfer is that heat can only be transferred from the high temperature zone to the low temperature zone, the high temperature body to the low temperature body, and the high temperature part to the low temperature part. Therefore, it is only effective when the external heat and temperature are significantly higher than or higher than the object to be heated. This requires a lot of energy to build a much higher temperature zone than the heat of the object being heated. Such as furnaces, ovens, etc. In this way, not only a small part of this heat can be transferred to the heated body, resulting in a great waste of energy. Moreover, the heating time is long, and a large amount of harmful substances and gases are generated during the combustion and heating. They cause corrosive damage to the heated body and cause pollution to the atmosphere. Even if electric energy heating methods such as electric furnaces are used, although there is no pollution, there are still disadvantages such as low efficiency, high cost, and slow heating rate.

The advancement and development of science has enabled us to heat up metal objects or non-metallic objects today in an efficient, fast, and energy-efficient and environmentally friendly way. This is the direct heating method. For non-metallic materials, the operating frequency of about 240MHZ and above can be used to make the internal molecules and atoms vibrate and rub the hundreds of millions of times of microwave heating. For metallic materials, intermediate frequency, super-audio, high-frequency, ultra-high frequency induction heating with operating frequencies in the order of several kilohertz (KHZ) to several hundred kilohertz, megahertz (MHZ) or higher can be used. Low-frequency induction heating can also be used, such as power frequency 50HZ.

IF, super audio, high frequency induction heating, is the conversion of power frequency (50HZ) AC into a frequency of generally 1KHZ to hundreds of KHZ, and even higher frequency AC. Using the principle of electromagnetic induction, after the inductor is converted into a magnetic field of the same frequency, it acts on the metal object in the magnetic field. Using the eddy current effect, an induced rotating current (ie, eddy current) proportional to the strength of the magnetic field is generated in the metal object. The rotating current is converted into thermal energy by means of a resistor in the metal object. At the same time, there are hysteresis effect, skin effect, edge effect, etc., and can also generate a certain amount of heat, which together make the temperature of the metal object rise rapidly and achieve the purpose of rapid heating.

The skin effect of high-frequency current can make the eddy current in the metal object increase with frequency and concentrate on the metal surface circulation. In this way, the control of the heating depth of the metal object can be achieved by controlling the frequency of the operating current. It not only improves the quality of the processing technology, but also ensures that the energy is fully utilized. When used in red punching, hot calcining and overall annealing of workpieces, the heating depth required for the workpiece is large, and even heat is required. At this time, the operating frequency of the induction heating device can be reduced (such as intermediate frequency, super audio); In the case of surface quenching, welding, etc., they require a small heating depth, at which time the operating frequency can be increased (such as high frequency). On the other hand, for small workpieces or pipes and plates, high-frequency heating is used. For larger workpieces, medium-frequency and super-audio heating are used.

Because the induction heating time is short, the speed is fast, and it is also non-contact (the heating object does not need to be in contact with the induction coil) heating. Therefore, the oxidation and decarburization phenomena are milder than other heating methods, and generally do not require gas protection treatment, and it is also easier to perform gas protection when necessary.

The rapid development of electronic technology has made great progress in electronic components in terms of quality, efficiency, and reliability. It is also more compact and miniaturized in terms of volume. This provides better development conditions and space for induction heating technology. In the small signal generation and processing, control and protection, adjustment and display, etc., more digital circuits with higher reliability, better stability and stronger anti-interference ability are used. In the power components, the electron tube with large energy consumption, low efficiency, high working voltage and large radiation amount has been developed into IGBT (Insulated Gate Bipolar Transistor) through thyristors and field effect transistors (MOSFETs) from generation to generation. The power utilization rate of the whole machine has been increased to more than 95% (the tube power utilization rate is only about 60%), and the cooling water saves about 60% compared with the tube product. And can achieve 24 hours of continuous work. This can not only be used normally during the day, but also can work at night during the low-cost electricity discount period.

Inductive heating, low energy consumption, low power consumption, fast heating, no pollution, no noise, no preheating, no oxidation, easy gas protection, automatic control, multiple intelligent protection, safe and reliable, easy to operate It can work continuously without interruption. More and more manufacturers and customers, from coal heating, diesel heating, liquefied gas heating, and electric furnace, electric oven heating, to high-frequency induction heating! Whether it is state-owned enterprises, private enterprises, private or foreign companies, high-intermediate frequency induction heating equipment is increasingly used in metal heat treatment, metal thermal processing, metal welding and metal melting and refining industries. Therefore, the market is very broad!

Main uses of high and medium frequency induction heating equipment:

First, heat treatment

For example: shafts, gears, quenching and annealing of stainless steel products.

Second, the workpiece is diathermy

For example: fasteners, standard parts, auto parts, hardware tools, rigging, hot and hot rolling of twist drills.

Third, smelting

For example: precious metals such as gold, silver, copper, aluminum, and lead.

Fourth, thermal coordination

For example: motors, solenoid valves, bushings, etc.

Five, welding

For example: the same or different types of metal welding of all metal materials.


In summary, we can see that:

Under the same power conditions, when the workpiece is quenched or welded, the efficiency of the high frequency machine is higher than that of the super audio machine and the intermediate frequency machine. Because high frequency currents can concentrate heat on the surface of the workpiece. There is little unnecessary loss inside the workpiece.

The high-frequency welding machine is a kind of pertinence and limitation of the high-frequency machine. In fact, its function is far more than the welding of various metal materials, and it is more widely used than other types of welding machines.

Danyang Zhongfa Electronics Co., Ltd.

Address: Jiajing Tiancheng, Development Zone, Danyang City, Jiangsu Province E-mail*qq.com Service Phone 13306107699

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Xuzhou Jitian Intelligent Equipment Co. Ltd , https://www.jitianintelligent.com