Mitsubishi Heavy Industries Limited

Mitsubishi Jukogyo Kabushiki Kaisha

Mitsubishi Hitachi Power Systems, Ltd.

The Japan Steel Works, Ltd.

Daido Tokushuko Kabushiki Kaisha

Kabushiki Kaisha Kobe Seiko Sho

Nkk Corporation

Yoshikuni Kadoya

Ryuichi Yamamoto

Takashi Nakano

Hisataka Kawai

Shin Nishimoto

Ryotaro Magoshi

Yuichi Hirakawa

Ryotarou Magoshi

Yoshinori Tanaka

Kenji Kawasaki

Koji Takahashi

Toshiharu Noda

Shigeki Ueta

Tatsuaki Fujikawa

Eiji Maeda

Tatsuya Takahashi

Takashi Shige

Satoru Ohsaki

Koji Kajikawa

Michio Okabe

Naoto Tochitani

Yutaka Moriya

Haruo Suzuki

Toshio Yonezawa

Takemi Yamada

Susumu Isobe

Katsumi Masamura

Shuji Hamano

Tatsuya Furukawa

Tomohiro Tsuchiyama

Yasuhiko Yasumoto

Toru Inazumi

Naotake Ito

Ichirou Tsuji

Toshio Sakon

Hiroharu Ooyama

A subject for the invention is to diminish the occurrence of streak-type segregation in producing a material comprising a Ni-based superalloy. The invention relates to a Ni-based superalloy having excellent unsusceptibility to segregation, characterized by comprising: 0.005 to 0.15 mass % of C; 8 to 22 mass % of Cr; 5 to 30 mass % of Co; equal or greater than 1 and less than 9 mass % of Mo; 5 to 21 mass % of W; 0.1 to 2.0 mass % of Al; 0.3 to 2.5 mass % of Ti; up to 0.015 mass % of B; and up to 0.01 mass % of Mg, with the remainder comprising Ni and unavoidable impurities.

Ni-based superalloy with excellent unsusceptibility to segregation

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 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

The present invention relates to a low thermal expansion Ni-base superalloy containing, in terms of mass %, C: 0.15% or less; Si: 1% or less; Mn: 1% or less; Cr: 5% or more but less than 20%; at least one of Mo, W and Re, in which Mo+&#xbd;(W+Re) is 5% or more but less than 20%; W: 10% or less; Al: 0.1 to 2.5%; Ti: 0.10 to 0.95%; Nb+&#xbd;Ta: 1.5% or less; B: 0.001 to 0.02%; Zr: 0.001 to 0.2%; Fe: 4.0% or less; and a balance of inevitable impurities and Ni, in which the total amount of Al, Ti, Nb and Ta is 2.0 to 6.5% in terms of atomic %. The low thermal expansion Ni-base superalloy of the present invention has a thermal expansion coefficient almost equal to that of 12 Cr ferritic steel, excellent high temperature strength, excellent corrosion and oxidation resistance, good hot-workability, and excellent weldability.

Low thermal expansion Ni-base superalloy

A method for producing a low thermal expansion Ni-base superalloy including the steps of subjecting the alloy to a solution heat treatment under the condition of at a temperature of 1000 to 1200&#xb0; C. and subjecting the alloy to either a carbide stabilizing treatment for making aggregated carbides on grain boundaries and stabilizing the carbides under the conditions of at a temperature of not less than 850&#xb0; C. and less than 1000&#xb0; C. and for 1 to 50 hours, or a carbide stabilizing treatment for making aggregated carbides on grain boundaries and stabilizing the carbides by cooling from the temperature in the solution heat treatment to 850&#xb0; C. at a cooling rate of 100&#xb0; C. or less per hour. The method also including the steps of subjecting the alloy to a first aging treatment for precipitating y' phase under the conditions of at a temperature of 720 to 900&#xb0; C. and for 1 to 50 hours, and subjecting the alloy to a second aging treatment for precipitating AB phase under the conditions of at a temperature of 550 to 700&#xb0; C. and for 5 to 100 hours.

