JPS61112702A - Method of forming coating layer on steam turbine rotor - Google Patents
Method of forming coating layer on steam turbine rotorInfo
- Publication number
- JPS61112702A JPS61112702A JP59233454A JP23345484A JPS61112702A JP S61112702 A JPS61112702 A JP S61112702A JP 59233454 A JP59233454 A JP 59233454A JP 23345484 A JP23345484 A JP 23345484A JP S61112702 A JPS61112702 A JP S61112702A
- Authority
- JP
- Japan
- Prior art keywords
- coating layer
- rotor
- turbine rotor
- steam turbine
- alloy steel
- 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.)
- Pending
Links
Classifications
-
- 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
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/007—Preventing corrosion
Abstract
Description
【発明の詳細な説明】
〔発明の属する技術分野〕
本発明は蒸気タービンロータに低合金被覆層を形成する
方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method of forming a low alloy coating layer on a steam turbine rotor.
近年蒸気タービンの高効率化１大容量化に伴って、より
高温、高応力に耐えるタービンが設計され、そのためタ
ービンロータの素材も高圧タービン、中圧タービンにお
いてはクロム１モリブデン・バナジウム鋼のような低合
金鋼から１２％クロム鋼のような高合金鋼への材料変更
が必要となっている。In recent years, as steam turbines have become more efficient and larger in capacity, turbines that can withstand higher temperatures and higher stress have been designed, and for this reason, the materials for turbine rotors have changed to chromium-molybdenum-vanadium steel for high-pressure turbines and intermediate-pressure turbines. There is a need to change materials from low alloy steel to high alloy steel such as 12% chromium steel.
しかしながら１２％クロム鋼をロータ材として使用する
場合、１２チクロム鋼の熱伝導率が低いことや、表面に
生成されたクロム炭化物などが原因で、軸受メタルと接
触する軸受ジャーナル部などにおいて焼付き、かじりな
どが発生するという問題が生ずる。However, when using 12% chromium steel as a rotor material, the low thermal conductivity of 12% chromium steel and the chromium carbide formed on the surface cause seizures in the bearing journal, etc. that come into contact with the bearing metal. A problem arises in that galling occurs.
この問題を解決するために従来焼付き、かじりなどを発
生する部分のロータ材表面に被覆層を形成してこれらの
欠陥を防止する手段がとられている。第１図は要部のみ
を断面で示したロータ材の外観図であって、例えば軸受
ジャーナル部のロータ材基部１の表面に低合金鋼からな
る被覆層２を形成しである。このような被覆層を設ける
ために従来上として次の三つの方法が用いられている。In order to solve this problem, conventional methods have been taken to prevent these defects by forming a coating layer on the surface of the rotor material in areas where seizure, galling, etc. occur. FIG. 1 is an external view of a rotor material showing only the main parts in cross section. For example, a coating layer 2 made of low alloy steel is formed on the surface of a rotor material base 1 of a bearing journal portion. Conventionally, the following three methods have been used to provide such a coating layer.
１）低合金鋼でつくられたスリーブを嵌め込む。1) Insert a sleeve made of low alloy steel.
２）低合金鋼を用いてオーツ（レイ溶接を施こす。2) Perform oat (lay welding) using low alloy steel.
３）低合金鋼を溶射する。3) Spray low alloy steel.
しかし、これらの方法にもそれぞれ欠点があり、スリー
ブを一体として所定の位置に嵌め込むためにはロータ軸
端のカップリング７ランジ部３に妨げられるのでロータ
材とカップリングフランジ部３を一体構造とすることが
できなくなり、したがってカップリング７ランジ部３も
嵌め込みとしなければならず、このようなロータの構造
は強度。However, each of these methods has its drawbacks, and the flange portion 3 of the coupling 7 at the end of the rotor shaft prevents the sleeve from fitting into the specified position as one piece. Therefore, the flange portion 3 of the coupling 7 must also be fitted, and such a rotor structure requires strength.
耐撮動性などの点で信頼性を損うものでおる。オーバレ
イ溶接は溶接および熱処理に高度の技術と多くの時間を
要するので、他の方法に比べて経済的に不利である。金
属溶射法は形成された被覆層２とロータ材基部１との接
着強度および被覆層２自体の強度が比較的小さいために
、使用条件の荷酷な大型のロータに適用するには必ずし
も十分ではない。This impairs reliability in terms of photographic resistance, etc. Overlay welding requires advanced technology and a lot of time for welding and heat treatment, so it is economically disadvantageous compared to other methods. Since the metal spraying method has relatively low adhesive strength between the formed coating layer 2 and the rotor material base 1 and the strength of the coating layer 2 itself, it is not necessarily sufficient to be applied to large rotors with severe usage conditions. do not have.
