Abstract: A method for producing a bearing ring of a rolling bearing includes the steps of: preparing a formed body constituted of hypereutectoid steel; forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region; and simultaneously cooling the whole of the heated region to a temperature of not more than an Ms point.

Abstract: Each of an outer race, an inner race and a ball as a bearing part is a bearing part made of JIS standard SUJ2 and having a carbonitrided layer formed in a surface thereof, wherein, after heat treatment at a heating temperature of 500° C. for a retention time of one hour is performed, a Vickers hardness at a position with a depth of 0.02×T+0.175 (mm) from the surface is higher than a Vickers hardness at a core portion, which is a region where the carbonitrided layer is not formed in a thickness direction of the bearing part, by not less than 80 HV, where T represents the time of carbonitriding treatment for forming the carbonitrided layer.

Abstract: A bearing component (an outer ring, an inner ring, and a ball) is made of bearing steel, and has a surface layer portion that is nitrided and includes an outer ring raceway surface and an inner ring raceway surface or a rolling surface. A nitrogen concentration in the surface layer portion is 0.4 mass % or higher. An area ratio of a precipitate in an inner portion that is not nitrided is 11% or higher.

Abstract: An outer ring, an inner ring, and a ball, each of which is a bearing part, are made of a quench-hardened steel containing not less than 0.90 mass % and not more than 1.05 mass % of carbon, not less than 0.15 mass % and not more than 0.35 mass % of silicon, not less than 0.01 mass % and not more than 0.50 mass % of manganese, and not less than 1.30 mass % and not more than 1.65 mass % of chromium with the rest consisting of an impurity. A contact surface thereof with another part has a nitrogen concentration of not less than 0.25 mass %. A remaining austenite amount in the contact surface is not less than 6 volume % and not more than 12 volume %.

Abstract: A method for heat-treating a ring-shaped member includes the steps of: forming, by relatively rotating an coil along the circumferential direction of the formed body, an annular heated region in the formed body, the heated region having the steel austenitized therein; and simultaneously cooling a whole of the heated region to a temperature of not more than an Ms point. In the step of forming the heated region, the heating is performed to repeatedly change over for a plurality of times between a state in which each region of the rolling contact surface has a temperature exceeding a temperature of an A1 point and a state in which each region of the rolling contact surface has a temperature that is less than the temperature of the A1 point and that maintains a supercooled austenite state.

Abstract: A carbonitriding method that can improve the nitrogen permeating rate to render the carbonitriding process effective includes an atmosphere control step, and a heating pattern control step. The atmosphere control step includes an undecomposed NH3 partial pressure control step, and a CO/CO2 partial pressure control step. The undecomposed NH3 partial pressure control step and the CO/CO2 partial pressure control step are carried out in the atmosphere control step such that ac* defined by the following equation (1) is at least 0.88 and not more than 1.27, and ? defined by equation (2) is at least 0.012 and not more than 0.020, where PN is the undecomposed ammonia partial pressure and PH is the hydrogen partial pressure in the heat treatment furnace, wherein a c * = ( Pco ) 2 ? K × Pco 2 ( 1 ) PCO: partial pressure of carbon monoxide (atm), PCO2: partial pressure of carbon dioxide (atm) K: equilibrium constant at <C>+CO2 2CO ? = P N 0.

Abstract: An inspection method which quantitatively and simply assures a nitrogen concentration in a carbonitriding-treated bearing part, and a bearing part and a bearing for which a nitrogen concentration is quantitatively assured are obtained. An inner race, an outer race, and balls as bearing parts are each a bearing part made of JIS standard SUJ2 and having a carbonitrided layer formed in a surface thereof, wherein, after heat treatment at a heating temperature of 500° C. for a retention time of one hour is performed, a Vickers hardness at a position with a depth of 30 ?m from the surface is higher than a Vickers hardness at a core portion, which is a region where the carbonitrided layer is not formed in a thickness direction of the bearing part, by not less than 130 HV.

