JP3666315B2 - Method for manufacturing low-pressure steam turbine blades in a steam turbine power plant - Google Patents

Description

【００３７】
【表２】

【００３８】
表３は、衝風冷却による１／２ｔ部（冷却速度の最も遅い部分）の引張強さ及び衝撃吸収エネルギを示す。水冷材同様、目標強度を得るための時効温度と溶体化温度の関係を整理すると、溶体化処理時に衝風冷却した場合、前述のダブティル部と翼部とで強度差が小さくするには図２に示すハッチング部、すなわち、Ｅ(５２５℃，８５５℃），Ｆ(５１０℃，７９０℃），Ｇ(４１０℃，７９０℃)，Ｈ（４１０℃，８５５℃）の４点を結ぶ範囲での時効処理温度及び溶体化処理温度が好適である。
【００３９】
表３に示す様に、ダブティル部に相当する強度は翼部のそれに対して９６％以上の優れた強度が得られることが分る。
【００４０】
８００℃衝風冷却材の０.０２％ 耐力は１／４ｔ部で９３〜１０１kg／mm² ，１／２ｔ部で９３〜１００kg／mm²，０.２％耐力は１／４ｔ部で１０３〜１０６kg／mm² ，１／２ｔ部で９６〜１０７kg／mm² であり、伸び率はいずれも１５〜１７％，絞り率は１／４ｔ部で２２〜４３％，１／２ｔ部で４０〜５０％であった。Ｈｖ硬さは３３５〜３５６であった。
【００４１】
【表３】

【００４２】
一方、厚肉部の冷却速度を増加させる方法として、熱処理前にダブティルの粗加工、すなわちダブティルをフォーク型にした場合には各フォークに対応してスリットを加工しておく方法がある。この方法では、スリットの間隔が１／４ｔより小さく、５から１０個程度はいるため、前表面から冷却され、全体の冷却速度は加工前の状態の１／４ｔ部並み以上になる。したがって、表１の結果から、厚肉部と薄肉部での目標強度を得るための時効温度と溶体化温度の関係を整理すると、スリット加工後、溶体化，水冷する場合、図３に示すハッチング部、すなわち、Ｊ(６８５℃，８５５℃)，Ｋ(５８５℃，７９０℃)，Ｌ（４１０℃，７９０℃），Ｍ（４１０℃，８５５℃）の４点を結ぶ範囲の熱処理が可能となる。溶体化時衝風冷却の場合も同様で、表３の結果から、目標強度を得るための時効温度と溶体化温度の関係を整理すると、スリット加工後、溶体化，衝風冷却する場合、図４に示すハッチング部、すなわち、Ｎ（５７５℃，８５５℃），Ｏ（５６０℃，７９０℃），Ｐ（４１０℃，７９０℃），Ｑ（４１０℃，８５５℃）の４点を結ぶ範囲の熱処理が可能となる。
【００４３】
尚、ダブティルの形にはフォーク型，逆クリスマスツリー型，鞍型があり、いずれにも対応できる。
【００４４】
図５は１／２ｔと１／４ｔの引張強さの関係を示す線図である。図５に示すように、溶体化処理温度が８００℃及び８５０℃では溶体化処理温度における肉厚の影響による差が小さく、１／４ｔの厚さに対し１／２ｔの厚さでの強度が96.0％以上である。しかし、９００℃での溶体化処理では肉厚に対する影響を受け、９４.４％ 以下と強度が低下してしまうので好ましくない。
【００４５】
図６は翼部の厚さに相当する１／４ｔにおける衝撃吸収エネルギ（ｙ）と引張強さ（ｘ）との関係を示す線図である。下限の線はｙ＝−０.０２ｘ＋３.９８に相当し、上限の線はｙ＝−０.０２ｘ＋４.１２に相当し、本実施例におけるＴｉ基合金は翼部に相当する部分をこれらの線の範囲内とすることによって肉厚の差による影響の少ないブレードを得ることができる。
【００４６】
図７はダブティルの厚さに相当する１／２ｔにおける衝撃吸収エネルギ(ｙ)と引張強さ(ｘ）との関係を示す線図である。下限の線はｙ＝−０.０２２ｘ＋４.１０ に相当し、上限の線はｙ＝−０.０２２ｘ＋４.３５に相当し、本実施例におけるＴｉ基合金はダブティルに相当する部分をこれらの線の範囲内とすることによって上述の翼部との引張強さ及び衝撃吸収エネルギの差の少ないブレードを得ることができる。
【００４７】
更に、１／２ｔ及び１／４ｔにおける衝撃吸収エネルギ値は水冷材がダブティル部にくらべ翼部の方が高く、衝風冷却材が翼部にくらべダブティル部の方が高く、いずれも５％以内で高くなっている。
【００４８】
〔実施例２〕
図８は３６００rpm 用翼部長さ１０９２ mm （４３インチ）の蒸気温度５３８〜６５０℃蒸気タービン用の低圧タービンの最終段蒸気タービン翼の斜視図である。ダブティル５２は８本のフォークによって形成され、翼部長さ１１６８ mm （４６インチ）においては９本となる。本実施例では実施例１に記載のＴｉ基合金が用いられ、特にダブティル部の引張強さが１１０kg／mm² 以上で、ダブティル部の引張強さを翼部の引張強さの９６％以上とするものを用いるのが好ましい。５３はピンを挿入する穴であり、５４はエロージョンシールドでＶ１０〜２０％，Ｃｒ１.５〜５％，Ａｌ１.５〜５％及びＳｎ１.５〜５％ を含むＴｉ基合金又はステライトのＣ２〜３％，Ｃｒ２０〜３５％，Ｗ１０〜２５％，Ｆｅ０〜１０％を含むＣｏ基合金がろう付け又は電子ビーム溶接されるが、前者のＴｉ基合金を用いた。５７はコンティニュアスカバーである。５５はタイボスである。
【００４９】
本実施例によるタービン翼の製造例を以下説明する。
【００５０】
先ず、実施例１に示す合金組成と同等の組成を有するインゴットをα＋β温度域の約８５０℃で丸棒素材に荒鍛造後、更に同等の温度で型打ち鍛造によって翼部とダブティル部の相似形の翼素材を形成した。いずれの部分も最終仕上がり寸法の約１.３ 倍の厚さとした。次いで、８５０℃，１時間保持し、全体を水中に投入して焼入れを行った。焼入れ後、ＮＣ加工によってほぼ最終形状に機械加工し、次いで重量で１５％Ｖ，３％Ｃｒ，３％Ａｌ及び３％Ｓｎを含むＴｉ基合金板を翼部先端のリーデングエッヂ部にろう付けした。次いで、翼部を所定のプロファイル形状を持つ治具に固定して強制的に拘束した状態で時効を兼ねて５００℃，４時間加熱した。エロージョンシールド５４は予め８００℃で２０分加熱後油焼入れしたものである。
【００５１】
以上の最終熱処理後、最終機械加工によって最終形状の翼プロファイル，翼植込み部とそのピン挿入孔が加工され、製品となる。本実施例の翼部に対する翼植込み部の引張強さは９８％以上であり、衝撃値は同等のものであった。
【００５２】
本実施例の翼植込み部５２は８本のフォーク型であり、ピン挿入孔は１フォークに対し３個有している。また、図８の側面から見た翼部５１先端には図９と同様にコンティニュアスカバー５７が設けられ、互いに接して全周でリング状に形成される。そして、翼部５１の植込み部でロータシャフトの軸方向に対してほぼ平行であるが、その先端ではその軸方向に対して約７５.５ 度交わるようにねじれて形成されている。コンティニュアスカバー５７は翼材と同じ組成であり、１／４ｔの肉厚に相当する。
【００５３】
尚、３０００rpm 用では同じく翼部長さが５２インチ以上のものを本実施例と同様に製造することができる。この翼のフォーク数は９本である。
【００５４】
〔実施例３〕
図９は翼植込み部をフォーク型に代わって逆クリスマスツリー型としたもので、その側面図である。本図面に示す蒸気タービン翼は前述の図８とは翼植込み部５２の型が違うだけで、他の構造は同様である。また、本実施例においても実施例１のＴｉ基合金を用いられる。本図に示す様に翼植込み部５２は両側に４段のストレートな突起を有し、この突起によって高速回転による翼部をロータシャフトに植設され固定されるものである。そして、ロータシャフトにはこの外形と同一の空間を有する溝がロータシャフトの軸方向に沿って植込まれるように形成されている。更に、翼部５１の先端部にはコンティニュアスカバー５７が設けられ、植込み部の翼部はロータシャフトの軸方向にほぼ平行に形成されており、その先端部は前述と同様に軸方向に対して約７５.５ 度交わるように形成されている。
【００５５】
本実施例においても、回転数３６００rpm に対して翼部長さ１０９２ mm （４３インチ），１１６８ mm （４６インチ），１２１９ mm （４８インチ）のものを形成することができ、また、回転数３０００rpm に対して１３２０ mm （５２インチ）以上のものを形成することができる。前述の突起は１１６８ mm （４６インチ）までは４段であるが、１２１９ mm （４８インチ）以上に対しては５段とした。
【００５６】
更に、エロージョンシールド５４が前述と同様にＴｉ基合金板又はＣｏ基合金板が用いられ、同様に接合される。
【００５７】
〔実施例４〕
表４は本発明に係る蒸気温度６２５℃，１０５０ＭＷ蒸気タービンの主な仕様である。本実施例は、クロスコンパウンド型４流排気，低圧タービンにおける最終段動翼の翼部長さが１０９２ mm （４３インチ）であり、ＡはＨＰ−ＩＰ及びＬＰ２台で３６００rpm 、ＢはＨＰ−ＬＰ及びＩＰ−ＬＰで各々同じく３６００Rpm の回転数を有し、高温部においては表４に示す主な材料によって構成される。高圧部（ＨＰ）の蒸気温度は６２５℃，２５０kgｆ／cm² の圧力であり、中圧部（ＩＰ）の蒸気温度は６２５℃に再熱器によって加熱され、４５〜６５kgｆ／cm² の圧力で運転される。低圧部（ＬＰ）は蒸気温度は４００℃で入り、１００℃以下，７２２mmＨｇの真空で復水器に送られる。
【００５８】
本実施例における低圧タービンの最終段動翼の翼部長さに対する高圧タービン及び中圧タービンをタンデムに結合した軸受間距離、及びタンデムに結合した２台の前記低圧タービンの軸受間距離の合計は約３１.５ｍであり、その比が28.8 であり、コンパクトになっている。
【００５９】
また、本実施例における蒸気タービン発電プラントの定格出力（ＭＷ）に対する前記高圧タービン及び中圧タービンをタンデムに結合した軸受間距離、及びタンデムに結合した２台の前記低圧タービンの軸受間距離の合計距離（mm）の比が３０である。
【００６０】
【表４】

【００６１】
図１０は表４のタービン構成のＡにおける高圧及び中圧蒸気タービンの断面構成図である。高圧蒸気タービンは高圧内部車室１８とその外側の高圧外部車室１９内に高圧動翼１６を植設した高圧車軸（高圧ロータシャフト）２３が設けられる。高温高圧の蒸気は前述のボイラによって得られ、主蒸気管を通って、主蒸気入口を構成するフランジ，エルボ２５より主蒸気入口２８を通り、ノズルボックス３８より初段複流の動翼に導かれる。初段は複流であり、片側に８段設けられる。これらの動翼に対応して各々静翼が設けられる。動翼は鞍型ダブティル型式，ダブルティノン，初段翼長約３５mmである。車軸間の長さは約５.８ｍ 及び静翼部に対応する部分で最も小さい部分の直径は約７１０mmであり、直径に対する長さの比は約８.２である。
【００６２】
本実施例においては後述する表７に示す材料を初段ブレード及び初段ノズルを使用し、他のブレード及びノズルはいずれもＷ，Ｃｏ及びＢを含まない１２％Ｃｒ系鋼によって構成したものである。本実施例における動翼の翼部の長さは初段が３５〜５０mm、２段目から最終段になるに従って各段で長くなっており、特に蒸気タービンの出力によって２段から最終段までの長さが６５〜１８０mmであり、段数は９〜１２段で、各段の翼部の長さは下流側が上流側に対して隣り合う長さで１.１０〜１.１５の割合で長くなっているとともに、下流側でその比率が徐々に大きくなっている。
【００６３】
本実施例における高圧タービンは軸受間距離が約５.３ｍ であり、低圧タービンの最終段動翼の翼部長さに対するその軸受間距離の比が４.８ である。また、発電プラントの定格出力（ＭＷ）に対する前記高圧タービンの軸受間距離（mm) の比は５.０である。
【００６４】
中圧蒸気タービンは高圧蒸気タービンより排出された蒸気を再度６２５℃に再熱器によって加熱された蒸気によって高圧蒸気タービンと共に発電機を回転させるもので、３０００回／min の回転数によって回転される。中圧タービンは高圧タービンと同様に中圧内部第２車室２１と中圧外部車室２２とを有し、中圧動翼１７と対抗して静翼が設けられる。動翼１７は６段で２流となり、中圧車軸（中圧ロータシャフト）の長手方向に対しほぼ対称に左右に設けられる。軸受中心間距離は約５.８ｍ であり、初段翼長さ約１００mm，最終段翼長さ約２３０mmである。初段，２段のダブティルは逆クリ型である。最終段動翼前の静翼に対応するロータシャフトの直径は約６３０mmであり、その直径に対する軸受間距離の比は約９.２倍である。
【００６５】
本実施例の中圧蒸気タービンのロータシャフトは動翼植込み部の軸方向幅が初段から４段，５段及び最終段に従って３段階で段階的に大きくなっており、最終段での幅は初段に対して約１.４倍と大きくなっている。
【００６６】
また、本蒸気タービンのロータシャフトは静翼部に対応した部分の直径が小さくなっており、その幅は初段動翼，２〜３段及び最終段動翼側に従って４段階で段階的に小さくなっており、前者に対する後者の軸方向の幅が約０.７５ 倍と小さくなる。
【００６７】
本実施例においては後述する表７に示す材料を初段ブレード，ノズルに使用される他はＷ，Ｃｏ及びＢを含まない１２％Ｃｒ系鋼が用いられる。本実施例における動翼の翼部の長さは初段から最終段になるに従って各段で長くなっており、蒸気タービンの出力によって初段から最終段までの長さが６０〜３００mmで、６〜９段で、各段の翼部の長さは下流側が上流側に対して隣り合う長さで１.１〜 １.２の割合で長くなっている。
【００６８】
動翼の植込み部は静翼に対応する部分に比較して直径が大きくなっており、その幅は動翼の翼部長さの大きい程その植込み幅は大きくなっている。その幅の動翼の翼部長さに対する比率は初段から最終段で０.３５〜０.８であり、初段から最終段になるに従って段階的に小さくなっている。
【００６９】
本実施例における中圧タービンは、その軸受間距離が約５.５ｍであり、低圧 タービンの最終段動翼の翼部長さに対する中圧タービンの軸受間距離の比が5.0 であり、また、発電プラントの定格出力（ＭＷ）に対するその軸受間距離（mm）の比が５.２である。
【００７０】
高圧タービンの初段に植込まれるタービン翼は鞍型の植込み型であり、高圧タービンの２段以降及び中圧タービンの全段に植込まれるタービン翼は逆クリスマスツリー型である。
【００７１】
図１１は３６００rpm の回転数の低圧タービンの断面図である。低圧タービンは２基タンデムに結合され、ほぼ同じ構造を有している。各々動翼４１は左右に８段あり、左右ほぼ対称になっており、また動翼に対応して静翼４２が設けられる。最終段動翼には実施例２又は３に示した翼部長さが４３インチダブルティノンであるＴｉ基合金からなる蒸気タービン翼を用いた。ノズルボックス４５は複流型である。
【００７２】
ロータシャフト４４には表５に示すスーパークリーンされた全焼戻しベーナイト鋼の鍛鋼が用いられる。表５に示す鋼は５kgの鋼塊を用い各種特性を調べた。これらの鋼は熱間鍛造後８４０℃×３ｈ加熱後、１００℃／ｈで冷却する焼入れ後、５７５℃×３２ｈ加熱する焼戻しを施したものである。表６は室温の特性である。
【００７３】
【表５】

