Abstract: A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece includes a treatment tank in which the workpiece is set and thermally treated, a holding portion that holds the workpiece at a predetermined position, an induction heating coil that surrounds the workpiece to inductively heat the workpiece, and a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece.

Abstract: A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece includes a treatment tank in which the workpiece is set and thermally treated, a holding portion that holds the workpiece at a predetermined position, an induction heating coil that surrounds the workpiece to inductively heat the workpiece, and a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece.

Abstract: A hardening method for an annular workpiece made of metal includes a heating process that heats the annular workpiece to a hardening temperature; an analyzing process that obtains a diameter of the annular workpiece heated to the hardening temperature, and divides the heated annular workpiece into at least a small diameter portion and a large diameter portion based on the obtained diameter; and a cooling process that injects cooling liquid under an injection condition toward the annular workpiece that has been divided into at least the large diameter portion and the small diameter portion in the analyzing process such that a dimensional difference between the large diameter portion and the small diameter portion decreases, the injection condition for the large diameter portion being different from the injection condition for the small diameter portion.

Abstract: A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece includes a treatment tank in which the workpiece is set and thermally treated, a holding portion that holds the workpiece at a predetermined position, an induction heating coil that surrounds the workpiece to inductively heat the workpiece, and a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece.

Abstract: A bearing ring formed of quenched and tempered high carbon chromium bearing steel, including an inner layer portion formed of tempered martensite or sorbite and having a Vickers hardness of more than 490 HV and 710 HV or less, and a surface layer portion formed to enclose an entire periphery of the inner layer portion, formed of tempered martensite, and having a higher hardness than the inner layer portion.

Abstract: A hardening method for an annular workpiece made of metal includes a heating process that heats the annular workpiece to a hardening temperature; an analyzing process that obtains a diameter of the annular workpiece heated to the hardening temperature, and divides the heated annular workpiece into at least a small diameter portion and a large diameter portion based on the obtained diameter; and a cooling process that injects cooling liquid under an injection condition toward the annular workpiece that has been divided into at least the large diameter portion and the small diameter portion in the analyzing process such that a dimensional difference between the large diameter portion and the small diameter portion decreases, the injection condition for the large diameter portion being different from the injection condition for the small diameter portion.

Abstract: A bearing ring formed of quenched and tempered high carbon chromium bearing steel, including an inner layer portion formed of tempered martensite or sorbite and having a Vickers hardness of more than 490 HV and 710 HV or less, and a surface layer portion formed to enclose an entire periphery of the inner layer portion, formed of tempered martensite, and having a higher hardness than the inner layer portion.

Abstract: A heat treatment apparatus that thermally treats an annular workpiece formed of a steel material by inductively heating the workpiece includes a treatment tank in which the workpiece is set and thermally treated, a holding portion that holds the workpiece at a predetermined position, an induction heating coil that surrounds the workpiece to inductively heat the workpiece, and a cooling medium that cools surfaces of the workpiece during the induction heating of the workpiece.

Abstract: A steel material which contains 0.16 to 0.19% of carbon by mass, 0.15 to 0.35% of silicon by mass, 0.20 to 1.55% of manganese by mass, and 2.5 to 3.2% of chromium by mass, of which remaining part is formed of iron and incidental impurities, and which contains 0.01 to 0.2% of nickel by mass as an incidental impurity and higher than or equal to 0.001% and lower than 0.15% of molybdenum by mass as an incidental impurity, and which has a hardenability index of higher than or equal to 5.4 is subjected to a carbonitriding step, a process annealing step, a quenching step, a tempering step and a finishing step. Thus, there is obtained a rolling sliding member made of the steel material, and having satisfactory corrosion resistance and crack resistance and having a sufficiently long useful life even under an environment where rust is easily formed.