Abstract: An outer ring, an inner ring, and a ball, each of which is a bearing part, are made of a quench-hardened steel containing not less than 0.90 mass % and not more than 1.05 mass % of carbon, not less than 0.15 mass % and not more than 0.35 mass % of silicon, not less than 0.01 mass % and not more than 0.50 mass % of manganese, and not less than 1.30 mass % and not more than 1.65 mass % of chromium with the rest consisting of an impurity. A contact surface thereof with another part has a nitrogen concentration of not less than 0.25 mass %. A remaining austenite amount in the contact surface is not less than 6 volume % and not more than 12 volume %.

Abstract: An outer ring, an inner ring and a ball are each constituted of steel containing at least 0.60 mass % and not more than 1.50 mass % of carbon, at least 0.15 mass % and not more than 2.50 mass % of silicon, at least 0.30 mass % and not more than 1.50 mass % of manganese, and at least 0.20 mass % and not more than 2.00 mass % of chromium with the rest consisting of an impurity. A nitrogen concentration in surface layer portions is at least 0.3 mass %. An average quantity of residual austenite as a whole in each of the outer ring, the inner ring and the ball is not more than 20 volume %.

Abstract: A method for heat-treating a ring-shaped member includes the steps of: forming, by relatively rotating an coil along the circumferential direction of the formed body, an annular heated region in the formed body, the heated region having the steel austenitized therein; and simultaneously cooling a whole of the heated region to a temperature of not more than an Ms point. In the step of forming the heated region, the heating is performed to repeatedly change over for a plurality of times between a state in which each region of the rolling contact surface has a temperature exceeding a temperature of an A1 point and a state in which each region of the rolling contact surface has a temperature that is less than the temperature of the A1 point and that maintains a supercooled austenite state.

Abstract: A bearing for alternators and a bearing for pulleys is capable of reducing hydrogen embrittlement or cracking despite that the bearing is used in an environment under such a severe condition that hydrogen is generated from grease or the like and the bearing experiences a load of a condition facilitating hydrogen embrittlement or cracking. The bearing includes a rolling element, an inner ring and an outer ring, and at least one of the rolling element and the inner and outer rings has a nitrogen enriched layer and contains austenite crystal grains having a grain size number exceeding 10.

Abstract: A carbonitriding method that allows the permeating rate of nitrogen to be increased to improve the efficiency of the carbonitriding process is directed to carbonitriding a workpiece formed of steel containing at least 0.8 mass % of carbon, including an atmosphere control step of controlling the atmosphere in a heat treatment furnace, and a heating pattern control step of controlling the temperature history applied to a workpiece. The atmosphere control step includes an undecomposed ammonia concentration control step of controlling the undecomposed ammonia concentration in the heat treatment furnace, and a partial pressure control step of controlling the partial pressure of at least one of carbon monoxide and carbon dioxide in the heat treatment furnace.

Abstract: Provided is a gas nitrocarburizing method forming a nitride layer in a surface layer portion of a workpiece made of steel by heating the workpiece within a heat treatment furnace into which a heat treatment gas is introduced, the heat treatment gas containing ammonia gas and at least one of carbon dioxide gas and hydrogen gas, and having a remainder formed of an impurity.

Abstract: A method for producing a bearing ring of a rolling bearing includes the steps of: preparing a formed body constituted of hypereutectoid steel; forming an annular heated region heated to a temperature of at least an A1 point on the formed body by relatively rotating an induction heating member arranged to face part of an annular region for becoming a rolling contact surface of the bearing ring in the formed body to induction-heat the formed body along the circumferential direction of the annular region; and simultaneously cooling the whole of the heated region to a temperature of not more than an Ms point.

