JPS6151010B2 - - Google Patents
Info
- Publication number
- JPS6151010B2 JPS6151010B2 JP53122575A JP12257578A JPS6151010B2 JP S6151010 B2 JPS6151010 B2 JP S6151010B2 JP 53122575 A JP53122575 A JP 53122575A JP 12257578 A JP12257578 A JP 12257578A JP S6151010 B2 JPS6151010 B2 JP S6151010B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- heat treatment
- power generation
- steel
- ductile
- 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.)
- Expired
Links
- 238000000034 method Methods 0.000 claims description 15
- 238000010248 power generation Methods 0.000 claims description 14
- 229910000831 Steel Inorganic materials 0.000 claims description 13
- 239000010959 steel Substances 0.000 claims description 13
- 238000001816 cooling Methods 0.000 claims description 11
- 238000005496 tempering Methods 0.000 claims description 6
- 238000011282 treatment Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 229910001563 bainite Inorganic materials 0.000 claims description 4
- 230000009466 transformation Effects 0.000 claims description 3
- 229910001566 austenite Inorganic materials 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- VGIPUQAQWWHEMC-UHFFFAOYSA-N [V].[Mo].[Cr] Chemical compound [V].[Mo].[Cr] VGIPUQAQWWHEMC-UHFFFAOYSA-N 0.000 claims 1
- 229910052804 chromium Inorganic materials 0.000 claims 1
- 239000012535 impurity Substances 0.000 claims 1
- 229910052750 molybdenum Inorganic materials 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 description 21
- 230000007704 transition Effects 0.000 description 13
- 239000000463 material Substances 0.000 description 7
- 238000010791 quenching Methods 0.000 description 7
- 230000000171 quenching effect Effects 0.000 description 7
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000037237 body shape Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/28—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for plain shafts
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Description
本発明は地熱発電用タービンロータシヤフトの
製造法に係り、特に１％Cr―１％Mo―1/4％Ｖ
鋼の切欠靭性の改善に関する。
地熱蒸気や地熱水環境にさらされる地熱発電用
機器材料は、これらの環境が火山性の腐食性ガス
（H2S、その他）やＣ、SO4、その他の種々のイ
オンを多量に含み一般にPHも低く苛酷な腐食環境
下で使用される。これらの機器材料のうちタービ
ンロータは入口温度が約200℃、出口温度が約50
℃程度の低い蒸気温度条件下で運転される。しか
し、火力発電用のように、あまり腐食環境が問題
とならない低い温度条件で使用されるタービンロ
ータには延性脆性遷移温度が室温以下で優れた切
欠靭性を有するNiを３〜４％程度含有するCr―
Mo―Ｖ鋼が使用されている。したがつて、この
鋼を地熱発電用タービンロータ材として使用すれ
ばよいが、Ni含有量の多い低合金鋼は、硫化物
を含む環境下での耐食性腐食割れ性並びに腐食に
よる疲労限が極度に低下し、長年の使用によつて
破壊を誘発するという欠点を有している。このこ
とから、火力発電用高圧中圧タービンロータとし
て開発された、Niを含まない1Cr―1Mo―1/4Ｖ
鋼製のロータを地熱発電用タービンロータに使用
している。ところが、この鋼は、550℃程度の高
い温度条件で優れたクリープ特性を有するが、延
性脆性遷移温度が80〜120℃と高いため地熱発電
のように低い蒸気温度条件での使用は、延性脆性
遷移温度が高すぎて脆性破壊に対する安全性の点
で不安を残している。そこで、1Cr―1Mo―1/4
Ｖ鋼の熱処理の焼入温度の低下や焼入冷却速度を
小さくしたりして延性脆性遷移温度を低める方法
が検討されている。しかし、これらの単なる熱処
理法によつてはせいぜい50〜60℃まで遷移温度を
下げるのが限度である。したがつて、地熱発電用
タービンロータの設計上から要求される延性脆性
遷移温度は40℃が理想とされ、これらに近づける
または40℃以下とする熱処理による検討が要望さ
れる。
本発明は上記の問題点を考慮し、地熱環境下で
