US20110076153A1 - Steam turbine rotor and steam turbine using the same - Google Patents

Steam turbine rotor and steam turbine using the same Download PDF

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Publication number
US20110076153A1
US20110076153A1 US12/862,954 US86295410A US2011076153A1 US 20110076153 A1 US20110076153 A1 US 20110076153A1 US 86295410 A US86295410 A US 86295410A US 2011076153 A1 US2011076153 A1 US 2011076153A1
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US
United States
Prior art keywords
steam turbine
forging material
turbine rotor
temperature
rotor
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.)
Abandoned
Application number
US12/862,954
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English (en)
Inventor
Shinya Imano
Hiroyuki Doi
Jun Sato
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Assigned to HITACHI, LTD. reassignment HITACHI, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DOI, HIROYUKI, SATO, JUN, IMANO, SHINYA
Publication of US20110076153A1 publication Critical patent/US20110076153A1/en
Abandoned legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K31/00—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups
    • B23K31/02—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups relating to soldering or welding
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/02—Blade-carrying members, e.g. rotors
    • F01D5/06—Rotors for more than one axial stage, e.g. of drum or multiple disc type; Details thereof, e.g. shafts, shaft connections
    • F01D5/063—Welded rotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/02—Blade-carrying members, e.g. rotors
    • F01D5/06—Rotors for more than one axial stage, e.g. of drum or multiple disc type; Details thereof, e.g. shafts, shaft connections
    • F01D5/066—Connecting means for joining rotor-discs or rotor-elements together, e.g. by a central bolt, by clamps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/001—Turbines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/18—Dissimilar materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/18—Dissimilar materials
    • B23K2103/26—Alloys of Nickel and Cobalt and Chromium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F05C2201/0466—Nickel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/10—Metals, alloys or intermetallic compounds
    • F05D2300/13—Refractory metals, i.e. Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W
    • F05D2300/132—Chromium

