WO2019059240A1 - ガスタービンディスク材及びその熱処理方法 - Google Patents
ガスタービンディスク材及びその熱処理方法 Download PDFInfo
- Publication number
- WO2019059240A1 WO2019059240A1 PCT/JP2018/034683 JP2018034683W WO2019059240A1 WO 2019059240 A1 WO2019059240 A1 WO 2019059240A1 JP 2018034683 W JP2018034683 W JP 2018034683W WO 2019059240 A1 WO2019059240 A1 WO 2019059240A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- gas turbine
- content
- strength
- creep
- less
- Prior art date
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
-
- 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
-
- 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
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
Definitions
- the present invention relates to a gas turbine disk material and a heat treatment method thereof.
- Priority is claimed on Japanese Patent Application No. 2017-181196, filed on Sep. 21, 2017, the content of which is incorporated herein by reference.
- 12Cr heat-resistant steel containing about 8 to 12% of Cr is widely used as a gas turbine disk material.
- This type of gas turbine disc material contains Ni to secure toughness, and in addition to Cr, Mo, V, etc. is contained to achieve solid solution strengthening of the base structure and dispersion strengthening by carbides and carbonitrides. , Creep strength is improved.
- Patent Document 1 C: 0.05 to 0.15%, Si: 0.10% or less, Mn: 0.40% or less, Cr: 9.0 to 12.0%, Ni: 1.0 to 3.5%, M 2 O : 0.50 to 0.90%, W: 1.0 to 2.0%, V: 0.10 to 0.30%, Nb: 0.01 to 0 .10%, N: 0.01 to 0.05%, the balance consists of Fe and unavoidable impurities, and the content of Ni, Mo, W is -1.5% ⁇ Mo + W / 2 ⁇ Gas turbine disc material satisfying the relationship of Ni ⁇ 0.5%, and each component described above, Co: 0.01 to 4.0%, B: one or two of 0.0001 to 0.010% The gas turbine disc material contained is shown.
- the present invention has been made against the background described above, and an object of the present invention is to provide a gas turbine disc material having better creep characteristics and sufficient toughness, and a heat treatment method for producing the same.
- the inventors of the present invention conducted extensive experiments and studies, and set the Ni content in a suitable range lower than that of the conventional 12C heat resistant steel, and further, the effects of N, Al and B. It has been found that creep characteristics can be remarkably improved as compared with the prior art while securing toughness as a gas turbine disc material by clarifying the specific component range, and the invention of the gas turbine disc material has been achieved. Furthermore, as heat treatment at the time of manufacture of gas turbine disk material, it is found that creep characteristics and toughness can be reliably ensured by optimizing the quenching temperature of forged material, and a heat treatment method for manufacturing gas turbine disk material It came to make an invention of
- the gas turbine disc material of the basic aspect (first aspect) of the present invention is In mass%, C: 0.05 to 0.15%, Ni: 0.25 to 1.50%, Cr: 9.0 to 12.0%, Mo: 0.50 to 0.90%, W: 1.0 to 2.0%, V: 0.10 to 0.30%, Nb: 0.01 to 0.10%, Co: 0.01 to 4.0%, B: 0.0005 to 0.010%, N: 0.01 to 0.05%, Mn: 0.40% or less, Si: 0.10% or less, It is characterized in that Al contains 0.020% or less, and the balance consists of Fe and unavoidable impurities.
- the ratio [N%] of the content [N%] of N to the content [Al%] of Al ] / [Al%] is 2.4 or more.
- the gas turbine disc material of the fourth aspect of the present invention is characterized in that, in the gas turbine disc material of any of the first to third aspects, the absorbed energy in a room temperature Charpy impact test is 40 J or more. .
- the gas turbine disc material of the fifth aspect of the present invention is characterized in that the creep rupture time at 596 ° C. ⁇ 310 MPa is 750 hours or more in the gas turbine disc material of any of the first to fourth aspects. I assume.
- the forging material having the component composition according to any one of the first to third aspects is subjected to a heat treatment for heating and quenching and then tempering.
- the quenching temperature is in the range of 1050 to 1150 ° C.
- gas turbine disc material of the first aspect of the present invention it is possible to ensure balanced material properties in which high creep strength and high toughness are compatible. Further, according to the minor component definition of the second aspect or the third aspect of the present invention or the heat treatment method of the sixth aspect, a gas turbine disc material having high toughness can be obtained reliably and stably while improving creep strength. be able to.
- C 0.05 to 0.15%
- C is an element that secures hardenability and combines with Cr, Mo, Nb, V, Nb, etc. in the tempering process to form fine and high hardness carbides and carbonitrides, and has a large effect on high temperature strength is there.
- the content is less than 0.05%, a sufficient amount of carbides and carbonitrides can not be formed, and a uniform martensitic structure can not be obtained. That is, when the amount of C is less than 0.05%, a mixed structure of martensite and delta ferrite is formed, and the high temperature strength and the high temperature fatigue strength are significantly reduced.
