US20090145527A1 - Method of introducing residual compressive stresses into a shaft - Google Patents

Method of introducing residual compressive stresses into a shaft Download PDF

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Publication number
US20090145527A1
US20090145527A1 US12/227,926 US22792607A US2009145527A1 US 20090145527 A1 US20090145527 A1 US 20090145527A1 US 22792607 A US22792607 A US 22792607A US 2009145527 A1 US2009145527 A1 US 2009145527A1
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US
United States
Prior art keywords
shaft
treatment
quenching
contour
tempering
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
US12/227,926
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English (en)
Inventor
Michael Brandle
Torsten-Ulf Kern
Christoph Richter
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Publication of US20090145527A1 publication Critical patent/US20090145527A1/en
Assigned to SIEMENS AKTIENGESELLSCHAFT reassignment SIEMENS AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: RICHTER, CHRISTOPH, BRAENDLE, MICHAEL, KERN, TORSTEN-ULF
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/28—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for plain shafts

Definitions

  • the invention relates to a method of introducing residual compressive stresses into shaft notches of a shaft which is configured as a stepped shaft having successive stages of a different diameter, wherein diameter transitions or notch regions are arranged between respectively adjacent stages.
  • Shafts of this type are known and are used, for example, in turbomachines, for example steam turbines, which have a low-pressure part and can therefore also be referred to as low-pressure shafts.
  • the shaft bears rotor blades which, together with associated guide vanes, form a blade cascade through which a flow medium, for example steam, flows.
  • the shaft consists of a base material which is tough at low temperatures; by way of example, 2-3.5-NiCrMoV steels are used for producing the low-pressure shaft.
  • the flow medium partly acts as a corrosive medium on the components of the turbomachine, for example on disks in disk rotors or on regions of the shaft, particularly of the shafts of low-pressure subturbines, which are close to the surface.
  • the influence of these corrosive media can considerably reduce the fatigue strength of the base material.
  • a reduction in the fatigue strength of the base material, for example of the shafts in low-pressure subturbines also disadvantageously reduces the service life of the shaft.
  • the invention is based on the object of improving a method of introducing residual compressive stresses into shaft notches of a shaft of the type mentioned in the introduction using simple means, to the effect that the resistance to component failure as a result of corrosion and dynamic loading is considerably improved.
  • the object is achieved by virtue of the fact that the diameter transitions or notch regions of the shaft are quenched in a controlled manner after a final tempering treatment, for example a hardening and tempering heat treatment, at tempering temperature and/or below the tempering temperature.
  • a final tempering treatment for example a hardening and tempering heat treatment
  • the shaft particularly the shaft notches thereof, is thereby protected against a reduction in fatigue strength as a result of, for example, wet steam.
  • a protective layer for example, a method of specifically increasing the residual compressive stresses in diameter transitions or notch regions is advantageously carried out according to the invention.
  • the diameter transitions or notch regions are specifically sprayed with a cooling liquid or a quenching medium for quenching purposes.
  • a cooling liquid or a quenching medium for quenching purposes.
  • the shaft as a whole is transferred into a dipping bath.
  • tempering treatment of the hardening and tempering it is also possible for the tempering treatment of the hardening and tempering to be followed by a separate heat treatment which has the sole aim of introducing residual compressive stresses.
  • this expedient in order to avoid influencing the mechanical properties achieved, this expediently involves selecting a temperature which is sufficiently different from the final heat-treatment temperature but which is still high enough to achieve the desired effect.
  • cooling liquid or quenching medium for quenching purposes; however, it is also possible to use air/water mixtures, suitable polymers or oil and emulsions as the cooling liquid or quenching medium.
  • the diameter transitions or the notch regions in a heat-treatment contour are produced with an allowance provided in relation to an ultimate final contour, wherein the heat-treatment contour is removed during the production of the ultimate final contour after the quenching.
  • the provided allowance means that sufficiently high residual compressive stresses are maintained in the shaft surface, specifically in the transition radii (diameter transitions or notch regions), with a defined action at depth.
  • the allowance has a magnitude of at most from 10 to 40 mm on final use in relation to the final contour of the shaft.
