JPH05340208A - High temperature bolt material - Google Patents
High temperature bolt materialInfo
- Publication number
- JPH05340208A JPH05340208A JP12858892A JP12858892A JPH05340208A JP H05340208 A JPH05340208 A JP H05340208A JP 12858892 A JP12858892 A JP 12858892A JP 12858892 A JP12858892 A JP 12858892A JP H05340208 A JPH05340208 A JP H05340208A
- Authority
- JP
- Japan
- Prior art keywords
- less
- high temperature
- bolt material
- ductility
- strength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は高温ボルト材に関し、特
に火力発電用蒸気タービン用の高温ボルト材に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high temperature bolt material, and more particularly to a high temperature bolt material for a steam turbine for thermal power generation.
【０００２】[0002]
【従来の技術】火力発電用蒸気タービンプラントに用い
られるボルト材としては、主に低温域（５００℃以下）
で用いられる１２Ｃｒ鋼や高温域で用いられる超合金の
リフラクトアロイ２６（３７Ｎｉ−２０Ｃｏ−１８Ｃｒ
系）、もしくはニッケル基超合金ナイモニック８０Ａが
あげられる。このうち、低温用の１２Ｃｒ鋼は５００℃
以上の温度での使用は困難であり、５００℃を越える高
温で用いられるボルト材としては、ここに示す超合金の
リフラクトアロイ２６もしくはナイモニック８０Ａに限
定される。2. Description of the Related Art Bolt materials used in steam turbine plants for thermal power generation are mainly used in low temperature regions (500 ° C. or lower).
Refraction Alloy 26 (37Ni-20Co-18Cr), which is a 12Cr steel used in
System) or nickel-based superalloy Nimonic 80A. Of these, the low temperature 12Cr steel is 500 ° C.
It is difficult to use at the above temperature, and the bolt material used at a high temperature exceeding 500 ° C. is limited to the superalloy refract alloy 26 or Nimonic 80A shown here.
【０００３】このうち、リフラクトアロイ２６は高温強
度に優れ、また高温延性も良好であることからこれまで
高温ボルト材として広く用いられていた。しかし、この
材料の熱膨張係数は大きく、蒸気タービンを構成する車
室材（車室とはタービンの回転系の回りを包む容器であ
って、高温ボルトによって締めつけられているものであ
る）との熱膨張差によって車室の締め付け力が低下し、
蒸気漏れの原因となっている。また、コバルトを多量に
含むため（２０％程度）コストが高い材料である。一
方、ナイモニック８０Ａはニッケル基の超合金であり高
温強度も良好であり、また，熱膨張係数もリフラクトア
ロイ２６程大きくなく、車室材との熱膨張係数の差も少
なくなく、さらにコバルトを含まないことからコスト的
にもリフラクトアロイ２６より安い。しかし、この材料
の高温の延性は低く、使用中にクリープ破断により主に
結晶粒界に亀裂が発生しやすいとの問題がある。Of these, the refract alloy 26 has been widely used as a high temperature bolt material so far because it has excellent high temperature strength and good high temperature ductility. However, the coefficient of thermal expansion of this material is large, and it is said that the material of the vehicle interior that constitutes the steam turbine (the vehicle interior is a container that wraps around the rotating system of the turbine and is fastened with high temperature bolts). Due to the difference in thermal expansion, the tightening force of the passenger compartment decreases,
This is the cause of steam leakage. In addition, since it contains a large amount of cobalt (about 20%), it is a high cost material. On the other hand, Nimonic 80A is a nickel-based superalloy, has good high-temperature strength, has a thermal expansion coefficient not so large as that of Refract Alloy 26, and has a small difference in thermal expansion coefficient from that of the vehicle interior material. It is cheaper than Refract Alloy 26 because it does not contain it. However, this material has low ductility at high temperatures, and there is a problem that cracks are likely to occur mainly in the crystal grain boundaries due to creep rupture during use.
【０００４】[0004]
【発明が解決しようとする課題】そこで、本発明はフェ
ライト系（ＣｒＭｏ系、１２Ｃｒ系などのフェライト
系、マルテンサイト系の材料）の車室材との熱膨張係数
の差が少なく、高温強度、高温延性の優れた５００℃以
上の高温で使用できる高温用ボルト材を提供するもので
ある。Therefore, the present invention has a small difference in the coefficient of thermal expansion from a ferrite-based (ferrite-based material such as CrMo-based, 12Cr-based or martensite-based material) cabin material, high temperature strength, It is intended to provide a high temperature bolt material which has excellent high temperature ductility and can be used at a high temperature of 500 ° C. or higher.
