A bearing steel includes, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, Al.sub.2O.sub.3, and complex oxides including Al and Ca, wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 μm or more is 0.001 pieces to 2 pieces in an observed section of 1 mm.sup.2, and a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 μm or more is 0.001 pieces to less than 1.0 piece in an observed section of 1 mm.sup.2.

A bearing steel includes, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, Al.sub.2O.sub.3, and complex oxides including Al and Ca, wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 μm or more is 0.001 pieces to 2 pieces in an observed section of 1 mm.sup.2, and a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 μm or more is 0.001 pieces to less than 1.0 piece in an observed section of 1 mm.sup.2.

A method of treating bearing rolling elements or bearing rings after a hardening and temper heat treatment is disclosed. The method may include treating the bearing rolling elements in a tumbling treatment and then in a duplex hardening treatment. The method may include treating the bearing rings in a peening treatment and then in a duplex hardening treatment. The duplex hardening treatment may also include at least one sequential process segment consisting of subjecting the bearing rolling element & rings to a nitriding process to increase the surface hardness and compressive residual stress. The combined two-step process produces a deep surface/sub-surface residual stress greater than the depth of the maximum operating von-Mises shear stress along with an ultra-hard surface with high magnitude of compressive residual stress. In so doing, the bearing ring and rolling elements will have significantly enhanced rolling contact fatigue resistance and resistance to surface imperfections and debris.

A method of treating bearing rolling elements or bearing rings after a hardening and temper heat treatment is disclosed. The method may include treating the bearing rolling elements in a tumbling treatment and then in a duplex hardening treatment. The method may include treating the bearing rings in a peening treatment and then in a duplex hardening treatment. The duplex hardening treatment may also include at least one sequential process segment consisting of subjecting the bearing rolling element & rings to a nitriding process to increase the surface hardness and compressive residual stress. The combined two-step process produces a deep surface/sub-surface residual stress greater than the depth of the maximum operating von-Mises shear stress along with an ultra-hard surface with high magnitude of compressive residual stress. In so doing, the bearing ring and rolling elements will have significantly enhanced rolling contact fatigue resistance and resistance to surface imperfections and debris.

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.

A tapered roller bearing includes an outer ring, an inner ring, a plurality of tapered rollers, and a holder. A nitrogen concentration in a surface layer portion under a contact surface is 0.3 mass % or more. The holder includes a small annular portion, a large annular portion, and a plurality of column portions. A pocket has a trapezoidal shape in which a portion housing a small diameter side of the tapered roller is located on a reduced width side while a portion housing a large diameter side of the tapered roller is located on an increased width side. Each of the column portions on the reduced width side of the pocket is provided with a cutout.

A tapered roller bearing includes an outer ring, an inner ring, a plurality of tapered rollers, and a holder. A nitrogen concentration in a surface layer portion under a contact surface is 0.3 mass % or more. The holder includes a small annular portion, a large annular portion, and a plurality of column portions. A pocket has a trapezoidal shape in which a portion housing a small diameter side of the tapered roller is located on a reduced width side while a portion housing a large diameter side of the tapered roller is located on an increased width side. Each of the column portions on the reduced width side of the pocket is provided with a cutout.

A method for producing a metallic component, The method includes the method steps of first machining (103) the component and thereafter cooling (105) the component from a first temperature down to a lower second temperature. The cooling (105) occurs after the machining (103) of the component.

A method for producing a metallic component, The method includes the method steps of first machining (103) the component and thereafter cooling (105) the component from a first temperature down to a lower second temperature. The cooling (105) occurs after the machining (103) of the component.

A heat treatment process for through hardening results in high surface compressive stresses. The method includes heating a steel component to a first temperature, quenching the steel component to a second temperature, maintaining the steel component at the second temperature for a first duration of time, heating the steel component to a third temperature, maintaining the steel component at the third temperature for a second duration of time, and quenching the steel component to a fourth temperature when austenite to martensite+bainite or bainite transformation is at least 10% but less than 85% complete.