The principle of high frequency machine
High frequency machine and induction heating technology is currently the highest heating efficiency of metal materials, the fastest, and low consumption of environmental protection. It has been widely used in all walks of life on the thermal processing of metal materials, heat treatment, thermal assembly and welding, melting and other processes. It can not only the workpiece as a whole heating, but also on the workpiece part of the targeted heating; can achieve deep penetration of the workpiece, but also only on its surface, the surface of the central heating; not only metal materials can be heated directly, but also non-metallic Material for indirect heating. and many more. Therefore, induction heating technology will be applied in all walks of life more and more widely. A surface heat treatment process for locally heating the workpiece with an induced current. This heat treatment process is often used for surface hardening, can also be used for local annealing or tempering, and sometimes for the overall quenching and tempering. The early 1930s, the United States, the Soviet Union has begun to use induction heating method for surface hardening. With the development of industry, induction heating heat treatment technology continues to improve, the application is also expanding. The workpiece into the sensor (coil), when the sensor into a certain frequency of alternating current, the surrounding that produces alternating magnetic field.
The electromagnetic induction of the alternating magnetic field produces a closed induced current - eddy current in the workpiece. Induced current distribution in the workpiece section is very uneven, the workpiece surface current density is high, gradually reduced inward, this phenomenon is called skin effect. The workpiece surface high-density current energy into heat, so that the surface temperature, that is, to achieve surface heating. The higher the current frequency, the greater the difference between the surface and the internal current density, the thinner the heating layer. Surface hardening can be achieved by rapidly cooling the temperature of the heating layer beyond the critical point temperature of the steel.