【０００５】[0005]
【課題を解決するための手段】このため、本発明者らは
鋭意研究を重ねた結果、以下に示す優れた高温用ボルト
材を発明した。すなわち、本発明は （１）重量比で炭素：０．０４〜０．１％、シリコン：
１％以下、マンガン：１％以下、クロム：１８〜２１
％、アルミニウム：１〜２％、チタン：１〜２％、ボロ
ン：０．００１〜０．０１％、鉄：１．５％以下及び不
可避的不純物及びニッケルからなることを特徴とする高
温ボルト材。Therefore, as a result of intensive studies, the present inventors have invented the following excellent high temperature bolt material. That is, the present invention is: (1) Carbon: 0.04 to 0.1% by weight, silicon:
1% or less, manganese: 1% or less, chromium: 18 to 21
%, Aluminum: 1 to 2%, titanium: 1 to 2%, boron: 0.001 to 0.01%, iron: 1.5% or less, and inevitable impurities and nickel. ..
【０００６】（２）重量比で炭素：０．０４〜０．１
％、シリコン：１％以下、マンガン：１％以下、クロ
ム：１８〜２１％、アルミニウム：１〜２％、チタン：
１〜２％、ボロン：０．００１〜０．０１％、鉄：１．
５％以下及び不可避的不純物及びニッケルからなり、溶
解後熱間鍛造を行ったのち、１０００〜１１２０℃での
溶体化処理、８２０〜８８０℃での第１段時効処理、７
００〜７５０℃での第２段時効処理、６００〜６５０℃
での第３段時効処理を行ってなることを特徴とする高温
ボルト材。である。(2) Carbon by weight ratio: 0.04 to 0.1
%, Silicon: 1% or less, manganese: 1% or less, chromium: 18 to 21%, aluminum: 1 to 2%, titanium:
1-2%, boron: 0.001-0.01%, iron: 1.
Consists of 5% or less and inevitable impurities and nickel, and after hot forging after melting, solution treatment at 1000 to 1120 ° C., first stage aging treatment at 820 to 880 ° C., 7
Second stage aging treatment at 00-750 ° C, 600-650 ° C
A high-temperature bolt material characterized by being subjected to a third-stage aging treatment in. Is.
【０００７】[0007]
【作用】本発明はナイモニック８０Ａを基本成分とする
がチタンの成分範囲を異なるものとし、かつその他の成
分範囲を限定すると共にボロンを添加し、さらに熱処理
を限定することにより、優れた特性を有する高温用ボル
ト材としたものである。以下に本発明ボルト材における
成分限定理由を述べる。 Ｃ：Ｃは炭化物を形成し高温強度の向上に寄与する。し
かし、０．０４％未満では十分な効果は得られず、また
０．１％を越えると過剰な炭化物を形成し靱性を低下さ
せるため０．０４〜０．１％とする。 Ｓｉ：Ｓｉは脱酸材として必要な元素である。しかし、
Ｓｉを必要以上に加えるとクリープ脆性などを引き起こ
すため１％以下とした。 Ｍｎ：Ｍｎも脱酸材として有用な元素である。この元素
も必要以上に加えると靱性を低下させるため１％以下と
した。 Ｃｒ：Ｃｒは炭化物を形成し高温強度の改善に寄与する
とともに、マトリックス中に溶け込んで耐酸化性を改善
する。１８％未満ではその効果は十分ではなく、また２
１％を越えると脆化をもたらすので１８〜２１％とす
る。 Ａｌ：ＡｌはマトリックスのＮｉやＴｉとともに金属間
化合物であるγ′〔Ｎｉ3 （Ａｌ，Ｔｉ）〕相となり高
温強度の向上に寄与する。１％未満ではその効果は十分
ではなく、また２％を越えるとクリープ破断における延
性が低下し、切欠弱化を示すようになるため１〜２％と
する。 Ｔｉ：ＴｉはＡｌやＮｉとともにγ′〔Ｎｉ3 （Ａｌ，
Ｔｉ）〕相を形成する。Ｔｉの含有量は高温強度、延性
に大きく影響を与える。すなわち、Ｔｉ含有量が増すと
それに比例して常温〜高温までの強度は向上する。しか
し、延性はＴｉ含有量の増加とともに低下する。１％未
満であると十分な強度が得られず、また２％を越える量
を添加するとクリープ延性が低下する。従って、１〜２
％とする。 Ｂ：Ｂは結晶粒界の強度向上に大きく寄与
する。Ｂを含有すると結晶粒界の結合力が高まりクリー
プ破断に対する結晶粒界強度が向上するためクリープ破
断強度及びクリープ破断延性が向上する。このＢの添加
によりＡｌ，Ｔｉの添加が若干多い場合でも良好なクリ
ープ破断延性が得られるため高温強度を向上させること
ができる。しかし、０．００１％未満ではその効果が小
さく、また０．０１％を越えると偏析を生じ結晶粒界の
靱性を低下させるため延性が低下する。従って、０．０
０１〜０．０１％とする。 Ｆｅ：ＦｅはＮｉとともにマトリックスを形成する元素
であり、延性、靱性の向上に寄与する。しかし１．５％
を越えて添加すると、高温強度、特にクリープ破断強度
を低下させるため１．５％以下とする。The present invention has excellent characteristics by using Nimonic 80A as a basic component but different in the component range of titanium, limiting the range of other components, adding boron, and further limiting the heat treatment. It is a high temperature bolt material. The reasons for limiting the components in the bolt material of the present invention will be described below. C: C forms a carbide and contributes to the improvement of high temperature strength. However, if it is less than 0.04%, a sufficient effect cannot be obtained, and if it exceeds 0.1%, excessive carbides are formed and the toughness is lowered, so the content is made 0.04 to 0.1%. Si: Si is an element required as a deoxidizer. But,