このような状況においてこれら三つの方法の中で欠点の
解決が最も期待できるのは金属溶射法である。Under these circumstances, among these three methods, the metal spraying method is the most promising for solving the drawbacks.
本発明←台→は上述の点に鑑みてなされたものであり、
その目的は金属溶射法による問題点を解決し、ロータの
使用上十分な強度と密着性をもったロータ材への被覆層
を形成する方法を提供することにある。The present invention has been made in view of the above points,
The purpose is to solve the problems caused by the metal spraying method and to provide a method for forming a coating layer on the rotor material that has sufficient strength and adhesion for the use of the rotor.
本発明は爆発溶射法を用いて低合金鋼の被覆層を形成し
ロータ材基部との接着強度および被覆層自体の強度を高
め、しかも被覆層の厚さを少なくとも５００μｍとして
５５０〜６００℃に焼鈍して被覆層の残留応力を解放す
ることにより外力に対する抵抗力を増大したものである
。The present invention uses an explosive thermal spraying method to form a coating layer of low alloy steel to increase the adhesive strength with the base of the rotor material and the strength of the coating layer itself, and furthermore, the coating layer is annealed at 550 to 600°C with a thickness of at least 500 μm. This increases resistance to external forces by releasing residual stress in the coating layer.
以下本発明を実施例に基づき説明する。 The present invention will be explained below based on examples.
先づロータ材の被覆層を形成すべき部分を十分に脱脂洗
浄した後ホーニングを施し、この部分を粗面化し活性化
させる。次にこの面に炭素０．２〜０．３％、クロム１
．０−１．５ ％を含有する鋼の粉末を溶射材として爆
発溶射を行なう。爆発溶射法はアセチレンと酸素の混合
ガスによって生ずる高速燃焼エネルギーを利用して粉末
材料をコーティングする方法であって、特殊な溶射ガン
内で混合ガスが爆発した瞬間、溶射ガン内の温度は３，
３００℃以上となり、音速の約１０倍の衝撃波を発生し
、溶射ガン内に供給されている溶射材がこの爆発により
溶融状態になり音速の２倍の速さで素材に衝突し素材表
面に強固な溶射皮膜を形成するものであり、爆発溶射に
より形成される被覆層の嵌着強度および被覆層自体の強
度は溶射時の溶射材の飛翔速度の大きい程強くなる。こ
の溶射材の飛翔速度は爆発溶射では通常のガス溶射の５
〜１０倍、プラズマアーク溶射に比べても２．５〜５倍
の速度をもっている。First, the portion of the rotor material where the coating layer is to be formed is thoroughly degreased and cleaned, and then honed to roughen and activate this portion. Next, apply 0.2 to 0.3% carbon and 1 chromium to this surface.
．． Explosive spraying is carried out using steel powder containing 0-1.5% as the spraying material. Explosive thermal spraying is a method of coating powder materials using high-speed combustion energy generated by a mixed gas of acetylene and oxygen.At the moment the mixed gas explodes in a special thermal spray gun, the temperature inside the thermal spray gun reaches 3.
The temperature exceeds 300℃, generating a shock wave approximately 10 times faster than the speed of sound, and the thermal spray material being supplied into the spray gun becomes molten due to this explosion, colliding with the material at twice the speed of sound and solidifying it to the surface of the material. The fitting strength of the coating layer formed by explosive thermal spraying and the strength of the coating layer itself become stronger as the flying speed of the thermal spray material during thermal spraying increases. The flying speed of this thermal spraying material is 5 times faster than that of normal gas spraying in explosive thermal spraying.
It is ~10 times faster, and 2.5 to 5 times faster than plasma arc spraying.
爆発溶射法は通常耐摩耗性の賦与、改善のために用いら
れ、したがって溶射材もその目的に応じて金属酸化物例
えばＡ’ｌ ２０５や金属炭化物、例えば０ｒ５Ｇ２な
どが主体となっているが本発明では軸受部などの焼付き
やかじりを防ぐためであるから前述のように低合金鋼を
用いるのがよく、この点通常の爆発溶射とは目的、材料
が異なる。Explosive thermal spraying is usually used to impart or improve wear resistance, and therefore thermal spraying materials are mainly made of metal oxides, such as A'l 205, or metal carbides, such as 0r5G2, depending on the purpose. In the invention, since the purpose is to prevent seizure or galling of bearing parts, it is preferable to use low-alloy steel as mentioned above, and in this respect, the purpose and material are different from ordinary explosive thermal spraying.