の1Cr―1Mo―1/4Ｖ低合金鋼製タービンロータ
の脆性破壊に対する安全性を向上させる熱処理法
を適用し、切欠靭性の優れた地熱発電用タービン
ロータシヤフトの製造法を提供することを目的と
している。
本発明は地熱環境下で使用されるタービンロー
タ材としての1Cr―1Mo―1/4Ｖ鋼の延性脆性遷
移温度を低める熱処理法の改善をはかつたもので
ある。すなわち、1Cr―1Mo―1/4Ｖ合金を溶
解、鍛造したタービンロータ素体形状に製作した
のち920℃〜1050℃のオーステナイト領域から150
℃〜250℃／ｈの冷却速度で焼入れし、ついで770
〜850℃のAC1〜AC3変態温度の中間領域に再加
熱し150〜250℃／ｈで冷却後、650〜750℃で焼戻
処理を行うことによつて、結晶粒度を微細にする
とともに、実質的に焼戻し下部ベイナイト組織を
生じせしめることによつて地熱発電用タービンロ
ータ材1Cr―1Mo―1/4Ｖ鋼の低温切欠靭性の改
善をはかつたものである。
なお冷却速度を150〜250℃／ｈとしたのは150
℃／ｈ未満ではフエライト相が生成し、強度を低
め、靭性値を低下する。更に、250℃／ｈを越え
てもそれ以上の効果がなく、実ロータ中心部の冷
却速度が約200℃／ｈ程度であるため、150〜250
℃／ｈとした。
920〜1050℃でオーステナイト化し焼入れする
ことによつて強度を高める。920℃未満では強度
が低下し、更に1050℃を越えると結晶粒が粗大化
し、靭性が低下する。
770〜850℃での処理はオーステナイト相とフエ
ライト相領域からの急冷によつて結晶粒を微細化
するとともに焼戻しによる下部ベーナイト相を形
成し靭性を向上させる。770℃未満の温度及び850
℃を越える温度ではいずれも結晶粒を微細化し及
び焼戻しによる下部ベーナイト組織が形成させる
ことができず、靭性を向上させることができな
い。
1Cr―1Mo―1/4Ｖ鋼の通常の熱処理は920〜
1050℃で焼入後、650〜750℃で焼戻し処理を行つ
ている。また、延性脆性遷移温度を40℃に近づけ
るため焼入温度を低めたり、焼入冷却速度を小さ
くするなどの熱処理による検討がなされている
が、目的に合つた熱処理法が見出されていない。
したがつて、地熱発電用タービンロータに要求さ
れる理想的設計基準である延性脆性遷移温度40℃
を満足する熱処理法の検討が必要である。以下に
本発明を実施例により詳細に説明する。
第１表に示した組成を有する実ロータから切出
した1Cr―1Mo―1/4Ｖ鋼を第２表に示す条件で
熱処理を施したのち引張試験、衝撃試験及び組織
観察等を行なつた。
なお、本発明での引張強さが89.1Kg／mm2及び
0.02％耐力が68.2Kg／mm2で、低圧ロータ基準を十
分満足した結果が得られた。
The present invention relates to a method for manufacturing a turbine rotor shaft for geothermal power generation, and particularly relates to a method for manufacturing a turbine rotor shaft for geothermal power generation, and in particular, 1% Cr-1% Mo-1/4% V
Concerning improvement of notch toughness of steel. Geothermal power generation equipment materials that are exposed to geothermal steam or geothermal water environments generally contain large amounts of corrosive volcanic gases (H 2 S, etc.), C, SO 4 , and other various ions. It has a low pH and is used in harsh corrosive environments. Among these equipment materials, the turbine rotor has an inlet temperature of approximately 200℃ and an outlet temperature of approximately 50℃.
It is operated under steam temperature conditions as low as ℃. However, turbine rotors used in low-temperature conditions where corrosive environments are not a problem, such as those used in thermal power generation, contain about 3 to 4% Ni, which has excellent notch toughness when the ductile-brittle transition temperature is below room temperature. Cr―
Mo-V steel is used. Therefore, this steel can be used as a turbine rotor material for geothermal power generation, but low-alloy steel with a high Ni content has extremely low corrosion resistance, corrosion cracking resistance, and fatigue limits due to corrosion in environments containing sulfides. It has the disadvantage that it deteriorates and is likely to break down after many years of use. Based on this, 1Cr-1Mo-1/4V, which does not contain Ni, was developed as a high-pressure and intermediate-pressure turbine rotor for thermal power generation.