If Si is added more than necessary, creep brittleness and the like will occur, so the content was made 1% or less. Mn: Mn is also an element useful as a deoxidizer. If this element is also added more than necessary, the toughness is lowered, so the content was made 1% or less. Cr: Cr forms a carbide and contributes to the improvement of high temperature strength, and dissolves in the matrix to improve the oxidation resistance. If it is less than 18%, the effect is not sufficient, and 2
If it exceeds 1%, embrittlement occurs, so the content is made 18 to 21%. Al: Al becomes a γ '[Ni 3 (Al, Ti)] phase which is an intermetallic compound together with Ni and Ti of the matrix, and contributes to improvement of high temperature strength. If it is less than 1%, the effect is not sufficient, and if it exceeds 2%, the ductility in creep rupture decreases and the notch weakening is exhibited, so the content is made 1 to 2%. Ti: Ti together with Al and Ni is γ ′ [Ni 3 (Al,
Ti)] phase is formed. The Ti content greatly affects high temperature strength and ductility. That is, as the Ti content increases, the strength from room temperature to high temperature increases in proportion thereto. However, ductility decreases with increasing Ti content. If it is less than 1%, sufficient strength cannot be obtained, and if it exceeds 2%, the creep ductility decreases. Therefore, 1-2
%. B: B greatly contributes to the strength improvement of the crystal grain boundary. When B is contained, the bond strength of the grain boundaries is increased and the grain boundary strength against creep rupture is improved, so that the creep rupture strength and the creep rupture ductility are improved. By adding B, good creep rupture ductility can be obtained even when the amounts of Al and Ti are slightly large, so that the high temperature strength can be improved. However, if it is less than 0.001%, its effect is small, and if it exceeds 0.01%, segregation occurs and the toughness of the grain boundaries is lowered, so that the ductility is lowered. Therefore, 0.0
It is set to 01 to 0.01%. Fe: Fe is an element that forms a matrix together with Ni and contributes to the improvement of ductility and toughness. But 1.5%
If it is added in excess of 0.1%, the high temperature strength, especially the creep rupture strength is lowered, so the content is made 1.5% or less.
【０００８】次に熱処理の限定理由について述べる。本
発明材料においてボルト材を製造する場合、熱処理方法
によってγ′相などの析出物の形態が変わり、機械的性
質やクリープ破断特性などに大きく影響を与える。そこ
で本発明者らは熱処理条件について鋭意検討を行った結
果、溶体化処理後３段時効処理を施し、析出物を十分に
安定化させることにより、高温強度を劣化させることな
く安定した延性を得ることができることを明らかにし
た。詳細については、実施例にて述べる。Next, the reasons for limiting the heat treatment will be described. When a bolt material is produced from the material of the present invention, the morphology of precipitates such as the γ'phase changes depending on the heat treatment method, which greatly affects the mechanical properties and creep rupture properties. Therefore, as a result of diligent study on the heat treatment conditions, the present inventors obtained a stable ductility without deteriorating the high temperature strength by performing a three-step aging treatment after the solution treatment and sufficiently stabilizing the precipitates. Revealed that you can. Details will be described in Examples.