- the C content is made 0.05 to 0.15%.
- Ni is an element that can improve hardenability and toughness at normal temperature, and can satisfy desired toughness at 0.25% or more.
- the Ni content is set to 0.25 to 1.50%.
- the amount of Ni is an element that affects the toughness and creep characteristics in the opposite direction, so there is 0.25 to 1.50% as an appropriate amount of Ni that can balance high temperature creep characteristics and toughness.
- Ni content 0.25 to 1.50% is appropriate is newly found by the experiment of the present inventors, and the experiment will be described later again.
- the Ni content may be 0.25% to 0.99% or 0.25% to 0.90% in consideration of the high temperature creep characteristics.
- Cr 9.0-12.0%
- Cr improves oxidation resistance and creep rupture strength. However, if the Cr content is less than 9.0%, sufficient oxidation resistance and creep rupture strength can not be obtained. On the other hand, if Cr is contained in excess of 12.0%, the creep rupture strength does not decrease so much, but delta ferrite precipitates, and the toughness and the high-temperature fatigue characteristics decrease. Therefore, the Cr content is set to 9.0 to 12.0%.
- Mo 0.50 to 0.90%
- Mo improves the high temperature strength and the creep rupture strength by both the solid solution strengthening and the precipitation strengthening.
- the Mo content is set to 0.50 to 0.90%.
- W 1.0 to 2.0%
- W is an element that improves high-temperature strength and creep rupture strength. However, if the content of W is less than 1.0%, the effect can not be sufficiently obtained. In addition, if the W content exceeds 2.0%, there is a possibility that the delta ferrite which is harmful to the high temperature characteristics may be precipitated. Therefore, the W content is set to 1.0 to 2.0%.
- V forms carbides (V 4 C 3 ) and nitrides (VN) and forms complex carbonitrides (Nb, V) (C, N) with Nb to enhance high temperature strength and creep rupture strength It is an element. However, if the V content is less than 0.10%, the effect is not sufficient, and if the V content exceeds 0.30%, the carbides and carbonitrides become coarsened and coarsened during long-term use, Creep rupture strength decreases. Therefore, the V content is 0.10 to 0.30%.
- Nb is an element that forms carbides (NbC), forms complex carbonitrides (Nb, V) (C, N) with V, and enhances high-temperature strength and coup fracture strength.
- NbC carbides
- Nb, V complex carbonitrides
- the Nb content is made 0.01 to 0.10%.
- Co 0.01 to 4.0%
- Co increases the solid solution amount of carbides and carbonitrides in the matrix, and Co itself exhibits a solid solution strengthening action, and is an element effective in improving the high temperature strength and the creep rupture strength.
- the Co content is less than 0.01%, the effect is small, and if Co exceeds 4.0%, the toughness and the creep rupture strength are reduced. Therefore, the Co content is made 0.01 to 4.0%.
- B is an element that enhances high temperature strength and creep rupture strength. However, if the B content is less than 0.0005%, the effect is small, and if B is contained in excess of 0.010%, eutectic Fe when heated to 900 to 1200 ° C. during forging 2 B and BN are formed and adversely affect hot workability and mechanical properties. Therefore, the B content is made 0.0005 to 0.010%.
- B content is B equivalent (B + 0.5N) represented by the sum of B content [B%] and 0.5 content of N content [N%], as will be described later. It is desirable to adjust so as to be 0.030% or less.
- N 0.01 to 0.05%
- N is an element which contributes to the improvement of high temperature strength and creep rupture strength through precipitation of carbonitrides of Nb and V by appropriate heat treatment, and is also effective in preventing the formation of delta ferrite.
- the N content is made 0.01 to 0.05%.
- the steel so that the ratio [N%] / [Al%] of the N content [N%] to the Al content [Al%] in the steel is 2.4 or more. It is desirable to adjust the amount of N according to the amount of medium Al. Furthermore, in order to suppress the formation of BN which is harmful to hot workability and mechanical properties, it is represented by the sum of the content of B [B%] and the content of N [0.5% of the content of N [N%]. It is desirable to adjust the N amount according to the B content so that the B equivalent (B + 0.5 N) becomes 0.030% or less.
- Mn is an element which is often used as a deoxidizer at the time of melting steel and is often contained as an impurity in steel. The effect as a deoxidizer is sufficiently achieved with a Mn content of 0.40% or less. In addition, since Mn is an element that promotes embrittlement, the content is preferably small. Therefore, the Mn content is regulated to 0.40% or less.
- Si 0.10% or less
- Si is an element which is often used as a deoxidizer at the time of melting steel, and is often contained as an impurity. If the Si content exceeds 0.10%, segregation in large steel ingots becomes severe, and the toughness after prolonged use decreases. Therefore, the Si content is regulated to 0.10% or less.
- Al 0.020% or less
- a trace amount of Al is contained as an impurity derived from Al used as a deoxidizer at the time of melting.
