The current frequencies commonly used in high-frequency nga ekipo sa pagpalong mao ang:

1. Taas nga frequency sa pagpainit: 100～500KHZ, kasagarang gigamit 200～300KHZ, kini mao ang electronic tube type high frequency pagpainit, ang hardening layer giladmon mao ang 0.5～2.5mm, angay alang sa gagmay ug medium-kadako nga mga bahin.

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.