【００７４】
【表６】

【００７５】
いずれの試料も全焼戻しベーナイト組織を有する。０.０２％耐力８０kg／mm²以上，引張強さ１００kg／mm² 以上，Ｖノッチ衝撃値１０kg−ｍ以上、ＦＡＴＴは−２０℃以下と高強度及び高靭性を有し、本実施例の最終段動翼として翼部長さ１０９２ mm （４３インチ）以上は勿論、１１６８ mm （４６インチ）の植設を満足するものであった。Ｃｒ量が若干高いＮo.４は強度が低くなっており、Ｃｒは２.２０％ 位までが好ましい。特に、０.２％耐力（ｙ）は０.０２％耐力（ｘ）より、（１.３５ｘ−２０）、より好ましくは（１.３５ｘ−１９）によって求められる値以上とするのが好ましい。
【００７６】
最終段以外の動翼及び静翼にはいずれもＭｏを０.１％ 含有する１２％Ｃｒ鋼が用いられる。内外部ケーシング材にはＣ０.２５％ の鋳鋼が用いられる。本実施例における軸受４３での中心間距離は７５００mmで、静翼部に対応するロータシャフトの直径は約１２８０mm，動翼植込み部での直径は２２７５mmである。このロータシャフト直径に対する軸受中心間の距離は約５.９ である。
【００７７】
コンティニュアスカバー５７は本実施例においては全体一体の鍛造後に切削加工によって形成されたものである。尚、コンティニュアスカバー５７は機械的に一体に形成することもできる。
【００７８】
本実施例の低圧タービンは動翼植込み部の軸方向の幅が初段〜３段，４段，５段，６〜７段及び８段の４段階で徐々に大きくなっており、最終段の幅は初段の幅に比べ約２.５倍と大きくなっている。
【００７９】
また、静翼部に対応する部分の直径は小さくなっており、その部分の軸方向の幅は初段動翼側から５段目，６段目及び７段目の３段階で徐々に大きくなっており、最終段側の幅は初段と２段の間に対して約１.９倍大きくなっている。
【００８０】
本実施例における動翼は８段であり、その翼部長さは初段の７６ mm(３インチ )から１０９２ mm （４３インチ）の最終段になるに従って各段で長くなっており、蒸気タービンの出力によって初段から最終段の長さが９０〜１２７０mmで、８段又は９段で、各段の翼部長さは下流側が上流側に対して隣り合う長さで１.３ 〜１.６倍の割合で長くなっている。
【００８１】
動翼の植込み部は静翼に対応する部分に比較して直径が大きくなっており、その幅は動翼の翼部長さの大きい程その植込み幅は大きくなっている。その幅の動翼の翼部長さに対する比率は初段から最終段で０.１５〜０.１９であり、初段から最終段になるに従って段階的に小さくなっている。
【００８２】
また、各静翼に対応する部分のロータシャフトの幅は初段と２段目との間から最終段とその手前との間までの各段で段階的に大きくなっている。その幅の動翼の翼部長さに対する比率は０.２５〜１.２５で上流側から下流側になるに従って小さくなっている。
【００８３】
本実施例における低圧タービンはタンデムに２台連結され、その合計の軸受間距離は約１８.３ｍ であり、低圧タービンの最終段動翼の翼部長さに対するタンデムに結合した２台の前記低圧タービンの軸受間距離の合計の比が１６.７ であり、更に発電プラントの定格出力１０５０（ＭＷ）に対するタンデムに結合した２台の両端での低圧タービンの軸受間距離（mm）の合計の比が１７.４である。
本実施例の他、高圧蒸気タービン及び中圧蒸気タービンへの蒸気入口温度610 ℃，２基の低圧蒸気タービンへの蒸気入口温度３８５℃とする１０００ＭＷ級大容量発電プラントに対しても同様の構成とすることができる。
【００８４】
本実施例における高温高圧蒸気タービンプラントは主として石炭専焼ボイラ，高圧タービン，中圧タービン，低圧タービン２台，復水器，復水ポンプ，低圧給水加熱器系統，脱気器，昇圧ポンプ，給水ポンプ，高圧給水加熱器系統などより構成される。すなわち、ボイラで発生した超高温高圧蒸気は高圧タービンに入り動力を発生させたのち再びボイラにて再熱されて中圧タービンへ入り動力を発生させる。この中圧タービン排気蒸気は、低圧タービンに入り動力を発生させた後、復水器にて凝縮する。この凝縮液は復水ポンプにて低圧給水加熱器系統，脱気器へ送られる。この脱気器にて脱気された給水は昇圧ポンプ，給水ポンプにて高圧給水加熱器へ送られ昇温された後、ボイラへ戻る。
【００８５】
ここで、ボイラにおいて給水は節炭器，蒸発器，過熱器を通って高温高圧の蒸気となる。また一方、蒸気を加熱したボイラ燃焼ガスは節炭器を出た後、空気加熱器に入り空気を加熱する。ここで、給水ポンプの駆動には中圧タービンからの抽気蒸気にて作動する給水ポンプ駆動用タービンが用いられている。
【００８６】
このように構成された高温高圧蒸気タービンプラントにおいては、高圧給水加熱器系統を出た給水の温度が従来の火力プラントにおける給水温度よりもはるかに高くなっているため、必然的にボイラ内の節炭器を出た燃焼ガスの温度も従来のボイラに比べてはるかに高くなってくる。このため、このボイラ排ガスからの熱回収をはかりガス温度を低下させないようにする。
【００８７】
また、本実施例に代えて同じ高圧タービン及び中圧タービンの各々に対し１基の低圧タービンをタンデムに連結し、各々に１台の発電機を連結して発電するタンデムコンパウンド型発電プラントとしても同様に構成することができる。本実施例の出力１０５０ＭＷ級の発電機においてはその発電機シャフトとしてはより高強度のものが用いられる。特に、Ｃ０.１５〜０.３０％，Ｓｉ０.１〜０.３％，Ｍｎ０.５％以下，Ｎｉ３.２５〜４.５％，Ｃｒ２.０５〜３.０％，Ｍｏ0.25 〜０.６０％,Ｖ０.０５〜０.２０％を含有する全焼戻しベーナイト組織を有し、室温引張強さ９３kgｆ／mm²以上、特に１００kgｆ／mm²以上，５０％ＦＡＴＴが０℃以下、特に−２０℃以下とするものが好ましく、２１.２ＫＧ における磁化力が９８５ＡＴ／cm以下とするもの、不純物としてのＰ，Ｓ，Ｓｎ，Ｓｂ，Ａｓの総量を０.０２５％以下，Ｎｉ／Ｃｒ比を２.０以下とするものが好ましい。
【００８８】
高圧タービンシャフトは多段側の初段ブレード植設部を中心に９段のブレードが植設される構造である。中圧タービンシャフトは多段ブレードが左右に各６段ほぼ対称にブレード植設部が設けられ、ほぼ中心を境にしたものである。低圧タービン用ロータシャフトは図示されていないが、高圧，中圧，低圧タービンのいずれのロータシャフトにおいても中心孔が設けられ、この中心孔を通して超音波検査，目視検査及びけい光探傷によって欠陥の有無が検査される。また、外表面から超音波検査により行うことができ、中心孔が無でもよい。
【００８９】
表７は実施例の発電プラントに係る高圧タービン，中圧タービン及び低圧タービンの主要部に用いた化学組成（重量％）を示す。本実施例においては、高圧部及び中圧部の高温部を全部フェライト系の結晶構造を有する熱膨張係数約１２×１０^-6／℃のものにしたので、熱膨張係数の違いによる問題は全くなかった。
【００９０】
高圧タービン及び中圧タービンのロータシャフトは、表７（重量％）に記載の耐熱鋳鋼を電気炉で３０トン溶解し、カーボン真空脱酸し、金型鋳型に鋳込み、鍛伸して電極棒を作製し、この電極棒として鋳鋼の上部から下部に溶解するようにエレクトロスラグ再溶解し、ロータ形状（直径１０５０mm，長さ３７００mm）に鍛伸して成型した。この鍛伸は、鍛造割れを防ぐために、１１５０℃以下の温度で行った。またこの鍛鋼を焼鈍熱処理後、１０５０℃に加熱し水噴霧冷却焼入れ処理，５７０℃及び６９０℃で２回焼戻しを行い、最終形状に切削加工によって得られるものである。本実施例においてはエレクトロスラグ鋼塊の上部側を初段翼側にし、下部を最終段側にするようにした。いずれのロータシャフトも中心孔を有しており、不純物を低下させることにより中心孔をなくすことができる。高圧部及び中圧部のブレード及びノズルは、同じく表７に記載の耐熱鋼を真空アーク溶解炉で溶解し、ブレード及びノズル素材形状（幅１５０mm，高さ５０mm，長さ１０００mm）に鍛伸して成型した。この鍛伸は、鍛造割れを防ぐために、１１５０℃以下の温度で行った。またこの鍛鋼を１０５０℃に加熱し油焼入れ処理，６９０℃で焼戻しを行い、次いで所定形状に切削加工したものである。
【００９１】
高圧部及び中圧部の内部ケーシング，主蒸気止め弁ケーシング及び蒸気加減弁ケーシングは、表７に記載の耐熱鋳鋼を電気炉で溶解し、とりべ精錬後、砂型鋳型に鋳込み作製した。鋳込み前に、十分な精錬及び脱酸を行うことにより、引け巣等の鋳造欠陥のないものができた。このケーシング材を用いた溶接性評価は、ＪＩＳ Ｚ３１５８に準じて行った。予熱，パス間及び後熱開始温度は２００℃に、後熱処理は４００℃×３０分にした。本発明材には溶接割れが認められず、溶接性が良好であった。
【００９２】
【表７】

【００９３】
表８は、上述したフェライト系鋼製高温蒸気タービン主要部材を切断調査した機械的性質及び熱処理条件を示す。
【００９４】
このロータシャフトの中心部を調査した結果、高圧，中圧タービンロータに要求される特性（６２５℃，１０⁵ｈ強度≧１０kgｆ／mm²，２０℃衝撃吸収エネルギ≧１.５kgｆ−ｍ)を十分満足することが確認された。これにより、６２０℃以上の蒸気中で使用可能な蒸気タービンロータが製造できることが実証された。またこのブレードの特性を調査した結果、高圧，中圧タービンの初段ブレードに要求される特性（６２５℃，１０⁵ｈ強度≧１５kgｆ／mm²）を十分満足することが確認された。これにより、６２０℃以上の蒸気中で使用可能な蒸気タービンブレードが製造できることが実証された。
【００９５】
さらにこのケーシングの特性を調査した結果、高圧，中圧タービンケーシングに要求される特性（６２５℃，１０⁵ｈ強度≧１０kgｆ／mm²，２０℃衝撃吸収エネルギ≧１kgｆ−ｍ）を十分満足することと溶接可能であることが確認された。これにより、６２０℃以上の蒸気中で使用可能な蒸気タービンケーシングが製造できることが実証された。
【００９６】
【表８】

【００９７】
本実施例においては、高圧及び中圧ロータシャフトのジャーナル部にＣｒ−Ｍｏ低合金鋼を肉盛溶接し、軸受特性を改善させた。肉盛溶接は次の通りである。
【００９８】
供試溶接棒として被覆アーク溶接棒(直径４.０φ）を用いた。その溶接棒を用いて溶接したものの溶着金属の化学組成（重量％）を表９に示す。この溶着金属の組成は溶接材の組成とほぼ同じである。溶接条件は溶接電流１７０Ａ，電圧２４Ｖ，速度２６cm／minである。
【００９９】
【表９】

【０１００】
肉盛溶接を上述の供試母材表面に表１０に示すごとく、各層ごとに使用溶接棒を組合せて、８層の溶接を行った。各層の厚さは３〜４mmであり、全厚さは約２８mmであり、表面を約５mm研削した。
【０１０１】
溶接施工条件は、予熱，パス間，応力除去焼鈍（ＳＲ）開始温度が２５０〜３５０℃及びＳＲ処理条件は６３０℃×３６時間保持である。
【０１０２】
【表１０】

