A bearing steel composition contains 0.1 to 0.2 wt % C, 3.25 to 4.25 wt % Cr, 9.5 to 11.5 wt % Mo, 5.75 to 6.75 wt % W, 1.5 to 2.5 wt % V, and 2.5 to 3.5 wt % Ni. A bearing component, such as a rolling element, an inner race or outer race, is formed from the bearing steel composition, for example, by a powder metallurgical technique and then is subjected to a case hardening treatment. The bearing component may have a microstructure composed of martensite, retained austenite and at least one of carbides and/or carbonitrides. The carbon level at the surface of the bearing component may be 0.5 to 1.1 wt %.

A bearing component composed of a chromium-molybdenum-vanadium alloyed tool steel is produced by a process that includes: (i) performing a first preheating within a temperature range of 600-650° C., (ii) performing a second preheating within a temperature range of 850-900° C., (iii) austenitizing in vacuum at 1000-1180° C. for 20-40 min, (iv) gas quenching at a minimum of 4-5 bar overpressure, and (v) tempering by performing either a double temper at 520-560° C. for 1.5-2.5 hours in each temper, or a triple temper at 520-560° C. for 0.5-1.5 hours in each temper. The steel alloy may be composed (in mass percent) of 1.32-1.45 C, 0.32-0.50 Si, 0.26-0.48 Mn, 4.0-4.85 Cr, 3.35-3.55 Mo, 3.55-3.85 V, 0-0.13 W, 0-0.20 Ni, 0-0.15 Cu, 0-0.8 Co, 0-0.03 P, and 0-0.03 S, the balance being iron and unavoidable impurities. Mo may be replaced with W or vice versa in a replacement ratio Mo:W of 1:2.

A roller retainer cage for a roller thrust bearing, including a first cage half with an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, a second cage half including an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, wherein the first flange of the first cage half is disposed radially-outwardly of the first flange of the second cage half, the second flange of the first cage half is disposed radially-inwardly of the second flange of the second cage half, and the first cage half is comprised of a through-hardened metal.

A roller retainer cage for a roller thrust bearing, including a first cage half with an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, a second cage half including an annular portion, a first flange extending axially from an inner peripheral edge of the annular portion and a second flange extending axially from an outer peripheral edge of the annular portion, wherein the first flange of the first cage half is disposed radially-outwardly of the first flange of the second cage half, the second flange of the first cage half is disposed radially-inwardly of the second flange of the second cage half, and the first cage half is comprised of a through-hardened metal.

A rolling sliding member includes a base part and a surface layer. The base part has a composition that includes 0.30 mass % to 0.45 mass % of carbon, 0.15 mass % to 0.45 mass % of silicon, 0.40 to 1.50 mass % of manganese, 0.60 mass % to 2.00 mass % of chromium, 0.10 mass % to 0.35 mass % of molybdenum, 0.20 mass % to 0.40 mass % of vanadium, and 0.005 mass % to 0.100 mass % of aluminum, and a remainder of iron and inevitable impurities. The surface layer is positioned around the base part. The surface layer has a Vickers hardness of 700 to 800 and a retained austenite content of 25 volume % to 50 volume %. The thickness of a grain boundary oxide layer satisfies Formula: thickness of grain boundary oxide layer≤equivalent diameter of rolling sliding member×1.4×10.sup.−3.

Provided is a steering function-equipped hub unit including: a hub unit body including a hub bearing; a unit support member configured to be provided to a chassis frame component, the unit support member supporting the hub unit body such that the hub unit body is rotatable about a turning axis extending in a vertical direction; and a steering actuator configured to rotationally drive the hub unit body about the turning axis, wherein the hub bearing includes an outer race integrally provided with turning shaft parts protruding upward and downward in the vertical direction on an outer peripheral surface of the outer race, each of the turning shaft parts having an axis coinciding with the turning axis, and the hub unit body is rotatably supported by the unit support member through the turning shaft parts.

The invention relates to a carburizing bearing steel and a preparation method thereof. The carburizing bearing steel of the invention comprises: 0.18˜0.24 wt % of C, 0.4˜0.6 wt % of Cr, 0.20˜0.40 wt % of Si, 0.40˜0.70 wt % of Mn, 1.6˜2.2 wt % of Ni, 0.15˜0.35 wt % of Mo, 0.001˜0.01 wt % of S, 0.001˜0.015 wt % of P, 0˜0.20 wt % of Nb, 0˜0.20 wt % of V and the remaining is iron, wherein the contents of Nb and V are not 0 at the same time. In the invention, an appropriate amount of Nb and V is added in combination with other elements so as to refine the grain size, inhibit the generation of large granular carbides in the steel during carburization and improve the uniformity of the microstructure of steel materials, thus further enhancing the contact fatigue life of the carburizing bearing steel.

A novel hollow shaft manufacturing method includes the steps of hollow cold-rolling of seamless steel pipe, cutting, annealing and surface treatment, forming by forging, precision machining, and heat treatment. The present invention uses a new process instead of the traditional process. The forging process using high-strength cold-rolled seamless steel pipes has fewer steps than using bar stock: saving three forging passes, one annealing pass and one surface treatment pass, hence saving about ½ in time and cost, shortening the cycle, reducing costs, reducing energy consumption and reducing the three wastes, increasing the stock utilization rate to about 68%, and reducing the inter-process cost calculated by weight. For the same products, using this process can shorten the production cycle.

A rolling bearing is disclosed which comprises an outer ring and an inner ring, wherein rolling elements are arranged between the outer ring and the inner ring, and wherein the rolling elements are spaced apart by a cage being arranged between the outer ring and the inner ring, wherein the cage is made of polymer containing reinforcing fibers, and the outer ring and/or the inner ring are steel rings with fine carbide precipitation.

An inner ring or and outer ring for a roller bearing includes: 0.30-0.45 wt. % carbon, 0.1-0.7 wt. % silicon, 0.6-0.9 wt. % manganese, 0.9-1.2 wt. % chromium, 0.15-0.7 wt. % molybdenum, 0-2.0 wt. % nickel, 0-0.02 wt. % phosphorus, and 0-0.02 wt. % sulfur, the balance being iron and unavoidable impurities. The microstructure of the steel composition contains bainite, and a carbonitrided case layer is provided on a surface of the inner ring or outer ring.