- Al fixes N as AlN to reduce the amount of effective nitrogen, and reduces the amount of carbonitrides such as Nb and V to reduce high temperature strength and creep rupture strength. It is desirable to limit the amount to 0.020% or less.
- the amount of N is also related to the formation amount of carbonitride, as described later, it is preferable to set the [N%] / [Al%] ratio to 2.4 or more.
- each of the above elements is Fe and an unavoidable impurity.
- this impurity, P, S, etc. are contained, but since these elements make the material brittle and adversely affect the impact characteristics, it is preferable that the content thereof be as small as possible. Preferably, it is 0.015% or less.
- Ni is contained in a range of 1.0 to 3.5%.
- creep rupture strength is insufficient at a use temperature exceeding 500 ° C., and it is necessary to further improve creep strength. Therefore, as a result of experiments and studies conducted by the present inventors in detail, it is necessary to make the Ni content in the range of 0.25 to 1.50%, which is lower than the turbine disk material of Patent Document 1, It has been found that the high temperature creep characteristics are further improved while securing the toughness desired as a material, so that it can be used even at a use temperature which greatly exceeds 500 ° C.
- the Ni content according to the present invention may be 0.25% to 0.99% of the range lower than the Ni content of the turbine disk material of Patent Document 1 in consideration of high temperature creep characteristics, or 0 It may be 25% to 0.90%.
- the inventors of the present invention examined the toughness and high-temperature creep characteristics under high stress for the forged material of the heat-treated 12Cr-based heat-resistant steel with various amounts of Ni, and the results shown in FIG. It is done.
- the components of the 12Cr heat resistant steel used in the experiments are the test materials J1 to J3 of the examples of Table 1 and the test materials C1, C4, AL15, and AL20 of the comparative examples.
- the forged material was heated to 1050 ° C. or 1090 ° C., held for 3.5 hours, quenched by oil cooling, then tempered at 670 ° C., and subjected to a material test.
- Table 2 shows the results of the room temperature tensile test and the room temperature Charpy impact test.
- Table 3 shows creep rupture times under the test conditions of 596 ° C. ⁇ 310 MPa. The test result in the table is shown in FIG. 1 as a result of arranging the amount of Ni of the test material.
- quenching is considered as a range in which the toughness required for a gas turbine disk material (energy absorbed by room temperature Charpy impact test is 40 J or more) and creep strength (creep rupture time at 596 ° C. ⁇ 310 MPa is 750 hours or more) are compatible After setting the temperature to 1050 ° C. or higher, the amount of Ni was made 0.25 to 1.50% in the appropriate range.
- the alloy having the above composition is melted and cast in a conventional manner to form an ingot.
- the resulting ingot is homogenized as required, and then heated, for example, to 900 to 1200 ° C. for hot forging.
- the resulting forged material is subjected to a quenching-tempering tempering heat treatment.
- the process of this refining heat treatment is a heat treatment method as another aspect of the present invention.
- the tempering heat treatment is a process necessary to improve creep strength by depositing carbides and carbonitrides as well as obtaining a high strength desired for the gas turbine disk material by making the steel structure a substantially uniform martensitic structure. is there. That is, the forging material is heated to a high temperature to achieve austenitizing of the steel structure, and an element contributing to carbide or carbonitride formation is once dissolved in the matrix and then quenched (quenched). It is a necessary step to attain martensite formation and to make the element contributing to the formation of carbides and carbonitrides into supersaturated solid solution in the steel and to precipitate carbides and carbonitrides finely by tempering.
- the quenching temperature (heating temperature for quenching)
- the solid solution amounts of C, N, Nb and V which contribute to carbonitride formation can be increased, and as a result, Nb precipitated by tempering
- the creep strength can be improved by increasing the precipitated amount of carbonitrides of V and V.
- the hardening temperature is too high, coarsening of crystal grains will occur, leading to a decrease in toughness. Therefore, there is a suitable temperature range for the quenching temperature in order to prevent the loss of toughness while improving the creep strength.
- the inventors of the present invention examined the influence of the quenching temperature on the toughness and the creep strength using a test material which was quenched at a quenching temperature of 1050 ° C. or 1090 ° C. and tempered at 670 ° C. The results shown in Table 3 and FIG. 1 were obtained.
- the components of the 12Cr heat resistant steel used in the experiments are the respective test materials of the examples of Table 1 and the respective test materials of the comparative example.
- the forged material was heated to 1050 or 1090 ° C., held for 3.5 hours, quenched by oil cooling, then tempered at 670 ° C. and subjected to material testing.
- the absorbed energy of the specimen of the hardening temperature of 1050 ° C. and 1090 ° C. is equal, and the influence of the hardening temperature on the absorbed energy is not recognized.
- creep rupture time is longer for 1090 ° C. quenching than for 1050 ° C. quenching, and creep rupture strength is higher for higher quenching temperatures.
- the quenching temperature range is set to 1050 to 1150 ° C. in order to enter the temperature range in which the delta ferrite precipitates and to cause significant coarsening of the crystal grain size to lower the toughness.
- it is around 1090 ° C.