Steel rotors are used in geothermal power generation turbine rotors. However, although this steel has excellent creep properties under high temperature conditions of around 550°C, its ductile-brittle transition temperature is as high as 80 to 120°C, so it cannot be used in low steam temperature conditions such as geothermal power generation. The transition temperature is too high, leaving concerns about safety against brittle fracture. Therefore, 1Cr―1Mo―1/4
Methods of lowering the ductile-brittle transition temperature by lowering the quenching temperature or decreasing the quenching cooling rate in heat treatment of V-steel are being considered. However, these simple heat treatment methods can only lower the transition temperature to 50 to 60°C at most. Therefore, the ductile-brittle transition temperature required from the design of geothermal power generation turbine rotors is ideally 40°C, and it is desired to consider heat treatment to bring it closer to this or to lower it to 40°C or less. In consideration of the above problems, the present invention applies a heat treatment method that improves the safety of 1Cr-1Mo-1/4V low alloy steel turbine rotor against brittle fracture in a geothermal environment. The purpose of this invention is to provide a method for manufacturing a turbine rotor shaft for power generation. The present invention aims to improve a heat treatment method for lowering the ductile-brittle transition temperature of 1Cr-1Mo-1/4V steel used as a turbine rotor material used in a geothermal environment. In other words, the 1Cr-1Mo-1/4V alloy is melted and forged into a turbine rotor body shape, and then 150
Quenched at a cooling rate of ℃~250℃/h, then 770℃
After reheating to the intermediate range of AC 1 to AC 3 transformation temperature of ~850℃ and cooling at 150 to 250℃/h, tempering treatment is performed at 650 to 750℃ to refine the grain size and , the low-temperature notch toughness of 1Cr-1Mo-1/4V steel, which is a turbine rotor material for geothermal power generation, is improved by substantially producing a tempered lower bainite structure. The cooling rate was set to 150 to 250℃/h.
If the temperature is less than 0.degree. C./h, a ferrite phase will form, lowering the strength and toughness value. Furthermore, even if the cooling rate exceeds 250°C/h, there is no further effect, and the actual cooling rate of the center of the rotor is approximately 200°C/h.
It was set as °C/h. Strength is increased by austenitizing and quenching at 920-1050℃. If it is less than 920°C, the strength will decrease, and if it exceeds 1050°C, the crystal grains will become coarser and the toughness will decrease. The treatment at 770 to 850°C refines grains by rapid cooling from the austenite and ferrite phase regions, and forms a lower bainite phase by tempering, improving toughness. Temperature below 770℃ and 850℃
At temperatures exceeding .degree. C., crystal grains cannot be refined and a lower bainite structure cannot be formed by tempering, and toughness cannot be improved. The normal heat treatment for 1Cr-1Mo-1/4V steel is 920 ~
After quenching at 1050℃, tempering treatment is performed at 650-750℃. In addition, heat treatments such as lowering the quenching temperature and slowing the quenching cooling rate have been considered in order to bring the ductile-brittle transition temperature closer to 40°C, but a heat treatment method that meets the purpose has not been found.
Therefore, the ductile-brittle transition temperature of 40°C is the ideal design standard required for geothermal power generation turbine rotors.
It is necessary to consider a heat treatment method that satisfies the following. The present invention will be explained in detail below using examples. 1Cr-1Mo-1/4V steel cut from an actual rotor having the composition shown in Table 1 was heat treated under the conditions shown in Table 2, and then subjected to tensile tests, impact tests, and microstructural observations. In addition, the tensile strength in the present invention is 89.1Kg/mm 2 and
The 0.02% proof stress was 68.2Kg/ mm2 , which fully satisfied the low-pressure rotor standards.
【表】【table】
【表】
但し、
オーステナイト化処理
冷却速度は200℃〓h
中 間 処 理
第１図は1Cr―1Mo―1/4Ｖ鋼の従来熱処理と
本発明による熱処理法の衝撃遷移曲線の代表例を
示す。本発明による熱処理による衝撃値は従来熱
処理によるものより非常に高い値が得られ、低温
になるほどその差が大きくなる。このことから、
低温靭性が非常にすぐれていることが知られる。
第２図は第１図の衝撃試験片から延性脆性破面
率を求めた結果を示す。この結果から50％延性脆
性遷移温度は従来の熱処理法では80℃以上である
が、本発明による熱処理法は40℃を充分満足し、
30〜35℃であり、非常にすぐれた延性脆性遷移温
度を示す。
以上のように、従来の熱処理法で不可能であつ
た延性脆性遷移温度の低下は、従来の焼入焼戻処
理の中間に、AC1〜AC3の変態温度領域に加熱す
る方法を採用することによつて非常にすぐれた切
欠靭性を示すことが明らかとなつた。したがつ
て、地熱発電用タービンロータ材としての本発明
の熱処理による製造法は顕著な効果が得られる。[Table] However,
Austenitizing treatment
Cooling rate is 200℃〓h
Intermediate Treatment Figure 1 shows typical examples of impact transition curves for conventional heat treatment and heat treatment according to the present invention for 1Cr-1Mo-1/4V steel. The impact value obtained by the heat treatment according to the present invention is much higher than that obtained by conventional heat treatment, and the difference becomes larger as the temperature becomes lower. From this,
It is known to have excellent low-temperature toughness. FIG. 2 shows the results of determining the ductile-brittle fracture surface ratio from the impact test piece shown in FIG. 1. From this result, the 50% ductile-brittle transition temperature is 80℃ or higher in the conventional heat treatment method, but the heat treatment method according to the present invention fully satisfies the temperature of 40℃.