【０１０３】
溶接部の性能を確認するために板材に同様に肉盛溶接し、１６０゜の側曲げ試験を行ったが、溶接部に割れは認められなかった。
【０１０４】
更に、本発明における回転による軸受摺動試験を行ったが、いずれも軸受に対する悪影響もなく、耐酸化性に対しても優れたものであった。
【０１０５】
本実施例に代えて高圧蒸気タービン，中圧蒸気タービン及び１基又は２基の低圧蒸気タービンをタンデムに結合し、３６００回転としたタンデム型発電プラント及び表４のタービン構成Ｂにおいても本実施例の高圧タービン，中圧タービン及び低圧タービンを同様に組み合わせて構成できるものである。
【０１０６】
〔実施例５〕
表１１は主蒸気温度５３８℃／５６６℃，定格出力７００ＭＷ蒸気タービンの主な仕様である。本実施例は、タンデムコンパウンドダブルフロー型、低圧タービンにおける最終段翼長が１１６８ mm （４６インチ）であり、ＨＰ（高圧）・ＩＰ（中圧）一体型及びＬＰ１台（Ｃ）又は２台（Ｄ）で３６００rpm の回転数を有し、高温部においては表に示す主な材料によって構成される。高圧部(ＨＰ)の蒸気温度は５３８℃，２４６kgｆ／cm² の圧力であり、中圧部（ＩＰ）の蒸気温度は５６６℃に再熱器によって加熱され、４５〜６５kgｆ／cm² の圧力で運転される。低圧部（ＬＰ）は蒸気温度は４００℃で入り、１００℃以下，７２２mmＨｇの真空で復水器に送られる。
【０１０７】
本実施例における高圧タービンと中圧タービンとを一体にした高中圧一体タービン及び２台の低圧タービンをタンデムに備えた蒸気タービン発電プラントは、軸受間距離が約２２.７ｍ であり、その低圧タービンの最終段動翼の翼部長さ （１１６８mm）に対する高中圧一体タービンの軸受間距離及びタンデムに結合した２台の前記低圧タービンの軸受間距離の合計の比が１９.４ である。
【０１０８】
更に、本実施例における高圧タービンと中圧タービンとを一体にした高中圧一体タービン及び１台の低圧タービンを備えた蒸気タービン発電プラントは、軸受間距離が約１４.７ｍであり低圧タービンの最終段動翼の翼部長さ（１１６８mm)に対する高中圧一体タービンの軸受間距離及び１台の前記低圧タービンの軸受間距離の合計の比が１２.６ である。また発電プラントの定格出力７００ＭＷにおける１ＭＷに対する高中圧一体タービンの軸受間距離及び１台の前記低圧タービンの軸受間距離の合計の比が２１.０である。
【０１０９】
【表１１】

