EP2292807A1 - Gusslegierung auf Ni-Basis und Turbinengehäuse - Google Patents

Gusslegierung auf Ni-Basis und Turbinengehäuse Download PDF

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Publication number
EP2292807A1
EP2292807A1 EP10008945A EP10008945A EP2292807A1 EP 2292807 A1 EP2292807 A1 EP 2292807A1 EP 10008945 A EP10008945 A EP 10008945A EP 10008945 A EP10008945 A EP 10008945A EP 2292807 A1 EP2292807 A1 EP 2292807A1
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EP
European Patent Office
Prior art keywords
weight
phase
alloy
cast
steam turbine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP10008945A
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English (en)
French (fr)
Inventor
Jun Sato
Shinya Imano
Hiroyuki Doi
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Hitachi Ltd
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Hitachi Ltd
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Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP2292807A1 publication Critical patent/EP2292807A1/de
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/055—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 20% but less than 30%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/056—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 10% but less than 20%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon

Definitions

  • the present invention relates to a Ni based casting alloy suitable for high temperature parts for steam turbines and a steam turbine casing.
  • ferritic steels such as Cr-Mo-V steels or 12Cr steels have been utilized.
  • the ferritic steels are excellent in high temperature strength and productivity and they are of low cost. Therefore, they have been utilized as forging materials for turbine rotors and casting materials for turbine casings, etc. (Patent document Nos. 1, 2).
  • Ni based superalloys that have higher strength than the conventional ferritic heat resisting steels have been utilized as high temperature parts for gas turbines.
  • the Ni based superalloys have higher heat resisting temperature than the ferritic heat resisting steels, and when they are utilized, it is expected to obtain higher power generation efficiency.
  • the Ni based superalloys generally contain Al and/or Ti, which precipitates an intermetallic compound phase of Ni 3 (Al,Ti) type, called ⁇ ' phase to thereby increase a mechanical strength (patent document No. 3 etc). Since the ⁇ ' phase increases mechanical strength as temperatures increase, it is suitable for strengthening phase for heat resisting materials. However, these elements have a problem in production of the steel because they tend to be oxidized during melting of the materials for the steels. If Al and Ti are oxidized, a desired mechanical strength is not obtained because of shortage of strengthening elements in the alloys, and in addition, reliability of the alloys decrease because of inclusion of the oxides as casting defects in the alloys.
  • Patent document No. 4 relates to a Ni-Fe based alloy containing Al and Ti.
  • the above technologies cannot be applied to such large scale and complicated parts such as turbine casings, and therefore, it was difficult to produce Ni based casting alloys of high temperature parts with high mechanical strength and high reliability.
  • Ni based cast alloys having the precipitated ⁇ ' phase and high mechanical strength which can be produced by a low cost casting process that is similar to that of the conventional heat resisting steels.
  • the Ni based cast alloy has an as-cast structure and consists essentially of C: 0.01 to 0.2 % by weight, Si: 0.5 to 4.0 % by weight, Cr: 14 to 22 % by weight, Mo + W: 4.0 to 10 % by weight, B: 0.001 to 0.02 % by weight, Co: up to 10 % by weight, Al: up to 0.5 % by weight, Ti: up to 0.5 % by weight, Nb: up to 5.0 % by weight, Fe: up to 10 % by weight, the balance being Ni and incidental impurities, wherein ⁇ ' phase precipitates in a matrix phase.
  • the matrix phase in this specification means a dominant part of an alloy structure, and the alloy structure of the alloy means a group of different phases and grains constituting the alloy.
  • the cast alloy consisting essentially of C: 0.01 to 0.2 % by weight, Si: 0.5 to 4.0 % by weight, Cr: 14 to 22 % by weight, Mo + W: 4.0 to 10 % by weight, B: 0.001 to 0.02 % by weight, the balance being Ni and incidental impurities.
  • the cast alloy consists essentially of C: 0.01 to 0.2 % by weight, Si: 0.5 to 4.0 % by weight, Cr: 14 to 22 % by weight, Co: 0.1 to 10 % by weight, Al: 0.1 to 0.5 % by weight, Ti: 0.1 to 0.5 % by weight, Nb: 1.0 to 4.0 % by weight, Mo + W: 4.0 to 10 % by weight, Fe: 0.1 to 10 % by weight, B: 0.001 to 0.02 % by weight, the balance being Ni and incidental impurities.
  • the Ni based cast alloy consists essentially of C: 0.05 to 0.15 % by weight, Si: 1.0 to 3.5 % by weight, Cr: 15 to 20 % by weight, Al: 0.1 to 0.5 % by weight, Ti: 0.1 to 0.5 % by weight, Nb: 1.0 to 4.0 % by weight, Co: 1.0 to 5 % by weight, Fe: 1.0 to 5 % by weight, Mo + W: 5.0 to 8 % by weight, B: 0.002 to 0.01 % by weight, the balance being Ni and incidental impurities.
  • These alloys precipitate the ⁇ ' Ni 3 Si phase as the strengthening phase by a suitable heat treatment, and the phase can exist during in its service, to thereby obtain excellent high temperature mechanical strength. Since there is no loss of strengthening elements by oxidation even in conventional melting process and no inclusion of oxides, reliability of the castings is high, which are suitable for high temperature parts such as steam turbine casings.
