Abstract: coating film having excellent adhesion, even without the presence of a chemical conversion film treatment out as an undercoat and a metal automotive part having the coating film. A powder is deposited by powder-coating onto the surface of a metal automotive part that has been quenched after simultaneously forging, and tempering the metal automotive part and bake-hardening the deposited powder to form a skin film on the surface of the metal automotive part. The surface of the metal automotive part before the powder is powder-coated thereon is a work-hardened material surface that has been not been subjected to a chemical conversion filming treatment.

Abstract: The invention provides a coating film having excellent adhesion, even without a chemical conversion film treatment being carried out as an undercoat treatment, and a metal automotive part having the coating film. A powder is deposited by powder-coating onto the surface of a metal automotive part that has been quenched after forging, and tempering of the metal automotive part and bake-hardening of the deposited powder are carried out simultaneously, thereby forming a skin film on the surface of the metal automotive part. The surface of the metal automotive part before the powder is powder-coated thereon is a work-hardened basis material surface that has been not subjected to a chemical conversion filming treatment.

Abstract: Provided is a cage (5, 65, 95) for a constant velocity universal joint, which is formed into a ring shape with a substantially uniform thickness, including a plurality of pockets (20, 80, 110) formed in a circumferential direction of the cage (5, 65, 95), for receiving torque transmitting balls, respectively, the cage (5, 65, 95) being formed of carbon steel including 0.41 to 0.51 mass % of C, 0.10 to 0.35 mass % of Si, 0.60 to 0.90 mass % of Mn, 0.005 to 0.030 mass % of P, and 0.002 to 0.035 mass % of S, with the balance being Fe and an element inevitably remaining at the time of steelmaking and refining, the cage (5, 65, 95) being subjected to carburizing, quenching, and tempering as heat treatment, each of the plurality of pockets (20, 80, 110) having a side surface (23, 83, 113) finished after the heat treatment.

Abstract: The invention provides a coating film having excellent adhesion, even without a chemical conversion film treatment being carried out as an undercoat treatment, and a metal automotive part having the coating film. A powder is deposited by powder-coating onto the surface of a metal automotive part that has been quenched after forging, and tempering of the metal automotive part and bake-hardening of the deposited powder are carried out simultaneously, thereby forming a skin film on the surface of the metal automotive part. The surface of the metal automotive part before the powder is powder-coated thereon is a work-hardened basis material surface that has been not subjected to a chemical conversion filming treatment.

Abstract: Provided is a cage (5, 65, 95) for a constant velocity universal joint, which is formed into a ring shape with a substantially uniform thickness, including a plurality of pockets (20, 80, 110) formed in a circumferential direction of the cage (5, 65, 95), for receiving torque transmitting balls, respectively, the cage (5, 65, 95) being formed of carbon steel including 0.41 to 0.51 mass % of C, 0.10 to 0.35 mass % of Si, 0.60 to 0.90 mass % of Mn, 0.005 to 0.030 mass % of P, and 0.002 to 0.035 mass % of S, with the balance being Fe and an element inevitably remaining at the time of steelmaking and refining, the cage (5, 65, 95) being subjected to carburizing, quenching, and tempering as heat treatment, each of the plurality of pockets (20, 80, 110) having a side surface (23, 83, 113) finished after the heat treatment.