... 30-80KHZ 4. Metal superficial heating is perfect This high frequency induction heating machine A. Heating (hot forging, hot fitting and smelting ... through forging press with the help of punch press, forging machine or other equipments, for instances, hot extrusion of watch ... . Annealing of various other metal work pieces, such as golf ball head, cue, brass lock, hardware copper fitting, kitchen knife ...