  • the present inventors have investigated influences of alloying elements on properties of Ni based alloys, and as a result, they invented Ni based casting alloys suitable for steam turbines. In the following, alloying elements and adding ranges thereof are explained.
  • Table 1 shows alloy compositions of the example Nos. 1 to 8 and comparative example alloy Nos. 1 to 5.
  • the first one was a solution heat treatment, which makes non-uniform cast structure uniform.
  • the higher the temperature the better the result is obtained; however, in order to avoid partial melting or coarsening of the structure, the heat treatment at 1100 to 1200 °C is preferable.
  • a heat treatment after the solution heat treatment is carried out for precipitating a strengthening phase.
  • a temperature for the second heat treatment may be chosen based on materials or use conditions of components, an amount of precipitation of the strengthening phase is too small if the temperature is higher than 800 °C, but on the other hand, precipitation is hard to take place if the temperature is lower than 700 °C. Therefore, the temperature for precipitating the strengthening phase is preferably 700 to 800 °C. Table 1 No.
  • Fig. 1 shows a diagrammatic view of the alloy structures of example alloy Nos. 1 to 8.
  • the ⁇ ' phase for strengthening precipitates dispersedly and a small amount of carbides precipitate at grain boundaries.
  • the structure is similar to the conventional ⁇ ' precipitation strengthening type Ni based alloys. This shows an effect of Si addition.
  • comparative example alloy No. 1 since an amount of Si is small, and since no Al and T are added, the ⁇ ' phase did not precipitate. In the comparative alloy No. 2, since a sufficient amount of Si was added, the ⁇ ' phase precipitated, but large precipitation of the ⁇ ' phase was observed at the grain boundaries and boundaries of dendrites. In comparative alloy No. 3, though Al and Ti were added in addition to Si, it was observed that oxides formed during casting were included in the alloy. The comparative alloy No. 4 is the same. The comparative example alloy No. 5 corresponds to alloy 625, which has been commercially available on the market. Though inclusion of oxides was not observed since amounts of Al and Ti were small, alloy materials that have been subjected to holding at high temperatures such as creep tests, precipitation of Ni 3 Nb was observed.
  • Figs, 2 and 3 show creep rupture time and creep rupture elongation of the alloys shown in Table 1.
  • the creep test was conducted at 700 °C under a load of 333 MPa. Every inventive alloy exhibited superior creep rupture time to the conventional alloy (Comparative example alloy No. 5). Addition of Si precipitated the ⁇ ' phase to thereby improve high temperature strength. As to the high temperature ductility, 25 % or more of elongation was observed.
  • the comparative example alloy No. 1 contained small amounts of strengthening elements and no ⁇ ' phase exists. Therefore, it has low creep rupture strength.
  • the comparative example alloy No. 2 which contained a large amount of Si, it has higher creep rupture strength than that of the comparative example alloy No. 1, but it has a low creep elongation. This is because large precipitates existed at grain boundaries and dendrite boundaries, which means the amount of Si was excess.
  • the comparative example alloy Nos. 3 and 4 there was observed inclusion of oxides. Rupture cracks were found wherein the ruptures started at included oxides so that the creep rupture time and creep rupture elongation were quite low. Accordingly, active amounts of Al and Ti should be made small to improve characteristics of the alloys for the present invention. Since the amounts of Al and Ti in the comparative alloy No. 5 are controlled to small amounts, deterioration of characteristics due to oxidation was not observed, but Ni 3 Nb precipitated as the time goes at high temperatures. Therefore, the example alloy of the present invention showed excellent structure stability by virtue of Si.
  • the alloys of the present invention are applied to high temperature components such as a casing for a rotor or a steam valve of a steam turbine.
  • Fig. 4 shows a cross sectional view of a steam valve comprising a valve casing 1, a valve body 2, a valve sheet 3, a piping 4, a sleeve 5, a shaft bush 6 and a valve shaft 7.
  • the alloy of the present invention is applied to the valve casing 1, valve body 2 and valve sheet 3, which are produced by casting.
  • These components that have as-cast structures having ⁇ ' precipitate in the matrix phase are subjected to proper heat treatments before assembling.
  • Detailed descriptions of the steam valve are omitted because the structure and functions of the components are well known in the art.
  • Fig. 5 shows a cross sectional view of a steam turbine rotor comprising nozzles 14, 15, blades 16, 17, inner casings 18, 20, 21, outer casings 19, 22, flange and elbow 25, a steam inlet 28, a rotor shaft 33, a nozzle box 38 and a journal 43.
  • the alloy of the present invention is applied to the inner casings 18, 20, 21 and the outer casings 19, 22, which are produced by casting. These components as-cast structures having ⁇ ' precipitate in the matrix phase are subjected to proper heat treatments before assembling. Detailed descriptions of the steam turbine rotor are omitted because the structure and functions of the components are well known in the art.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
EP10008945A 2009-09-04 2010-08-27 Gusslegierung auf Ni-Basis und Turbinengehäuse Withdrawn EP2292807A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2009204246A JP4982539B2 (ja) 2009-09-04 2009-09-04 Ｎｉ基合金、Ｎｉ基鋳造合金、蒸気タービン用高温部品及び蒸気タービン車室

