The current frequencies commonly used in korkeataajuiset sammutuslaitteet ovat:

1. Korkeataajuinen lämmitys: 100 – 500 KHZ, yleisesti käytetty 200 – 300 KHZ, se on elektroninen putkityyppinen suurtaajuuslämmitys, kovettumiskerroksen syvyys on 0.5 – 2.5 mm, sopii pienille ja keskikokoisille osille.

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.