【０１１０】
図１２は高圧中圧一体型蒸気タービンの断面構成図の断面図である。高圧側蒸気タービンは高圧内部車室１８とその外側の高圧外部車室１９内に高圧動翼１６を植設した高中圧車軸（高圧ロータシャフト）３３が設けられる。前述の高温高圧の蒸気は前述のボイラによって得られ、主蒸気管を通って、主蒸気入口を構成するフランジ，エルボ２５より主蒸気入口２８を通り、ノズルボックス３８より初段の動翼に導かれる。蒸気はロータシャフトの中央側より入り、軸受側に流れる構造を有する。動翼は図中左側の高圧側に８段及び（図中右側約半分の）中圧側に６段設けられる。これらの動翼に対応して各々静翼が設けられる。動翼は鞍型又はゲタ型，ダブティル型式，ダブルティノン，高圧側初段翼長約４０mm，中圧側初段翼長が１００mmである。軸受４３間の長さは約６.７ｍ 及び静翼部に対応する部分で最も小さい部分の直径は約７４０mmであり、直径に対する長さの比は約９.０である。
【０１１１】
高圧側ロータシャフトの初段と最終段の動翼植込み付根部分の幅は初段が最も広く、２段目〜７段目がそれより小さく、初段の０.４０〜０.５６倍でいずれも同等の大きさであり、最終段が初段と２〜７段目の大きさの間にあり、初段の０.４６〜０.６２倍の大きさである。
【０１１２】
高圧側においてはブレード及びノズルを前述の表７に示す１２％Ｃｒ系鋼によって構成したものである。本実施例における動翼の翼部の長さは初段が３５〜５０mm、２段目から最終段になるに従って各段で長くなっており、特に蒸気タービンの出力によって２段から最終段までの長さが５０〜１５０mmの範囲内であり、段数は７〜１２段の範囲内にあり、各段の翼部の長さは下流側が上流側に対して隣り合う長さで１.０５〜１.３５倍の範囲内で長くなっているとともに、下流側でその比率が徐々に大きくなっている。
【０１１３】
中圧側蒸気タービンは高圧側蒸気タービンより排出された蒸気を再度５６６℃に再熱器によって加熱された蒸気によって高圧蒸気タービンと共に発電機を回転させるもので、３６００rpm の回転数によって回転される。中圧側タービンは高圧側タービンと同様に中圧内部第２車室２１と中圧外部車室２２とを有し、中圧動翼１７と対抗して静翼が設けられる。中圧動翼１７は６段である。初段翼長さ約１３０mm，最終段翼長さ約２６０mmである。ダブティルは逆クリ型である。
【０１１４】
中圧蒸気タービンのロータシャフトは動翼植込み付根部の軸方向幅が初段が最も大きく、２段目がそれより小さく、３〜５段目が２段目より小さくいずれも同じで、最終段の幅は３〜５段目と２段目の間の大きさで、初段の０.４８〜0.64倍である。初段は２段目の１.１〜１.５倍である。
【０１１５】
中圧側においてはブレード及びノズルを前述の表７に示す１２％Ｃｒ系鋼が用いられる。本実施例における動翼の翼部の長さは初段から最終段になるに従って各段で長くなっており、蒸気タービンの出力によって初段から最終段までの長さが９０〜３５０mm、段数が６〜９段の範囲内にあり、各段の翼部の長さは下流側が上流側に対して隣り合う長さで１.１０〜１.２５の割合で長くなっている。
【０１１６】
動翼の植込み部は静翼に対応する部分に比較して直径が大きくなっており、その幅は動翼の翼部長さと位置に関係する。その幅の動翼の翼部長さに対する比率は初段が最も大きく、１.３５〜１.８０倍，２段目が０.８８〜１.１８倍，３〜６段目が最終段になるに従って小さくなっており、０.４０〜０.６５倍である。本実施例におけるタンデムに結合した２台の低圧タービンを備えた蒸気タービン発電プラント用高中圧一体タービンは、軸受間距離が約５.７ｍ であり、低圧タービンの最終段動翼の翼部長さ（１１６８mm)に対する軸受間距離の比が５.７である。
【０１１７】
本実施例においても、軸受部には実施例３と同様に低合金鋼の肉盛溶接層が設けられる。
【０１１８】
図１３は３６００rpm の低圧タービン及び図１４はそのロータシャフトの断面図である。
【０１１９】
低圧タービンは１基で主蒸気５３８℃／５６６℃の高中圧にタンデムに結合される。動翼４１は左右に６段あり、左右ほぼ対称になっており、また動翼に対応して静翼４２が設けられる。最終段の動翼長さは１１６８ mm （４６インチ）あり、Ｔｉ基合金が使用される。Ｔｉ基合金は実施例１及び２に示すものが用いられる。特に、重量でＡ１６％，Ｖ６％及びｓｎ２％を含むものである。更に、ロータシャフト４３には実施例２と同じものが用いられ、Ｎｉ３.７５％，Ｃｒ1.75％，Ｍｏ０.４％ ，Ｖ０.１５％，Ｃ０.２５％，Ｓｉ０.０５％，Ｍｎ０.１０％，残Ｆｅからなるスーパークリーン材の全焼戻しベーナイト組織を有する鍛鋼が用いられる。最終段とその前段以外の動翼及び静翼にはいずれもＭｏを０.１％含有する１２％Ｃｒ鋼が用いられる。内外部ケーシング材にはＣ０.２５％ の鋳鋼が用いられる。本実施例における軸受４３での中心間距離は７０００mmで、静翼部に対応するロータシャフトの直径は約８００mm，動翼植込み部での直径は各段同じである。静翼部に対応するロータシャフト直径に対する軸受中心間の距離は約８.８ である。
【０１２０】
低圧タービンは動翼植込み付根部の軸方向の幅が初段が最も小さく、下流側に従って２，３段が同等、４段，５段が同等で４段階で徐々に大きくなっており、最終段の幅は初段の幅に比べ６.２〜７.０倍と大きくなっている。２，３段は初段の１.１５〜１.４０倍、４，５段が２，３段の２.２〜２.６倍、最終段が４，５段の２.８〜３.２倍となっている。付根部の幅は末広がりの延長線とロータシャフトの直径とを結ぶ点で示す。
【０１２１】
本実施例における動翼の翼部長さは初段の４″から４６″の最終段になるに従って各段で長くなっており、蒸気タービンの出力によって初段から最終段の長さが１００〜１２７０mmの範囲内で、最大で８段で、各段の翼部長さは下流側が上流側に対して隣り合う長さで１.２〜１.９倍の範囲内で長くなっている。
【０１２２】
動翼の植込み付根部は静翼に対応する部分に比較して直径が大きく末広がりになっており、その幅は動翼の翼部長さの大きい程その植込み幅は大きくなっている。その幅の動翼の翼部長さに対する比率は初段から最終段の前までが０.３０ 〜１.５であり、その比率は初段から最終段の前になるに従って徐々に小さくな っており、後段の比率はその１つ手前のものより０.１５〜０.４０の範囲内で徐々に小さくなっている。最終段は０.５０〜０.６５の比率である。
【０１２３】
本実施例におけるエロージョンシールドは実施例２と同様に設けられる。
【０１２４】
本実施例の他、高中圧蒸気タービンの蒸気入口温度６１０℃以上，低圧蒸気タービンへの蒸気入口温度約４００℃及び出口温度が約６０℃とする１０００ＭＷ級大容量発電プラントに対しても同様の構成とすることができる。
【０１２５】
本実施例における高温高圧蒸気タービン発電プラントは主としてボイラ，高中圧タービン，低圧タービン，復水器，復水ポンプ，低圧給水加熱器系統，脱気器，昇圧ポンプ，給水ポンプ，高圧給水加熱器系統などより構成される。すなわち、ボイラで発生した超高温高圧蒸気は高圧側タービンに入り動力を発生させたのち再びボイラにて再熱されて中圧側タービンへ入り動力を発生させる。この高中圧タービン排気蒸気は、低圧タービンに入り動力を発生させた後、復水器にて凝縮する。この凝縮液は復水ポンプにて低圧給水加熱器系統，脱気器へ送られる。この脱気器にて脱気された給水は昇圧ポンプ，給水ポンプにて高圧給水加熱器へ送られ昇温された後、ボイラへ戻る。
【０１２６】
ここで、ボイラにおいて給水は節炭器，蒸発器，過熱器を通って高温高圧の蒸気となる。また一方、蒸気を加熱したボイラ燃焼ガスは節炭器を出た後、空気加熱器に入り空気を加熱する。ここで、給水ポンプの駆動には中圧タービンからの抽気蒸気にて作動する給水ポンプ駆動用タービンが用いられている。
【０１２７】
このように構成された高温高圧蒸気タービンプラントにおいては、高圧給水加熱器系統を出た給水の温度が従来の火力プラントにおける給水温度よりもはるかに高くなっているため、必然的にボイラ内の節炭器を出た燃焼ガスの温度も従来のボイラに比べてはるかに高くなってくる。このため、このボイラ排ガスからの熱回収をはかりガス温度を低下させないようにする。
【０１２８】
前述の表７は本実施例の高中圧タービン及び低圧タービンの主要部に用いた化学組成（重量％）を示す。本実施例においては、高圧側及び中圧側とを一体にしたロータシャフトとして、Ｃ０.１１％，Ｓｉ０.０２％，Ｍｎ０.４５％ ，Ｎｉ０.５０％，Ｃｒ１１.２１％，Ｍｏ０.２５％，Ｗ２.７８％，Ｖ０.２０％,Ｎｂ０.０７％，Ｃｏ１.５０％，Ｎ０.０２５％，Ｂ０.０１６％，残部Ｆｅからなるマルテンサイト鋼を使用した他は表７のものを用い、全部フェライト系の結晶構造を有する熱膨張係数１２×１０^-6／℃のものにしたので、熱膨張係数の違いによる問題は全くなかった。
【０１２９】
尚、本実施例では高中圧タービン及び１基の低圧タービンを１台の発電機タンデムに連結し発電するタンデムコンパウンドダブルフロー型発電プラントに構成したものである。別の実施例として、２台の低圧タービンをタンデムに連結し、出力１０５０ＭＷ級の発電においても本実施例と同様に構成できるものである。その発電機シャフトとしてはより高強度のものが用いられる。特に、Ｃ０.１５ 〜０.３０％，Ｓｉ０.１〜０.３％，Ｍｎ０.５％以下，Ｎｉ３.２５〜４.５％，Ｃｒ２.０５〜３.０％，Ｍｏ０.２５〜０.６０％，Ｖ０.０５〜０.２０％を含有する全焼戻しベーナイト組織を有し、室温引張強さ９３kgｆ／mm² 以上、特に１００kgｆ／mm² 以上、５０％ＦＡＴＴが０℃以下、特に−２０℃以下とするものが好ましく、２１.２ＫＧ における磁化力９８５ＡＴ／cm以下とするもの、不純物としてのＰ，Ｓ，Ｓｎ，Ｓｂ，Ａｓの総量を０.０２５％ 以下，Ｎｉ／Ｃｒ比を２.０ 以下とするものが好ましい。
【０１３０】
前述の表７は本実施例の高中圧タービン及び低圧タービンの主要部にも同様に用いられる。本実施例においては、高圧側及び中圧側とを一体にした高中圧一体ロータシャフトの他回転部周辺に対してマルテンサイト鋼を使用することにより全部フェライト系の結晶構造を有する熱膨張係数１２×１０^-6／℃のものにしたので、熱膨張係数の違いによる問題は全くなかった。
【０１３１】
また、本実施例における高中圧一体ロータシャフトは前述の耐熱鋳鋼を電気炉で３０トン溶解し、カーボン真空脱酸し、金型鋳型に鋳込み、鍛伸して電極棒を作製し、この電極棒として鋳鋼の上部から下部に溶解するようにエレクトロスラグ再溶解し、ロータ形状（直径１４５０mm，長さ５０００ｍmm）に鍛伸して成型した。この鍛伸は、鍛造割れを防ぐために、１１５０℃以下の温度で行った。またこの鍛鋼を焼鈍熱処理後、１０５０℃に加熱し水噴霧冷却焼入れ処理、５７０℃及び６９０℃で２回焼戻しを行い、所定の形状に切削加工によって得られるものである。更に、軸受部へはＣｒ−Ｍｏ低合金鋼の肉盛溶接層が施される。
【０１３２】
本実施例におけるタンデムに結合した２台の低圧タービンを備えた蒸気タービン発電プラント用低圧タービンは合計の軸受間距離が１３.９ｍ であり、低圧タービンの最終段動翼の翼部長さに対するタンデムに結合した２台の低圧タービンの軸受間距離の比が１６.３ であり、またその発電プラントの定格出力（ＭＷ）に対するタンデムに結合した２台の低圧タービンの軸受間距離の合計距離（mm）の比が２３.１ である。
【０１３３】
本実施例における高圧タービンと中圧タービンとを一体にした高中圧一体タービン及び１台の低圧タービンを備えた蒸気タービン発電プラント用低圧タービンは軸受間距離が約６ｍであり、その低圧タービンの最終段動翼の翼部長さに対する比が５.５ であり、また１台の低圧タービンの軸受間距離の発電プラントの定格出力（ＭＷ）に対する１台の低圧タービンの軸受間距離（mm）の比が１０.０ である。
【０１３４】
本実施例における高中圧一体型ロータシャフトはいずれのロータシャフトにおいても中心孔を有しているが、特に、Ｐ０.０１０％以下，Ｓ０.００５％以下，Ａｓ０.００５％以下，Ｓｎ０.００５％以下，Ｓｂ０.００３％ 以下とすることによりいずれの実施例においても高純化によって中心孔をなくすことができる。
本実施例の発電プラントは３０００rpm に対して適用することができ、最終段ブレートの翼長は１３２０ mm （５２インチ）又は１４２２ mm （５６インチ）に適用できる。
【０１３５】
【発明の効果】
本発明によれば、低圧蒸気タービン最終段動翼用Ｔｉ基合金として、質量効果の影響が大きい大型鍛造品で目標の引張強さ１１０kg／mm² 以上が確保でき、３６００rpmに対し１０９２ mm(４３インチ)以上，３０００rpmに対して１２７０ mm(５０インチ)以上の蒸気タービン長翼が可能となり、蒸気温度５３８〜６６０℃の蒸気タービン発電プラントとしてより大容量化が可能となり、より高効率化が達成される。
【図面の簡単な説明】
【図１】溶体化水冷材の目標の引張強さを得る時効温度と溶体化温度の関係を示す図。
【図２】溶体化衝風冷却材の目標の引張強さを得る時効温度と溶体化温度の関係を示す図。
【図３】ダブティル粗加工後溶体化水冷材の目標の引張強さを得る時効温度と溶体化温度の関係を示す図。
【図４】ダブティル粗加工後溶体化衝風冷却材の目標の引張強さを得る時効温度と溶体化温度の関係を示す図。
【図５】１／２ｔと１／４ｔの引張強さの関係を示す線図。
【図６】衝撃吸収エネルギと引張強さとの関係を示す線図。
【図７】衝撃吸収エネルギと引張強さとの関係を示す線図。
【図８】蒸気タービン翼の斜視図。
【図９】低圧タービン翼の側面図。
【図１０】高圧タービンと中圧タービンとが連結した断面図。
【図１１】低圧蒸気タービンの断面図。
【図１２】高中圧タービンの断面図。
【図１３】低圧蒸気タービンの断面図。
【図１４】低圧蒸気タービン用ロータシャフトの断面図。
【符号の説明】
１…第１軸受、２…第２軸受、３…第３軸受、４…第４軸受、５…推力軸受、１０…第１シャフトパッキン、１１…第２シャフトパッキン、１２…第３シャフトパッキン、１３…第４シャフトパッキン、１４…高圧隔板、１５…中圧隔板、１６…高圧動翼、１７…中圧動翼、１８…高圧内部車室、１９…高圧外部車室、２０…中圧内部第１車室、２１…中圧内部第２車室、２２…中圧外部車室、２３…高圧車軸、２４…中圧車軸、２５…フランジ，エルボ、２６…前側軸受箱、２７…軸受部、２８…主蒸気入口、２９…再熱蒸気入口、３０…高圧蒸気排気口、３１…気筒連絡管、３３…高中圧車軸、３８…ノズルボックス（高圧第１段）、３９…推力軸受摩耗遮断装置、４０…暖機蒸気入口、４１…動翼、４２…静翼、４３…軸受、４４…ロータシャフト、５１…翼部、５２…翼植込み部、５３…ピン挿入孔、５４…エロージョンシールド、５５…タイボス、５７…コンティニュアスカバー。[0001]
BACKGROUND OF THE INVENTION
The present inventionMethod for producing Ti-based alloy low-pressure steam turbine blades in a steam turbine power plantAbout.
[0002]
[Prior art]
Conventionally, in the steam turbine low pressure final stage,850 mm (33.5 inches)12Cr steel on the long wings,1016 mm (40 inches)Ti-6Al-4V is the long wing, and the longest machine in Japan and overseas1092 mm (43 inches)High-strength 12Cr steel has been developed for long blades, but the demand for higher efficiency by making the last blade stage longer and the size of the plant more compact is increasing, and further longer blades are required. For that purpose, a lightweight and high-strength titanium alloy is indispensable instead of Ti-6Al-4V which has been used in the past.
[0003]
1016 mm (40 inches)Up to long blades, tensile strength 95kg / mm² Grade titanium alloy, which was able to cope with the increase in centrifugal force associated with longer blades.1143 mm (45 inches)With the above long blades, the tensile strength is 100 kg / mm² Grade titanium alloy is required. Tensile strength 100kg / mm² As the above titanium alloy, there is an age-hardening β-type titanium alloy. However, since this β-type titanium alloy has a drawback of low toughness, there is a problem in manufacturing the entire blade with this alloy. On the other hand, with α + β type titanium alloys with high toughness, the cooling rate during solution treatment greatly affects the strength as the blade thickness increases, and the strength obtained with small steel ingots cannot be reproduced with large products. Often, 100kg / mm² It was difficult to obtain a grade titanium alloy.
[0004]
In JP-A-1-202389, solution treatment is carried out at 10-60 ° C. of the β transformation point, that is, 867-917 ° C., for the heat treatment conditions of Ti-6Al-6V-2Sn, which is an α + β type high strength Ti alloy. Then, although it is said that the aging treatment is performed at 500 to 650 ° C., there is a problem that the strength of the thin-walled blade profile portion is obtained, but the strength of the thick-walled dovetail portion having a low cooling rate cannot be secured.
[0005]
Further, JP-A-7-150316 discloses a Ti-based alloy having Al 3 to 5%, V 2.1 to 3.7%, Mo 0.85 to 3.15%, and Fe 0.85 to 3.15% as turbine blade materials. A turbine blade is described, but no aging treatment is shown.
[0006]
[Problems to be solved by the invention]
The purpose of the present invention is to1092 mm (43 inches)As a steam turbine blade with the above blade length, the difference in tensile strength between the blade portion and the dovetail portion is small, and the tensile strength of dovetil at room temperature is 100 kg / mm² A Ti-based alloy steam turbine composed of an α + β-type phase having the above strength and suitable toughnessHow to make wingsIt is to provide.
[0007]
[Means for Solving the Problems]
The present inventionA method for producing a last stage moving blade of a low pressure turbine in a steam turbine power plant including a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine, the blade portion having a blade portion and a dovetail, and the blade portion length is 3000 rpm. rpm Against 1320 mm Or the wing rotation speed 3600 rpm Against 1092 mm With respect to the steam turbine blade made of Ti base alloy as described above, solution treatment and aging treatment for cooling after heating within a range connecting points shown in (Aging temperature, solution temperature) shown in FIGS. It is characterized by giving.
[0008]
The present inventionAccording to, Consisting of a Ti-based alloy containing Al 4-8%, V4-8% and Sn 1-4% by weight, and the dovetil has a tensile strength at room temperature of 100 kg / mm² Or more, preferably 110 kg / mm²As described above, the V-notch impact value (y) at room temperature is not less than the value (kg-m) obtained by (−0.022x + 4.10), or the wing part has a tensile strength (x) at room temperature of 105 kg / mm.²The V-notch impact value (y) at room temperature is equal to or greater than the value (kg-m) obtained by (−0.02x + 3.98), and the room temperature tensile strength of the dovetail is the room temperature tensile strength of the wing part. More than 96%SteamAir turbine bladeIs obtained.
[0009]
The present inventionAccording toThe blade length is 3,000 rpm for the blade rotation speed1320 mm (52 inches)Above or for the rotation speed of 3600 rpm1092 mm (43 inches)It is made of a Ti-based alloy containing Al 4 to 10%, V4 to 10%, and Sn 1 to 5% by weight, and the wing portion has a tensile strength (x) at room temperature of 105 kg / mm.² The V-notch impact value (y) at room temperature is not less than the value (kg-m) obtained by (−0.02x + 3.98), or the dovetil has a room-temperature tensile strength (x) of 100 kg / mm.²As described above, the V-notch impact value (y) at room temperature is not less than the value (kg-m) obtained by (−0.022x + 4.10).SteamAir turbine bladeIs obtained.
[0010]
The present invention relates to a Ti-based alloy steam turbine blade manufacturing method shown in FIG. 1 (aging temperature, solution temperature) A (605 ° C., 855 ° C.), B (590 ° C., 790 ° C.), C. (410 ° C., 790 ° C.) and D (410 ° C., 855 ° C.) are subjected to solution treatment and aging treatment in which water is cooled after heating within a range connecting the four points; The region represented by the crystallization temperature) is E (525 ° C., 855 ° C.), F (510 ° C., 790 ° C.), G (410 ° C., 790 ° C.), H (410 ° C., 855 ° C.) shown in FIG. It is characterized by performing solution treatment and aging treatment in which blast cooling is performed after heating within a range connecting four points, and before the final heat treatment, the dovetail portion is roughly processed to a state close to the final shape, and then the present application J (68) represented by (aging temperature, solution temperature) shown in FIG. Solution treatment and aging treatment in which water is cooled after heating within a range connecting four points of K (585 ° C., 790 ° C.), L (410 ° C., 790 ° C.), and M (410 ° C., 855 ° C.). Before the final heat treatment, the dovetail portion is roughly processed to a state close to the final shape, and then N (575 ° C.) represented by (aging temperature, solution temperature) shown in FIG. , 855 ° C.), O (560 ° C., 790 ° C.), P (410 ° C., 790 ° C.), and Q (410 ° C., 855 ° C.). Or any of the above.
[0013]
After hot forging, the Ti-base alloy is heated and held in a temperature range with an α + β phase and forced cooling (solution), so that the α phase and α 'martensite two-phase structure are refined and homogenized, resulting in high ductility.・ High toughness can be obtained. Furthermore, α 'martensite is decomposed into α + β2 phase by the subsequent aging treatment, forming a mixed grain form of pre-precipitated α grains and old β grains precipitating α by aging (aging hardening), thereby increasing the strength. Strength and fatigue strength can be obtained. The solution temperature is β transformation point (about 927 ° C.) in Ti-6% Al-6% V-2% Sn among Ti-based alloys containing Al4-8%, V4-8% and Sn1-4%. The following 800-900 ° C range is suitable. In particular, 790 to 855 ° C. is more suitable depending on the combination. Above the β transformation point, the ductility and toughness are reduced due to the coarsening of crystal grains and the decrease in the amount of proeutectoid α. On the other hand, if the solution temperature is too low, a hot forged structure remains and the amount of pro-eutectoid α increases, so that an appropriate strength cannot be obtained.
The subsequent aging temperature is suitably in the range of 500 to 600 ° C. The higher the aging temperature, the lower the tensile strength, and the ductility and toughness are improved. In particular, a specific combination at 410 to 685 ° C. is suitable depending on the combination with the solution treatment temperature.
[0014]
The reason for the preferable range of the components of the Ti-based alloy used in the present invention is as follows.
[0015]
Al: A typical α-stabilizing element, which is an essential additive element for the (α + β) type Ti-based alloy. If the Al content is less than 4%, it is difficult to form an (α + β) type alloy, and it is difficult to obtain sufficient strength as a material. On the other hand, if the amount of Al exceeds 10%, the intermetallic compound Ti_ThreeSince Al is generated and the toughness is remarkably lowered, it is not preferable.
[0016]
In particular, the Al content is preferably 4 to 8%.
[0017]
V: An important additive element that stabilizes the β phase and simultaneously lowers the β transformation point. It has the effect of suppressing the rapid generation and increase of the α phase after annealing or solution treatment, and finely depositing the α phase. If the V content is less than 4%, the β transformation point cannot be sufficiently lowered, and the effect of stabilizing the β phase is reduced, so that the effect of suppressing the formation of the α phase during annealing or after solution treatment is obtained. I can't get it. On the other hand, if the V content exceeds 10%, the stability of the β phase becomes too large, and it is difficult to obtain a preferable two-phase structure of (α + β), so that the strength is insufficient. In particular, the V content is preferably 4 to 8%.
[0018]
It has the effect of stabilizing the Sn: β phase and simultaneously suppressing grain growth. Therefore, similar to Al, it is important to suppress rapid formation and increase of the α phase after annealing or solution treatment, to suppress rapid formation and increase of the α phase, and to precipitate the α phase finely. It is an additive component that has the effect of miniaturizing the entire structure and occupies an important position in increasing strength. If the Sn content is less than 1%, the crystal grains become coarse during annealing or after solution treatment, and it is difficult to obtain the desired effect described above. On the other hand, if the Sn content exceeds 5%, the β phase is excessively stabilized and a preferable two-phase structure is difficult to obtain, and higher strength cannot be expected. In particular, the Sn content is preferably 1 to 4%.
[0019]
The above-mentioned Ti alloy as the last stage rotor blade of the low pressure turbine has a blade length of 3600 rpm.1092 mm (43 inches)Above or 3000rpm1320 mm (52 inches)that's allAtIn particular, an alloy composed of Al 5 to 7%, V 5 to 7% and Sn 1 to 3%, Fe 0.2 to 1.5%, O 0.20% or less, Cu 0.3 to 1.5%, and residual Ti is used. Preferably, the same heat treatment as described above is performed.
[0020]
The above-mentioned requirements can be applied to the following inventions.
[0021]
The present invention provides the steam turbine power plant described above, wherein the steam inlet temperature to the first stage blade is 538 to 660 ° C. (preferably 593 to 620 ° C., 620 to 630 ° C. 630 to 640 ° C), the low-pressure turbine is exposed to the steam inlet temperature of the high-pressure turbine and the medium-pressure turbine or high-medium-pressure turbine, while the steam inlet temperature to the first stage blade is 350 to 400 ° C. The rotor shaft or rotor shaft, the rotor blade, the stationary blade and the inner casing are all made of high-strength martensitic steel containing Cr 8 to 13% by weight, or among these, the first stage or the second stage of the rotor blade, or 3 It is preferable that the step is made of a Ni-based alloy.
[0022]
A high-pressure turbine, an intermediate-pressure turbine, or a high-medium-pressure turbine according to the present invention includes a rotor shaft, a moving blade implanted in the rotor shaft, a stationary blade that guides the inflow of water vapor into the moving blade, and the stationary blade. A temperature of 538 to 660 ° C. and a pressure of 250 kgf / cm.²Or more (preferably 246 to 316 kgf / cm²) Or 170-200kgf / cm²The rotor shaft or the rotor shaft and at least the first stage of the moving blade and the stationary blade correspond to each steam temperature (preferably 566 ° C, 593 ° C, 610 ° C, 625 ° C, 640 ° C, 650 ° C, 660 ° C). 10 at the temperature^FiveTime creep rupture strength is 10kgf / mm²Above (preferably 17kgf / mm²Or a high strength martensitic steel having a total tempered martensitic structure containing 8.5 to 13 wt% (preferably 10.5 to 11.5 wt%) of Cr, or among these, The first stage, the second stage, or the third stage is made of a Ni-based alloy, and the inner casing is 10 at a temperature corresponding to each steam temperature.^FiveTime creep rupture strength is 10kgf / mm²Above (preferably 10.5 kgf / mm²The steam emitted from the high-pressure steam turbine, medium-pressure steam turbine, or high-pressure side turbine made of martensitic cast steel containing 8 to 9.5% by weight of Cr is heated to the same level as or higher than the high-pressure side inlet temperature. It is preferable to use a high / medium pressure integrated steam turbine to be sent to the intermediate pressure side turbine.
[0023]
In the high-pressure turbine, the intermediate-pressure turbine, or the high-medium-pressure integrated steam turbine, the first stage of at least one of the rotor shaft or the moving blade and the stationary blade is C0.05 to 0.20%, Si 0.6% or less, preferably Is 0.15% or less, Mn is 1.5% or less, preferably 0.05 to 1.5%, Cr 8.5 to 13%, preferably 9.5 to 13%, Ni 0.05 to 1.0%, V0. 0.05 to 0.5%, preferably 0.05 to 0.35%, at least one of Nb and Ta 0.01 to 0.20%, N 0.01 to 0.1%, preferably 0.01 to 0.06%, Mo 1.5% or less, preferably 0.05 to 1.5%, W 0.1 to 4.0%, preferably 1.0 to 4.0%, Co 10% or less, preferably 0.0. High strength mars containing 5-10%, B 0.03% or less, preferably 0.0005-0.03% and having Fe of 78% or more Insight steel, preferably corresponding to a steam temperature of 593-660 ° C., or C 0.1-0.25%, Si 0.6% or less, Mn 1.5% or less, Cr 8.5-13%, Ni 0.5%. 05 to 1.0%, V 0.05 to 0.5%, W 0.10 to 0.65%, at least one of Nb and Ta, 0.01 to 0.20%, Al 0.1% or less, Mo 1.5 %, N0.025 to 0.1%, and high strength martensitic steel having 80% or more of Fe is preferable, and preferably corresponds to less than 600 to 620 ° C. The inner casing is C0.06-0.16% by weight, Si 0.5% or less, Mn 1% or less, Ni 0.2-1.0%, Cr 8-12%, V 0.05-0.35%, Nb and Ta. High strength including at least one kind of 0.01 to 0.15%, N 0.01 to 0.8%, Mo 1% or less, W 1 to 4%, B 0.0005 to 0.003%, and 85% or more of Fe It is preferably made of martensitic steel.
[0024]
In the steam turbine power plant according to the present invention, the high-pressure steam turbine has seven or more stages, preferably 9 to 12 or more stages of the moving blades, and the first stage is a double flow. It has a double flow structure in which there are six or more stages symmetrically and the first stage is planted in the center of the rotor shaft, and the high and medium pressure integrated steam turbine has six or more stages, preferably 7 More than 8 stages, more preferably 8 stages or more, and the intermediate pressure side blades have 5 stages or more, preferably 6 stages or more, and the low-pressure steam turbine has 5 stages or more, preferably 6 stages, each of the blades symmetrically. As described above, it is preferable to have a double flow structure having 8 to 10 stages and having the first stage implanted in the center of the rotor shaft.
[0025]
In the low-pressure turbine according to the present invention, the steam inlet temperature to the first stage rotor blade is preferably 350 to 400 ° C., and the rotor shaft has a bearing center distance (L) of 6500 mm or more (preferably 6600 to 7500 mm) and the stationary blade is The minimum diameter (D) at the provided portion is 750 to 1300 mm (preferably 760 to 900 mm), and the (L / D) is 5 to 10, preferably 7 to 10 (more preferably 8.0 to 9). 0.0) is preferably made of Ni-Cr-Mo-V low alloy steel containing the aforementioned Ni 3.25 to 4.25 wt%.
[0026]
The low-pressure steam turbine according to the present invention has a blade length of 80 to 1300 mm from the upstream side to the downstream side of the water vapor flow, and the diameter of the portion of the rotor shaft corresponding to the stationary blade is the diameter of the moving blade. More preferably, the axial width of the implanted portion is increased stepwise in the downstream side, preferably in three or more steps (more preferably 4 to 7 steps) compared to the upstream side, and the ratio to the wing length is 0. 0.2 to 0.8 (preferably 0.3 to 0.55), and the length from the upstream side to the downstream side becomes smaller, and the length of the blade portion of each adjacent stage is larger on the downstream side than on the upstream side. The ratio is gradually in the range of 1.2 to 1.8 (preferably 1.4 to 1.6), and the ratio is gradually increased on the downstream side, the stator blade of the rotor shaft The axial width of the part corresponding to the part is The flow side is preferably stepwise larger than the upstream side in three or more stages (more preferably 4 to 7 stages), and the ratio of the moving blade to the adjacent downstream blade length is 0.2 to 1.4 ( Preferably, any one or combination of the ratios gradually decreasing toward the downstream side in the range of 0.25 to 1.25, particularly 0.5 to 0.9).
[0027]
Hereinafter, other constituent materials of the low-pressure turbine will be described.
[0028]
(1) The low-pressure steam turbine rotor shaft is C0.2 to 0.35%, Si 0.1% or less, Mn 0.2% or less, Ni 3.25 to 4.25%, Cr 1.25 to 2.25% by weight. , Mo 0.1-0.6%, V 0.05-0.25% low alloy steel having a tempered bainitic structure is preferable, and is manufactured by the same manufacturing method as the above-described high pressure, medium pressure rotor shaft. preferable. In particular, the amount of Si is 0.01 to 0.05%, Mn is 0.05 to 0.2%, and other materials such as P, S, As, Sb, and Sn are used as much as possible, and the total amount is 0.025% or less. It is preferable to make a super-clean production using a raw material with less impurities. P and S are each preferably 0.010% or less, Sn, As 0.005% or less, and Sb 0.001% or less.
[0029]
(2) Other than the last stage of the low-pressure turbine blade and nozzles are C 0.05 to 0.2%, Si 0.1 to 0.5%, Mn 0.2 to 1.0%, Cr 10 to 13%, Mo 0.04 Fully tempered martensitic steel with ˜0.2% is preferred.
[0030]
(3) Carbon cast steel having C0.2 to 0.3%, Si 0.3 to 0.7%, and Mn 1% or less is preferable for both low pressure turbine internal and external canongs.
[0031]
(4) The main steam stop valve casing and steam control valve casing are C0.1 to 0.2%, Si 0.1 to 0.4%, Mn 0.2 to 1.0%, Cr 8.5 to 10.5%, Mo 0.3 to 1.0%, W 1.0 to 3.0%, V 0.1 to 0.3%, Nb 0.03 to 0.1%, N 0.03 to 0.08%, B 0.0005 to 0 All tempered martensitic steel containing 0.003% is preferred.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
[Example 1]
As a steam turbine blade material according to the present invention, α + β-type Ti consisting of Al 5.89%, V 5.98%, Fe 0.33%, O 0.16%, Sn 2.31%, Cu 0.40% and the balance Ti. An alloy was used. The pro-eutectoid α phase had a solution temperature of 48 to 55% at 800 ° C, 37 to 46% at 850 ° C, and 22 to 28% at 900 ° C.
[0033]
Wing length is1143 mm (45 inches)Fabricate a forged product (400mm, 190mm, 110mm) that will be the thickest part of the long blades of wings, and perform solution treatment at 800-900 ° C x 1 hour and aging treatment at 500-600 ° C x 4 hours The test pieces were collected from the 1/2 t part corresponding to the center of the thickness of the dovetail part and the 1/4 t part corresponding to the wing part, and subjected to a tensile test and an impact test at room temperature. The impact test is of V-notch and the cross-sectional area is 0.8cm²It is. The cooling in the solution treatment was performed in two ways: water cooling and blast cooling. The strength according to the cooling rate was evaluated based on the specimen collection position.
[0034]
Table 1 shows the tensile strength and impact absorption energy of 1/4 t part of the water-cooled material by water cooling as solution treatment, and Table 2 shows the tensile strength and impact absorption energy of 1/2 t part. In the 1 / 4t part where the cooling rate is fast, the target strength is 110 kg / mm for any heat treatment.²Although the above is satisfied, as the aging temperature increases, the strength decreases and the tolerance decreases. On the other hand, in the 1 / 2t part where the cooling rate is slow, the target strength is 110 kg / mm by solution at 900 ° C.²Although the above is not satisfied, the combination of solution treatment and aging temperature at 800 ° C., 500 ° C. and 600 ° C., 850 ° C., 500 ° C. and 600 ° C. is almost satisfactory. Moreover, compared with the result of the 1/4 t part where the cooling rate is fast, the influence of the cooling rate is smaller as the solution temperature is lower, and the influence of the aging temperature is smaller as the solution temperature is higher. On the other hand, there is no significant difference in impact absorbed energy, and it is considered that the decrease in fracture toughness value due to securing strength is small. From these results, the relationship between the aging temperature and the solution temperature for obtaining the target strength is summarized. In the case of water cooling during solution treatment, the hatched portions shown in FIG. 1, that is, A (605 ° C., 855 ° C.), B A range connecting four points (590 ° C., 790 ° C.), C (410 ° C., 790 ° C.), and D (410 ° C., 855 ° C.) is preferable.
[0035]
Further, as described above, the strength of the dovetail portion has about 99% of the strength of the blade portion when the solution treatment temperature is 800 ° C. or lower, but decreases to 96% and 92% when increased to 850 ° C. and 900 ° C., respectively. Therefore, the solution treatment temperature and the aging treatment temperature are adjusted as shown in FIG. 1 so that the strength of the dovetail portion is 96% or more with respect to the wing portion.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
Table 3 shows the tensile strength and impact absorption energy of the 1 / 2t part (the slowest part of the cooling rate) by blast cooling. Similar to the water-cooled material, the relationship between the aging temperature and the solution temperature for obtaining the target strength can be summarized as shown in FIG. In the hatching portion shown in FIG. 1, that is, within a range connecting four points of E (525 ° C., 855 ° C.), F (510 ° C., 790 ° C.), G (410 ° C., 790 ° C.), and H (410 ° C., 855 ° C.). Aging treatment temperature and solution treatment temperature are preferred.
[0039]
As shown in Table 3, it can be seen that the strength corresponding to the dovetail portion is 96% or more superior to that of the wing portion.
[0040]
0.02% of 800 ° C air blast coolant is 93 to 101kg / mm at 1 / 4t.², 1 / 2t part, 93-100kg / mm², 0.2% proof stress is 103-106kg / mm at 1 / 4t part², 96-107kg / mm at 1 / 2t²The elongation was 15 to 17% in all cases, and the drawing ratio was 22 to 43% at the 1/4 t portion and 40 to 50% at the 1/2 t portion. Hv hardness was 335-356.
[0041]
[Table 3]