Publications (1)

Publication Number Publication Date
EP2292807A1 true EP2292807A1 (de) 2011-03-09

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US (1) US20110058977A1 (de)
EP (1) EP2292807A1 (de)
JP (1) JP4982539B2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2730670A1 (de) * 2012-11-07 2014-05-14 Hitachi Ltd. Ni-basierte Gusslegierung und Dampfturbinengussteil damit
EP2796578A1 (de) * 2013-04-23 2014-10-29 General Electric Company Gegossene Superlegierung auf Nickelbasis mit Eisen

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5646521B2 (ja) * 2012-02-08 2014-12-24 株式会社東芝 蒸気タービンの鋳造用Ｎｉ基合金および蒸気タービン用鋳造部品
JP5921401B2 (ja) * 2012-02-10 2016-05-24 株式会社東芝 Ｎｉ基合金、その製造方法およびタービン用部品
DK177487B1 (en) * 2012-07-06 2013-07-15 Man Diesel & Turbo Deutschland An exhaust valve spindle for an exhaust valve in an internal combustion engine
JP6148843B2 (ja) * 2012-10-02 2017-06-14 三菱日立パワーシステムズ株式会社 ニッケル基合金からなる大型鋳造部材およびその製造方法
US10112254B2 (en) 2014-08-21 2018-10-30 Huntington Alloys Corporation Method for making clad metal pipe
JP6688598B2 (ja) * 2015-11-11 2020-04-28 三菱日立パワーシステムズ株式会社 オーステナイト鋼およびそれを用いたオーステナイト鋼鋳造品

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US4764225A (en) * 1979-05-29 1988-08-16 Howmet Corporation Alloys for high temperature applications
JPH0776721A (ja) * 1993-09-10 1995-03-20 Nidatsuku Kk 耐熱鋳造合金の熱処理方法
DE19525983A1 (de) * 1994-07-19 1996-02-01 Hitachi Metals Ltd Hochhitzebeständige Nickelbasislegierung und Verfahren zu ihrer Herstellung
JP2000169924A (ja) 1998-12-04 2000-06-20 Hitachi Metals Ltd Ｎｉ基超耐熱鋳造合金およびＮｉ基超耐熱合金製タービンホイール鋳物
WO2001053551A1 (en) * 2000-01-24 2001-07-26 Inco Alloys International, Inc. High temperature thermal processing alloy
JP2006022343A (ja) 2004-07-06 2006-01-26 Hitachi Ltd 耐熱鋼とそれを用いた蒸気タービン用ロータシャフト及び蒸気タービン並びに蒸気タービン発電プラント
JP2006118016A (ja) 2004-10-25 2006-05-11 Hitachi Ltd Ｎｉ−Ｆｅ基超合金とその製造法及びガスタービン
WO2006067189A1 (en) * 2004-12-23 2006-06-29 Siemens Aktiengesellschaft A ni based alloy, a component, a gas turbine arrangement and use of pd in connection with such an alloy
JP2007092123A (ja) 2005-09-29 2007-04-12 Hitachi Ltd 高強度耐熱鋳鋼とその製造方法及びそれを用いた用途

