... . Metal superficial heating is perfect This high frequency induction heating machine A. Heating (hot forging, hot fitting and smelting):1 ... through forging press with the help of punch press, forging machine or other equipments, for instances, hot extrusion of watch ... crankshaft, connecting rod, piston pin, chain wheel, aluminum wheel, valve, rock arm shaft, semi drive shaft, small shaft and fork. 3 ...