| 摘要 |
PROBLEM TO BE SOLVED: To provide sliding parts which can be improved in surface hardness, have excellent wear resistance and can suppress the degradation in strength by annealing of base materials. SOLUTION: A second wheel pinion 6a which is the sliding parts is formed of carbon steel subjected to hardening and tempering. Its sliding surface is coated with a surface treatment film of electroless Ni-P plating and is subjected to heat treatment at 200 to 300 deg.C in the state of the sliding surface coated with this surface treatment film. Since the second wheel pinion 6a is coated with the surface treatment film of the electroless Ni-P plating, rust preventive performance is obtained. Further, the electroless Ni-P plating is heat treated at 200 to 300 deg.C and therefore the film hardness can be made higher and the wear resistance is betted. Since the heat treatment temperature is not so much higher, the second wheel pinion 6a composed of the hardened carbon steel is prevented from annealing and the degradation in the strength of the base material can be prevented.
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