[0042]
On the other hand, as a method of increasing the cooling rate of the thick-walled portion, there is a method of roughing dovetil before heat treatment, that is, a method of machining a slit corresponding to each fork when the dovetil is made into a fork type. In this method, the interval between the slits is smaller than 1/4 t, and there are about 5 to 10 slits. Therefore, the slit is cooled from the front surface, and the overall cooling rate is equal to or higher than the 1/4 t portion of the state before processing. Therefore, from the results shown in Table 1, the relationship between the aging temperature and the solution temperature for obtaining the target strength in the thick and thin portions can be summarized as shown in FIG. Part, that is, heat treatment in a range connecting four points of J (685 ° C, 855 ° C), K (585 ° C, 790 ° C), L (410 ° C, 790 ° C), M (410 ° C, 855 ° C) is possible. Become. The same applies to blast cooling at the time of solution. From the results in Table 3, the relationship between the aging temperature and the solution temperature for obtaining the target strength is summarized. The hatched portion shown in FIG. 4, that is, a range connecting four points of N (575 ° C., 855 ° C.), O (560 ° C., 790 ° C.), P (410 ° C., 790 ° C.), Q (410 ° C., 855 ° C.) Heat treatment is possible.
[0043]
In addition, there are fork type, reverse Christmas tree type, and saddle type in the form of dove-til, and any of them can be used.
[0044]
FIG. 5 is a diagram showing the relationship between the tensile strength of 1 / 2t and 1 / 4t. As shown in FIG. 5, when the solution treatment temperatures are 800 ° C. and 850 ° C., the difference due to the influence of the thickness at the solution treatment temperature is small, and the strength at the thickness of 1/2 t is smaller than the thickness of 1/4 t. 96.0% or more. However, the solution treatment at 900 ° C. is not preferable because it is affected by the wall thickness and the strength decreases to 94.4% or less.
[0045]
FIG. 6 is a diagram showing the relationship between the impact absorption energy (y) and the tensile strength (x) at ¼ t corresponding to the thickness of the wing portion. The lower limit line corresponds to y = −0.02x + 3.98, the upper limit line corresponds to y = −0.02x + 4.12, and the Ti-based alloy in this example represents the portion corresponding to the wing part. By making it within this range, it is possible to obtain a blade that is less affected by the difference in wall thickness.
[0046]
FIG. 7 is a diagram showing the relationship between the impact absorption energy (y) and the tensile strength (x) at 1 / 2t corresponding to the thickness of the dovetail. The lower limit line corresponds to y = −0.022x + 4.10, the upper limit line corresponds to y = −0.022x + 4.35, and the Ti-based alloy in this example corresponds to the portion of these lines. By setting it within the range, it is possible to obtain a blade having a small difference in tensile strength and impact absorption energy from the above-described wing portion.
[0047]
Furthermore, the impact absorption energy value at 1 / 2t and 1 / 4t is higher for the water cooling material in the wing than in the dovetail, and in the gust cooling material is higher in the dovetail than in the wing, both within 5%. It is getting higher.
[0048]
[Example 2]
Fig. 8 shows blade length for 3600rpm1092 mm (43 inches)It is a perspective view of the last stage steam turbine blade of the low-pressure turbine for steam temperature 538-650 ° C steam turbine of. Dovetil 52 is formed by eight forks and has a wing length1168 mm (46 inches)Will be nine. In this example, the Ti-based alloy described in Example 1 is used, and in particular, the tensile strength of the dovetail part is 110 kg / mm.² As described above, it is preferable to use a material in which the tensile strength of the dovetail portion is 96% or more of the tensile strength of the wing portion. 53 is a hole for inserting a pin, and 54 is an erosion shield, which is a C2 to Ti-based alloy or stellite containing V10 to 20%, Cr 1.5 to 5%, Al 1.5 to 5% and Sn 1.5 to 5%. A Co-based alloy containing 3%, Cr 20 to 35%, W 10 to 25%, Fe 0 to 10% is brazed or electron beam welded. The former Ti-based alloy was used. Reference numeral 57 denotes a continuous cover. 55 is a tie boss.
[0049]
A manufacturing example of the turbine blade according to this embodiment will be described below.
[0050]
First, an ingot having a composition equivalent to the alloy composition shown in Example 1 is roughly forged into a round bar material at about 850 ° C. in the α + β temperature range, and then a similar shape of the blade portion and the dovetail portion by stamping forging at the same temperature. The wing material was formed. All parts were about 1.3 times thicker than the final finished dimensions. Subsequently, it hold | maintained at 850 degreeC for 1 hour, and the whole was thrown into water and quenched. After quenching, it was machined to almost the final shape by NC processing, and then a Ti-based alloy plate containing 15% V, 3% Cr, 3% Al and 3% Sn by weight was brazed to the leading edge of the wing tip. . Next, the blade portion was fixed to a jig having a predetermined profile shape, and heated for aging at 500 ° C. for 4 hours while serving as aging. The erosion shield 54 is pre-heated at 800 ° C. for 20 minutes and then oil-quenched.
[0051]
After the final heat treatment as described above, the final profile blade profile, blade implant portion and its pin insertion hole are processed by final machining to obtain a product. The tensile strength of the wing implantation part with respect to the wing part of this example was 98% or more, and the impact value was equivalent.
[0052]
The wing implantation part 52 of this embodiment is of eight fork types, and has three pin insertion holes for one fork. Further, a continuous cover 57 is provided at the tip of the wing 51 as seen from the side surface of FIG. 8 in the same manner as in FIG. In addition, the implanted portion of the wing portion 51 is substantially parallel to the axial direction of the rotor shaft, but the tip thereof is twisted so as to intersect with the axial direction at about 75.5 degrees. The continuous cover 57 has the same composition as the wing material, and corresponds to a thickness of 1/4 t.
[0053]
For 3000 rpm, a blade having a blade length of 52 inches or more can be manufactured in the same manner as in this embodiment. The number of forks on this wing is nine.
[0054]
Example 3
FIG. 9 is a side view of an inverted Christmas tree type in which the wing implantation part is replaced with a fork type. The steam turbine blade shown in this drawing is the same as the above-described FIG. Also in this example, the Ti-based alloy of Example 1 is used. As shown in this figure, the wing implantation part 52 has four straight projections on both sides, and the wing part by high speed rotation is implanted and fixed to the rotor shaft by these projections. And the groove | channel which has the space same as this external shape is formed in the rotor shaft so that it may be implanted along the axial direction of a rotor shaft. Furthermore, a continuous cover 57 is provided at the tip of the wing 51, and the wing of the implanted portion is formed substantially parallel to the axial direction of the rotor shaft. On the other hand, it is formed so as to cross about 75.5 degrees.
[0055]
Also in this embodiment, the blade length is at a rotational speed of 3600 rpm.1092 mm (43 inches),1168 mm (46 inches),1219 mm (48 inches)Can be formed, and for a rotational speed of 3000 rpm1320 mm (52 inches)The above can be formed. The aforementioned protrusion is1168 mm (46 inches)Up to 4 stages,1219 mm (48 inches)For the above, five steps were used.
[0056]
Furthermore, the erosion shield 54 is joined in the same manner using a Ti-base alloy plate or a Co-base alloy plate as described above.
[0057]
Example 4
Table 4 shows the main specifications of the steam temperature of 625 ° C. and 1050 MW steam turbine according to the present invention. In this embodiment, the blade length of the final stage blade in a cross-compound type four-flow exhaust, low-pressure turbine is1092 mm (43 inches)A is two HP-IP and LP units, 3600 rpm, B is HP-LP and IP-LP, each having the same rotational speed of 3600 RPM, and is composed of the main materials shown in Table 4 in the high temperature part. Steam temperature of high pressure part (HP) is 625 ° C, 250kgf / cm² The steam temperature of the intermediate pressure part (IP) is heated to 625 ° C. by a reheater and is 45 to 65 kgf / cm.² It is operated at the pressure of The low pressure part (LP) enters at a steam temperature of 400 ° C., and is sent to the condenser with a vacuum of 100 ° C. or less and 722 mmHg.
[0058]
In this embodiment, the total distance between the bearings of the two low-pressure turbines connected to the tandem and the distance between the bearings connecting the high-pressure turbine and the medium-pressure turbine to the tandem with respect to the blade length of the last stage moving blade of the low-pressure turbine is about It is 31.5m and the ratio is 28.8, making it compact.
[0059]
Further, the total distance between the bearings of the high-pressure turbine and the medium-pressure turbine coupled to the tandem and the distance between the bearings of the two low-pressure turbines coupled to the tandem with respect to the rated output (MW) of the steam turbine power plant in this embodiment. The ratio of distance (mm) is 30.
[0060]
[Table 4]