- Steel ingots were produced by the electroslag remelting method so as to have the chemical components shown in the test materials J1 to J3 of the examples of Table 1 and the test materials C1, C4, AL15, and AL20 of the comparative example.
- This was forged by heating to 900 to 1200 ° C. to produce a disc-shaped forged material.
- the forging was heated to 1050 ° C. or 1090 ° C., held for 3.5 hours, quenched by oil cooling, and then subjected to 670 ° C. tempering.
- Tensile test pieces are prepared from each forged material after tempering, and room temperature tensile test is conducted according to the JIS Z 2241 tensile test method, and Charpy V-notch impact test pieces are prepared and Charpy impact test according to JIS Z 2242. The impact test was performed according to the law. The results are shown in Table 2. Further, a round bar-like smooth test piece for creep rupture test was prepared from the same specimen, and the creep rupture test was performed under the condition of 596 ° C. ⁇ 310 MPa in accordance with the high temperature creep test method of JIS Z 2272. The results are shown in Table 3.
- Test materials J1 to J3 in the examples are inventive examples within the component composition range defined in the present invention.
- the room temperature shock absorption energy satisfied 40 J required as a gas turbine disc material.
- the creep rupture time 596 ° C. ⁇ 310 MPa ⁇ 750 hours or more necessary for the gas turbine disk material was satisfied.
- Comparative Example C1 in which the amount of Ni was high, it was found that the creep rupture time was extremely short and the high temperature strength was inferior.
- the comparative example C1 is a comparative example corresponding to the material described in the patent document 1.
- Comparative Example C2 in which the amount of Ni is low has a room temperature absorbed energy as low as 20 J, and does not satisfy 40 J necessary for a gas turbine disk material.
- Comparative Examples AL15 and AL20 show that the creep strength decreases sharply in the low N / Al region as compared with Examples J1 to J3. It is understood that, in order to stably secure creep rupture strength, it is necessary to increase N / Al to 2.4 or more.
- the well-balanced material characteristic which made high creep strength and high toughness make compatible can be ensured. Further, according to the minor component definition and the heat treatment method according to the present invention, it is possible to reliably and stably obtain a gas turbine disc material having high toughness while simultaneously improving creep strength.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
本願は、2017年9月21日に日本に出願された特願2017-181196号について優先権を主張し、その内容をここに援用する。
質量%で、
C:0.05~0.15%、
Ni:0.25~1.50%、
Cr:9.0~12.0%、
Mo:0.50~0.90%、
W:1.0~2.0%、
V:0.10~0.30%、
Nb:0.01~0.10%、
Co:0.01~4.0%、
B:0.0005~0.010%、
N:0.01~0.05%、
Mn:0.40%以下、
