Methods of making magnesium-based alloy components, such as automotive components, include treating a casting comprising a magnesium-based alloy to a first deforming process to form a preform. In one aspect, the first deforming process has a first maximum predetermined strain rate of greater than or equal to about 0.001/s to less than or equal to about 1/s in an environment having a temperature of ≥to about 250° C. to ≤to about 450° C. In another aspect, the first deforming process is cold deforming that is followed by annealing. The preform is then subjected to a second deforming process having a second maximum predetermined strain rate of ≥about 1/s to ≤about 100/s in an environment having a temperature of ≥about 150° C. to ≤about 450° C. to form the magnesium-based alloy component substantially free of cracking. A solid magnesium-based alloy component having select microstructures are also provided.

A differential hypoid gear, a pinion gear, and paired hypoid gears formed by a combination thereof are provided. The differential hypoid gear includes a ring-shaped main body and a tooth-forming surface, and has a chemical component composition including C: 0.15-0.30 mass %, Si: 0.55-1.00 mass %, Mn: 0.50-1.20 mass %, Cr: 0.50-1.50 mass %, Al: 0.020-0.080 mass %, B: 0.0005-0.0050 mass %, Ti: 0.01-0.08 mass %, N: 0.0020-0.0100 mass %, Mo: 0.25 mass % or less, and Nb: less than 0.10 mass %, the remainder being Fe and unavoidable impurities. The chemical component composition satisfies Formulae 1 and 2. The differential hypoid gear has a metallographic structure including mainly tempered martensite. A martensite ratio at an inside of a dedendum differs between an end portion of a tooth and a central portion of the tooth within a range of 15% or less. A core hardness of the dedendum at the central portion falls within 350-500 HV.

A sintered material includes a composition composed of iron-based alloy, and a texture containing 200 or more and 1350 or less of compound particles having a size of 0.3 μm or more per unit area of 100 μm×100 μm in a cross section, and a relative density is 93% or more.

The present invention discloses a portable multi-azimuth ultrasonic-assisted vibration rolling device and an application method thereof. The vibration rolling device includes an ultrasonic rolling unit, a hydraulic power unit, a pneumatic cooling unit, a main body frame and an indexing device; an amplitude transformer assembly at the ultrasonic rolling unit comes into rolling contact with the surface of a tooth space of a gear workpiece, the hydraulic power unit is articulated with the main body frame, and the hydraulic power unit is articulated with the horn assembly, the indexing device is provided at the main body frame, and the gear workpiece is mounted at the indexing device. The present invention has the advantages that the device is flexible and portable, enables a transducer to be cooled continuously, and facilitates fixation of a rolling steel ball and adjustment of a station of the gear workpiece.

The present invention discloses a portable multi-azimuth ultrasonic-assisted vibration rolling device and an application method thereof. The vibration rolling device includes an ultrasonic rolling unit, a hydraulic power unit, a pneumatic cooling unit, a main body frame and an indexing device; an amplitude transformer assembly at the ultrasonic rolling unit comes into rolling contact with the surface of a tooth space of a gear workpiece, the hydraulic power unit is articulated with the main body frame, and the hydraulic power unit is articulated with the horn assembly, the indexing device is provided at the main body frame, and the gear workpiece is mounted at the indexing device. The present invention has the advantages that the device is flexible and portable, enables a transducer to be cooled continuously, and facilitates fixation of a rolling steel ball and adjustment of a station of the gear workpiece.

The invention relates to a method for producing a sintered gear comprising a gear body on which at least one elastomer element is arranged, according to which a green compact is produced by pressing a powder, the green compact is sintered into a gear body and is hardened by carburization and subsequent quenching or sinter-hardening and subsequent quenching with a gas and afterwards the at least one elastomer element is vulcanized onto the gear body.

The invention relates to a method for producing a sintered gear comprising a gear body on which at least one elastomer element is arranged, according to which a green compact is produced by pressing a powder, the green compact is sintered into a gear body and is hardened by carburization and subsequent quenching or sinter-hardening and subsequent quenching with a gas and afterwards the at least one elastomer element is vulcanized onto the gear body.

A machine component includes a core made up of a steel for machine structural use, and a medium carbon-containing layer and a high carbon-containing layer formed of the steel for machine structural use, the medium carbon-containing layer covering the core, the high carbon-containing layer covering the medium carbon-containing layer and having a carbon concentration of 0.8-1.5%. The high carbon-containing layer is made up of a martensitic structure having carbides dispersed therein and a residual austenitic structure, wherein spheroidized carbides with an aspect ratio of 1.5 or less constitute 90% or more of a total number of the carbides, and the number of spheroidized carbides on prior austenite grain boundaries is 40% or less of the total number of the carbides.

A machine component includes a core made up of a steel for machine structural use, and a medium carbon-containing layer and a high carbon-containing layer formed of the steel for machine structural use, the medium carbon-containing layer covering the core, the high carbon-containing layer covering the medium carbon-containing layer and having a carbon concentration of 0.8-1.5%. The high carbon-containing layer is made up of a martensitic structure having carbides dispersed therein and a residual austenitic structure, wherein spheroidized carbides with an aspect ratio of 1.5 or less constitute 90% or more of a total number of the carbides, and the number of spheroidized carbides on prior austenite grain boundaries is 40% or less of the total number of the carbides.

A method for producing a machine component excellent in pitting resistance characteristics and toughness includes a carburizing step, performed on a steel material containing 0.13-0.30% C and 0.90-2.00% Cr in mass % and at least one of Si, Mn, Ni, Mo, Nb, V, Ti, B, Al, and N, balance Fe and unavoidable impurities; heating the material to 850-1030 C. to attain carbon concentration in a surface of 0.8-1.5%; cooling the material at an average rate of 5 C./sec or lower from a temperature higher than the A.sub.cm point of a surface layer to a cooling end temperature that is at least 50 C. lower than the A.sub.1 point to cause the surface layer to have a pearlite or bainite structure with dispersion; spheroidizing annealing at a temperature not higher than the A.sub.cm point at the surface layer; heating the material to not higher than the A.sub.cm point at the surface layer; and performing tempering.