[0061]
FIG. 10 is a cross-sectional configuration diagram of the high-pressure and intermediate-pressure steam turbine in A of the turbine configuration in Table 4. The high-pressure steam turbine is provided with a high-pressure axle (high-pressure rotor shaft) 23 in which high-pressure rotor blades 16 are implanted in a high-pressure internal casing 18 and a high-pressure external casing 19 outside thereof. The high-temperature and high-pressure steam is obtained by the above-described boiler, passes through the main steam pipe, passes through the main steam inlet 28 from the flange and elbow 25 constituting the main steam inlet, and is led from the nozzle box 38 to the first stage double-flow rotor blade. The first stage is a double flow, and eight stages are provided on one side. A stationary blade is provided for each of these blades. The moving blade is a vertical dovetail type, double tinon, and the first stage blade length is about 35 mm. The length between the axles is about 5.8 m, the diameter of the smallest part corresponding to the stationary blade part is about 710 mm, and the ratio of the length to the diameter is about 8.2.
[0062]
In this embodiment, the first stage blade and the first stage nozzle are used for the materials shown in Table 7 to be described later, and the other blades and nozzles are all made of 12% Cr steel containing no W, Co and B. The length of the blade portion of the moving blade in the present embodiment is 35 to 50 mm in the first stage and becomes longer in each stage from the second stage to the last stage, and in particular, the length from the second stage to the last stage depending on the output of the steam turbine. The length is 65 to 180 mm, the number of stages is 9 to 12, and the length of the wing portion of each stage is longer at a rate of 1.10 to 1.15 with the downstream side being adjacent to the upstream side. The ratio gradually increases on the downstream side.
[0063]
The distance between the bearings of the high-pressure turbine in this embodiment is about 5.3 m 2, and the ratio of the distance between the bearings to the blade length of the last stage blade of the low-pressure turbine is 4.8. The ratio of the distance (mm) between the bearings of the high-pressure turbine to the rated output (MW) of the power plant is 5.0.
[0064]
The medium pressure steam turbine rotates the generator together with the high pressure steam turbine by the steam heated from the high pressure steam turbine to 625 ° C. again by the reheater, and is rotated at a rotational speed of 3000 times / min. . Similar to the high-pressure turbine, the intermediate-pressure turbine has an intermediate-pressure internal second casing 21 and an intermediate-pressure external casing 22, and a stationary blade is provided in opposition to the intermediate-pressure moving blade 17. The rotor blades 17 have six stages and two flows, and are provided on the left and right sides almost symmetrically with respect to the longitudinal direction of the medium pressure axle (medium pressure rotor shaft). The distance between the bearing centers is about 5.8 m, the first stage blade length is about 100 mm, and the last stage blade length is about 230 mm. The first and second stage dovetails are reverse chestnut type. The diameter of the rotor shaft corresponding to the stationary blade before the final stage moving blade is about 630 mm, and the ratio of the distance between the bearings to the diameter is about 9.2 times.
[0065]
The rotor shaft of the medium pressure steam turbine of this embodiment has a stepwise increase in the axial width of the rotor blade implantation portion in three stages from the first stage to the fourth stage, the fifth stage, and the last stage. It is about 1.4 times larger than that.
[0066]
Further, the diameter of the portion of the rotor shaft of the steam turbine corresponding to the stationary blade portion is small, and the width thereof is gradually reduced in four stages according to the first stage blade, the second stage, and the last stage blade. Therefore, the width in the latter axial direction with respect to the former is reduced to about 0.75 times.
[0067]
In this embodiment, 12% Cr steel not containing W, Co and B is used except that the materials shown in Table 7 to be described later are used for the first stage blade and nozzle. The length of the blade portion of the moving blade in this embodiment becomes longer in each stage from the first stage to the last stage, and the length from the first stage to the last stage is 60 to 300 mm depending on the output of the steam turbine. In the stage, the length of the wing portion of each stage is a length adjacent to the upstream side on the downstream side, and is increased at a rate of 1.1 to 1.2.
[0068]
The diameter of the implanted portion of the moving blade is larger than that of the portion corresponding to the stationary blade, and the width of the implanted portion increases as the blade length of the moving blade increases. The ratio of the width to the blade length of the moving blade is 0.35 to 0.8 from the first stage to the last stage, and is gradually reduced from the first stage to the last stage.
[0069]
The intermediate pressure turbine in this embodiment has a bearing distance of about 5.5 m, the ratio of the intermediate pressure turbine bearing distance to the blade length of the last stage rotor blade of the low pressure turbine is 5.0, and power generation The ratio of the distance (mm) between the bearings to the rated output (MW) of the plant is 5.2.
[0070]
The turbine blades implanted in the first stage of the high-pressure turbine are of a saddle type, and the turbine blades implanted in the second and subsequent stages of the high-pressure turbine and in all stages of the intermediate-pressure turbine are of an inverted Christmas tree type.
[0071]
FIG. 11 is a cross-sectional view of a low-pressure turbine having a rotational speed of 3600 rpm. The low-pressure turbine is coupled to two tandems and has almost the same structure. Each of the moving blades 41 has eight stages on the left and right sides and is substantially symmetric with respect to the left and right. As the final stage moving blade, the steam turbine blade made of a Ti-based alloy having a blade length of 43 inches double tinon shown in Example 2 or 3 was used. The nozzle box 45 is a double flow type.
[0072]
For the rotor shaft 44, super-clean tempered bainite steel shown in Table 5 is used. The steel shown in Table 5 was examined using a 5 kg steel ingot. These steels are subjected to tempering by heating at 575 ° C. × 32 h after quenching at 840 ° C. × 3 h after hot forging, cooling at 100 ° C./h. Table 6 shows the characteristics at room temperature.
[0073]
[Table 5]

[0074]
[Table 6]

