Abstract: Provided are: a closed-die forging method capable of preventing a temperature decrease in a to-be-forged member during forging, easy temperature monitoring during forging, and filling the cavity end portions of a die with the to-be-forged member; and a method of manufacturing a forged article using the closed-die forging method. The closed-die forging method includes covering a surface of the to-be-forged member (preferably a super-alloy) that contacts the lower die with a metal heat-insulation member (preferably stainless steel) prior to forging, except for at least a part of the surface that contacts an upper die during forging, placing the heated to-be-forged member on a lower die, and hammer-forging the to-be-forged member integrally with the metal heat-insulation member. A forged article is prepared by heat-treating the forged article obtained by the closed-die forging method (preferably in a disk shape) at temperatures not lower than the recrystallization temperature of the forged article.

Abstract: Provided is a hot upset forging method enabling high shape precision to be obtained. The hot upset forging method includes inserting a workpiece (1), with a bottom face diameter d and a height h satisfying h/d>3, into an insertion hole provided passing through a mold (2) of a height H disposed on an anvil (4), and increasing the diameter of the workpiece (1) while decreasing the height of the workpiece (1) to form a forged material. The mold satisfies the following relationships (1) to (3). (1) A shape of the insertion hole and the cross-sectional shape of the workpiece are substantially similar shapes. (2) The height h of the workpiece (1)?the height H of the mold (2). (3) A largest diameter dl of the workpiece 1, and the maximum inner diameter D of the insertion hole, in the height range of the workpiece (1), satisfy dl<D?dl×1.5.

Abstract: Provided are a manufacturing method for a blade material and a manufacturing device for a blade material, by which a long blade material can be manufactured without using a large-sized press forging machine. A manufacturing method for a blade material, in which hot forging is sequentially performed by molds from the root side to a blade (vane) tip, wherein when a root-side portion is grasped and a material to be forged is restrained by a mold, twisting is performed on a region between the grasped portion and the restrained portion. A manufacturing method for a blade material, in which hot forging and twisting are repeated, is preferable, and a manufacturing method for a blade material, in which hot forging is performed while molds are sequentially changed, is more preferable.

Abstract: Provided is a hot upset forging method enabling high shape precision to be obtained. The hot upset forging method includes inserting a workpiece (1), with a bottom face diameter d and a height h satisfying h/d>3, into an insertion hole provided passing through a mold (2) of a height H disposed on an anvil (4), and increasing the diameter of the workpiece (1) while decreasing the height of the workpiece (1) to form a forged material. The mold satisfies the following relationships (1) to (3). (1) A shape of the insertion hole and the cross-sectional shape of the workpiece are substantially similar shapes. (2) The height h of the workpiece (1)?the height H of the mold (2). (3) A largest diameter dl of the workpiece 1, and the maximum inner diameter D of the insertion hole, in the height range of the workpiece (1), satisfy dl<D<dl×1.5.

Abstract: Provided are: a closed-die forging method capable of preventing a temperature decrease in a to-be-forged member during forging, easy temperature monitoring during forging, and causing cavity end portions of a die to be filled with the to-be-forged member; and a method of manufacturing a forged article using the closed-die forging method. The closed-die forging method, which involves placing a heated to-be-forged member on a lower die and hammer-forging the to-be-forged member with a reciprocating upper die, includes covering the whole of a portion of the to-be-forged member that contacts the lower die with a metal heat-insulation member prior to forging, except for at least a part of a portion that contacts an upper die during forging, and then forging the to-be-forged member integrally with the metal heat-insulation member. Preferably, the to-be-forged member is a superalloy and the metal heat-insulation member is stainless steel. Further preferably, the to-be-forged member is forged into a disk shape.

Abstract: Provided are a manufacturing method for a blade material and a manufacturing device for a blade material, by which a long blade material can be manufactured without using a large-sized press forging machine. A manufacturing method for a blade material, in which hot forging is sequentially performed by molds from the root side to a blade (vane) tip, wherein when a root-side portion is grasped and a material to be forged is restrained by a mold, twisting is performed on a region between the grasped portion and the restrained portion. A manufacturing method for a blade material, in which hot forging and twisting are repeated, is preferable, and a manufacturing method for a blade material, in which hot forging is performed while molds are sequentially changed, is more preferable.