A method for use in manufacturing a metal part is provided. The method may include casting liquid metal in a ceramic mold. The ceramic mold may be formed via an investment casting process in which a wax mold is used to as a form for the ceramic mold, and the wax is melted away from the ceramic mold prior to its use. The method may further include cooling the liquid metal in the ceramic mold to form a solid metal part, and then divesting the ceramic mold to release the metal part. The metal part may include an imperfection in a shape of the metal part. To correct the imperfection, the method may include shaping the metal part by near-net shape forging.

A high-strength stainless steel rotor and a method for preparing the same, are provided. The high-strength stainless steel rotor, including the following element components by mass percentage: C: 0.03-0.050%, Cr: 14.90-15.80%, Ni: 5.00-5.70%, Cu: 2.20-2.80%, (Nb+Ta): 0.35-0.44%, Mo: 0.45-0.54%, V: 0.06-0.10%, Si: 0.20-0.60%, Mn: 0.40-0.80%, P?0.010%, S?0.010%, O?0.003%, and the balance of iron and inevitable impurities.

The disclosure describes example systems and techniques for controlling microstructure of a superalloy substrate by controlling temperature during forging and using multiple die forging stages to formation of grain boundary phases of the superalloy, and components formed by such example systems and techniques. The method includes heating a substrate to within a forging temperature range. The substrate includes a nickel-based superalloy, and the forging temperature range is below an eta phase solvus temperature of the substrate. The method includes applying a plurality of die forging stages to the substrate to form a component preform. The method includes maintaining the substrate within the forging temperature range during application of the plurality of die forging stages and cooling the component preform.

A gas sensor (1) has a sensor element (21) extending in an axis direction and having, at a top end side thereof, a detecting portion (22) that detects gas; a stainless steel-made tubular metal shell (11) enclosing a radial direction periphery of the sensor element (21) and holding the sensor element (21) and having (a) a brim portion (14) protruding outwards in a radial direction and (b) a crimp portion (16) formed at a rear end side of the metal shell (11); and a sealing member (41) placed between the sensor element (21) and the metal shell (11). The crimp portion (16) is bent inwards in the radial direction and pressing down a rear end of the sealing member (41) toward the top end side. A Micro Vickers hardness of a cross section along the axis direction of the crimp portion (16) is 140 to 210 Hv.

In a forming system in particular for metallic workpieces (31, 32) with several forming stations (21-23) a transport device (1) is provided with one or more rails (13) on which carriages (141, 142) can be moved. In a conventional mode of operation of the rails, it is provided that two carriages (141, 142) on the same rail (13) are moved by a varying distance relative to each other during the transport of a respective workpiece (31, 32) from one forming station (21-23) to another forming station (21-23), namely in particular are driven towards each other or away from each other with their distance relative to each other being increased or decreased. New production sequences can thereby be provided.

Provided is a production method, including a first preforming process, a second preforming process, a final preforming process, and a finish forging process. In the first preforming process, regions to be a pin and a journal are pressed respectively from a direction perpendicular to an axial direction of the billet, thus reducing cross sectional areas of each region and forming a plurality of flat parts. In the second preforming process, the first preform is pressed in the pressing direction, which is a direction perpendicular to decentering direction of a region to be a second pin. In the final preforming process, the second preform is pressed from a direction perpendicular to an axial direction of the second preform, and further a region to be a counterweight and a region to be a crank arm integrally including a counterweight are pressed in the axial direction of the second preform.

Provided is a production method, including a first preforming process, a second preforming process, a final preforming process, and a finish forging process. In the first preforming process, regions to be a pin and a journal are pressed respectively from a direction perpendicular to an axial direction of the billet, thus reducing cross sectional areas of each region and forming a plurality of flat parts. In the second preforming process, the first preform is pressed in the pressing direction, which is a width direction of the flat parts. In the final preforming process, the second preform is pressed from a direction perpendicular to an axial direction of the second preform, and further a region to be a counterweight and a region to be a crank arm integrally including a counterweight are pressed in the axial direction of the second preform.

An embodiment includes a method for net shape forging of a large rotor shaft that includes a reduced central cylindrical section and integrally forged segments along the longitudinal length thereof. In an embodiment, the net shaped forging is produced by sequentially pressing the work piece such that a near net shaped forging of the machined work piece is produced, including upset geometries such as eccentric or concentric disks. This permits a reduction in waste material (e.g., due to the machining process) and improves the strength of the upset geometries. Other aspects are described and claimed.

A method of manufacturing a cylindrical ring member includes a step of forming a metal intermediate material having a cylindrical portion and a chamfering step by cold forging in which a normal chamfer portion is formed on an axial end peripheral edge of the cylindrical portion by pressing a radial end portion of an axial end surface of the cylindrical portion against an annular chamfering surface provided in a mold configuring a mold device. A chamfering step is performed by cold forging in a state where a preliminary chamfer portion, of which a width dimension in a radial direction is larger than a width dimension of the normal chamfer portion in a radial direction, is formed on the axial end peripheral edge of the cylindrical portion.

Provided is a large crankshaft comprising a pin fillet portion, wherein: an average initial compression stress in a surface layer region from a surface of the pin fillet portion to a depth of 500 m is 500 Mpa or more; an average Vickers hardness of the surface of the pin fillet portion is 600 or more; an arithmetic average roughness Ra of the surface of the pin fillet portion is 1.0 m or less; and an average prior austenite grain size of a metallographic structure is 100 m or less. The large crankshaft has composition comprising C: 0.2% by mass to 0.4% by mass, Si: 0% by mass to 1.0% by mass, Mn: 0.2% by mass to 2.0% by mass, Al: 0.005% by mass to 0.1% by mass, N: 0.001% by mass to 0.02% by mass, and a balance being Fe and inevitable impurities.