[0075]
All samples have a total tempered bainite structure. 0.02% yield strength 80kg / mm²Above, tensile strength 100kg / mm² As described above, the V notch impact value is 10 kg-m or more, FATT is −20 ° C. or less, and has high strength and high toughness.1092 mm (43 inches)Of course,1168 mm (46 inches)Satisfied the planting of. No. 4 having a slightly high Cr content has a low strength, and Cr is preferably up to about 2.20%. In particular, the 0.2% proof stress (y) is preferably set to be not less than the value obtained by (1.35x-20), more preferably (1.35x-19), from 0.02% proof stress (x).
[0076]
For the moving blades and stationary blades other than the final stage, 12% Cr steel containing 0.1% Mo is used. The inner and outer casing material is C0.25% cast steel. The distance between the centers of the bearings 43 in this embodiment is 7500 mm, the diameter of the rotor shaft corresponding to the stationary blade portion is about 1280 mm, and the diameter at the moving blade implantation portion is 2275 mm. The distance between the bearing centers for this rotor shaft diameter is about 5.9.
[0077]
In this embodiment, the continuous cover 57 is formed by cutting after forging as a whole. The continuous cover 57 can also be formed mechanically and integrally.
[0078]
In the low-pressure turbine of the present embodiment, the axial width of the moving blade implantation portion is gradually increased in four stages from the first stage to the third stage, the fourth stage, the fifth stage, the sixth stage to the seventh stage, and the eighth stage. Is about 2.5 times larger than the width of the first stage.
[0079]
In addition, the diameter of the part corresponding to the stationary blade part is small, and the axial width of that part gradually increases from the first stage moving blade side to the fifth, sixth and seventh stages. The width on the final stage side is about 1.9 times larger than that between the first stage and the second stage.
[0080]
In this embodiment, there are 8 blades, and the blade length is the first stage.76 mm (3inch )From1092 mm (43inch)The length from the first stage to the last stage is 90 to 1270 mm depending on the output of the steam turbine, and 8 stages or 9 stages. The blade length of each stage is the upstream side on the downstream side. The length adjacent to each other is 1.3 to 1.6 times longer.
[0081]
The diameter of the implanted portion of the moving blade is larger than that of the portion corresponding to the stationary blade, and the width of the implanted portion increases as the blade length of the moving blade increases. The ratio of the width to the blade length of the moving blade is 0.15 to 0.19 from the first stage to the last stage, and is gradually reduced from the first stage to the last stage.
[0082]
Further, the width of the rotor shaft at the portion corresponding to each stationary blade is gradually increased in each stage from between the first stage and the second stage to between the last stage and the front thereof. The ratio of the width to the blade length of the moving blade is 0.25 to 1.25, and decreases from the upstream side to the downstream side.
[0083]
Two low-pressure turbines in this embodiment are connected in tandem, and the total distance between the bearings is about 18.3 m 2, and the two low-pressure turbines connected in tandem with respect to the blade length of the last stage blade of the low-pressure turbine The total ratio of the distance between the bearings of the low-pressure turbines at both ends of the two units coupled in tandem to the rated output 1050 (MW) of the power plant is 16.7. 17.4.
In addition to this embodiment, the same configuration is applied to a 1000 MW class large-capacity power plant in which the steam inlet temperature to the high-pressure steam turbine and the medium-pressure steam turbine is 610 ° C. and the steam inlet temperature to the two low-pressure steam turbines is 385 ° C. It can be.
[0084]
The high-temperature high-pressure steam turbine plant in this embodiment is mainly a coal-fired boiler, high-pressure turbine, medium-pressure turbine, two low-pressure turbines, a condenser, a condensate pump, a low-pressure feed water heater system, a deaerator, a boost pump, and a feed water pump. It consists of a high-pressure feed water heater system. That is, the super high temperature and high pressure steam generated in the boiler enters the high pressure turbine to generate power, and then is reheated again in the boiler and enters the intermediate pressure turbine to generate power. The intermediate-pressure turbine exhaust steam enters the low-pressure turbine, generates power, and then condenses in the condenser. This condensate is sent to a low-pressure feed water heater system and a deaerator by a condensate pump. The feed water deaerated by the deaerator is sent to a high-pressure feed water heater by a booster pump and a feed water pump, and after being heated, returns to the boiler.
[0085]
Here, in the boiler, the feed water passes through a economizer, an evaporator, and a superheater and becomes high-temperature and high-pressure steam. On the other hand, the boiler combustion gas that has heated the steam exits the economizer and enters the air heater to heat the air. Here, a feed water pump driving turbine that is operated by extracted steam from an intermediate pressure turbine is used to drive the feed water pump.
[0086]
In a high-temperature and high-pressure steam turbine plant configured in this way, the temperature of the feed water leaving the high-pressure feed water heater system is much higher than the feed water temperature in the conventional thermal power plant, so inevitably the node in the boiler The temperature of the combustion gas leaving the charcoal is also much higher than that of a conventional boiler. For this reason, heat recovery from this boiler exhaust gas is carried out so as not to lower the gas temperature.
[0087]
Further, instead of the present embodiment, a tandem compound power plant that generates power by connecting one low-pressure turbine to each of the same high-pressure turbine and medium-pressure turbine in tandem and connecting one generator to each tandem. It can be configured similarly. In the output 1050 MW class generator of this embodiment, a generator shaft having higher strength is used. In particular, C 0.15 to 0.30%, Si 0.1 to 0.3%, Mn 0.5% or less, Ni 3.25 to 4.5%, Cr 2.05 to 3.0%, Mo 0.25 to 0.3. It has a total tempered bainitic structure containing 60%, V 0.05 to 0.20%, and a room temperature tensile strength of 93 kgf / mm.²Above, especially 100kgf / mm²As described above, 50% FATT is preferably 0 ° C. or less, particularly −20 ° C. or less, the magnetizing force at 21.2 KG is 985 AT / cm or less, and the total amount of P, S, Sn, Sb, As as impurities Is preferably 0.025% or less and the Ni / Cr ratio is 2.0 or less.
[0088]
The high-pressure turbine shaft has a structure in which nine stages of blades are planted around the first stage blade planting section on the multi-stage side. The medium pressure turbine shaft has multistage blades provided with blade planting portions approximately symmetrically on the left and right sides, each having a substantially centered border. The rotor shaft for the low-pressure turbine is not shown in the figure, but any rotor shaft of high-pressure, medium-pressure, or low-pressure turbine has a center hole, and through this center hole there is no defect by ultrasonic inspection, visual inspection and fluorescence flaw detection Is inspected. Moreover, it can carry out by ultrasonic inspection from the outer surface, and there may be no central hole.
[0089]
Table 7 shows the chemical composition (% by weight) used in the main parts of the high-pressure turbine, intermediate-pressure turbine, and low-pressure turbine according to the power plant of the example. In this example, the high-temperature part and the high-temperature part of the medium-pressure part all have a thermal expansion coefficient of about 12 × 10 having a ferrite crystal structure.^-6Since there was no difference in thermal expansion coefficient, there was no problem at all.
[0090]
The rotor shaft of the high-pressure turbine and the medium-pressure turbine is prepared by melting 30 tons of heat-resistant cast steel listed in Table 7 (wt%) in an electric furnace, decarbonizing it in a vacuum, casting it in a mold, and forging it to form an electrode rod. The electroslag was remelted as an electrode rod so as to melt from the upper part to the lower part of the cast steel, and forged into a rotor shape (diameter 1050 mm, length 3700 mm). This forging was performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. The forged steel is annealed and then heated to 1050 ° C., subjected to water spray cooling quenching, tempered twice at 570 ° C. and 690 ° C., and obtained into a final shape by cutting. In this embodiment, the upper side of the electroslag steel ingot is set to the first stage blade side, and the lower side is set to the final stage side. Each rotor shaft has a central hole, and the central hole can be eliminated by reducing impurities. The high pressure and intermediate pressure blades and nozzles are similarly melted in the vacuum arc melting furnace in Table 7 and forged into blade and nozzle material shapes (width 150mm, height 50mm, length 1000mm). And molded. This forging was performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. The forged steel is heated to 1050 ° C., subjected to oil quenching, tempered at 690 ° C., and then cut into a predetermined shape.
[0091]
The inner casing, the main steam stop valve casing, and the steam control valve casing of the high-pressure part and the intermediate-pressure part were prepared by melting the heat-resistant cast steel shown in Table 7 in an electric furnace, ladle refining, and casting into a sand mold. By carrying out sufficient refining and deoxidation before casting, a product having no casting defects such as shrinkage cavities was obtained. The weldability evaluation using this casing material was performed according to JIS Z3158. Preheating, between passes, and after heat start temperature were 200 ° C., and post heat treatment was 400 ° C. × 30 minutes. The material of the present invention had no weld cracks and good weldability.
[0092]
[Table 7]

[0093]
Table 8 shows the mechanical properties and heat treatment conditions obtained by cutting the above-described ferritic steel high-temperature steam turbine main members.
[0094]
As a result of investigating the center portion of the rotor shaft, the characteristics required for the high-pressure and medium-pressure turbine rotor (625 ° C., 10^Fiveh Strength ≧ 10kgf / mm², 20 ° C. shock absorption energy ≧ 1.5 kgf−m) was sufficiently satisfied. This demonstrated that a steam turbine rotor that can be used in steam at 620 ° C. or higher can be manufactured. Further, as a result of investigating the characteristics of this blade, the characteristics required for the first stage blade of a high-pressure / medium-pressure turbine (625 ° C., 10^Fiveh Strength ≧ 15kgf / mm²) Was sufficiently satisfied. This demonstrated that a steam turbine blade that can be used in steam at 620 ° C. or higher can be produced.
[0095]
Furthermore, as a result of investigating the characteristics of this casing, the characteristics required for high-pressure and medium-pressure turbine casings (625 ° C., 10^Fiveh Strength ≧ 10kgf / mm², 20 ° C. impact absorption energy ≧ 1 kgf-m) and sufficiently weldable. This demonstrated that a steam turbine casing that can be used in steam at 620 ° C. or higher can be produced.
[0096]
[Table 8]

[0097]
In this example, Cr—Mo low alloy steel was overlay welded to the journal portion of the high and medium pressure rotor shafts to improve the bearing characteristics. Overlay welding is as follows.
[0098]
A coated arc welding rod (diameter: 4.0φ) was used as a test welding rod. Table 9 shows the chemical composition (% by weight) of the deposited metal of the welded metal using the welding rod. The composition of the deposited metal is almost the same as the composition of the welding material. The welding conditions are a welding current of 170 A, a voltage of 24 V, and a speed of 26 cm / min.
[0099]
[Table 9]

[0100]
As shown in Table 10, the overlay welding was performed on the surface of the above-mentioned specimen base material, and the welding rods used for each layer were combined to carry out eight layers of welding. The thickness of each layer was 3-4 mm, the total thickness was about 28 mm, and the surface was ground about 5 mm.
[0101]
The welding conditions are preheating, between passes, stress relief annealing (SR) start temperature is 250 to 350 ° C., and SR treatment condition is 630 ° C. × 36 hours.
[0102]
[Table 10]

[0103]
In order to confirm the performance of the welded portion, overlay welding was similarly performed on the plate material, and a 160 ° side bending test was performed, but no crack was observed in the welded portion.
[0104]
Furthermore, a bearing sliding test by rotation according to the present invention was performed, and none of the bearings had an adverse effect on the bearing and was excellent in oxidation resistance.
[0105]
In place of the present embodiment, a high pressure steam turbine, an intermediate pressure steam turbine, and one or two low pressure steam turbines are connected to a tandem to form a tandem power plant with 3600 revolutions and a turbine configuration B shown in Table 4 The high-pressure turbine, medium-pressure turbine, and low-pressure turbine can be combined in the same manner.
[0106]
Example 5
Table 11 shows the main specifications of the main steam temperature of 538 ° C./566° C. and the rated output 700 MW steam turbine. In this example, the final stage blade length in a tandem compound double flow type low pressure turbine is1168 mm (46 inches)HP (high pressure) / IP (medium pressure) integrated type and LP (1) (C) or 2 (D) have a rotation speed of 3600rpm, and the high temperature part is composed of the main materials shown in the table . Steam temperature of high pressure part (HP) is 538 ° C, 246kgf / cm² The steam temperature of the intermediate pressure part (IP) is heated to 566 ° C. by a reheater and is 45 to 65 kgf / cm.² It is operated at the pressure of The low pressure part (LP) enters at a steam temperature of 400 ° C., and is sent to the condenser with a vacuum of 100 ° C. or less and 722 mmHg.
[0107]
The steam turbine power plant equipped with a high-medium pressure integrated turbine in which the high-pressure turbine and the medium-pressure turbine are integrated in the present embodiment and two low-pressure turbines in tandem has a distance between the bearings of about 22.7 m. The total ratio of the distance between the bearings of the high-medium pressure integrated turbine to the blade length (1168 mm) of the last stage rotor blade and the distance between the bearings of the two low-pressure turbines coupled to the tandem is 19.4.
[0108]
Further, the steam turbine power plant including the high- and intermediate-pressure integrated turbine in which the high-pressure turbine and the intermediate-pressure turbine are integrated in this embodiment and one low-pressure turbine has a bearing distance of about 14.7 m, and the final low-pressure turbine. The ratio of the total distance between the bearings of the high- and medium-pressure integrated turbine and the distance between the bearings of the one low-pressure turbine to the blade length (1168 mm) of the step rotor blade is 12.6. Further, the ratio of the total distance between the bearings of the high-medium-pressure integrated turbine and the distance between the bearings of one low-pressure turbine to 1 MW at the rated output 700 MW of the power plant is 21.0.
[0109]
[Table 11]