ロータ材への爆発溶射はロータ材を回転させ、溶射ガン
をロータ材の軸方向に移動させながら、被覆層を形成す
べき領域に順次溶射することにより行なう。この際溶射
ガンの１回の爆発によって形成されるコーティング被膜
の厚さは数μｍ程度であるから、爆発を繰り返すことに
より、この数μｍの被膜を積層させ、最終的に必要な被
覆層の厚さとすることができる。かくして得られた被覆
層は他の溶射法では得られない高硬度、高接着強度。Explosive thermal spraying on the rotor material is carried out by rotating the rotor material and moving a thermal spray gun in the axial direction of the rotor material, while sequentially spraying the areas where the coating layer is to be formed. At this time, the thickness of the coating film formed by one explosion of the thermal spray gun is about several micrometers, so by repeating the explosion, the coating film of several micrometers is laminated, and the final thickness of the coating layer is required. It can be done. The coating layer thus obtained has high hardness and adhesive strength that cannot be obtained with other thermal spraying methods.
高密度をもつようになるが、爆発溶射法では被覆層の厚
さとともに増加する被覆層内の残留応力によって、被覆
層の外力に対する抵抗力が減少し被覆層が見掛は上膜化
するため、一般に被覆層は実用土の最大厚さとして２５
０μｍ付近に止めておくのが普通である。この残留応力
は主として溶射材の粒子が素材に高速で衝突して喰い込
む結果楔作用によって発生する圧縮応力である。However, in the explosive thermal spraying method, the resistance to external forces of the coating layer decreases due to residual stress within the coating layer, which increases with the thickness of the coating layer, and the coating layer appears to become a top layer. Generally, the maximum thickness of the covering layer is 25 mm for practical soil.
It is normal to keep it around 0 μm. This residual stress is mainly compressive stress generated by the wedge action resulting from particles of the thermal spray material colliding with the material at high speed and biting into it.
しかしながら本発明においては大型のロータに対処せね
ばならぬから、被覆層の厚さを２５０μｍ程度に止める
ことなく少くとも５００μｍとする必要がある。この際
発生する残留応力は、溶射終了後、被覆層またはロータ
材基部を含む被覆層をロータ材の焼戻し温度を越えない
範囲５５０〜６００℃に加熱し焼鈍することにより解放
されるので、被覆層の厚さを少くとも５００μｍ以上と
することは可能であり、この焼鈍の結果被覆層の外力に
対する抵抗性を増すことができる。However, in the present invention, since it is necessary to deal with a large rotor, it is necessary to make the thickness of the coating layer not limited to about 250 μm but at least 500 μm. The residual stress generated at this time is released by annealing the coating layer or the coating layer including the base of the rotor material by heating it to a temperature of 550 to 600℃ that does not exceed the tempering temperature of the rotor material after the thermal spraying is completed. It is possible to increase the thickness of the coating layer to at least 500 μm or more, and as a result of this annealing, the resistance of the coating layer to external forces can be increased.
このような焼鈍による残留応力除去効果は通常の高温に
おける材料の降伏による焼鈍効果゛に加え−て、本発明
の場合はロータ材基部の１２％クロム鋼の方が溶射材の
低合金鋼に比べて熱膨張係数が小さいために、焼鈍後の
冷却時に発生する被覆層の引張り残留応力が、被覆層を
形成する際に生じてここに残留していた圧縮応力の一部
を相殺する効果に基づくものである。This residual stress removal effect by annealing is in addition to the normal annealing effect due to material yield at high temperatures. Because the thermal expansion coefficient is small, the tensile residual stress in the coating layer that occurs during cooling after annealing cancels out a portion of the compressive stress that was generated when forming the coating layer and remained there. It is something.
このように本発明では通常行なわれている金属酸化物や
金属炭化物を鼎射材とする耐摩耗性の被覆層を形成する
爆発溶射ではみられない５００μｍ以上の厚さをもった
被覆層を設けることができるが、その厚さの上限はロー
タ材の使用条件を堪案して実状に最も好ましい厚さとす
ればよく、爆発溶射による被膜の積層を繰り返し行なう
ことによって得られる。得られた被覆層は焼鈍冷却後最
終仕上げ寸法に加工する。In this way, in the present invention, a coating layer with a thickness of 500 μm or more is provided, which is not seen in the conventional explosive thermal spraying that forms a wear-resistant coating layer using metal oxide or metal carbide as a spraying material. However, the upper limit of the thickness may be set to the most preferable thickness considering the usage conditions of the rotor material, and can be obtained by repeatedly laminating coatings by explosive spraying. The obtained coating layer is annealed and cooled, and then processed to the final finished dimensions.