Si:0.10%以下、
Al:0.020%以下
を含有し、残部がFeおよび不可避的不純物からなることを特徴とする。
また本発明の第2態様もしくは第3態様の微量成分規定や第6態様の熱処理方法によれば、さらにクリープ強度を向上させると同時に高い靭性を有するガスタービンディスク材を、確実かつ安定して得ることができる。
[C:0.05~0.15%]
Cは、焼入れ性を確保し、焼戻し過程でCr、Mo、Nb、V、Nb等と結合して微細かつ高硬度の炭化物や炭窒化物を形成するとともに、高温強度に大きな影響を与える元素である。しかし、含有量が0.05%未満では、充分な量の炭化物や炭窒化物を生成させることができず、また均一なマルテンサイト組織を得ることができない。すなわち、C量が0.05%未満では、マルテンサイトとデルタフェライトなどの混在組織となり、高温強度や高温疲労強度が著しく低下する。一方、0.15%を越える含有量では靱性が低下するだけでなく、高温での使用中に炭化物や炭窒化物の凝集粗大化が著しくなり、クリープ破断強度の低下が起こる。従って、C含有量は0.05~0.15%とする。
Niは、焼入性および常温における靱性を向上させ得る元素であり、0.25%以上で所望の靭性を満足することができる。一方、Ni量が1.50%を超えて多くなれば、靭性は向上するものの、クリープ破断強度が著しく低下し、500℃を越える高温で使用されるガスタービンディスク材として不適切となる。従って、Ni含有量は0.25~1.50%とする。このようにNi量は、靭性とクリープ特性に対して反対方向に影響を与える元素であり、そこで、高温クリープ特性と靭性とを両立させ得る適正Ni量範囲として、0.25~1.50%の範囲内と規定した。このように、Ni量0.25~1.50%が適切であることは、本発明者等の実験により新規に見出されたことであり、その実験については、後に改めて説明する。
なお、高温クリープ特性を考慮して、Ni含有量は0.25%~0.99%としても良く、又は、0.25%~0.90%としても良い。
Crは、耐酸化性およびクリープ破断強度を向上させる。しかし、Cr含有量が9.0%未満では、充分な耐酸化性およびクリープ破断強度が得られない。一方、12.0%を越えてCrが含有されれば、クリープ破断強度はさほど低下しないが、デルタフェライトが析出し、靱性および高温疲労特性が低下する。従ってCr含有量は、9.0~12.0%とする。
Moは、固溶体強化および析出強化の両作用により高温強度およびクリープ破断強度を向上させる。しかし、Moの含有量が0.50%未満では、その効果は小さく、またMo含有量が0.90%を越えれば、デルタフェライトを生成して、靱性やクリープ破断強度を劣化させるおそれがある。従って、Mo含有量は0.50~0.90%とする。
Wは、高温強度およびクリープ破断強度を向上させる元素である。しかし、Wの含有量が1.0%未満では、その効果が充分に得られない。またW含有量が2.0%を越えれば、高温特性に害を及ぼすデルタフェライトが析出するおそれがある。従って、W含有量は1.0~2.0%とする。
Vは、炭化物(V4C3)および窒化物(VN)を形成し、またNbとの複合炭窒化物(Nb,V)(C,N)を形成し、高温強度およびクリープ破断強度を高める元素である。しかし、Vの含有量が0.10%未満では、その効果が充分ではなく、また、0.30%を越えるV含有量では、長時間使用中に炭化物や炭窒化物が凝集粗大化して、クリープ破断強度が低下する。従って、V含有量は0.10~0.30%とする。
Nbは、炭化物(NbC)を形成し、またVとの複合炭窒化物(Nb,V)(C,N)を形成し、高温強度およびクープ破断強度を高める元素である。しかし、Nbの含有量が0.01%未満では、その効果が少なく、また、0.10%を越える含有量では、1100℃以上の高い焼入温度でも炭化物や炭窒化物が充分固溶されず、かつ、析出した炭化物や炭窒化物がクリープ中に凝集粗大化してクリープ破断強度が低下する。従って、Nb含有量は0.01~0.10%とする。
Coは、マトリクスへの炭化物、炭窒化物の固溶量を増大させるとともに、Co自身も固溶強化作用を示し、高温強度およびクリープ破断強度の改善に効果のある元素である。しかし、Co含有量が0.01%未満では、その効果は小さく、またCoが4.0%を越えてしまえば、靱性およびクリープ破断強度を低下させてしまう。従って、Co含有量は0.01~4.0%とする。
Bは、高温強度およびクリープ破断強度を高める元素である。しかし、Bの含有量が0.0005%未満では、その効果は小さく、また、0.010%を越えてBが含有されれば、鍛造時に900~1200℃に加熱した際に、共晶Fe2BおよびBNが生成し、熱間加工性および機械的性質に悪影響を及ぼす。従ってB含有量は、0.0005~0.010%とする。なお、後に改めて説明するように、B含有量は、Bの含有量[B%]とNの含有量[N%]の0.5倍との和で表されるB当量(B+0.5N)が0.030%以下となるように調整することが望ましい。
Nは、適切な熱処理によってNbやVの炭窒化物を析出させることを通じて、高温強度やクリープ破断強度の向上に寄与し、またデルタフェライトの生成防止に効果を示す元素である。しかし、N含有量が0.01%未満では、その効果は充分に現れず、また0.05%を超えれば、靱性が低下する。そこでN含有量は0.01~0.05%とする。なお、Nは鋼中にAlが含まれる場合、AlNとして固定されてしまって、NbやVの炭窒化物の生成のために寄与するN量(有効窒素量)が少なくなってしまう。そこで、後に改めて説明するように、鋼中のN含有量[N%]とAl含有量[Al%」との比[N%]/[Al%」が2.4以上となるように、鋼中Al量に応じてN量を調整することが望ましい。
さらに、熱間加工性および機械的性質に有害なBNの生成を抑制するために、Bの含有量[B%]とNの含有量[N%]の0.5倍との和で表されるB当量(B+0.5N)が0.030%以下となるように、B含有量に応じてN量を調整することが望ましい。
Mnは、鋼の溶製時に脱酸剤として使用されることが多く、また鋼中の不純物として含有されることが多い元素である。脱酸材としての効果は、0.40%以下のMn含有量で充分に達成される。また、Mnは脆化を助長する元素であるため、含有量は少ないことが望ましい。従ってMn含有量は、0.40%以下に規制する。
Siは、Mnと同様に鋼の溶製時に脱酸剤として使用されることが多く、また不純物として含有されることが多い元素である。0.10%を越えるSi含有量では、大型鋼塊中での偏析が激しくなり、また長時間使用後の靱性が低下する。従って、Si含有量は0.10%以下に規制する。