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US5556594A (en) * 1986-05-30 1996-09-17 Crs Holdings, Inc. Corrosion resistant age hardenable nickel-base alloy
JPS63140055A (ja) * 1986-12-03 1988-06-11 Sumitomo Metal Ind Ltd 高耐食性析出硬化型Ｎｉ基合金
US5059257A (en) * 1989-06-09 1991-10-22 Carpenter Technology Corporation Heat treatment of precipitation hardenable nickel and nickel-iron alloys
JP4509664B2 (ja) * 2003-07-30 2010-07-21 株式会社東芝 蒸気タービン発電設備
JP2008075171A (ja) * 2006-09-25 2008-04-03 Nippon Seisen Co Ltd 耐熱合金ばね、及びそれに用いるＮｉ基合金線
DE102007025758A1 (de) * 2007-06-01 2008-12-04 Mahle International Gmbh Dichtring
JP5082112B2 (ja) * 2008-02-07 2012-11-28 日本冶金工業株式会社 常温での強度と加工性およびクリープ特性に優れるＮｉ基合金材料とその製造方法
JP5232492B2 (ja) * 2008-02-13 2013-07-10 株式会社日本製鋼所 偏析性に優れたＮｉ基超合金

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4764225A (en) * 1979-05-29 1988-08-16 Howmet Corporation Alloys for high temperature applications
JPH0776721A (ja) * 1993-09-10 1995-03-20 Nidatsuku Kk 耐熱鋳造合金の熱処理方法
DE19525983A1 (de) * 1994-07-19 1996-02-01 Hitachi Metals Ltd Hochhitzebeständige Nickelbasislegierung und Verfahren zu ihrer Herstellung
JP2000169924A (ja) 1998-12-04 2000-06-20 Hitachi Metals Ltd Ｎｉ基超耐熱鋳造合金およびＮｉ基超耐熱合金製タービンホイール鋳物
WO2001053551A1 (en) * 2000-01-24 2001-07-26 Inco Alloys International, Inc. High temperature thermal processing alloy
JP2006022343A (ja) 2004-07-06 2006-01-26 Hitachi Ltd 耐熱鋼とそれを用いた蒸気タービン用ロータシャフト及び蒸気タービン並びに蒸気タービン発電プラント
JP2006118016A (ja) 2004-10-25 2006-05-11 Hitachi Ltd Ｎｉ−Ｆｅ基超合金とその製造法及びガスタービン
WO2006067189A1 (en) * 2004-12-23 2006-06-29 Siemens Aktiengesellschaft A ni based alloy, a component, a gas turbine arrangement and use of pd in connection with such an alloy
JP2007092123A (ja) 2005-09-29 2007-04-12 Hitachi Ltd 高強度耐熱鋳鋼とその製造方法及びそれを用いた用途

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2730670A1 (de) * 2012-11-07 2014-05-14 Hitachi Ltd. Ni-basierte Gusslegierung und Dampfturbinengussteil damit
US9464343B2 (en) 2012-11-07 2016-10-11 Mitsubishi Hitachi Power Systems, Ltd. Ni-based casting alloy and steam turbine casting part using the same
EP2796578A1 (de) * 2013-04-23 2014-10-29 General Electric Company Gegossene Superlegierung auf Nickelbasis mit Eisen
US10266926B2 (en) 2013-04-23 2019-04-23 General Electric Company Cast nickel-base alloys including iron
US11001913B2 (en) 2013-04-23 2021-05-11 General Electric Company Cast nickel-base superalloy including iron

Also Published As

Publication number Publication date
US20110058977A1 (en) 2011-03-10
JP4982539B2 (ja) 2012-07-25
JP2011052303A (ja) 2011-03-17

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