Definitions

  • the present invention relates to a steam turbine rotor and a steam turbine using the same.
  • a rise of the main steam temperature is valid.
  • the temperature of a high-temperature part increases, so that a heat resistant material of a higher resistant temperature is necessary.
  • the Ni group super-alloy is excellent in the high-temperature intensity, and even a forging material withstands steam at 700° C. or higher, though a problem arises that the productivity of a large forged material is low.
  • the steam turbine rotor is generally often more than 10 tons in weight, though the Ni group super-alloy, even in a type of steel excellent in productivity, under the restriction of the equipment, has a weight limit of about 10 tons.
  • the temperature on the entrance side is close to the main steam temperature and in a steam turbine of the 700° C. class, it is 700° C.
  • the temperature goes down as approaching the exit side and the temperature at the exit portion is 400° C. or lower.
  • the back waves internally remaining cannot be removed, thus a problem arises that a state occurs where an internal defect remains. Further, the Ni group super-alloy is bad in the ultrasonic wave permeability and in a welding metal composed of coarse particles, the ultrasonic wave permeability is deteriorated even more.
  • a welding metal of the Ni group super-alloy is generally used, so that in the aforementioned weld type rotor, the internal defect detection limit is lowered, thus causing a staying of the back waves and a reduction in reliability.
  • a rotor of the joint structure with a bolt is well-known, though strong tension is applied to the bolt portion, so that if the bolt portion rises in temperature, the bolt is subject to creep deformation and is loosened, so a bolt joint portion having a temperature limit and insurance reliability at 500° C. or higher is difficult.
  • An object of the present invention is to provide a steam turbine rotor and a steam turbine that are highly reliable.
  • the solving means is as indicated below.
  • a forged material A of a Ni group super-alloy at a resistant temperature of 700° C. or higher a forged material B having a hollow structure is joined by welding, and then the weld back waves on the inner surface are removed by machining to smooth the inner surface, and a forged material C and the forged material B are joined with a bolt.
  • an ultrasonic inspection is executed from the inner surface where the back waves are removed, thus a minute defect that cannot be detected externally can be detected, and in addition to the effect of the removal of the back waves, the reliability can be improved.
  • the forged material A is a Ni group super-alloy at a resistant temperature of 700° C. or higher, though it may be a NiFe group super-alloy including Fe.
  • the forged material B from the viewpoint of cost, when the temperature of the welded portion is 600° C. or lower, is preferably ferrite steel, though if a Ni group super-alloy is used for the forged material B, even when the temperature of the welded portion is high, the reliability can be ensured.
  • the forged material C may be inexpensive ferrite steel that can be used at 500° C. at its maximum, though the use of CrMo V steel that is resistant to abrasion with a bearing is valid. When using 12-Cr steel as a forging material, at the shaft portion in contact with the bearing, CrMo V steel must be built up.
  • the reliability can be improved by the inspection at the time of manufacture, though by removing the bolt at the time of the periodic inspection, the inner surface of the welded portion can be re-inspected, and the inspection at the time of the periodic inspection is executed, thus long term reliability can be ensured even further.
  • the back waves on the inner surface as a starting point of cracking can be smoothed by machining and the welded portion can be subject to X-ray inspection and ultrasonic inspection from the inner surface.
  • the bolt joint portion can be reduced to 500° C. or lower by adjusting the length of the forging material B. By doing this, a rotor having high reliability can be provided. Further, the welded portion is decomposed at the time of the periodic inspection and the inner surface of the welded portion can be inspected and repaired.
  • a steam turbine rotor and a steam turbine that are highly reliable can be realized.
  • FIG. 1 is a configuration example of the steam turbine plant that is an embodiment of the present invention
  • FIG. 2-1 is a diagram showing an example of the constitution of the steam turbine rotor that is a comparison example
  • FIG. 2-2 is a diagram showing another example of the constitution of the steam turbine rotor that is a comparison example
  • FIG. 2-3 is a diagram showing still another example of the constitution of the steam turbine rotor that is a comparison example
  • FIG. 2-4 is a configuration example showing a further example of the constitution of the steam turbine rotor as a comparison example of the steam turbine rotor applied to the steam turbine (the back waves remaining internally after the forging material A and forging material B are welded are not removed) and the constitution of the steam turbine rotor as an embodiment of the present invention (the back waves remaining internally after the forging material A and forging material B are welded are removed), and
  • FIG. 3 is a graph showing the steam temperature at which the steam turbine rotor is exposed.
  • Table 1 shows the chemical components of the forging materials of the steam turbine rotor of the present invention that are used in the embodiment.
  • FIG. 1 shows a configuration example of the steam turbine plant to which the steam turbine rotor that is an embodiment of the present invention is applied.
  • the main steam temperature is 700° C. and the main steam works in the high-pressure turbine (HP) and then is reduced in temperature to about 400° C. However, the steam is returned again to the boiler, is re-heated up to 720° C., and becomes reheat steam.
  • HP high-pressure turbine
  • the pressure of the reheat steam is lower than that of the main steam, so that the burden imposed on the pressure resistant member of the steam turbine is almost the same as that imposed on the main steam side lower in temperature by 20° C.
  • the reheat steam enters the intermediate-pressure turbine, works there, then is lowered in temperature to about 400° C., works in the low-pressure turbine, then is lowered in temperature to room temperature, and enters the steam condenser.
  • the steam turbine rotor to which the present invention is applied with fixed blades working upon receipt of steam is a shaft for driving the generator and a member exposed in a severest environment in the turbine.
