Cryogenic treatment enables an additional step in the heat treatment hardening process. Cooling treatment is completed after induction hardening and is used to provide a uniform hardened surface (no soft zones, no pitting) and the material’s greater hardness and wear resistance.
The cryogenic chamber is designed for improving the quality of the hardened layer after the induction hardening. The sub-zero treatment (cooling temperature of -150˚C) of hardened large rolls is used to complete the transformation of the steel microstructure from austenite to the stronger and harder martensitic structure, to provide a uniform distribution of the martensite, a uniform hardened surface (no soft zones, no pitting) and the material’s greater hardness (additional + 2 HRC) and wear resistance. The rollers are cooled with liquid nitrogen, using jets and fans.
The chamber is equipped with:
- a PLC controller and an operating panel with a touch screen that enables all parameters to be monitored, all the settings to be changed etc.
- a fan for air circulation (controlled by a contactor)
- a valve to add cold gas
- hydraulic opening/closing of the cover
- heaters for heating the chamber (power 25 kW)
- seal heaters (special version with electric heated seals)