Casehardened steel can be provide with tough core and abrasion-resistant surface, wherein high surface hardness will be beneficial for polishing treatment. Carbon content in the casehardened steel is less than 0.25%. during heat treatment, carbon element can strengthen the intensity of core. To get higher surface hardness, carbon content on the surface must be increased, whereby can be achieved through adding carbon accelerant during the course of heat treatment. The ideal carbonization temperature depth is 0.6—1mm. after quenching and tempering, the surface hardness can reach 58—62HRC. Since the carbonization temperature is rather high, the dimension change is bound to occur, which requires extra follow-up treatment.