  • the present invention can be applied to the rotors of the high-pressure turbine and intermediate-pressure turbine, though hereinafter, an inspection example when the present invention is applied to the high-pressure turbine rotor will be indicated.
  • FIGS. 2-1 to 2 - 4 show the characteristics of the steam turbine rotors given in Table 2.
  • Comparison 1 uses a conventional weld type rotor and the characteristics thereof are shown in FIG. 2-1 as an example of the steam turbine rotor of the comparison example.
  • the inside of the rotor is closed, so that the removal of the back waves and the ultrasonic inspection from the inside are impossible.
  • the welded portion of a supper-alloy is bad in the ultrasonic wave permeability, so that it is difficult to detect weld defects on the inner surface from the outside. Further, the back waves remain, so that there are possibilities that this portion may be a starting point of cracking and it is difficult to obtain high reliability.
  • Comparison 2 is another example of the steam turbine rotor of the comparison example having the characteristics shown in FIG. 2-2 .
  • the forging material B has a center hole formed, so that the inner surface of the welded portion can be observed through the center hole, thus if there is a remarkable defect, it can be detected, though it is difficult to execute the inspection using ultrasonic waves and remove the back waves.
  • Comparison 3 is still another example of the steam turbine rotor of the comparison example having the characteristics shown in FIG. 2-3 .
  • a ferrite steel ring which is the same material as that of the forging material B is welded with a welding metal of the Ni group alloy and then the ferrite steel ring and the forging material B of ferrite steel are welded with a welding metal of ferrite steel.
  • the welding metal of ferrite steel compared with the welding metal of a supper-alloy, has good ultrasonic wave permeability. Therefore, compared with Comparison 1 and Comparison 2, Comparison 3 is excellent in reliability, though the reliability of the ferrite steel welded portion where the back waves remain and the inspection from the inner surface cannot be executed cannot be ensured sufficiently. Further, after the forging material B is welded, the inspection of the inner surface is impossible, thus at the time of the periodic inspection, the inner surface cannot be inspected and the long term insurance of reliability becomes a problem.
  • Comparison 4 has the structure of the steam turbine rotor shown in FIG. 2-4 , which is a structure that the forging material C is directly joined to the forging material A with a bolt, though after welding of the forging material A and forging material B, the back waves remaining internally may not be removed.
  • FIG. 3 shows graphs indicating the steam temperature at which the steam turbine rotor is exposed and the cumulative weight, that is, the change in the steam temperature from the exit of the rotor to the entrance thereof and the cumulative weight from the entrance to the exit.
  • the rotor diameter is 700 mm ⁇ , so that the cumulative weight from the entrance to the exit is about 10 tons.
  • FX700 a forging material of the 10-ton class can be manufactured, so that the interval from the entrance to the exit can be manufactured by a monoblock. At both ends of the entrance and exit, the temperature is low, so that the shaft can be joined with a bolt.
  • the rotor diameter becomes 800 mm ⁇
  • the ratio of “distance from steam exit/gas path length” becomes 0.4 or less
  • the cumulative weight exceeds 10 tons, so that the entrance side from this portion must be joined to another forging material.
  • the steam temperature exceeds 500° C., so that the reliability of the bolt joint is low and joint by welding is necessary.
  • Invention 1 is an embodiment of the present invention and has the characteristic of the steam turbine rotor which is an embodiment of the present invention shown in FIG. 2-4 , so that after welding of the forging material A and forging material B, the back waves remaining internally are removed.
  • the rotor diameter is 800 mm and the forging material A is A263.
  • A263 is higher in intensity than FX700, thereby is suitable for welding with ferrite, though a forged material up to about 7 tons is a manufacturing limit, so that the portion at a steam temperature of 550° C. is joined to the forging material B by welding.
  • the forging material B is 12-Cr steel (FE02).
  • the interval from the portion at 550° C. to the exit portion is composed of the forging material B and the portion at 400° C. or lower is joined to the forging material C (FE01) with a bolt.
  • the back waves are removed and the ultrasonic inspection is executed from both the inner surface and outer surface.
  • the forging material C is joined to the forging material B with a bolt, though even at the time of periodic inspection after use of the equipment, by removing the bolt, the inner surface can be inspected and repaired.
  • Invention 2 having a rotor diameter of 1000 mm, by use of FX700 capable of manufacturing a larger one, can structure a rotor similarly to Invention 1.
  • In Invention 3 having a rotor diameter of 1200 mm, under the restriction (10 tons) of the forging weight of the forging material A, the temperature at the welded portion becomes 600° C. or higher.
  • the forging material B is set to ferrite steel, the reliability of the welded portion cannot be obtained, so that the forging material B is set to A141 which is a Ni group super-alloy.
  • A141 since the coefficient of linear expansion is closer to ferrite steel than FX700, is suitable for bolt joint to ferrite steel.
  • the forging material C is joined to the forging material B with a bolt, though A141 can manufacture a forging material of the 10-ton class and the temperature at the bolt-joined portion can be lowered to 500° C.
  • Invention 4 having a rotor diameter of 700 mm similarly to Comparison 4, can structure a rotor only by bolt joint, though the portion of the forging material A at 600° C. or lower is made of the forging material B of ferrite steel, thus the quantity of the Ni group super-alloy can be reduced, and the cost can be decreased.
  • a steam turbine rotor and a steam turbine that are highly reliable can be realized.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Arc Welding In General (AREA)
  • Butt Welding And Welding Of Specific Article (AREA)
US12/862,954 2009-09-28 2010-08-25 Steam turbine rotor and steam turbine using the same Abandoned US20110076153A1 (en)