[0110]
FIG. 12 is a cross-sectional view of a cross-sectional configuration diagram of a high-pressure / medium-pressure integrated steam turbine. The high pressure side steam turbine is provided with a high / medium pressure axle (high pressure rotor shaft) 33 in which high pressure blades 16 are implanted in a high pressure internal casing 18 and a high pressure external casing 19 outside thereof. The above-mentioned high-temperature and high-pressure steam is obtained by the above-described boiler, passes through the main steam pipe, passes through the main steam inlet 28 from the flange and elbow 25 constituting the main steam inlet, and is led from the nozzle box 38 to the first stage blade. . Steam enters from the center side of the rotor shaft and flows to the bearing side. The rotor blades are provided in 8 stages on the high pressure side on the left side in the figure and 6 stages on the intermediate pressure side (about half of the right side in the figure). A stationary blade is provided for each of these blades. The rotor blades are saddle type or getter type, dovetail type, double tinon, high pressure side first stage blade length of about 40 mm, and medium pressure side first stage blade length is 100 mm. The length between the bearings 43 is about 6.7 m, and the diameter of the smallest portion corresponding to the stationary blade portion is about 740 mm, and the ratio of the length to the diameter is about 9.0.
[0111]
The first stage and the last stage of the rotor blade implantation root part of the high pressure side rotor shaft are the widest at the first stage, the second stage to the seventh stage are smaller, and the first stage is 0.40 to 0.56 times the same. The final stage is between the first stage and the second to seventh stages, and is 0.46 to 0.62 times larger than the first stage.
[0112]
On the high-pressure side, the blade and nozzle are made of 12% Cr steel shown in Table 7 above. The length of the blade portion of the moving blade in the present embodiment is 35 to 50 mm in the first stage and becomes longer in each stage from the second stage to the last stage, and in particular, the length from the second stage to the last stage depending on the output of the steam turbine. Is in the range of 50 to 150 mm, the number of stages is in the range of 7 to 12 stages, and the length of the wings of each stage is 1.05 to 1. While it becomes long within the range of 35 times, the ratio is gradually increased on the downstream side.
[0113]
The medium-pressure steam turbine rotates the generator together with the high-pressure steam turbine by steam heated from the high-pressure steam turbine again to 566 ° C. by the reheater, and is rotated at a rotational speed of 3600 rpm. The medium pressure side turbine has a medium pressure internal second casing 21 and a medium pressure external casing 22 in the same manner as the high pressure side turbine, and a stationary blade is provided in opposition to the medium pressure moving blade 17. The medium pressure rotor blade 17 has six stages. The first stage blade length is about 130 mm, and the last stage blade length is about 260 mm. Dovetil is a reverse chestnut type.
[0114]
The rotor shaft of the medium pressure steam turbine has the largest axial width at the root of the rotor blade implantation at the first stage, the second stage is smaller than that, the third to fifth stages are smaller than the second stage, and both are the same. The width is the size between the third and fifth stages and the second stage, and is 0.48 to 0.64 times that of the first stage. The first stage is 1.1 to 1.5 times the second stage.
[0115]
On the medium pressure side, the 12% Cr steel shown in Table 7 is used for the blade and nozzle. The length of the blade portion of the moving blade in this embodiment becomes longer in each stage from the first stage to the last stage, and the length from the first stage to the last stage is 90 to 350 mm and the number of stages is 6 to 6 depending on the output of the steam turbine. Within the range of 9 stages, the length of the wings of each stage is longer at a rate of 1.10 to 1.25, with the downstream side being adjacent to the upstream side.
[0116]
The implanted portion of the moving blade has a larger diameter than the portion corresponding to the stationary blade, and its width is related to the length and position of the moving blade. The ratio of the width to the blade length of the moving blade is the largest at the first stage, 1.35 to 1.80 times, the second stage is 0.88 to 1.18 times, and the third to sixth stages become the final stage. It is small, 0.40 to 0.65 times. The high-medium pressure integrated turbine for the steam turbine power plant including two low-pressure turbines coupled to the tandem in this embodiment has a bearing distance of about 5.7 m and the blade length of the last stage blade of the low-pressure turbine ( The ratio of the distance between the bearings to 1168 mm) is 5.7.
[0117]
Also in this embodiment, the bearing portion is provided with a built-up weld layer of low alloy steel as in the third embodiment.
[0118]
FIG. 13 is a cross-sectional view of a 3600 rpm low pressure turbine and FIG. 14 is a rotor shaft thereof.
[0119]
One low-pressure turbine is connected in tandem to a high medium pressure of main steam 538 ° C / 566 ° C. The moving blade 41 has six stages on the left and right sides, is substantially symmetrical, and a stationary blade 42 is provided corresponding to the moving blade. The last stage blade length is1168 mm (46 inches)Yes, a Ti-based alloy is used. As the Ti-based alloy, those shown in Examples 1 and 2 are used. In particular, it contains A16%, V6% and sn2% by weight. Further, the same rotor shaft 43 as in Example 2 was used, and Ni 3.75%, Cr 1.75%, Mo 0.4%, V 0.15%, C 0.25%, Si 0.05%, Mn 0.10. %, Forged steel having a fully tempered bainitic structure of super clean material composed of residual Fe. 12% Cr steel containing 0.1% Mo is used for the moving blades and stationary blades other than the final stage and the preceding stage. The inner and outer casing material is C0.25% cast steel. In this embodiment, the distance between the centers of the bearings 43 is 7000 mm, the diameter of the rotor shaft corresponding to the stationary blade portion is about 800 mm, and the diameter at the moving blade implantation portion is the same in each stage. The distance between the bearing centers with respect to the rotor shaft diameter corresponding to the stator blade is about 8.8.
[0120]
In the low-pressure turbine, the axial width of the root portion of the rotor blade implantation is the smallest at the first stage, the second and third stages are the same on the downstream side, the fourth and fifth stages are the same, and gradually increase in four stages. The width is 6.2 to 7.0 times larger than the width of the first stage. The second and third stages are 1.15 to 1.40 times the first stage, the fourth and fifth stages are 2.2 to 2.6 times the second and third stages, and the last stage is 4,8 to 3.2 times It has doubled. The width of the root portion is indicated by a point connecting a diverging extension line and the diameter of the rotor shaft.
[0121]
The blade length of the moving blade in this embodiment becomes longer in each stage as it reaches the final stage from 4 "to 46" in the first stage, and the length from the first stage to the last stage is in the range of 100 to 1270 mm depending on the output of the steam turbine. Among them, the maximum length is 8 stages, and the wing length of each stage is longer in the range of 1.2 to 1.9 times that the downstream side is adjacent to the upstream side.
[0122]
The root portion of the moving blade has a larger diameter than the portion corresponding to the stationary blade, and its width increases as the blade length of the moving blade increases. The ratio of the width to the blade length of the moving blade is 0.30 to 1.5 from the first stage to the last stage, and the ratio gradually decreases from the first stage to the last stage. The ratio of the latter stage is gradually smaller within the range of 0.15 to 0.40 than that of the immediately preceding stage. The final stage is a ratio of 0.50 to 0.65.
[0123]
The erosion shield in the present embodiment is provided in the same manner as in the second embodiment.
[0124]
In addition to this embodiment, the same applies to a 1000 MW class large-capacity power plant in which the steam inlet temperature of the high and medium pressure steam turbine is 610 ° C or higher, the steam inlet temperature to the low pressure steam turbine is about 400 ° C, and the outlet temperature is about 60 ° C. It can be configured.
[0125]
The high-temperature high-pressure steam turbine power plant in this embodiment is mainly a boiler, a high-medium pressure turbine, a low-pressure turbine, a condenser, a condensate pump, a low-pressure feed water heater system, a deaerator, a boost pump, a feed pump, and a high-pressure feed water heater system. Etc. That is, the super high temperature and high pressure steam generated in the boiler enters the high pressure turbine and generates power, and then is reheated again in the boiler to enter the intermediate pressure turbine and generate power. The high and medium pressure turbine exhaust steam enters the low pressure turbine to generate power, and then condenses in the condenser. This condensate is sent to a low-pressure feed water heater system and a deaerator by a condensate pump. The feed water deaerated by the deaerator is sent to a high-pressure feed water heater by a booster pump and a feed water pump, and after being heated, returns to the boiler.
[0126]
Here, in the boiler, the feed water passes through a economizer, an evaporator, and a superheater and becomes high-temperature and high-pressure steam. On the other hand, the boiler combustion gas that has heated the steam exits the economizer and enters the air heater to heat the air. Here, a feed water pump driving turbine that is operated by extracted steam from an intermediate pressure turbine is used to drive the feed water pump.
[0127]
In a high-temperature and high-pressure steam turbine plant configured in this way, the temperature of the feed water leaving the high-pressure feed water heater system is much higher than the feed water temperature in the conventional thermal power plant, so inevitably the node in the boiler The temperature of the combustion gas leaving the charcoal is also much higher than that of a conventional boiler. For this reason, heat recovery from this boiler exhaust gas is carried out so as not to lower the gas temperature.
[0128]
Table 7 above shows the chemical composition (% by weight) used in the main part of the high and medium pressure turbine and the low pressure turbine of this example. In this embodiment, the rotor shaft integrated with the high pressure side and the medium pressure side is C0.11%, Si 0.02%, Mn 0.45%, Ni 0.50%, Cr 11.21%, Mo 0.25%, Except for using martensitic steel consisting of W 2.78%, V 0.20%, Nb 0.07%, Co 1.50%, N 0.025%, B 0.016% and the balance Fe, all of those shown in Table 7 were used. Thermal expansion coefficient 12 × 10 having a ferrite-based crystal structure^-6Since there was no difference in thermal expansion coefficient, there was no problem at all.
[0129]
In this embodiment, a tandem compound double flow power plant is constructed in which a high-medium pressure turbine and one low-pressure turbine are connected to one generator tandem to generate power. As another embodiment, two low-pressure turbines are connected in tandem, and power generation with an output of 1050 MW can be configured in the same manner as in this embodiment. A higher strength shaft is used as the generator shaft. In particular, C 0.15 to 0.30%, Si 0.1 to 0.3%, Mn 0.5% or less, Ni 3.25 to 4.5%, Cr 2.05 to 3.0%, Mo 0.25 to 0.5. It has a total tempered bainitic structure containing 60%, V 0.05 to 0.20%, and a room temperature tensile strength of 93 kgf / mm.²Above, especially 100kgf / mm²As described above, 50% FATT is preferably 0 ° C. or lower, particularly −20 ° C. or lower. The magnetic force is 985 AT / cm or lower at 21.2 KG. Those with 0.025% or less and Ni / Cr ratio of 2.0 or less are preferable.
[0130]
The aforementioned Table 7 is similarly used for the main part of the high and medium pressure turbine and the low pressure turbine of this embodiment. In this example, the thermal expansion coefficient 12 × having a ferrite-based crystal structure is obtained by using martensite steel for the periphery of the other rotating portion of the high and medium pressure integrated rotor shaft in which the high pressure side and the medium pressure side are integrated. 10^-6Since there was no difference in thermal expansion coefficient, there was no problem at all.
[0131]
In addition, the high / medium pressure integrated rotor shaft in this example is prepared by melting 30 tons of the above heat-resistant cast steel in an electric furnace, decarbonizing it in a carbon mold, casting it in a mold, and forging it to produce an electrode rod. The electroslag was remelted so as to melt from the upper part to the lower part of the cast steel, and forged into a rotor shape (diameter 1450 mm, length 5000 mm). This forging was performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. Further, this forged steel is annealed and heated to 1050 ° C., water spray cooling quenching treatment, tempering twice at 570 ° C. and 690 ° C., and cutting into a predetermined shape. Further, a cladding weld layer of Cr—Mo low alloy steel is applied to the bearing portion.
[0132]
The low-pressure turbine for a steam turbine power plant having two low-pressure turbines coupled to the tandem in this embodiment has a total bearing distance of 13.9 m, which is in tandem with the blade length of the last stage rotor blade of the low-pressure turbine. The ratio of the distance between the bearings of the two low-pressure turbines connected is 16.3, and the total distance (mm) between the bearings of the two low-pressure turbines connected in tandem to the rated output (MW) of the power plant The ratio is 23.1.
[0133]
The low-pressure turbine for a steam turbine power plant including the high- and intermediate-pressure integrated turbine in which the high-pressure turbine and the intermediate-pressure turbine are integrated in this embodiment and one low-pressure turbine has a bearing distance of about 6 m. The ratio of the blade length of the stage blade to 5.5, and the ratio of the bearing distance (mm) of one low-pressure turbine to the rated output (MW) of the power plant of the distance between the bearings of one low-pressure turbine Is 10.0.
[0134]
The high-medium pressure integrated rotor shaft in this embodiment has a center hole in any of the rotor shafts. In particular, P is 0.010% or less, S is 0.005% or less, As is 0.005% or less, and Sn is 0.005%. Hereinafter, by setting Sb to 0.003% or less, the center hole can be eliminated by high purity in any of the examples.
The power plant of this embodiment can be applied to 3000 rpm, and the blade length of the final stage blade is1320 mm (52 inches)Or1422 mm (56 inches)Applicable to.
[0135]
【The invention's effect】
According to the present invention, a target tensile strength of 110 kg / mm is used as a Ti-based alloy for the last stage moving blade of a low-pressure steam turbine with a large forged product having a large mass effect.² The above can be secured and1092 mm (43 inches)Above 3000rpm1270 mm (50 inches)The above steam turbine long blades are possible, and the capacity can be increased as a steam turbine power plant having a steam temperature of 538 to 660 ° C., and higher efficiency is achieved.
[Brief description of the drawings]
FIG. 1 is a graph showing a relationship between an aging temperature for obtaining a target tensile strength of a solutionized water cooling material and a solution temperature.
FIG. 2 is a graph showing a relationship between an aging temperature for obtaining a target tensile strength of a solution-blasted coolant and a solution temperature.
FIG. 3 is a diagram showing a relationship between an aging temperature and a solution temperature for obtaining a target tensile strength of a solution-cooled water-cooled material after dovetil roughing.
FIG. 4 is a graph showing a relationship between an aging temperature and a solution temperature for obtaining a target tensile strength of a solution-blasted blast coolant after roughing of dovetil.
FIG. 5 is a diagram showing the relationship between the tensile strength of 1 / 2t and 1 / 4t.
FIG. 6 is a diagram showing the relationship between impact absorption energy and tensile strength.
FIG. 7 is a diagram showing the relationship between impact absorption energy and tensile strength.
FIG. 8 is a perspective view of a steam turbine blade.
FIG. 9 is a side view of a low-pressure turbine blade.
FIG. 10 is a cross-sectional view in which a high-pressure turbine and an intermediate-pressure turbine are connected.
FIG. 11 is a cross-sectional view of a low pressure steam turbine.
FIG. 12 is a cross-sectional view of a high intermediate pressure turbine.
FIG. 13 is a cross-sectional view of a low-pressure steam turbine.
FIG. 14 is a cross-sectional view of a rotor shaft for a low pressure steam turbine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st bearing, 2 ... 2nd bearing, 3 ... 3rd bearing, 4 ... 4th bearing, 5 ... Thrust bearing, 10 ... 1st shaft packing, 11 ... 2nd shaft packing, 12 ... 3rd shaft packing, DESCRIPTION OF SYMBOLS 13 ... 4th shaft packing, 14 ... High pressure diaphragm, 15 ... Medium pressure diaphragm, 16 ... High pressure moving blade, 17 ... Medium pressure moving blade, 18 ... High pressure internal casing, 19 ... High pressure external casing, 20 ... Medium Pressure inner first casing, 21 ... Medium pressure inner second casing, 22 ... Medium pressure outer casing, 23 ... High pressure axle, 24 ... Medium pressure axle, 25 ... Flange, elbow, 26 ... Front bearing box, 27 ... Bearing part, 28 ... main steam inlet, 29 ... reheat steam inlet, 30 ... high pressure steam exhaust port, 31 ... cylinder connecting pipe, 33 ... high and medium pressure axle, 38 ... nozzle box (high pressure first stage), 39 ... thrust bearing Wear shut-off device, 40 ... warm-up steam inlet, 41 ... moving blade, 42 ... static blade, 43 ... bearing, 44 ... Tashafuto, 51 ... wing section, 52 ... blade implanting portion, 53 ... pin insertion hole, 54 ... erosion shield, 55 ... tie boss, 57 ... continuous cover.

Claims (4)

A method for producing a final stage moving blade of a low pressure turbine in a steam turbine power plant equipped with a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine, wherein the blade and the tensile strength at room temperature are 100 kg / mm ² Has a dovetail is room temperature tensile strength of 96% or more of the wings above, be more 1092mm with respect to the rotational speed 3600rpm of 1320mm or more or wings the wings length with respect to the rotational speed 3000rpm wings After hot forging a blade material of a steam turbine blade made of a Ti-based alloy containing Al 4 to 8%, V 4 to 8% and Sn 1 to 4% by weight, it is shown in FIG. 1 of this application (aging temperature, solution temperature) After heating within the range connecting the four points of A (605 ° C, 855 ° C), B (590 ° C, 790 ° C), C (410 ° C, 790 ° C) and D (410 ° C, 855 ° C) The manufacturing method of the low pressure steam turbine blade in the steam turbine power plant characterized by performing solution treatment and aging treatment. A method for producing a final stage moving blade of a low pressure turbine in a steam turbine power plant equipped with a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine, wherein the blade and the tensile strength at room temperature are 100 kg / mm ² Wherein is the blade length having a dovetail is 96% or more of the wings of the room temperature tensile strength of 1092mm or more with respect to the rotational speed 3600rpm of 1320mm or more or blade with respect to the rotational speed 3000rpm wings, weight or more After hot forging a blade material of a steam turbine blade made of a Ti-based alloy containing Al 4 to 8%, V 4 to 8% and Sn 1 to 4%, as shown in FIG. 2 (aging temperature, solution temperature) E (525 ℃, 855 ℃), F (510 ℃, 790 ℃), G (410 ℃, 790 ℃) and H (410 ℃, 855 ℃) within the range connecting the four points, after blast cooling The manufacturing method of the low pressure steam turbine blade in the steam turbine power plant characterized by performing solution treatment and aging treatment. A method for producing a final stage moving blade of a low pressure turbine in a steam turbine power plant equipped with a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine, wherein the blade and the tensile strength at room temperature are 100 kg / mm ² The wing portion has a dovetail which is 96% or more of the tensile strength at room temperature of the wing portion, and the wing portion length is 1320 mm or more with respect to the blade rotation speed of 3000 rpm or 1092 mm or more with respect to the blade rotation speed of 3600 rpm, and the weight The dovetail is slit before final heat treatment of a steam turbine blade made of a Ti-based alloy containing Al 4 to 8%, V 4 to 8% and Sn 1 to 4%, and then shown in FIG. 3 (aging temperature, solution temperature) ) J (685 ° C, 855 ° C), K (585 ° C, 790 ° C), L (410 ° C, 790 ° C) and M (410 ° C, 855 ° C) The manufacturing method of the low pressure steam turbine blade in the steam turbine power plant characterized by performing the solution treatment and the aging treatment which perform. A method for producing a final stage moving blade of a low pressure turbine in a steam turbine power plant equipped with a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine, wherein the blade and the tensile strength at room temperature are 100 kg / mm ² Wherein is the blade length having a dovetail is 96% or more of the wings of the room temperature tensile strength of 1092mm or more with respect to the rotational speed 3600rpm of 1320mm or more or blade with respect to the rotational speed 3000rpm wings, weight or more The dovetail was slit before final heat treatment of a steam turbine blade made of a Ti-based alloy containing Al 4 to 8%, V 4 to 8% and Sn 1 to 4%, and then shown in FIG. 4 (aging temperature, solution temperature) ) N (575 ° C, 855 ° C), O (560 ° C, 790 ° C), P (410 ° C, 790 ° C) and Q (410 ° C, 855 ° C) The manufacturing method of the low pressure steam turbine blade in the steam turbine power plant characterized by performing the solution treatment and aging treatment which cool by wind.

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