Abstract: A method of producing a rolling sliding member, wherein, after a work for a rolling sliding member, which is made of a bearing steel and formed in a predetermined shape, is quenched, a heating start temperature is set to be 10 to 100° C., a heating finish temperature is set to be 220 to 350° C., a time between the heating finish time and the heating start time is set to be a heating time, the quenched work for the rolling sliding member is heated so that a rate of temperature increase indicated by the following formula becomes 7 to 35° C./s rate of temperature increase=(heating finish temperature?heating start temperature)/heating time, the work is tempered by being cooled without being maintained at a heating finish temperature from the heating finish time.

Abstract: A bearing constituent member includes a surface layer, at least one of particles composed of vanadium nitride having a particle diameter of 0.2 to 2 ?m and particles composed of vanadium carbonitride having a particle diameter of 0.2 to 2 ?m are present in the surface layer ranging from the surface to a depth of 10 ?m and at least one of the area ratio of the particles composed of vanadium nitride having a particle diameter of 0.2 to 2 ?m and the particles composed of vanadium carbonitride having a particle diameter of 0.2 to 2 ?m in the surface layer ranging from the surface to a depth of 10 ?m is 1 to 10%.

Abstract: A production method of a rolling/sliding part which includes applying a spherodizing annealing treatment to a steel to render an average particle diameter of the carbide of the surface layer portion in a range of 0.3 to 0.6 ?m and a maximum particle diameter thereof 4 ?m, to render the surface hardness 62 or more by Rockwell C hardness and to render a solid solution carbon amount in a residual austenite of the surface layer portion in a range of 0.95 to 1.15% by weight.

Abstract: There is provided a bearing constituent member capable of achieving a long life of a rolling bearing and securing sufficient static loading capacity and dimensional stability and a production process thereof as well as a rolling bearing having a long life and exhibiting sufficient static loading capacity and dimensional stability. A workpiece obtained from a steel containing 3.2 to 5.0% by mass of Cr and 0.05% by mass or more to less than 0.5% by mass of V is subjected to a heat treatment such as a carbonitriding treatment. Thereby, the following are achieved: the content of C in the surface layer ranging from the surface of the bearing constituent member of the rolling bearing to 10 ?m is 1.1 to 1.6% by mass, Vickers hardness at the position of a depth of 50 ?m from the surface is 740 to 900 (Rockwell C hardness is 62 to 67), the ? amount at the position of a depth of 10 ?m from the surface is 20 to 55% by volume, particles composed of vanadium nitride having a particle diameter of 0.

Abstract: A method of producing a rolling sliding member, wherein, after a work for a rolling sliding member, which is made of a bearing steel and formed in a predetermined shape, is quenched, a heating start temperature is set to be 10 to 100° C., a heating finish temperature is set to be 220 to 350° C., a time between the heating finish time and the heating start time is set to be a heating time, the quenched work for the rolling sliding member is heated so that a rate of temperature increase indicated by the following formula becomes 7 to 35° C./s rate of temperature increase=(heating finish temperature?heating start temperature)/heating time, the work is tempered by being cooled without being maintained at a heating finish temperature from the heating finish time.

Abstract: A rolling part formed by performing spheroidizing annealing, processing, carbonitriding and finishing on a steel material containing C in an amount of 0.90 mass % to 1.10 mass %, Si in an amount of more than 0.35% and up to 0.70%, Mn in an amount of less than 0.80 mass %, Cr in an amount of 1.85 mass % to 2.50 mass %, O in an amount of 12 ppm or less, and the balance of Fe and unavoidable impurities. The mean C amount on a surface is from 1.20 mass % to 1.50 mass %, and the mean N amount is from 0.10 mass % to 0.60 mass %. Deposits having a particle size of 0.1 ?m or more on the surface have a mean particle size of 0.6 ?m or less, exist as 700,000 particles or more per mm2, and have an area ratio of 10% or more. The amount of retained austenite of the surface is from 25% to 45% by volume ratio. The hardness of the surface is Hv 750 or more. The inside of the rolling part has an amount of retained austenite of 20% or less by volume ratio.