溶製時の脱酸材として使用したAlに由来して、微量のAlが不純物として含有される。Alは、NをAlNとして固定して有効窒素量を減少させ、NbやV等の炭窒化物生成量を減少させることにより高温強度およびクリープ破断強度を低下させてしまうことから、Al量は極力少ないことが望ましく、0.020%以下に規制することとした。なお、炭窒化物生成量には、N量も関係するから、後述するように、[N%]/[Al%]比を2.4以上とすることが好ましい。
特許文献1に示されるタービンディスク材の12Cr系耐熱鋼では、Niを1.0~3.5%の範囲内で含有させている。しかるにこのようなタービンディスク材では、500℃を大きく越える使用温度ではクリープ破断強度が不足し、さらなるクリープ強度の向上が必要である。
そこで本発明者等が詳細に実験・検討を重ねた結果、Ni量を、特許文献1のタービンディスク材よりも低めの0.25~1.50%の範囲内とすることが、ガスタービンディスク材として望まれる靭性を確保しながら、高温クリープ特性をより向上させて、500℃を大きく越える使用温度でも使用可能となることを見出した。
なお、高温クリープ特性を考慮して、本発明に係るNi含有量は特許文献1のタービンディスク材のNi含有量よりも低い範囲の0.25%~0.99%としても良く、又は、0.25%~0.90%としても良い。
高温・低応力側のクリープ破断強度の向上には、Nb、Vの炭窒化物を主体とした微細析出物の析出量増大が有効である。そのためには、鋼中に炭窒化物生成のために寄与する有効なNを充分な量、焼入れ時にマトリクス中に固溶させておくことが必要である。
一方、この種の鋼の溶製時には、脱酸材としてAlを用いることが多く、そのため、鋼中にはAlが存在していることが多い。そしてAlはNと結合してAlNとしてNを固定してしまう。そのためAl量に対してN量が少なすぎれば、Nb、Vの炭窒化物を生成するために有効なN量(有効窒素量)が少なくなって、充分な量の炭窒化物が析出しなくなってしまう。
BとNを多量に添加すると、鍛造時に900~1200℃に加熱した際に、共晶Fe2BおよびBNが生成し、熱間加工性および機械的性質に悪影響を及ぼす。そこで、特許第2948324号に示されているように、Bの含有量[B%]とNの含有量[N%]の0.5倍との和で表されるB当量(B+0.5N)が0.030%以下となるように、B含有量に応じてN量を調整することが望ましい。一方、BとNは、高温強度向上に有効な元素であることから、Bは0.0005%以上、Nは0.01%以上含有する必要があるため、B当量([B%]+0.5[N%])の下限値は0.0055%とした。
図3に、本発明における[N%]/[Al%]とB当量([B%]+0.5[N%])の好ましい範囲を示す。
本発明の別の態様の熱処理方法を含めて、ガスタービンディスク材の製造方法について次に説明する。
また、同じ供試体から、クリープ破断試験用の丸棒状の平滑試験片を作製し、JIS Z 2272の高温クリープ試験法に準拠して596℃×310MPaの条件でクリープ破断試験を行った。その結果を、表3中に示す。
さらに、比較例AL15およびAL20は、図2に示すように実施例J1~J3と比較して、低N/Al領域で急激にクリープ強度が低下することが分かる。安定してクリープ破断強度を確保するためには、N/Alを2.4以上に高めておく必要があることが分かる。
また本発明に係る微量成分規定や熱処理方法によれば、さらにクリープ強度を向上させると同時に高い靭性を有するガスタービンディスク材を、確実かつ安定して得ることができる。
Claims (6)
- 質量%で、
C:0.05~0.15%、
Ni:0.25~1.50%、
Cr:9.0~12.0%、
Mo:0.50~0.90%、
W:1.0~2.0%、
V:0.10~0.30%、
Nb:0.01~0.10%、
Co:0.01~4.0%、
B:0.0005~0.010%、
N:0.01~0.05%、
Mn:0.40%以下、
Si:0.10%以下、
Al:0.020%以下
を含有し、残部がFeおよび不可避的不純物からなることを特徴とするガスタービンディスク材。 - Nの含有量[N%]とAlの含有量[Al%]との比[N%]/[Al%]が2.4以上であることを特徴とする
請求項1に記載のガスタービンディスク材。 - Bの含有量[B%]とNの含有量[N%]の0.5倍との和で表されるB当量([B%]+0.5[N%])が0.0055~0.030%であることを特徴とする
請求項1、請求項2のいずれかの請求項に記載のガスタービンディスク材。 - 室温シャルピー衝撃試験における吸収エネルギーが40J以上であることを特徴とする
請求項1~請求項3のいずれかの請求項に記載のガスタービンディスク材。 - 596℃×310MPaにおけるクリープ破断時間が750時間以上であることを特徴とする
請求項1~請求項4のいずれかの請求項に記載のガスタービンディスク材。 - 請求項1~請求項3のいずれかの請求項に記載の成分組成を有する鍛造材を加熱して焼入れ、その後に焼戻す熱処理を施すにあたり、
焼入れ加熱温度を1050~1150℃の範囲内とすることを特徴とするガスタービンディスク材の熱処理方法。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16/637,903 US20200165709A1 (en) | 2017-09-21 | 2018-09-19 | Gas turbine disk material and heat treatment method therefor |
CN201880048158.2A CN110997960B (zh) | 2017-09-21 | 2018-09-19 | 燃气轮机盘材料以及其热处理方法 |
JP2019543680A JP6963624B2 (ja) | 2017-09-21 | 2018-09-19 | ガスタービンディスク材及びその熱処理方法 |
DE112018003750.9T DE112018003750T5 (de) | 2017-09-21 | 2018-09-19 | Gasturbinenscheibennmaterial und Wärmebehandlungsverfahren dafür |
KR1020207004268A KR102374800B1 (ko) | 2017-09-21 | 2018-09-19 | 가스 터빈 디스크재 및 그 열처리 방법 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2017-181196 | 2017-09-21 | ||