  • the heat-treatment contour of the diameter transitions or notch regions has a radius with a magnitude R of from 25 to 50 mm.
  • the radii (diameter transitions or notch regions) of the heat-treatment contour of the shaft are accordingly configured specifically with a defined dimension as a function of the residual compressive stresses and depth distribution required in the final contour.
  • the method according to the invention reduces the local stress load during shutdown and during operation of the shaft.
  • crack sensitivity is reduced at radii or diameter transitions, and this leads to an improved or increased service life of the shaft or of the component treated in accordance with the invention.
  • As a result of specifically setting residual compressive stresses of from ⁇ 100 to ⁇ 400 MPa at the shaft surface, particularly in the diameter transitions or transition radii as a result of the specific quenching of the shaft even relatively large defects which are close to the surface of the treated component or of the shaft may be admissible, and therefore the shaft as a whole can be produced at lower cost since stricter tolerances for defects which may arise from the production process no longer necessarily have to be maintained.
  • FIG. 1 shows a basic illustration of a shaft for a low-pressure part of a turbomachine or of a steam turbine.
  • FIG. 1 shows a detail of a shaft 1 which is configured as a stepped shaft having successive stages 2 of a different diameter D 1 to D 4 in relation to a mid-axis X, with four stages 2 being illustrated by way of example.
  • the exemplary shaft 1 illustrated is a component of a low-pressure part of a turbomachine, for example of a low-pressure subturbine of a steam turbine.
  • the shaft 1 is produced, for example, from a material which is tough at low temperatures; for example, 2-3.5-NiCrMoV steels are used for producing the low-pressure shaft.
  • the shafts it is of course also possible for the shafts to be produced from other materials or material combinations.
  • Diameter transitions 3 or notch regions are arranged between each two adjacent stages 2 .
  • the diameter transitions 3 are designed in relation to the mid-axis X to be slightly curved or convex with a radius R in the direction toward the mid-axis X.
  • said diameter transitions or the notch regions are quenched in a controlled manner as part of a heat treatment or after heating of the shaft.
  • the diameter transitions 3 or notch regions are preferably quenched in a controlled manner after a final tempering treatment at tempering temperature.
  • a subsequent, separate heating and quenching after the tempering as a separate process step is of course also possible.
  • a cooling liquid or a quenching medium is sprayed onto the diameter transitions 3 for the purpose of controlled quenching after the final tempering treatment at tempering temperature, and this is illustrated by means of the fan-shaped spray jets 4 .
  • any suitable medium preferably water
  • the shaft 1 can however also be dipped as a whole.
  • the shaft 1 is configured with a heat-treatment contour 6 .
  • a final contour dashed line 7 , illustrated in exaggerated fashion for illustration purposes
  • the allowance 8 of the shaft 1 in the heat-treatment contour 6 is therefore specifically increased for the hardening and tempering heat treatment (tempering treatment) by at most 10 to 40 mm, preferably in the respective shaft radius r or the respective diameter transition 3 , with respect to the final end contour 7 . This ensures that a possible distortion of the shaft 1 can still be compensated for after the quenching (spraying or dipping).
  • machining for example in the case of double tempering treatment.
  • the allowances can then be adapted or machining may also be effected when a separate heat treatment for producing residual (compressive) stresses is carried out after the tempering treatment from the hardening and tempering.
  • this maximum allowance 8 means that sufficiently high residual compressive stresses are maintained in the shaft surface and specifically in the transition radii or diameter transitions 3 , with a defined action at depth.
  • the radii R have a magnitude of R of approximately equal to 25 to 50 mm.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
US12/227,926 2006-06-06 2007-02-23 Method of introducing residual compressive stresses into a shaft Abandoned US20090145527A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP06011627A EP1865080A1 (de) 2006-06-06 2006-06-06 Verfahren zum Einbringen von Druckeigenspannungen in eine Welle, insbesondere in Wellenkerben
EP06011627.4 2006-06-06
PCT/EP2007/051744 WO2007141055A1 (de) 2006-06-06 2007-02-23 Verfahren zum einbringen von druckeigenspannungen in eine welle, insbesondere in wellenkerben

Publications (1)

Publication Number Publication Date
US20090145527A1 true US20090145527A1 (en) 2009-06-11

Family

ID=36950407

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/227,926 Abandoned US20090145527A1 (en) 2006-06-06 2007-02-23 Method of introducing residual compressive stresses into a shaft

Country Status (5)