Abstract: A case hardening bearing steel having an excellent rolling contact fatigue life in intermediate temperature, in addition, excellent toughness at room temperature is provided. Specific means for solving the problems are as follows. The composition contains, by mass percent, C of 0.15 to 0.30 mass percent, Si of 0.5 to 2.0 mass percent, Mn of 0.3 to 2.0 mass percent, Cr of 1.3 to 2.5 mass percent, Mo of 0.3 to 1.0 mass percent, and O of not more than 0.0012 mass percent in a range where (Si+Mo)?1.0 mass percent is satisfied, and contains iron and inevitable impurities as remnant; the maximum size of oxide nonmetallic inclusion is not more than 12.5 ?m when examined area is 320 mm2; number of the oxide nonmetallic inclusion having a diameter of equivalent circle of 3 ?m or more is not more than 250 when the examined area is 320 mm2; in addition, C density of an outer layer is adjusted to be in a range from 0.7 to 1.2 mass percent by carburization.

Abstract: The invention provides a rolling-sliding part which can attain more prolonged service lives even when used in rolling bearings which are exposed to contaminated lubricating oil. Rolling-sliding parts are made of steel which contains C: 0.7 to 0.9 wt. %, Si: 0.05 to 0.7 wt. %, Mn: 0.05 to 0.7 wt. %, Cr: 3.2 to 5.0 wt. %, Al: 0.04 wt. % or less, P: 0.03 wt. % or less, S: 0.03 wt. % or less, Ti: 0.005 wt. % or less, O: 0.0015 wt. % or less, at least one of Mo: less than 1.0 wt. % and V: less than 0.50 wt. %, and Fe and unavoidable impurities: balance, and which has a carburized layer in the surface. The precipitated carbide content of the layer is adjusted to 9 to 30% in terms of area ratio. At least 50% of the precipitated carbides present in the layer are of M7C3-type and/or M23C6-type in terms of area ratio. The average particle size of the carbides present in the layer is adjusted to 0.2 to 0.4 ?m and the residual austenite content of the layer is adjusted to 35 to 60%.

Abstract: The invention provides a rolling/sliding part that can elongate the service life and can increase the static load capacity to improve the indentation resistance to an indentation due to plastic deformation during rest and low-speed rotation. The rolling/sliding part is formed from a steel that contains C: 0.7 to 0.9% by weight and Cr: 3.2 to 5.0% by weight and has a surface layer portion of which surface is carburized. An area ratio of total precipitated carbide of the surface layer portion is set in the range of 15 to 25%. Of the total precipitated carbide present in the surface layer portion, 50% or more by area ratio of carbide is rendered a M7C3 type and/or M23C6 type. An average grain diameter and a maximum grain diameter of the surface layer portion are set in the range of 0.3 to 0.6 ?m and at 4 ?m, respectively. The surface hardness is set at 62 or more by Rockwell hardness C. A solid solution carbon amount in residual austenite of the surface layer portion is set in the range of 0.95 to 1.

Abstract: A rolling, sliding part comprises a bearing steel, is subjected to a carburizing treatment and has a surface layer from a surface the part to a depth to which a maximum shear stress acts. The surface layer is 1.0 to 1.6 wt. % in total carbon content, has a matrix containing 0.6 to 1.0 wt. % of solid-solution carbon, and contains a precipitating carbide in an amount of 5 to 20% in area ratio, the carbide being up to 3 ?m in particle size. The rolling or sliding part is improved in wear resistance, usable with a lubricant free of or less susceptible to impression by extraneous matter present in the lubricant, and less susceptible to compressive stress due to the extraneous matter, with the development of cracks suppressed.

Abstract: A roller member comprising high carbon chromium bearing steel having a carburization treatment. The bearing steel comprising a surface portion defined as a range between a surface of a rolling face of the roller member to a depth where a maximum shearing stress acts thereon, the surface portion containing carbon in a total amount comprising a range of 1.0 to 1.6 wt % and an amount of residual austenite comprising a range of 20 vol % to 35 vol % wherein a compression residual stress of the surface portion comprises a range of 150 to 1000 MPa, wherein a surface hardness of the surface portion comprises a range of 64 or higher in Rockwell C hardness, wherein an amount of carbide precipitate on the surface portion comprises a range of 10% to 25% in an area rate and each carbide particle size comprises a range of 3 ?m or less.