JP2017181196 | 2017-09-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019059240A1 true WO2019059240A1 (ja) | 2019-03-28 |
Family
ID=65810301
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2018/034683 WO2019059240A1 (ja) | 2017-09-21 | 2018-09-19 | ガスタービンディスク材及びその熱処理方法 |
Country Status (6)
Country | Link |
---|---|
US (1) | US20200165709A1 (ja) |
JP (1) | JP6963624B2 (ja) |
KR (1) | KR102374800B1 (ja) |
CN (1) | CN110997960B (ja) |
DE (1) | DE112018003750T5 (ja) |
WO (1) | WO2019059240A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111270164A (zh) * | 2020-01-23 | 2020-06-12 | 清华大学 | 一种相间析出强化的低活化铁素体钢及其制备方法 |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114277221A (zh) * | 2021-12-17 | 2022-04-05 | 无锡派克新材料科技股份有限公司 | 一种提高燃气轮机X22CrMoV12-1盘件探伤质量的方法 |
CN116713419A (zh) * | 2023-06-26 | 2023-09-08 | 重庆新承航锐科技股份有限公司 | 提高13Cr10Mo1W1VNbN燃气轮机轮盘锻件力学性能的热加工方法和系统 |
CN117051333B (zh) * | 2023-10-12 | 2024-01-23 | 山西同航特钢有限公司 | 一种锻钢支承辊及其制备方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10251809A (ja) * | 1997-03-18 | 1998-09-22 | Mitsubishi Heavy Ind Ltd | 高靭性フェライト系耐熱鋼 |
JP2012140666A (ja) * | 2010-12-28 | 2012-07-26 | Toshiba Corp | 鍛造用耐熱鋼、鍛造用耐熱鋼の製造方法、鍛造部品および鍛造部品の製造方法 |
JP2012219682A (ja) * | 2011-04-07 | 2012-11-12 | Hitachi Ltd | 蒸気タービン用ロータシャフトと、それを用いた蒸気タービン |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63171856A (ja) * | 1987-01-09 | 1988-07-15 | Hitachi Ltd | 耐熱鋼 |
JPH11209851A (ja) | 1998-01-27 | 1999-08-03 | Mitsubishi Heavy Ind Ltd | ガスタービンディスク材 |
DE10025808A1 (de) * | 2000-05-24 | 2001-11-29 | Alstom Power Nv | Martensitisch-härtbarer Vergütungsstahl mit verbesserter Warmfestigkeit und Duktilität |
FR2823226B1 (fr) * | 2001-04-04 | 2004-02-20 | V & M France | Acier et tube en acier pour usage a haute temperature |
JP4609491B2 (ja) * | 2005-04-07 | 2011-01-12 | 住友金属工業株式会社 | フェライト系耐熱鋼 |
JP4386364B2 (ja) * | 2005-07-07 | 2009-12-16 | 株式会社日立製作所 | 蒸気タービン用配管とその製造法及びそれを用いた蒸気タービン用主蒸気配管と再熱配管並びに蒸気タービン発電プラント |
CN101525727B (zh) * | 2009-04-22 | 2011-02-09 | 四川六合锻造股份有限公司 | 用做超超临界汽轮机叶片或螺栓的耐热钢材料及其制备方法 |
US20120070329A1 (en) * | 2009-05-22 | 2012-03-22 | Torsten-Ulf Kern | Ferritic martensitic iron based alloy, a component and a process |
CN102086494B (zh) * | 2009-12-04 | 2012-10-10 | 中国科学院金属研究所 | 高铬马氏体系耐热钢及其制造方法 |
CN101956055A (zh) * | 2010-10-19 | 2011-01-26 | 钢铁研究总院 | 一种大口径厚壁耐热钢管的热处理方法 |
JP5562825B2 (ja) * | 2010-12-28 | 2014-07-30 | 株式会社東芝 | 耐熱鋳鋼、耐熱鋳鋼の製造方法、蒸気タービンの鋳造部品および蒸気タービンの鋳造部品の製造方法 |
CN102181789A (zh) * | 2011-04-27 | 2011-09-14 | 四川六合锻造股份有限公司 | 用于超临界汽轮机叶片的耐热钢材料及其制备方法 |
CN103667967B (zh) * | 2013-12-28 | 2016-03-30 | 无锡透平叶片有限公司 | 一种超超临界汽轮机转子用耐热钢 |
CN106048413B (zh) * | 2016-06-30 | 2018-06-15 | 四川六合锻造股份有限公司 | 一种降低高性能耐热不锈钢材料链状碳化物的方法 |
CN106191701A (zh) * | 2016-08-30 | 2016-12-07 | 四川六合锻造股份有限公司 | 一种用作汽轮机叶片的耐热钢材料及其制备方法 |
-
2018
- 2018-09-19 US US16/637,903 patent/US20200165709A1/en active Pending