Method for producing low thermal expansion Ni-base superalloy

A low thermal expansion Ni-base superalloy contains, by weight % (hereinafter the same as long as not particularly defined) C: 0.15% or less; Si: 1% or less; Mn: 1% or less; Cr: 5 to 20%; at least one of Mo, W and Re of Mo+&#xbd;(W+Re) of 17 (exclusive) to 25%; Al: 0.2 to 2%; Ti: 0.5 to 4.5%; Fe of 10% or less; at least one of B: 0.02% and Zr: 0.2% or less; a remainder of Ni and inevitable impurities; wherein the atomic % of Al+Ti is 2.5 to 7.0.

A material for a gas turbine disk comprises 0.05 to 0.15 wt % of carbon, 0.10 wt % or less of silicon, 0.40 wt % or less of manganese, 9.0 to 12.0 wt % of chromium, 1.0 to 3.5 wt % of nickel, 0.50 to 0.90 wt % of molybdenum, 1.0 to 2.0 wt % of tungsten, 0.10 to 0.30 wt % of vanadium, 0.01 to 0.10 wt % of niobium, 0.01 to 0.05 wt % of nitrogen, and a remainder comprising iron and unavoidable impurities, wherein the contents of nickel, molybdenum and tungsten satisfy a relationship -1.5 wt %.ltoreq.Mo+W/2-Ni.ltoreq.0.7 wt %. Accordingly, unlike conventional gas turbine disk materials such as a heat resisting steel of 12Cr-type which can be used in an operation at about 400.degree. C., but has reduced toughness and high-temperature creep characteristics in an operation at about 500.degree. C., this material is allowed to have a satisfactory toughness and excellent high-temperature creep characteristics and can be suitably used at high temperatures.

Material for gas turbine disk

The present invention discloses ferritic heat resisting steels for manufacturing a rotor or a disk of a gas turbine, which have high creep rupture strength at high temperatures and excellent tenacity at room ordinary temperatures. The highly tenacious ferritic heat resisting steels contain, by weight, carbon of 0.08 to 0.25%, silicon of 0.5% or lower, manganese of 1.0% or lower, nickel exceeding 1.0% and lower than 3.0%, chromium of 9.0 to 12.5%, molybdenum exceeding 0.3% and lower than 1.5%, tungsten of 1.0 to 3.0%, vanadium of 0.10 to 0.35%, niobium of 0.02 to 0.10%, nitrogen of 0.01 to 0.80%, boron of 0.001 to 0.01% and cobalt of 1.0 to 5.0%, and a remaining part is mostly iron. Its structure is composed of a tempered martensite matrix.

Highly tenacious ferritic heat resisting steel

High-strength and high-toughness heat-resisting steel

There are provided high-strength and high-toughness heat-resistant cast steels applicable to steam turbine casings, precision cast vanes and valves. There is disclosed a high-strength and high-toughness heat-resistant cast steel formed of a heat-resistant cast steel consisting of, based on weight percentage: 0.08 to 0.25% of carbon; more than 0.1 not more than 0.5% of silicon; 1% or less of manganese; 0.05 to 1% of nickel; 9 to 12% of chromium; 0.3 to 1.5% of molybdenum; 1 to 1.95% of tungsten; 0.1 to 0.35% of vanadium; 0.02 to 0.1% of niobium; 0.01 to 0.08% of nitrogen; 0.001 to 0.01% of boron; and 2 to 8% of cobalt; the balance substantially being iron; and having a martensite matrix structure.

High-strength and high-toughness heat-resistant cast steel

Ferrous group shape memory alloys consisting essentially of Cr: 16.0-21.0 wt %, Si: 3.0-7.0 wt % and Ni: 11.0-21.0 wt % and satisfying Ni wt %.gtoreq.[0.67.times.{Cr+1.2.times.(Si+Ti+Zr+Hf+V+Nb+Ta)}-] wt % and (Cr+Si) wt %.gtoreq.20 wt %, these ferrous-group shape-memory alloys having a corrosion resistance, a shape-memorizing properties, an intergranular corrosion resistance and a stress corrosion cracking resistance in nitric acid for nuclear fuel reprocessing plants and high-temperature, high-pressure water for light-water reactors.

Fe-Cr-Ni-Si shape memory alloys with excellent stress corrosion cracking

Growing community of inventors

Nagasaki, Japan

Yoshikuni Kadoya