Induction tempering refers to the metal heat treatment process that reheats hardened parts to an appropriate temperature below the lower critical temperature (the initial temperature of pearlite to austenite during heating) and cools them at room temperature or in water, oil, and other media after holding for a period of time. Induction tempering is the next step after quenching or hardening. Only through the combination of induction hardening and induction tempering, can make the workpiece obtain the required mechanical properties. The function of the induction tempering machine is to eliminate the workpiece residual stress during quenching and prevent deformation and cracking. Adjust the workpiece hardness, strength, plasticity, and toughness to meet the performance requirements. Stabilize the workpiece organization and size to ensure accuracy. Improve the workpiece overall performance. It is mainly used to deal with the large load machine structure parts, such as machine tool spindle, automobile axle shaft, strong gear, and so on.