Induction hardening is mostly used for surface hardening of industrial metal parts. The coil is energized to generate a magnetic field and induce current in ferromagnetic materials. Due to the skin effect, the induced current accumulates on the surface of the material to generate heat and reach the phase transition temperature.
Commonly used current frequencies for induction hardening are:
1. High frequency heating: The current frequency is 100-500KHZ, 200-300KHZ is commonly used, it is tube type high-frequency heating, and the induction hardening layer depth is 0.5-2.5mm, suitable for small and medium-sized parts.
2. Intermediate frequency heating: The current frequency is 500～10000HZ, usually 2500～8000HZ, the power supply equipment is mechanical intermediate frequency heating device or thyristor intermediate frequency generator, the depth of induction hardening layer is 2-10 mm, suitable for larger diameter shafts , bigger geasr, etc.
3. Power frequency heating: The current frequency is 50HZ, and the mechanical power frequency heating power supply equipment is adopted. The depth of the induction hardenig layer can reach 10-20mm, which is suitable for surface quenching of large-diameter workpieces.