【０００９】[0009]
【実施例】以下に実施例に基づいて本発明を説明する。
本発明のボルト材は、ニッケル基超合金のナイモニック
８０Ａを基本としており、その成分を変更することによ
りクリープ延性の優れた高強度のボルト材の製造を可能
にしたものである。表１には試験に供した材料の化学成
分をまとめて示す。全ての材料は５０ｋｇ真空高周波溶
解炉にて溶製し、次いで高温にて鍛造を行い各種試験に
供した。表２に各試験材の常温における機械的性質を示
す。EXAMPLES The present invention will be described below based on examples.
The bolt material of the present invention is based on Nimonic 80A, which is a nickel-based superalloy, and by changing the composition thereof, it is possible to manufacture a high-strength bolt material having excellent creep ductility. Table 1 shows a summary of the chemical components of the materials used in the test. All materials were melted in a 50 kg vacuum high-frequency melting furnace, then forged at high temperature and subjected to various tests. Table 2 shows the mechanical properties of each test material at room temperature.
【００１０】[0010]
【表１】 [Table 1]
【００１１】[0011]
【表２】 [Table 2]
【００１２】この結果から、本発明材は強度的には比較
材と差はないが、伸びや絞りなどの延性や衝撃値で示さ
れる靱性が比較材に比べて良好であることがわかる。た
だし、比較材の中で材料番号６及び７は延性靱性とも本
発明材並びに良好であるが、後述するクリープ破断特性
において本発明材と比べると若干クリープ破断延性が劣
る。From these results, it is understood that the material of the present invention is not different from the comparative material in terms of strength, but the ductility such as elongation and drawing and the toughness represented by the impact value are better than those of the comparative material. However, among the comparative materials, the material numbers 6 and 7 are good in ductility and toughness as well as the material of the present invention, but the creep rupture ductility, which will be described later, is slightly inferior to that of the material of the present invention.
【００１３】また、表３に本発明材及び比較材のクリー
プ破断試験結果の例を示すが、本発明材のクリープ破断
延性は比較材に比べて格段に優れていることがわかる。Further, Table 3 shows an example of the results of creep rupture test of the material of the present invention and the comparative material. It can be seen that the creep rupture ductility of the material of the present invention is remarkably superior to that of the comparative material.
【００１４】[0014]
【表３】 [Table 3]
【００１５】さらに本発明材のクリープ破断試験結果を
図１、図２に示すが、本発明材は比較材と同等のクリー
プ破断強さを有すると同時に比較材に比べて遙に高い延
性を有することがわかる。ボロンを含まずかつ炭素、ア
ルミニウム、チタン等が適性範囲である材料に対しても
さらに優れたクリープ破断延性を有している。また、図
３には本発明材の時効処理条件の違いによるクリープ破
断延性への影響について示したものであるが、２段時効
材よりも３段時効処理材の方が高い延性を有することが
わかる。図１〜図３とも横軸はラルソン・ミラーパラメ
ータであり、温度と破断時間で決まる値である。Further, the results of the creep rupture test of the material of the present invention are shown in FIGS. 1 and 2. The material of the present invention has the same creep rupture strength as that of the comparative material and at the same time has a much higher ductility than that of the comparative material. I understand. It has excellent creep rupture ductility even for materials containing no boron and having carbon, aluminum, titanium and the like in the appropriate range. In addition, FIG. 3 shows the influence of the aging treatment conditions of the material of the present invention on the creep rupture ductility, but the three-stage aging treated material may have higher ductility than the two-stage aging treated material. Recognize. 1 to 3, the horizontal axis represents the Larson-Miller parameter, which is a value determined by the temperature and the breaking time.
【００１６】[0016]
【発明の効果】本発明のボルト材は優れた高温強度を有
し、延性、靱性の良好な材料であることから、５００℃
を越える温度で使用できる信頼性の高い高温用ボルト材
である。本発明により、今後多数製造が予定されている
超高温蒸気タービンの製造に寄与することはもとより通
常の蒸気タービンのボルト材の高信頼性の確保の上から
も産業上有益である。The bolt material of the present invention has excellent high-temperature strength, good ductility and toughness, and is therefore 500 ° C.