- 2018-09-19 WO PCT/JP2018/034683 patent/WO2019059240A1/ja active Application Filing
- 2018-09-19 DE DE112018003750.9T patent/DE112018003750T5/de active Pending
- 2018-09-19 CN CN201880048158.2A patent/CN110997960B/zh active Active
- 2018-09-19 JP JP2019543680A patent/JP6963624B2/ja active Active
- 2018-09-19 KR KR1020207004268A patent/KR102374800B1/ko active IP Right Grant
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10251809A (ja) * | 1997-03-18 | 1998-09-22 | Mitsubishi Heavy Ind Ltd | 高靭性フェライト系耐熱鋼 |
JP2012140666A (ja) * | 2010-12-28 | 2012-07-26 | Toshiba Corp | 鍛造用耐熱鋼、鍛造用耐熱鋼の製造方法、鍛造部品および鍛造部品の製造方法 |
JP2012219682A (ja) * | 2011-04-07 | 2012-11-12 | Hitachi Ltd | 蒸気タービン用ロータシャフトと、それを用いた蒸気タービン |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111270164A (zh) * | 2020-01-23 | 2020-06-12 | 清华大学 | 一种相间析出强化的低活化铁素体钢及其制备方法 |
Also Published As
Publication number | Publication date |
---|---|
KR20200030566A (ko) | 2020-03-20 |
CN110997960B (zh) | 2021-11-02 |
JPWO2019059240A1 (ja) | 2020-07-30 |
JP6963624B2 (ja) | 2021-11-10 |
DE112018003750T5 (de) | 2020-04-09 |
US20200165709A1 (en) | 2020-05-28 |
KR102374800B1 (ko) | 2022-03-15 |
CN110997960A (zh) | 2020-04-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6963624B2 (ja) | ガスタービンディスク材及びその熱処理方法 | |
WO2016043199A1 (ja) | オーステナイト系ステンレス鋼板 | |
KR20190046729A (ko) | 지열 발전 터빈 로터용 저합금강 및 지열 발전 터빈 로터용 저합금 물질, 및 이들의 제조 방법 | |
US6755920B2 (en) | Low-alloy heat-resistant steel, heat treatment method therefor, and turbine rotor comprising the same | |
CN103374687A (zh) | 强度和韧性优异的蒸汽轮机叶片用钢 | |
JP2001262286A (ja) | 高純度高Crフェライト系耐熱鋼および高純度高Crフェライト系耐熱鋼の製造方法 | |
WO2015163226A1 (ja) | 地熱発電用タービンロータ材及びその製造方法 | |
JP2016138320A (ja) | NiCrMo鋼およびNiCrMo鋼材の製造方法 | |
US6106766A (en) | Material for gas turbine disk | |
JP2010138465A (ja) | クリープ強度に優れる耐熱鋼およびその製造方法 | |
JP2016065265A (ja) | 蒸気タービン動翼用耐熱鋼および蒸気タービン動翼 | |
JP2001073092A (ja) | 高温強度および靱性に優れた9〜12%Cr系耐熱鋼、およびその製造方法 | |
WO2019035401A1 (ja) | 高硬度かつ靱性に優れる鋼 | |
JP6738010B2 (ja) | 高温強度特性および高温クリープ特性に優れたニッケル基合金 | |
JP5981357B2 (ja) | 耐熱鋼および蒸気タービン構成部品 | |
JPH05113106A (ja) | 高純度耐熱鋼および高純度耐熱鋼からなる高低圧一体型タービンロータの製造方法 | |
JP2017202495A (ja) | オーステナイト系耐熱鋼用溶接材料 | |
JP2958816B2 (ja) | 靱性およびクリープ強度に優れるフェライト系耐熱鋼の熱処理方法 | |
JPH0931600A (ja) | 高温用蒸気タービンロータ材 | |
JP2004018897A (ja) | 高クロム合金鋼及びそれを使用したタービンロータ | |
JPH11217655A (ja) | 高強度耐熱鋼およびその製造方法 | |
JP2017218634A (ja) | マルエージング鋼 | |
JP2016065280A (ja) | 耐熱鋼および蒸気タービン構成部品 | |
JP4774633B2 (ja) | マルテンサイト系耐熱鋼の製造方法 | |
JPH11131190A (ja) | 高低圧一体型ロータ用高強度耐熱鋼及びタービンロータ |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 18857715 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2019543680 Country of ref document: JP Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 20207004268 Country of ref document: KR Kind code of ref document: A |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 18857715 Country of ref document: EP Kind code of ref document: A1 |