Applications Claiming Priority (2)

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JP2009221814A JP2011069307A (ja) 2009-09-28 2009-09-28 蒸気タービンロータ、それを用いた蒸気タービン
JP2009-221814 2009-09-28

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140153693A1 (en) * 2012-12-05 2014-06-05 Mitsubishi Heavy Industries, Ltd. Inspection method for welded joint

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2637521A (en) * 1949-03-01 1953-05-05 Elliott Co Gas turbine rotor and method of welding rotor disks together
US4581816A (en) * 1984-04-27 1986-04-15 General Electric Company Method and apparatus for welding turbine rotor shafts
US6152697A (en) * 1998-06-09 2000-11-28 Mitsubishi Heavy Industries, Ltd. Steam turbine different material welded rotor
US6499946B1 (en) * 1999-10-21 2002-12-31 Kabushiki Kaisha Toshiba Steam turbine rotor and manufacturing method thereof
US6749518B2 (en) * 2002-04-08 2004-06-15 General Electric Company Inertia welded shaft and method therefor
US20070253812A1 (en) * 2006-04-26 2007-11-01 Kabushiki Kaisha Toshiba Steam turbine and turbine rotor
US20080166222A1 (en) * 2006-12-15 2008-07-10 Kabushiki Kaisha Toshiba Turbine rotor and steam turbine
US8128341B2 (en) * 2005-10-31 2012-03-06 Siemens Aktiengesellschaft Steam turbine

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JPH0371244U (fr) * 1989-11-15 1991-07-18
JPH05141202A (ja) * 1991-11-20 1993-06-08 Fuji Electric Co Ltd 蒸気タービンロータ
JP2837110B2 (ja) * 1995-04-18 1998-12-14 三菱重工業株式会社 急速起動用蒸気タービンロータ
EP1378629B2 (fr) * 2002-07-01 2017-08-30 General Electric Technology GmbH Rotor de moteur thermique rotatif, ainsi que procédé de fabrication d'un tel rotor
DE10348424A1 (de) * 2003-10-14 2005-05-19 Alstom Technology Ltd Geschweisster Rotor für eine thermische Maschine sowie Verfahren zur Herstellung eines solchen Rotors
JP2005344527A (ja) * 2004-05-31 2005-12-15 Toshiba Corp 蒸気タービンロータおよびその製造方法
JP4805728B2 (ja) * 2006-05-31 2011-11-02 株式会社東芝 蒸気タービンロータ及び蒸気タービン
JP4520481B2 (ja) * 2007-04-13 2010-08-04 株式会社日立製作所 高温蒸気タービンプラント
JP2009103097A (ja) * 2007-10-25 2009-05-14 Mitsubishi Heavy Ind Ltd ガスタービン、及びガスタービン用ロータ
JP4951488B2 (ja) * 2007-12-17 2012-06-13 株式会社日立製作所 蒸気タービンロータ及びその製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2637521A (en) * 1949-03-01 1953-05-05 Elliott Co Gas turbine rotor and method of welding rotor disks together
US4581816A (en) * 1984-04-27 1986-04-15 General Electric Company Method and apparatus for welding turbine rotor shafts
US6152697A (en) * 1998-06-09 2000-11-28 Mitsubishi Heavy Industries, Ltd. Steam turbine different material welded rotor
US6499946B1 (en) * 1999-10-21 2002-12-31 Kabushiki Kaisha Toshiba Steam turbine rotor and manufacturing method thereof
US6749518B2 (en) * 2002-04-08 2004-06-15 General Electric Company Inertia welded shaft and method therefor
US8128341B2 (en) * 2005-10-31 2012-03-06 Siemens Aktiengesellschaft Steam turbine
US20070253812A1 (en) * 2006-04-26 2007-11-01 Kabushiki Kaisha Toshiba Steam turbine and turbine rotor
US20080166222A1 (en) * 2006-12-15 2008-07-10 Kabushiki Kaisha Toshiba Turbine rotor and steam turbine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140153693A1 (en) * 2012-12-05 2014-06-05 Mitsubishi Heavy Industries, Ltd. Inspection method for welded joint
US9194820B2 (en) * 2012-12-05 2015-11-24 Mitsubishi Hitachi Power Systems, Ltd. Method for manufacturing a turbine rotor

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JP2011069307A (ja) 2011-04-07
EP2305952A3 (fr) 2012-01-18
EP2305952A2 (fr) 2011-04-06

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