It is a high-temperature bolt material with high reliability that can be used at temperatures above 100 ° C. INDUSTRIAL APPLICABILITY The present invention is industrially useful not only for contributing to the manufacture of ultra-high temperature steam turbines, which will be manufactured in large numbers in the future, but also for ensuring high reliability of bolt materials for ordinary steam turbines.
【図面の簡単な説明】[Brief description of drawings]
【図１】２段時効処理を施した本発明試験材のクリープ
破断強さを示す図表。FIG. 1 is a chart showing the creep rupture strength of a test material of the present invention that has been subjected to a two-step aging treatment.
【図２】３段時効処理を施した本発明試験材のクリープ
破断強さを示す図表。FIG. 2 is a chart showing the creep rupture strength of the test material of the present invention that has been subjected to a three-step aging treatment.
【図３】本発明材の２段時効処理材と３段時効処理材の
クリープ破断延性を比較した図表。FIG. 3 is a chart comparing the creep rupture ductility of the two-stage aging treated material and the three-stage aging treated material of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 近藤 武志 長崎県長崎市飽の浦町１番１号 三菱重工 業株式会社長崎造船所内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takeshi Kondo 1-1 1-1 Satinoura-cho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard Co., Ltd.
Claims (2)
リコン：１％以下、マンガン：１％以下、クロム：１８
〜２１％、アルミニウム：１〜２％、チタン：１〜２
％、ボロン：０．００１〜０．０１％、鉄：１．５％以
下及び不可避的不純物及びニッケルからなることを特徴
とする高温ボルト材。1. By weight ratio, carbon: 0.04 to 0.1%, silicon: 1% or less, manganese: 1% or less, chromium: 18
-21%, Aluminum: 1-2%, Titanium: 1-2
%, Boron: 0.001 to 0.01%, iron: 1.5% or less, and inevitable impurities and nickel.
リコン：１％以下、マンガン：１％以下、クロム：１８
〜２１％、アルミニウム：１〜２％、チタン：１〜２
％、ボロン：０．００１〜０．０１％、鉄：１．５％以
下及び不可避的不純物及びニッケルからなり、溶解後熱
間鍛造を行ったのち、１０００〜１１２０℃での溶体化
処理、８２０〜８８０℃での第１段時効処理、７００〜
７５０℃での第２段時効処理、６００〜６５０℃での第
３段時効処理を行ってなることを特徴とする高温ボルト
材。2. By weight ratio, carbon: 0.04 to 0.1%, silicon: 1% or less, manganese: 1% or less, chromium: 18
-21%, Aluminum: 1-2%, Titanium: 1-2
%, Boron: 0.001 to 0.01%, iron: 1.5% or less, and unavoidable impurities and nickel. After hot forging after melting, solution treatment at 1000 to 1120 ° C., 820 ~ 1st stage aging treatment at 880 ° C, 700 ~
A high-temperature bolt material characterized by being subjected to a second stage aging treatment at 750 ° C and a third stage aging treatment at 600 to 650 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04128588A JP3137426B2 (en) | 1992-05-21 | 1992-05-21 | High temperature bolt material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04128588A JP3137426B2 (en) | 1992-05-21 | 1992-05-21 | High temperature bolt material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05340208A true JPH05340208A (en) | 1993-12-21 |
| JP3137426B2 JP3137426B2 (en) | 2001-02-19 |
Family
ID=14988471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04128588A Expired - Fee Related JP3137426B2 (en) | 1992-05-21 | 1992-05-21 | High temperature bolt material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3137426B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0959747A (en) * | 1995-08-25 | 1997-03-04 | Hitachi Ltd | High strength heat resistant cast steel, steam turbine casing, steam turbine electric power plant, and steam turbine |
| CN110106397A (en) * | 2019-05-11 | 2019-08-09 | 温州市洲泰五金制造有限公司 | A kind of manufacturing method of high temperature resistant bolt alloy material and bolt |
-
1992
- 1992-05-21 JP JP04128588A patent/JP3137426B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0959747A (en) * | 1995-08-25 | 1997-03-04 | Hitachi Ltd | High strength heat resistant cast steel, steam turbine casing, steam turbine electric power plant, and steam turbine |
| CN110106397A (en) * | 2019-05-11 | 2019-08-09 | 温州市洲泰五金制造有限公司 | A kind of manufacturing method of high temperature resistant bolt alloy material and bolt |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3137426B2 (en) | 2001-02-19 |
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