以上実施例で説明したように、蒸気タービンの大型化を
指向して用いられる１２チクロム鋼からなるロータ材の
軸受ジャーナル部などに生ずる焼付きやかじりを防ぐた
めに、本発明によれば該当する部分のロータ材表面に、
低合金鋼を溶射材とし高エネルギーで溶射材の飛翔速度
の極めて速い爆発溶射法を用いて、通常の爆発溶射では
みられない５００μｍ以上の厚ぢをもった被覆層を形成
することにより、接着強度および被覆層自体の強度を高
めるとともに、被覆層に生ずる残留応力をロータ基材と
溶射材との材料特性を巧みに利用した焼鈍を施すことに
より除去し、被覆層の脆化をなくしているので、本発明
は使用条件の荷酷な大型ロータに適用して大きな効果を
もたらすものである。As explained above in the embodiments, in order to prevent seizure and galling that occur in the bearing journal portion of the rotor material made of 12 chromium steel used for the purpose of increasing the size of steam turbines, the present invention provides the relevant portions. on the rotor material surface of
Adhesion is achieved by using explosive thermal spraying, which uses low-alloy steel as a thermal spraying material and uses high energy and an extremely high flying speed of the thermal spraying material, to form a coating layer with a thickness of 500 μm or more, which cannot be seen with normal explosive thermal spraying. In addition to increasing the strength and the strength of the coating layer itself, the residual stress generated in the coating layer is removed by annealing that takes advantage of the material properties of the rotor base material and the thermal spray material, thereby eliminating embrittlement of the coating layer. Therefore, the present invention brings about great effects when applied to large rotors that are subjected to severe usage conditions.
【図面の簡単な説明】
第１図は要部のみを断面で示したロータ材の外観図であ
る。
１・・ロータ材基部、２・・・被覆層、３・・・カップ
リング７ランジ部。[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an external view of the rotor material showing only the main parts in cross section. DESCRIPTION OF SYMBOLS 1... Rotor material base, 2... Covering layer, 3... Coupling 7 lung part.
Claims (1)
る方法において、少なくとも５００μｍの厚さを有する
低合金鋼を爆発溶射した後、応力除去焼鈍を施すことを
特徴とする蒸気タービンロータの被覆層形成方法。 ２）特許請求の範囲第１項記載の方法において、ロータ
の素材は１２％クロム鋼を用いることを特徴とする蒸気
タービンロータの被覆層形成方法。 ３）特許請求の範囲第１項または第２項記載の方法にお
いて、低合金鋼は炭素０．２〜０．３％、クロム１．０
〜１．５％を含有するものを用いることを特徴とする蒸
気タービンロータの被覆層形成方法。 ４）特許請求の範囲第１項ないし第３項のいずれかに記
載の方法において、応力除去焼鈍の温度は５５０〜６０
０℃とすることを特徴とする蒸気タービンロータの被覆
層形成方法。[Claims] 1) A method for forming a coating layer on a predetermined surface of a steam turbine rotor, characterized in that low alloy steel having a thickness of at least 500 μm is explosively sprayed and then subjected to stress relief annealing. A method for forming a coating layer on a steam turbine rotor. 2) A method for forming a coating layer on a steam turbine rotor according to claim 1, wherein the rotor is made of 12% chromium steel. 3) In the method according to claim 1 or 2, the low alloy steel contains 0.2 to 0.3% carbon and 1.0% chromium.
1. A method for forming a coating layer for a steam turbine rotor, the method comprising using a coating layer containing 1.5% to 1.5%. 4) In the method according to any one of claims 1 to 3, the stress relief annealing temperature is 550 to 60°C.
A method for forming a coating layer on a steam turbine rotor, the method comprising: forming a coating layer at 0°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59233454A JPS61112702A (en) | 1984-11-06 | 1984-11-06 | Method of forming coating layer on steam turbine rotor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59233454A JPS61112702A (en) | 1984-11-06 | 1984-11-06 | Method of forming coating layer on steam turbine rotor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61112702A true JPS61112702A (en) | 1986-05-30 |
Family
ID=16955286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59233454A Pending JPS61112702A (en) | 1984-11-06 | 1984-11-06 | Method of forming coating layer on steam turbine rotor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61112702A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63149364A (en) * | 1986-12-12 | 1988-06-22 | Babcock Hitachi Kk | High-energy gas thermal spraying method |
| JPWO2006134831A1 (en) * | 2005-06-17 | 2009-01-08 | 株式会社日立製作所 | Rotor for steam turbine and manufacturing method thereof |
-
1984
- 1984-11-06 JP JP59233454A patent/JPS61112702A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63149364A (en) * | 1986-12-12 | 1988-06-22 | Babcock Hitachi Kk | High-energy gas thermal spraying method |
| JPWO2006134831A1 (en) * | 2005-06-17 | 2009-01-08 | 株式会社日立製作所 | Rotor for steam turbine and manufacturing method thereof |
| JP4584999B2 (en) * | 2005-06-17 | 2010-11-24 | 株式会社日立製作所 | Rotor for steam turbine and manufacturing method thereof |
| US8485788B2 (en) | 2005-06-17 | 2013-07-16 | Hitachi, Ltd. | Rotor for steam turbine and method of manufacturing the same |
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