The temperature is 30-35°C, showing an excellent ductile-brittle transition temperature. As described above, the reduction of the ductile-brittle transition temperature, which was not possible with conventional heat treatment methods, can be achieved by applying heating to the transformation temperature range of AC 1 to AC 3 during the conventional quenching and tempering process. In particular, it has become clear that this material exhibits extremely excellent notch toughness. Therefore, the method of manufacturing a geothermal power generation turbine rotor material by heat treatment according to the present invention provides remarkable effects.
第１図は1Cr―1Mo―1/4Ｖ鋼の熱処理法の違
いによる温度と衝撃値との関係を示す線図、第２
図は温度と延性破面率との関係を示す線図であ
る。
Ａ……従来の熱処理、Ｂ……本発明による熱処
理。
Figure 1 is a diagram showing the relationship between temperature and impact value due to different heat treatment methods for 1Cr-1Mo-1/4V steel.
The figure is a diagram showing the relationship between temperature and ductile fracture area ratio. A...Conventional heat treatment, B...Heat treatment according to the present invention.
Claims (1)
下、Mn：1.0％以下、Cr：0.5〜2.0％、Mo：0.3
〜1.5％、Ｖ：0.1〜0.3％、残部Feおよび不可避
の不純物からなるクロムーモリブデン―バナジウ
ム鋼を920〜1050℃のオーステナイト領域で加熱
保持した後、150〜250℃／ｈの冷却速度で焼入れ
し、ついで770〜850℃のAC1〜AC3変態温度領域
に再加熱し150〜250℃／ｈで冷却後、650〜750℃
で焼戻処理を行ない、実質的に焼戻しベイナイト
組織を形成させることを特徴とする地熱発電用タ
ービンロータシヤフトの製造法。1% by weight, C: 0.20-0.33%, Si: 0.3% or less, Mn: 1.0% or less, Cr: 0.5-2.0%, Mo: 0.3
Chromium-molybdenum-vanadium steel consisting of ~1.5%, V: 0.1-0.3%, balance Fe and unavoidable impurities is heated and held in the austenite region at 920-1050℃, and then quenched at a cooling rate of 150-250℃/h. Then, it is reheated to AC 1 to AC 3 transformation temperature range of 770 to 850℃, and after cooling at 150 to 250℃/h, it is heated to 650 to 750℃.
1. A method for manufacturing a turbine rotor shaft for geothermal power generation, which comprises performing a tempering treatment to substantially form a tempered bainite structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12257578A JPS5550430A (en) | 1978-10-06 | 1978-10-06 | Turbine rotor for geothermal electric power generation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12257578A JPS5550430A (en) | 1978-10-06 | 1978-10-06 | Turbine rotor for geothermal electric power generation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5550430A JPS5550430A (en) | 1980-04-12 |
| JPS6151010B2 true JPS6151010B2 (en) | 1986-11-07 |
Family
ID=14839292
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12257578A Granted JPS5550430A (en) | 1978-10-06 | 1978-10-06 | Turbine rotor for geothermal electric power generation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5550430A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05503653A (en) * | 1990-09-13 | 1993-06-17 | ハーバーメイヤー ピーター | Device for circumferential fixation of limbs |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6335759A (en) * | 1986-07-31 | 1988-02-16 | Mitsubishi Heavy Ind Ltd | Geothermal turbine rotor material |
| EP0849434B8 (en) * | 1989-02-03 | 2005-08-10 | Hitachi, Ltd. | Combined generator system |
| JP5362764B2 (en) * | 2011-04-18 | 2013-12-11 | 株式会社日本製鋼所 | Low alloy metal for geothermal power turbine rotor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50149518A (en) * | 1974-05-23 | 1975-11-29 |
-
1978
- 1978-10-06 JP JP12257578A patent/JPS5550430A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50149518A (en) * | 1974-05-23 | 1975-11-29 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05503653A (en) * | 1990-09-13 | 1993-06-17 | ハーバーメイヤー ピーター | Device for circumferential fixation of limbs |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5550430A (en) | 1980-04-12 |
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