A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec).sup.1/2 and three hundred (ft/sec).sup.1/2. In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

A bearing component such as a bearing ring includes a metallic base body and at least one alloy steel coating on the base body, the coating being applied to the base body by deposition welding. The base body is preferably non-alloy steel or cast iron, and the alloy includes at least one carbide-forming transition metal such as niobium, tantalum, zirconium, titanium, hafnium, tungsten, molybdenum, vanadium, or manganese. The coating can form a raceway of the bearing component or a structural element such as a flange. Also a method of forming such a bearing component is provided.

A bearing unit having a stationary radially outer ring provided with a raceway, a radially inner ring rotatable about a central rotation axis (X) of the bearing unit and provided with a raceway, a row of rolling elements interposed between the radially outer ring and the radially inner ring, at least one sealing device mounted by means of interference on the radially outer ring and in sliding contact with the radially inner ring, wherein both the radially outer ring and the radially inner ring are made of low carbon steel with a minimum percentage by weight of carbon equal to 0.42%, and a central portion of the radially outer ring situated along the raceway and a central portion of the radially inner ring situated along the raceway are heat treated by means of induction hardening.

The present invention provides a steel material which is excellent in both of the strength (particularly, fatigue strength) and the manufacturability (particularly, bending straightening properties), and thus can be used as an automobile component such as a crankshaft by being formed into a product shape, being subjected to a high strength treatment such as a nitrocarburizing treatment, and then being subjected to the bending straightening.

A bearing ring with integrated cooling channels and a method for producing a bearing ring with integrated cooling channels are provided.

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 %.

The invention relates to a crankshaft (1) for a reciprocating piston internal combustion engine having at least two main bearings (2) a crank pin (3). Crankshaft flanges (4) are arranged between each of the main bearings and the crank pin and connect the main bearings to the crank pin. The crankshaft has at least one ring gear (5) spaced apart axially from a main bearing for a drive of a chain drive. A crankshaft surface between the main bearing and the first ring gear has an averaged roughness depth R z of less than 3 micrometres. Due to the configuration of the crankshaft according to the invention for a reciprocating piston internal combustion engine, higher torsional moments can be transmitted or the crankshaft can be designed to be lighter in the area having the higher surface quality.

A bearing unit having a stationary radially outer ring provided with a raceway, a radially inner ring rotatable about a central rotation axis (X) of the bearing unit and provided with a raceway, a row of rolling elements interposed between the radially outer ring and the radially inner ring, at least one sealing device mounted by means of interference on the radially outer ring and in sliding contact with the radially inner ring, wherein both the radially outer ring and the radially inner ring are made of low carbon steel with a minimum percentage by weight of carbon equal to 0.42%, and a central portion of the radially outer ring situated along the raceway and a central portion of the radially inner ring situated along the raceway are heat treated by means of induction hardening.

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.

Steel for a crankshaft includes 0.37 to 0.42 wt % of carbon (C), 0.55 to 0.70 wt % of silicon (Si), 1.45 to 1.65 wt % of manganese (Mn), 0.025 wt % or less (excluding 0 wt %) of phosphorus (P), 0.020 to 0.035 wt % of sulfur (S), 0.15 to 0.30 wt % of chromium (Cr), 0.035 to 0.055% of vanadium (V), and the remainder of Fe and other inevitable impurities. The steel for a crankshaft has strength that is maintained high even when reducing the amount of vanadium.