Mitsubishi Heavy Industries Limited

Mitsubishi Hitachi Power Systems, Ltd.

National Institute for Materials Science

Yuichi Hirakawa

Shin Nishimoto

Hiroaki Fukushima

Takashi Nakano

Yoshikuni Kadoya

Yoshinori Tanaka

Kenji Kawasaki

Hidekazu Uehara

Tatsuaki Fujikawa

Hiroyuki Endo

Tanehiro Shinohara

Ryuichi Yamamoto

Nobuyoshi Komai

Takashi Shige

Hiroaki Yoshida

Naoto Tochitani

Takayuki Kurimura

Kazuhiro Kimura

Hiroyuki Ohyama

Nobuhiko Saito

Takeo Tokumoto

Tatsuya Furukawa

Kota Sawada

Masahiko Yamashita

Sin Koga

Tatsuji Takahasi

Sin Nisimoto

Takasi Nakano

Tanehiro Sinohara

Takeshi Miyazawa

Hiroharu Ooyama

Kaoru Sekido

A method for evaluating a crack in a metal member comprises a first removal step (S) and a second removal step (S). In the first removal step (S), a step for electrolyzing a metal member having an oxide scale formed on a surface thereof, a step for acquiring an image of the oxide scale as a first image, and a step for determining whether or not a scale crack has occurred are repeated until occurrence of a scale crack is determined. In the second removal step (S), a step for electrolyzing the metal member having the scale crack, a second image acquisition step for acquiring an image of the oxide scale as a second image, and a second determination step for determining whether or not the scale crack has disappeared are repeated until disappearance of the oxide scale is determined.

Method for evaluating crack in metal member and method for evaluating fatigue damage in metal member

A faulted condition determination method is designed to detect a chromium content and a nickel content in a predetermined boundary region proximate to a boundary between a high-strength ferrite steel and a weld material in a welded joint in which the high-strength ferrite steel and another steel are welded together using the weld material containing nickel and to thereby determine the faulted condition of the predetermined boundary region based on the chromium content and the nickel content. Accordingly, it is possible to appropriately determine the faulted condition of welding of a replacement part in which a high-strength ferrite steel and another steel are welded together using a nickel-based weld material.

Faulted condition determination device and faulted condition determination method

A method for manufacturing a shaft body by welding a plurality of shaft members together and forming the shaft body, the method including: a primary tempering step of subjecting a range in at least one of the shaft members, which is in the vicinity of an end of another shaft member side adjacent thereto, to tempering before the shaft members are welded together so that a strength of an end side of a region thereof is lower than a strength at a side which is opposite to the end of the region thereof; a welding step of welding the shaft members together after the primary tempering step; and a secondary tempering step of tempering the vicinity of a weld part between the shaft members after the welding step.

Method for manufacturing shaft body

The precipitation hardened martensitic stainless steel is characterized by containing, in percent by weight, 12.25 to 14.25% Cr, 7.5 to 8.5% Ni, 1.0 to 2.5% Mo, 0.05% or less C, 0.2% or less Si, 0.4% or less Mn, 0.03% or less P, 0.005% or less S, 0.008% or less N, 0.90 to 2.25% Al, the balance substantially being Fe, and the total content of Cr and Mo being 14.25 to 16.75%. A turbine moving blade and a steam turbine are manufactured by using this martensitic stainless steel.

Precipitation hardened martensitic stainless steel, manufacturing method therefor, and turbine moving blade and steam turbine using the same

A first measured value of a specific physical quantity at a target portion is correlated with a damage evaluation index to calculate a damage degree corresponding to the first measured value. The specific physical quantity is measured at least once at a position corresponding to the first measurement position in another time period having a different usage elapsed time from that of the first measurement, and these second and subsequent measured values are correlated with damage degrees calculated based on temporal changes corresponding to the second and subsequent measurements. A new damage evaluation index is approximately calculated based on a relationship between the first, second, and subsequent measured values and the damage degrees corresponding to the first, second, and subsequent measured values.

Damage evaluation method and maintenance evaluation index decision method

A turbine rotor which is composed by connecting Ni-based alloy and heat resisting steel such as 12-Cr steel by welding to be able to ensure strength of welded parts and can be used under steam conditions of 700&#xb0; C. class and method of manufacturing the rotor are also provided. The rotor of the rotating machine into which working fluid of 650&#xb0; C. or higher is introduced, the rotor being composed of a plurality of members connected by welding such that material of each member is different in accordance with temperature of working fluid which flows contacting the members, wherein the first member(s) is formed from Ni-based alloy having mean linear expansion coefficient of 12.4&#xd7;10/&#xb0; C.&#x2dc;14.5&#xd7;10/&#xb0; C., preferably 14.0&#xd7;10/&#xb0; C. or smaller within a temperature range from a room temperature to 700&#xb0; C. and second member(s) is formed from high-chrome steels, and the rotor is composed such that the first member(s) formed from Ni-base alloy is located in a portion which contact to the working fluid of 650&#xb0; C. or higher.

Rotor of rotating machine and method of manufacturing the rotor

There are provided an Ni-based alloy high-chrome steel structure and its manufacturing method capable of joining Ni-based alloys and high-chrome steels by welding, and performing suitable heat treatment, thereby maintaining the strength in the joints. In a manufacturing method of a structure formed by joining together at least two first members formed from Ni-based alloys by welding, and joining a second member formed from high-chrome steels to a member where the first members have been joined together, the manufacturing method includes the steps: joining together the at least two first members formed from Ni-based alloys by welding; performing first-stage aging treatment on a welded joint between the first members, and then, joining the second member formed from high-chrome steels to the member where the first members have been joined together by welding; and then, performing second-stage aging treatment on the welded joint between the first members, and performing heat treatment after welding on a welded portion between the first members and the second member.

Ni-based alloy high-chrome steel structure and manufacturing method of the same

A seal structure includes a thick abradable film, thereby improving sealing performance. A seal structure () is provided with at least one fin () that projects in a ring-shape from a circumferential surface of a rotating shaft () and that is provided along an axial direction (L) and a seal member () having a ring-shaped sealing surface () opposed to the fin (), and on which an abradable layer () is formed by thermally spraying abradable material onto the sealing surface (), the seal structure () is provided with tapered portions () inclined in a radial direction (K) at end portions of the sealing surface () in the axial direction (L).

Seal structure

In a method of manufacturing an axis seal, first, a roll of rolled metal material is cut into metal material plates of a predetermined size. Next, metal material plates are etched from both sides so as to form a predetermined size. Subsequently, the thin metal plates are arranged so as to be in a ring shape, oriented in the same direction, and are welded so as to be fixed. Additionally, during these processes, heat treatment is performed by heating rolls of rolled metal materials or metal material plates or thin metal plates at a predetermined timing, thereby eliminating residual stress (strain).

Method of manufacturing axis seals having reduced gas leakage properties and a rotary machine using axis seals

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Hyogo, Japan

Yuichi Hirakawa