What is the difference between high-frequency quenching and medium frequency quenching?

Difference: High frequency quenching is mostly used for surface quenching of industrial metal parts. It is a metal heat treatment method that generates a certain induced current on the surface of the workpiece, rapidly heats the surface of the part, and then rapidly quenches it. Induction heating equipment refers to a device that uses induction heating on workpieces for surface quenching. The principle of induction heating: The workpiece is placed inside an inductor, which is usually a hollow copper tube that inputs medium or high-frequency alternating current (100000-30000Hz or higher). The generation of alternating magnetic field generates induced current of the same frequency in the workpiece. This induced current is unevenly distributed on the workpiece, strong on the surface and weak inside, approaching zero at the center. By utilizing this skin effect, the surface of the workpiece can be rapidly heated, and the surface temperature can rise to 800-1000 ℃ within a few seconds, while the temperature at the center increases very little. And medium frequency quenching is to place metal parts in an induction coil, and the induction coil is energized with alternating current to generate an alternating electromagnetic field, inducing alternating current inside the metal parts. Due to the skin effect, the current is mainly concentrated on the surface of the metal part, so the surface temperature is the highest, followed by water spray cooling or other cooling below the induction coil. As heating and cooling are mainly concentrated on the surface, surface modification is obvious, while internal modification is basically non-existent, which can have a very special heat treatment effect.