Abstract: Provided is a ring-rolled member manufacturing method enabling stabilization of the attitude of the ring material without generating a defect and the like in the resulting ring-rolled member even when the main roll of the ring-rolling device is provided with the flange portions positioned on upper and lower sides of the ring material. A ring-rolling device used in the ring-rolled member manufacturing method of the present invention is provided with a main roll 10 and a mandrel roll 20. An outer peripheral face of the main roll includes a recessed portion 12 to accommodate the ring material and an outer peripheral face of the mandrel roll 20, an upper flange portion 11 positioned on an upper side thereof, and a lower flange portion 13 positioned on a lower side thereof.

Abstract: Provided is a ring-rolled member manufacturing method enabling stabilization of the attitude of the ring material without generating a defect and the like in the resulting ring-rolled member even when the main roll of the ring-rolling device is provided with the flange portions positioned on upper and lower sides of the ring material. A ring-rolling device used in the ring-rolled member manufacturing method of the present invention is provided with a main roll 10 and a mandrel roll 20. An outer peripheral face of the main roll includes a recessed portion 12 to accommodate the ring material and an outer peripheral face of the mandrel roll 20, an upper flange portion 11 positioned on an upper side thereof, and a lower flange portion 13 positioned on a lower side thereof.

Abstract: Various implementations include a ring material used for producing a ring molded article. The ring molded article has two convex portions which respectively protrude on opposite sides of the ring molded article in a direction of a center axis thereof and extend in a direction of a circumference of the ring molded article. A straight line passing through centers of gravity of first and second side regions is inclined by an angle relative to the center axis of the ring material, the first and second side regions are obtained by virtually dividing a one half section of the ring material based on a middle of a maximum height of the ring material in the direction of the center axis of the ring material, and a range of the angle is 7 degrees to 40 degrees.

Abstract: Various implementations include a ring material used for producing a ring molded article. The ring molded article has two convex portions which respectively protrude on opposite sides of the ring molded article in a direction of a center axis thereof and extend in a direction of a circumference of the ring molded article. A straight line passing through centers of gravity of first and second side regions is inclined by an angle relative to the center axis of the ring material, the first and second side regions are obtained by virtually dividing a one half section of the ring material based on a middle of a maximum height of the ring material in the direction of the center axis of the ring material, and a range of the angle is 7 degrees to 40 degrees.

Abstract: Various implementations include a method of manufacturing a ring molded article. The ring molded article has two convex portions which respectively protrude on both sides of the ring molded article in a direction of a center axis thereof and extend in a direction of a circumference of the ring molded article. The ring material is placed inside two molds on which concave portions respectively corresponding to the convex portions are formed. The ring material is supported by a region on an outer peripheral side from an outer peripheral side corner in the concave portion of one of the two molds and a region on an inner peripheral side from an inner peripheral side corner in the concave portion of another of the two molds. The ring material is then forged so as to be pressed by the two molds in a direction of a center axis of the ring material.

Abstract: A ring molded article manufacturing method capable of reliably and efficiently producing a ring molded article in which dead metal regions are reduced, is provided. In the present invention, a material is processed by first forging so as to be shaped in a shape including a bottom which is formed in a substantially disk shape, and a peripheral wall which is inclined to a direction from a center of the bottom toward an outer periphery thereof, in a direction from the outer periphery of the bottom toward one side in a direction of a center axis of the bottom, the bottom of a first forged article obtained by the first forging is drilled, a drilled article obtained by the drilling is ring-rolled, a ring material obtained by the ring rolling is placed inside two molds, the ring material is then processed by second forging so as to be pressed by the two molds in a direction of a center axis of the ring material, and the ring molded article is thus produced.

Abstract: A ring molded article manufacturing method capable of reliably and efficiently producing a ring molded article in which dead metal regions are reduced, and a ring material used for producing the ring molded article, are provided. The present invention relates to the method for manufacturing a ring molded article having two convex portions which respectively protrude on both sides of the ring molded article in a direction of a center axis thereof and extend in a direction of a circumference of the ring molded article.

Abstract: A method of manufacturing an annular material includes: a forging process of making a discoid forged material by forging an alloy material; and a ring rolling process of making an annular material by performing ring rolling on an annular intermediate made by forming a through-hole in the forged material. In the forging process, hot forging which achieves an absolute value ??1 of a strain in a circumferential direction of the forged material that is greater than or equal to 0.3, an absolute value ?h of a strain in a height direction of the forged material that is greater than or equal to 0.3, and a ratio ?h/??1 between the absolute values of the strains that is in a range of 0.4 to 2.5 is performed at least two or more times.

Abstract: A method of manufacturing an annular material includes: a forging process of making a discoid forged material by forging an alloy material; and a ring rolling process of making an annular material by performing ring rolling on an annular intermediate made by forming a through-hole in the forged material. In the forging process, hot forging which achieves an absolute value ??1 of a strain in a circumferential direction of the forged material that is greater than or equal to 0.3, an absolute value ?h of a strain in a height direction of the forged material that is greater than or equal to 0.3, and a ratio ?h/??1 between the absolute values of the strains that is in a range of 0.4 to 2.5 is performed at least two or more times.

Abstract: This ring-shaped disk for a gas turbine includes a ring-shaped disk material consisting of a Ni-based alloy, wherein the Ni-based alloy has a composition that includes, in terms of percent by mass, Ni: 50.00 to 55.00%, Cr: 17.0 to 21.0%, Nb: 4.75 to 5.60%, Mo: 2.8 to 3.3%, Ti: 0.65 to 1.15%, Al: 0.20 to 0.80%, and C: 0.01 to 0.08%, with the balance being Fe and inevitable impurities, and has a microstructure in which ? phase particles are distributed in a matrix thereof, and wherein, in the microstructure, flattened ? phase particles of which maximum length directions are oriented at angles within a range of 60 to 120° with respect to a radial direction of the ring-shaped disk material are present in an amount of 60% or more of a total amount of the ? phase particles distributed in the matrix.

Abstract: This ring-shaped disk for a gas turbine includes a ring-shaped disk material consisting of a Ni-based alloy, wherein the Ni-based alloy has a composition that includes, in terms of percent by mass, Ni: 50.00 to 55.00%, Cr: 17.0 to 21.0%, Nb: 4.75 to 5.60%, Mo: 2.8 to 3.3%, Ti: 0.65 to 1.15%, Al: 0.20 to 0.80%, and C: 0.01 to 0.08%, with the balance being Fe and inevitable impurities, and has a microstructure in which ? phase particles are distributed in a matrix thereof, and wherein, in the microstructure, flattened ? phase particles of which maximum length directions are oriented at angles within a range of 60 to 120° with respect to a radial direction of the ring-shaped disk material are present in an amount of 60% or more of a total amount of the ? phase particles distributed in the matrix.