Carbonitriding induction-hardened steel parts with excellent surface pressure fatigue strength at high temperatures and methods for producing the same

摘要

The present invention provides steel parts such as gears, continuously variable transmissions, constant velocity joints, hubs and the like, which are superior in surface fatigue strength than conventional, and a method for producing the same, and is made of steel having a specific chemical composition. Steel parts subjected to induction hardening after carbonitriding, and the surface N concentration is 0.1 to 0.8 mass% and the sum of N concentration and C concentration is 1.0 to 2.0 mass %, The amount of residual austenite on the surface is less than 15% by volume, the depth of the incompletely hardened layer from the surface is less than 5 μm, and the X-ray diffraction half width of the surface is 6.0 degrees or more A carbonitrided induction-hardened steel part and a method for producing the same.