Hitachi Metals, Ltd.

Nippon Institute of Technology

Mitsubishi Materials Corporation

Mmc Superalloy Corporation

Jun Ohsone

Hideo Takizawa

Masayuki Watanabe

Akira Mitsuhashi

Takanori Matsui

Yuji Ishiwari

Hiroaki Kikuchi

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.

Ring molded article manufacturing method and ring material

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.

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 &#x3b5;&#x3b8;of a strain in a circumferential direction of the forged material that is greater than or equal to 0.3, an absolute value &#x3b5;h of a strain in a height direction of the forged material that is greater than or equal to 0.3, and a ratio &#x3b5;h/&#x3b5;&#x3b8;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.

Method of manufacturing annular molding

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 &#x3b4; phase particles are distributed in a matrix thereof, and wherein, in the microstructure, flattened &#x3b4; phase particles of which maximum length directions are oriented at angles within a range of 60 to 120&#xb0; 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 &#x3b4; phase particles distributed in the matrix.

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Okegawa, Japan

Jun Ohsone