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 steering shaft assembly includes a male shaft having a plurality of teeth extending radially outwardly from a portion of the male shaft. The steering shaft assembly also includes a female shaft receiving a portion of the male shaft and fixed to the male shaft in a rotational direction, the male shaft axially moveable relative to the female shaft, the female shaft having an end portion and a body portion, wherein the end portion of the female shaft has an end wall thickness that is less than a body wall thickness of the body portion, the end portion curved radially inwardly to define a hard stop position during axial movement of the male shaft. An end of the plurality of teeth of the male shaft contact the curved end portion of the female shaft at the hard stop position.

The invention relates to the technical field of microstructure refinement and homogenization of bearing steel, and specifically relates to a high-carbon bearing steel and a method of preparing same. The high-carbon bearing steel of the invention has the following chemical composition: C: 0.80˜1.20 wt %, Cr: 0.40˜2.0 wt %, Mn: 0.15˜0.75 wt %, Si: 0.15˜0.75 wt %, Nb: 0˜0.20 wt %, Mo: 0˜0.20 wt %, V: 0˜0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities; the contents of Nb, Mo and V are not 0 at the same time. According to the invention, microalloying elements such as Nb, Mo and V, in combination with other elements, are added into the high-carbon bearing steel to effectively refine the bearing steel matrix and promote the precipitation of a large amount of nano-carbides, thereby enhancing the contact fatigue life of the high-carbon bearing steel.

A method of manufacturing a strip for a bearing may comprise roll-bonding a bearing layer comprising a tin-free aluminium alloy directly to a base layer to form a bimetal and heat-treating the bimetal at a temperature below a recrystallization initiation temperature of the aluminium alloy. A strip for a bearing manufactured using the method, and a bearing having a strip manufactured using the method, are also provided.

A large-scale axle intelligent cross wedge rolling mill for rail transit includes a main transmission device, a memorial arch unit, two worm-gear pressing devices, a roll assembly and two guide devices. The separation sleeves are engaged with the upper slide shaft and the lower slide shaft, respectively. Two lower shaft necks are detachably connected with the left end surface and the right end surface of the lower roller, respectively; two upper shaft necks are detachably connected with the left end surface and the right end surface of the upper roller, respectively, so that the quick disconnection of the upper and lower rollers with the upper and lower shaft necks is able to be achieved, so as to quickly operate and install the roll to meet the requirement of quick mold replacement, thus improving the flexibility of rolling.

The present disclosure is directed to methods for manufacturing a wind turbine slewing ring bearing having an integral stiffener configured to resist deformation of the bearing under a load. More specifically, the present disclosure is directed to methods for manufacturing components of a slewing ring bearing (e.g., an inner, center, and outer race) using near-net-shape (NNS) ring rolling techniques. In particular, the present disclosure is directed to methods for manufacturing slewing ring bearing races, via NNS ring rolling, that are not restricted to conventional (e.g., generally square, rectangular, quadrilateral, trapezoid, quadrilateral) cross-sectional profiles that necessitate attachment of a separate, non-integral stiffener (e.g., a non-integral stiffening plate, stiffening ring, or stiffening assembly).

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.

A method for surface treatment of a workpiece includes providing the workpiece with hardened workpiece surface, clamping the workpiece, removing material from the hardened workpiece surface with a material removal tool to produce a machined surface with first machining tracks, and rolling the machined surface with a rolling tool by overlapping the first machining tracks to produce a rolled surface with second machining tracks. A distance between the material removal tool and the rolling tool measured in an axial direction of the workpiece is varied in an oscillating manner. The material removal tool may be advanced in the axial direction at a constant speed and the rolling tool may be advanced in the axial direction at an oscillating speed, or the rolling tool may be advanced in the axial direction at a constant speed and the material removal tool may be advanced in the axial direction at an oscillating speed.

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.