| 摘要 |
<p>A steel part superior to conventional ones in rolling contact fatigue strength, such as, e.g., a gear, continuously variable transmission, constant-velocity joint, or hub; and a process for producing the part. The steel part is a carbonitrided induction-hardened steel part which is made of a steel having a specific chemical composition and which has undergone carbonitriding and subsequent induction hardening. The steel part is characterized in that the surface has a nitrogen concentration of 0.1-0.8 mass%, a total concentration of nitrogen and carbon of 1.0-2.0 mass%, and a residual austenite amount less than 15 vol.%, that the steel part has an incompletely hardened layer having a depth less than 5μm from the surface, and that the surface has an X-ray diffraction half-value width of 6.0 degrees or more.</p> |
