Abstract: A long-life bearing steel for general purpose use is provided at low cost with no use of specific secondary refining process. Specifically, a bearing material having a component composition in which C: 0.95 to 1.10 mass %, Si: 0.15 to 0.70 mass %, Mn: 1.15 mass % or less, Cr: 0.90 to 1.60 mass %, and P: 0.025 mass % or less are contained, S and O, that are elements forming nonmetallic inclusions, are contained at S: 0.025 mass % or less and O: 0.0012 mass % or less, and the rest is composed of Fe and incidental impurities, wherein the maximum diameter of the oxide-based nonmetallic inclusion is more than 10 ?m, but 15 ?m or less in an inspection area: 320 mm2, the number of oxide-based nonmetallic inclusions having an equivalent circle diameter of 3 ?m or more is 250 or less in the inspection area: 320 mm2, while in the material, AlN is contained at 0.

Abstract: An antifriction bearing comprises an inner race, an outer race having an outer peripheral surface to be brought into contact with other member for use as a roll, and a plurality of rolling elements arranged between the inner and outer races. The portion of the outer race from an outer peripheral surface thereof to a depth of 3 mm has a hardness of 58 to 62 in Rockwell C hardness (hereinafter referred to as “HRC”) and a hardness gradient of up to 1 HRC/1 mm from the outer peripheral surface inward, and contains 5 to 18 vol. % of retained austenite. The portion of the outer race from an inner peripheral surface thereof to a depth of 1 mm has a hardness of 61 to 64 in HRC and contains 5 to 15 vol. % of retained austenite. The center portion of the thickness of the outer race between the inner and outer peripheral surfaces thereof has a hardness of 35 to 42 in HRC. The outer race can be prevented from cracking or breaking and from undergoing plastic deformation due to use for a short period of time.

Abstract: Peeling occurring in a short period of time is avoided in a roller member such as a roller cam follower of a cam apparatus in a valve system of a car engine. The roller member is produced by heating an already processed a roller member material in a carburizing atmosphere of carbon potential being 1.2% or more at 840 to 870° C. for 3 hours or longer, thereby to carry out a carburization treatment, followed by quenching, said roller member material being formed in a predetermined shape from a bearing steel. Thereby, all amount of carbon are rendered to be 1.0 to 1.6 wt % in a surface portion of a range from a surface of a rolling face until a depth where a maximum shearing stress acts on, an amount of solute carbon is is rendered to be 0-6 to 1.0 wt % in a matrix of said surface portion, and said surface portion is precipitated with carbides of 5 to 20% in an area rate and of particle size being 3&mgr; or less.

Abstract: A long-life bearing steel for general purpose use is provided at low cost with no use of specific secondary refining process. Specifically, a bearing material having a component composition in which C: 0.95 to 1.10 mass %, Si: 0.15 to 0.70 mass %, Mn: 1.15 mass % or less, Cr: 0.90 to 1.60 mass %, and P: 0.025 mass % or less are contained, S and O, that are elements forming nonmetallic inclusions, are contained at S: 0.025 mass % or less and O: 0.0012 mass % or less, and the rest is composed of Fe and incidental impurities, wherein the maximum diameter of the oxide-based nonmetallic inclusion is more than 10 &mgr;m, but 15 &mgr;m or less in an inspection area: 320 mm2, the number of oxide-based nonmetallic inclusions having an equivalent circle diameter of 3 &mgr;m or more is 250 or less in the inspection area: 320 mm2, while in the material, AlN is contained at 0.

Abstract: A steel for a large bearing suitable for parts of a large-sized bearing which are excellent in resistance to breakage and rolling fatigue life characteristics, and having a chemical composition by mass percentage of 0.80 to 1.30% of C, more than 0.35% and not more than 0.80% of Si, 0.30 to 0.90% of Mn, 0.90 to 1.50% of Cr, one or both of not more than 0.25% of Mo and 0.20 to 1.50% of Ni, the remainder being Fe and inevitable impurities, and exhibiting the following quench-hardenability measured according to a method specified in JIS G 0561: a HRC of 64 or more at J 1.5 mm, a HRC of 63 to 66 at J 7 mm, a HRC of 37 to 50 at J 15 mm, a HRC of 30 to 45 at J 20 mm, a HRC of 28 to 38 at J 45 mm.

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 &mgr;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: An antifriction bearing comprises an inner race, an outer race having an outer peripheral surface to be brought into contact with other member for use as a roll, and a plurality of rolling elements arranged between the inner and outer races. The portion of the outer race from an outer peripheral surface thereof to a depth of 3 mm has a hardness of 58 to 62 in Rockwell C hardness (hereinafter referred to as “HRC”) and a hardness gradient of up to 1 HRC/1 mm from the outer peripheral surface inward, and contains 5 to 18 vol. % of retained austenite. The portion of the outer race from an inner peripheral surface thereof to a depth of 1 mm has a hardness of 61 to 64 in HRC and contains 5 to 15 vol. % of retained austenite. The center portion of the thickness of the outer race between the inner and outer peripheral surfaces thereof has a hardness of 35 to 42 in HRC. The outer race can be prevented from cracking or breaking and from undergoing plastic deformation due to use for a short period of time.