Abstract: An outer ring and an inner ring of a rolling bearing are constituted of steel containing 0.77 to 0.85% of carbon, 0.01 to 0.25% of silicon, 0.01 to 0.35% of manganese, 0.01 to 0.15% of nickel, 3.75 to 4.25% of chromium, 4 to 4.5% of molybdenum and 0.9 to 1.1% of vanadium with the rest consisting of iron and impurities, a nitrogen-enriched layer having a nitrogen concentration of at least 0.05 mass % is formed on a region including a rolling surface, and the total of a carbon concentration and the nitrogen concentration in the nitrogen-enriched layer is at least 0.82 mass % and not more than 1.9 mass %. A DLC coating layer is arranged on a region including an outer ring contact surface.

Abstract: An outer ring, an inner ring and a ball serving as mechanical components configuring a deep groove ball bearing are formed of steel containing at least 0.11 mass % and not more than 0.15 mass % of carbon, at least 0.1 mass % and not more than 0.25 mass % of silicon, at least 0.15 mass % and not more than 0.35 mass % of manganese, at least 3.2 mass % and not more than 3.6 mass % of nickel, at least 4 mass % and not more than 4.25 mass % of chromium, at least 4 mass % and not more than 4.5 mass % of molybdenum and at least 1.13 mass % and not more than 1.33 mass % of vanadium with a remainder consisting of iron and impurity, and have raceway/rolling contact surfaces, the surface being included in a region having a nitrogen enriched layer having a nitrogen concentration of at least 0.05 mass %, the nitrogen enriched layer having a carbon concentration and the nitrogen concentration, in total, of at least 0.55 mass % and not more than 1.9 mass % at a depth of 0.1 mm from the surface.

Abstract: A heat treatment furnace that allows the atmosphere in the heat treatment furnace to be controlled with favorable accuracy includes a second heating zone identified as a reaction chamber, having a floor belt to hold a workpiece, and an atmosphere collect pipe having an opening in the second heating zone to collect an atmosphere in the second heating zone through the opening. The atmosphere collect pipe is installed to allow the distance between the opening and the floor belt to be modified.

Abstract: A bearing part comprising steel subjected to carbonitriding at a carbonitriding temperature exceeding the A1 transformation temperature, and cooled to a temperature lower than the A1 transformation temperature. The steel is reheated to a temperature for quenching that is not lower than the A1 transformation temperature but lower than the carbonitriding temperature, and then quenched.

Abstract: An inspection method which quantitatively and simply assures a nitrogen concentration in a carbonitriding-treated bearing part, and a bearing part and a bearing for which a nitrogen concentration is quantitatively assured are obtained. An inner race, an outer race, and balls as bearing parts are each a bearing part made of JIS standard SUJ2 and having a carbon nitrided layer formed in a surface thereof, wherein, after heat treatment at a heating temperature of 500° C. for a retention time of one hour is performed, a Vickers hardness at a position with a depth of 30 ?m from the surface is higher than a Vickers hardness at a core portion, which is a region where the carbonitrided layer is not formed in a thickness direction of the bearing part, by not less than 130 HV.

Abstract: An outer ring, an inner ring and a ball serving as mechanical components configuring a deep groove ball bearing are formed of steel containing at least 0.77 mass % and not more than 0.85 mass % of carbon, at least 0.01 mass % and not more than 0.25 mass % of silicon, at least 0.01 mass % and not more than 0.35 mass % of manganese, at least 0.01 mass % and not more than 0.15 mass % of nickel, at least 3.75 mass % and not more than 4.25 mass % of chromium, at least 4 mass % and not more than 4.5 mass % of molybdenum and at least 0.9 mass % and not more than 1.1 mass % of vanadium with a remainder consisting of iron and impurity, and have raceway/rolling contact surfaces, the surface being included in a region having a nitrogen enriched layer having a nitrogen concentration of at least 0.05 mass %, the nitrogen enriched layer having a carbon concentration and the nitrogen concentration, in total, of at least 0.82 mass % and not more than 1.9 mass %.