... less oxide layer usage:heat treatment ,welding,forging,annealing and melting Intermediate frequency induction chain wheel hardening machineInduction hardening ... 250, also can hardeningGear wheel diameter within about 500 and 800.1. hardening parts of automobile, motorbike, mold, ... axis, pin.3. hardening the industrial of machine tool, such as : bed guide way of machine tool.4. heat treatment pliers, ...