Provided are a hollow drive shaft using an upsetting method and a method of manufacturing the same, in which hot forging and upsetting processes are applied to both ends of a workpiece so that an outer diameter at both ends of the workpiece is greater than an outer diameter of a middle part of the workpiece, thereby reducing a weight of the drive shaft and enabling the drive shaft to transmit higher driving power. According to the present invention, the upsetting process is applied during the hot forging process to manufacture the hollow drive shaft, portions to be substantially processed are limited to portions at both ends of the workpiece, and the number of upsetting processes is limited to a minimum number (2 or the like), such that initial investment costs and manufacturing costs are low because the number of processes is small.

Provided are a hollow drive shaft using an upsetting method and a method of manufacturing the same, in which hot forging and upsetting processes are applied to both ends of a workpiece so that an outer diameter at both ends of the workpiece is greater than an outer diameter of a middle part of the workpiece, thereby reducing a weight of the drive shaft and enabling the drive shaft to transmit higher driving power. According to the present invention, the upsetting process is applied during the hot forging process to manufacture the hollow drive shaft, portions to be substantially processed are limited to portions at both ends of the workpiece, and the number of upsetting processes is limited to a minimum number (2 or the like), such that initial investment costs and manufacturing costs are low because the number of processes is small.

This method for manufacturing a high-temperature component formed of a Ni-based alloy includes a step of subjecting a workpiece of the Ni-based alloy to hot die forging using predetermined dies to form a forge-molded article, the step including: a die/workpiece co-heating substep of heating the workpiece interposed between the dies to a forging temperature; and a hot forging substep of taking out the workpiece and the dies into a room temperature environment and immediately performing hot forging on the workpiece using a press machine. The predetermined dies are formed of another Ni-based superalloy comprising γ and γ′ phases, and have features in that: a solvus temperature of the γ′ phase is 1050-1250° C.; and the γ′ phase precipitates at least 10 vol. % at 1050° C. and has two kinds of forms of intra-grain γ′ phase precipitations within the γ phase grains and inter-grain γ′ phase precipitations between/among the γ phase grains.

A forging apparatus and a forged product manufacturing method aim to prevent decrease in the temperature of a forging space and the temperature of a forging material, efficiently maintain the uniformity of the temperatures of upper and lower dies, and improve forging efficiency. In the forging apparatus and the forged product manufacturing method according to the present invention, the upper and lower dies are heated by a heating mechanism in a housing in which a charging port of an integrally formed housing body is closed by a door, the upper and lower dies are moved relatively in a facing direction of the upper and lower dies, the heating mechanism is moved relatively in the facing direction with respect to at least one of the relatively moving upper and lower dies, and whereby the forging material is forged between the upper and lower dies. Furthermore, the forged product manufacturing method is used to manufacture a forged product from the forging material.

A forging apparatus and a forged product manufacturing method aim to prevent decrease in the temperature of a forging space and the temperature of a forging material, efficiently maintain the uniformity of the temperatures of upper and lower dies, and improve forging efficiency. In the forging apparatus and the forged product manufacturing method according to the present invention, the upper and lower dies are heated by a heating mechanism in a housing in which a charging port of an integrally formed housing body is closed by a door, the upper and lower dies are moved relatively in a facing direction of the upper and lower dies, the heating mechanism is moved relatively in the facing direction with respect to at least one of the relatively moving upper and lower dies, and whereby the forging material is forged between the upper and lower dies. Furthermore, the forged product manufacturing method is used to manufacture a forged product from the forging material.

Provided are a hollow drive shaft using an upsetting method and a method of manufacturing the same, in which hot forging and upsetting processes are applied to both ends of a workpiece so that an outer diameter at both ends of the workpiece is greater than an outer diameter of a middle part of the workpiece, thereby reducing a weight of the drive shaft and enabling the drive shaft to transmit higher driving power. According to the present invention, the upsetting process is applied during the hot forging process to manufacture the hollow drive shaft, portions to be substantially processed are limited to portions at both ends of the workpiece, and the number of upsetting processes is limited to a minimum number (2 or the like), such that initial investment costs and manufacturing costs are low because the number of processes is small.

Provided are a hollow drive shaft using an upsetting method and a method of manufacturing the same, in which hot forging and upsetting processes are applied to both ends of a workpiece so that an outer diameter at both ends of the workpiece is greater than an outer diameter of a middle part of the workpiece, thereby reducing a weight of the drive shaft and enabling the drive shaft to transmit higher driving power. According to the present invention, the upsetting process is applied during the hot forging process to manufacture the hollow drive shaft, portions to be substantially processed are limited to portions at both ends of the workpiece, and the number of upsetting processes is limited to a minimum number (2 or the like), such that initial investment costs and manufacturing costs are low because the number of processes is small.

A flywheel energy storage system incorporates various embodiments in design and processing to achieve a very high ratio of energy stored per unit cost. The system uses a high-strength steel rotor rotating in a vacuum envelope. The rotor has a geometry that ensures high yield strength throughout its cross-section using various low-cost quenched and tempered alloy steels. Low-cost is also achieved by forging the rotor in a single piece with integral shafts. A high energy density is achieved with adequate safety margins through a pre-conditioning treatment. The bearing and suspension system utilizes an electromagnet that off-loads the rotor allowing for the use of low-cost, conventional rolling contact bearings over an operating lifetime of several years.

A flywheel energy storage system incorporates various embodiments in design and processing to achieve a very high ratio of energy stored per unit cost. The system uses a high-strength steel rotor rotating in a vacuum envelope. The rotor has a geometry that ensures high yield strength throughout its cross-section using various low-cost quenched and tempered alloy steels. Low-cost is also achieved by forging the rotor in a single piece with integral shafts. A high energy density is achieved with adequate safety margins through a pre-conditioning treatment. The bearing and suspension system utilizes an electromagnet that off-loads the rotor allowing for the use of low-cost, conventional rolling contact bearings over an operating lifetime of several years.

A multistage press for the bulk deformation of a piece of wire includes a wire feed with associated apparatus for cutting to length, and a transfer device—having grippers—for receiving a piece of wire that has been cut to length and transferring the latter to subsequent forming stages, there being arranged, on that side of the cutting-to-length apparatus opposite from the wire feed, a device for partially heating a length of wire. A method produces a formed part with a multistage press of this type.