High-frequency quenching machines utilize induction heating. Engineers explain that the principle of induction heating is as follows: the workpiece is placed inside an inductor, typically a hollow copper tube that receives medium-frequency or high-frequency alternating current (1000-300000Hz or higher).
This generates an alternating magnetic field, producing an induced current of the same frequency within the workpiece. This induced current is unevenly distributed within the workpiece, being strong at the surface and very weak inside, approaching zero at the core. Utilizing this skin effect, the workpiece surface can be rapidly heated, with the surface temperature rising to 800-1000ºC within seconds, while the core temperature rises only slightly.