Country Link
US (1) US20090145527A1 (sv)
EP (2) EP1865080A1 (sv)
JP (1) JP5377297B2 (sv)
CN (1) CN101460639B (sv)
WO (1) WO2007141055A1 (sv)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107955874B (zh) * 2017-11-22 2020-09-04 株洲市九洲传动机械设备有限公司 一种设有表面局部淬火过渡区的轴类零件及其机加工工艺

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3257865A (en) * 1962-04-19 1966-06-28 Deutsche Edelstahlwerke Ag Crankshafts
US4497612A (en) * 1983-11-25 1985-02-05 General Electric Company Steam turbine wheel antirotation means
US4879793A (en) * 1987-03-16 1989-11-14 Siemens Aktiengesellschaft Method of manufacturing turbine wheel disks with locally high internal compressive strains in the hub bore
US5906691A (en) * 1996-07-02 1999-05-25 The Timken Company Induction hardened microalloy steel having enhanced fatigue strength properties
US5911842A (en) * 1996-05-07 1999-06-15 Hitachi, Ltd. Heat resisting steel and steam turbine rotor shaft and method of making thereof
US6364974B1 (en) * 1999-04-20 2002-04-02 Iq Technologies, Inc. Quenching apparatus and method for hardening steel parts

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE795973A (fr) * 1972-03-02 1973-06-18 Maschf Augsburg Nuernberg Ag Procede de fabrication d'un vilebrequin et vilebrequin obtenu par ce procede
DE2226530B2 (de) * 1972-05-31 1977-09-22 Aeg-Elotherm Gmbh, 5630 Remscheid Verfahren zur induktionshaertung einer lagerlaufflaeche und des sich anschliessenden hohlkehlenbereichs einer kurbelwelle
JPS5846533B2 (ja) * 1979-03-28 1983-10-17 日本国有鉄道 軸ならびに切欠付機械部品の疲れ強度および曲げ強度を向上する熱処理方法
JPS5964716A (ja) * 1982-10-02 1984-04-12 High Frequency Heattreat Co Ltd 焼入装置
JPS59116321A (ja) * 1982-12-22 1984-07-05 Nippon Steel Corp レ−ルあご下の耐破壊性改善の熱処理方法
JPH02136052U (sv) * 1989-04-17 1990-11-13
JPH05148531A (ja) * 1991-11-25 1993-06-15 Toyota Motor Corp フランジ付ワーク用高周波焼入装置
JPH08120347A (ja) * 1994-10-24 1996-05-14 Matsui Seisakusho:Kk 駆動軸の製造方法
JP2000087135A (ja) * 1998-09-09 2000-03-28 High Frequency Heattreat Co Ltd 足付軸部材の誘導加熱焼入装置
JP3676972B2 (ja) * 2000-12-06 2005-07-27 電気興業株式会社 クランクシャフトの高周波焼入冷却方法とその装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3257865A (en) * 1962-04-19 1966-06-28 Deutsche Edelstahlwerke Ag Crankshafts
US4497612A (en) * 1983-11-25 1985-02-05 General Electric Company Steam turbine wheel antirotation means
US4879793A (en) * 1987-03-16 1989-11-14 Siemens Aktiengesellschaft Method of manufacturing turbine wheel disks with locally high internal compressive strains in the hub bore
US5911842A (en) * 1996-05-07 1999-06-15 Hitachi, Ltd. Heat resisting steel and steam turbine rotor shaft and method of making thereof
US5906691A (en) * 1996-07-02 1999-05-25 The Timken Company Induction hardened microalloy steel having enhanced fatigue strength properties
US6364974B1 (en) * 1999-04-20 2002-04-02 Iq Technologies, Inc. Quenching apparatus and method for hardening steel parts

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
NPL-2: Heat Treater's guide: Practices and Procedures for irons and steels pp. 96-110, 1995 *

Also Published As

Publication number Publication date
CN101460639A (zh) 2009-06-17
WO2007141055A1 (de) 2007-12-13
JP2009540114A (ja) 2009-11-19
EP1865080A1 (de) 2007-12-12
EP2027299A1 (de) 2009-02-25
CN101460639B (zh) 2012-10-10
JP5377297B2 (ja) 2013-12-25

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AS Assignment

Owner name: SIEMENS AKTIENGESELLSCHAFT, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BRAENDLE, MICHAEL;KERN, TORSTEN-ULF;RICHTER, CHRISTOPH;SIGNING DATES FROM 20081020 TO 20090317;REEL/FRAME:027605/0587

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION