Most often, surface hardening of steel shafts is carried out by vertically fixing them in the rotating holders of the hardening machine. The rotational movement of the shaft ensures uniform heat distribution on the surface of the shaft. The inductor of induction heater moves along the hardened element with uniform motion, below which the spray cooling system is mounted, which provides immediate cooling of the heated zone. The moving inductor heats up the hardened shaft and the heated part is immediately cooled.
Zone heating with instant cooling eliminates the risk of shaft bending during hardening as it could occur in case of heating as a whole.