Abstract: A rolling member is formed of quenched steel having a contact surface. The rolling member includes a superficial part in a region up to a depth of 20 ?m from the contact surface. Steel contains greater than or equal to 0.70 mass % and less than or equal to 1.10 mass % of carbon, greater than or equal to 0.15 mass % and less than or equal to 0.35 mass % of silicon, greater than or equal to 0.30 mass % and less than or equal to 0.60 mass % of manganese, greater than or equal to 1.30 mass % and less than or equal to 1.60 mass % of chromium, greater than or equal to 0.01 mass % and less than or equal to 0.50 mass % of molybdenum, and greater than or equal to 0.01 mass % and less than or equal to 0.50 mass % of vanadium, and the remainder of iron and inevitable impurities.

Abstract: A method for selecting a steel material for a rolling component to be used in an environment in which hydrogen enters steel. The method includes determining a maximum contact surface pressure Pmax acting on a rolling surface of the rolling component, and using, as a material for the rolling component, a material whose inclusion has a radius not greater than a radius d determined by the following formula (1) and not less than 1.0 ?m, d=64729(Pmax/4)?1.441 ??(1).

Abstract: Provided is a rolling device in which hydrogen is not easily accumulated within a roller element made of steel, such as an inner race and an outer race, and premature separation due to hydrogen embrittlement is prevented from occurring. A rolling bearing 1 having an inner race 2, an outer race 3, and rolling bodies 4, and at least one selected from the inner race 2, the outer race 3, and the rolling bodies 4 is made of predetermined steel. At least a part of oxide-based inclusions included in the steel is covered by MnS, and a ratio of a number of oxide-based inclusions covered by MnS is over 40% of a total number of oxide-based inclusions having maximum diameter of 3 ?m or greater in the steel.

Abstract: A bearing component composed of steel which contains carbon not less than 0.95 mass % and not more than 1.1 mass %, silicon less than 0.3 mass %, manganese less than 0.5 mass %, sulfur less than 0.008 mass %, and chromium not less than 1.4 mass % and less than 1.6 mass % and is composed of remainder iron and an impurity and having a carbonitrided layer formed at a surface portion including a contact surface which is a surface in contact with other components is provided. An average concentration of nitrogen in the surface portion is not lower than 0.3 mass % and not higher than 0.6 mass % and variation in nitrogen concentration in the surface portion is not higher than 0.1 mass %. An amount of retained austenite in the surface portion is not greater than 8 volume %.

Abstract: A rolling component material of the present invention is a steel material for a rolling component to be used in an environment in which hydrogen enters steel, and is a material used for a rolling component of a rolling bearing, for example, a bearing ring. In the rolling component material, a non-metallic inclusion of the steel material has a radius not greater than a radius d determined by the following formula (1) and not less than 1.0 ?m, where Pmax is defined as a maximum contact surface pressure acting on a rolling surface of the rolling component, d=64729(Pmax/4)?1.441??(1).

Abstract: Provided is a rolling device in which hydrogen is not easily accumulated within a roller element made of steel, such as an inner race and an outer race, and premature separation due to hydrogen embrittlement is prevented from occurring. A rolling bearing 1 having an inner race 2, an outer race 3, and rolling bodies 4, and at least one selected from the inner race 2, the outer race 3, and the rolling bodies 4 is made of predetermined steel. At least a part of oxide-based inclusions included in the steel is covered by MnS, and a ratio of a number of oxide-based inclusions covered by MnS is over 40% of a total number of oxide-based inclusions having maximum diameter of 3 ?m or greater in the steel.

Abstract: A bearing component composed of steel which contains carbon not less than 0.95 mass % and not more than 1.1 mass %, silicon less than 0.3 mass %, manganese less than 0.5 mass %, sulfur less than 0.008 mass %, and chromium not less than 1.4 mass % and less than 1.6 mass % and is composed of remainder iron and an impurity and having a carbonitrided layer formed at a surface portion including a contact surface which is a surface in contact with other components is provided. An average concentration of nitrogen in the surface portion is not lower than 0.3 mass % and not higher than 0.6 mass % and variation in nitrogen concentration in the surface portion is not higher than 0.1 mass %. An amount of retained austenite in the surface portion is not greater than 8 volume %.

Abstract: A status monitoring system for accurately determining the contaminant water concentration in a lubricant oil used in a rolling device includes a contaminant water concentration monitoring device configured to monitor the contaminant water concentration in the lubricant oil. The contaminant water concentration monitoring device includes an electrostatic capacitance detector and an oil temperature measuring instrument, which are configured to detect the electrostatic capacitance and the oil temperature of the lubricant oil, respectively, and a water concentration calculation section configured to calculate the contaminant water concentration from the detected electrostatic capacitance and oil temperature in accordance with a predetermined rule.

Abstract: In order to provide a status monitoring system for accurately determining the contaminant water concentration in a lubricant oil used in a rolling device, the provision is made of a contaminant water concentration monitoring device (6) configured to monitor the contaminant water concentration in the lubricant oil (5). The contaminant water concentration monitoring device (6) includes an electrostatic capacitance detector (7) and an oil temperature measuring instrument (8), which are configured to detect the electrostatic capacitance and the oil temperature of the lubricant oil (5), respectively, and a water concentration calculation section (9) configured to detect the contaminant water concentration from the detected electrostatic capacitance and oil temperature in accordance with a predetermined rule.

Abstract: A combined roll is provided which offers excellent resistance to thermal shock. In this combined roll, an external ring portion is formed of a cemented carbide, and an internal ring portion is formed of a ductile iron metallurgically bonded to the external ring portion by means of casting. The external ring portion is formed of a cemented carbide containing, as binder phase-defining components, Co: 5-27%, Ni: 2-12% and Cr: 0.3-3% and WC as substantially all of the balance and as a hard phase-defining component. The internal ring portion is formed of a ductile iron composed of C: 3 4.5%, Si: 1.5-4.5%, Mn: 0.1-2% and Mg: 0.02-0.2% and, as the balance, Fe and incidental impurities. The internal ring portion may also contain 0.1-5% of one or more of Mo, Cu, Cr, V, W, Sn and Sb. The internal ring portion contains a cored spheroidal graphite structure dispersed in a mixed phase of either perlite, beinite and martensite phases with a ferrite phase.

Abstract: A cubic boron nitride-based very high pressure-sintered material very excellent in both toughness and wear resistance and adapted to be employed in cutting tools for milling hard steels and like machining purposes. The very high pressure-sintered material consists essentially of: 1-20 percent at least one compound selected from the group consisting of titanium carbide and titanium carbo-nitride; 1-20 percent at least one compound selected from the group consisting of CoAl, NiAl, and (Co, Ni)Al; and 75-97 percent cubic boron nitride and inevitable impurities. The very high pressure-sintered material may further contain 1-10 percent at least one metal selected from the group consisting of cobalt and nickel.