The principle of induction heating is widely used in our lives

In fact, the principle of induction heating has many applications in our life, whether it is an induction cooker or a hair dryer. Maybe we are not very clear about this principle. !Induction Heating Principle Induction Heating Principle Electromagnetic induction heating, or induction heating for short, is a method of heating conductor materials such as metallic materials. It is mainly used for metal thermal processing, heat treatment, welding and melting. As the name suggests, induction heating is the use of electromagnetic induction to generate current inside the heated material, and rely on the energy of these eddy currents to achieve the purpose of heating. The basic components of an induction heating system include an induction coil, an AC power source and a workpiece. Depending on the heating object, the coil can be made into different shapes. The coil is connected to a power source, and the power source provides an alternating current to the coil. The alternating current flowing through the coil generates an alternating magnetic field passing through the workpiece, and the magnetic field causes the workpiece to generate eddy currents to heat it. Process introduction Induction heating is a fairly new process, and its application is mainly due to its unique properties. When a rapidly changing current flows through a metal workpiece, the skin effect occurs, which concentrates the current on the surface of the workpiece and generates a highly selective heat source on the metal surface. Faraday discovered this advantage of the skin effect and discovered the remarkable phenomenon of electromagnetic induction. He is also the founder of induction heating. Induction heating does not require an external heat source, but uses the heated workpiece itself as a heat source, and this method does not require the workpiece to be in contact with the energy source, that is, the induction coil. Other features include the ability to select different heating depths based on frequency, precise localized heating based on coil coupling design, and high power density, or high power density. The heat treatment process suitable for induction heating should take full advantage of these characteristics and design a complete equipment according to the following steps. First of all, the process requirements must be consistent with the basic characteristics of induction heating. This chapter will describe the electromagnetic effects in the workpiece, the distribution of the resultant current and the absorbed power. According to the knowledge of the heating effect and temperature effect produced by the induced current, as well as the distribution of temperature under different frequencies, different metals and workpiece shapes, users and designers can decide whether to discard them according to the requirements of technical conditions. . Second, the specific form of induction heating must be determined according to whether it meets the requirements of technical conditions, and the application and development situation should also be widely grasped, and the main application trends of induction heating. Third, after the suitability of induction heating and the best use method are determined, the inductor and power supply system can be designed. Many problems in induction heating are very similar to some basic perceptual knowledge in engineering, and are generally derived from practical experience. It can also be said that it is impossible to design an induction heater or system without a proper understanding of the shape of the inductor, the frequency of the power supply, and the thermal properties of the heated metal. The effect of induction heating, under the influence of an invisible magnetic field, is the same as that of flame quenching. For example, higher frequencies (above 200,000 Hz) produced by high-frequency generators generally produce intense, rapid and localized heat sources, equivalent to the effect of small, concentrated, high-temperature gas flames. Conversely, the heating effect at intermediate frequencies (1000 Hz and 10,000 Hz) is more diffuse and slow, and the heat penetrates deeper, similar to a relatively large and open gas flame. Induction heating principle Induction heating principle Induction heating surface quenching is a quenching method that uses the principle of electromagnetic induction to generate a high-density induced current on the surface layer of the workpiece, rapidly heat it to austenite state, and then rapidly cool it to obtain a martensite structure. When an alternating current of a certain frequency passes through the induction coil, an alternating magnetic field with the same frequency as the current changes will be generated inside and outside it. When the metal workpiece is placed in the induction coil, under the action of the magnetic field, an induced current with the same frequency as the induction coil and the opposite direction will be generated in the workpiece. Because the induced current forms a closed loop along the surface of the workpiece, it is often called an eddy current. This eddy current converts electrical energy into heat, rapidly heating the surface of the workpiece. Eddy currents are mainly distributed on the surface of the workpiece, and there is almost no current passing through the workpiece. This phenomenon is called surface effect or skin effect. Induction heating uses the skin effect to rapidly heat the surface of the workpiece to the quenching temperature by means of the current thermal effect. The induction coil is made of copper pipe, and cooling water is passed through it. When the surface of the workpiece is heated to a certain temperature in the induction coil, it is immediately cooled by water spray, so that the surface layer can obtain a martensite structure. The principle of induction heating still needs to be understood. Many friends have learned this principle in middle school, but most of them have forgotten it because we have not used it. If you want to know more, then pay attention to Kehua.