The current frequencies commonly used in peralatan pendinginan frekuensi tinggi ialah:

1. Pemanasan frekuensi tinggi: 100～500KHZ, biasa digunakan 200～300KHZ, ia adalah pemanasan frekuensi tinggi jenis tiub elektronik, kedalaman lapisan pengerasan ialah 0.5～2.5mm, sesuai untuk bahagian kecil dan sederhana.

2. 2. Intermediate frequency heating: The current frequency is 500～10000HZ, usually 2500～8000HZ. The power supply equipment is a mechanical intermediate frequency heating device or a silicon controlled intermediate frequency generator. The depth of the hardened layer is 2-10 mm. Suitable for large diameter shafts, medium and large gears, etc. 3. Power frequency heating: The current frequency is 50HZ. Using mechanical power frequency heating power equipment, the depth of the hardened layer can reach 10-20mm, which is suitable for surface quenching of large-diameter workpieces.