JPH0770679A - High corrosion resistant and high strength cemented carbide, high corrosion resistant and high strength single crystal casting, gas turbine and combined cycle generating system - Google Patents

Abstract

PURPOSE:To provide a cemented carbide combining corrosion resistance more excellent than that of the existing single crystal alloys and oxidation resistance, high strength and creep fracture strength on a high level among the existing single crystal alloys, to provide single crystal cast parts for blades and nozzles using the same and to provide a combined cycle generating system using the same parts. CONSTITUTION:This high corrosion resistant and high strength cemented carbide is the one contg., by weight, 5.5 to 12% Cr, 4.5 to 6.5% Al, 0.1 to 5% Ti, 2 to 12% W, 2.5 to 10% Ta, <=5.8% Mo, 0.1 to 3% Co, <=3% Nb, 0.1 to 4% Re, <=0.3% Hf, and the balance Ni with inevitable impurities. Furthermore, the single crystal casting for blades and nozzles using the same is provided, and the same parts are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for blades (moving blades) and nozzles (stating blades) of gas turbines for aircraft or ground power generation, which require high creep rupture strength in a high temperature combustion gas atmosphere. Novel superalloy, a single crystal cast produced by using the superalloy, a single crystal part for a gas turbine produced by using the single crystal cast, and a high efficiency obtained by using the single crystal part The present invention relates to a gas turbine, and more particularly, to a gas turbine that requires high corrosion resistance for ground power generation. Further, the present invention relates to a high efficiency combined cycle power generation system using the high efficiency gas turbine.

[0002]

2. Description of the Related Art Turbine blades that are exposed to the most severe operating environment against the increase in combustion temperature due to higher power output and higher efficiency of gas turbine engines are made of polycrystalline ordinary casting alloys, and have crystal grains in the stress loading direction. It has undergone a transition from a unidirectional columnar solidified alloy with no boundaries to a single crystal alloy with no grain boundaries. The history of such development is mainly centered on aircraft gas turbines, and continuous running time is relatively short and high creep rupture strength and high low cycle fatigue strength have been emphasized.

Alloy 444 (US Pat. No. 4,11)
6,723, Japanese Patent Publication No. 59-34776), PWA1
484 (U.S. Pat. No. 4,719,080, JP-A-61)
-284545, "Second-generation Nickel-base
Single Crystal Superalloy "; ADCetel and DNDuhl;
Superalloys 1988, The Metall. Soc., (1988), pp235-24
4), CMSX-4 (U.S. Pat. No. 4,643,782)
No. 60-211031, "Process and Allo"
y Optimization for CMSX-4 Superalloy Single Cristal
Airfoils "; DJ Fraisier, JR Whetstone, K. Harris,
GLErickson, RESchwer; High Temp. Mater. Power
Eng. 1990 Part2, (1990), pp1281-1300), SC-83K
(U.S. Pat. No. 4,976,791, JP-A-2-138
No. 431, "Development of Ni-base single crystal superalloys"; Takehiro Ohno,
Ryzo Watanabe; Iron and Steel, vol.77, (1991), pp832-839) and TUT31D
And TUT95 ("Realstic Advancement for Nickel-based Sin
gle Crystal Superalloys by the d-electrons Concep
t "; K.Matsugi, Y.Murata, M.Morinaga and N.Yukawa; Super
alloys 1992, The Minerals, Metals and Materials So
c., (1992), pp307-316, etc. were all developed for the purpose of aircraft gas turbine blades, and it cannot be said that they have sufficient corrosion resistance.

Currently, the components of gas turbine blades or nozzles are protected from severe corrosive environments by spraying a highly corrosion resistant alloy and then ceramics on the surface. However, the surface coating has a problem of peeling,
It is desirable that the rate of progress of corrosion in the peeled portion is as slow as possible. In gas turbines for aircraft, the continuous operation time is short and the inspection cycle is short, so even if the corrosion resistance of the single crystal superalloy is insufficient, it can be used. However, reducing maintenance work leads to improved reliability, so it is desirable to improve the corrosion resistance of superalloys.

On the other hand, the operating temperature of the blade of the gas turbine for terrestrial power generation has not been so high as that for aircraft, and ordinary cast alloy has been mainly used. However, due to recent global scale environmental pollution problems, there is an urgent need to improve the efficiency of gas turbines for ground power generation, the combustion temperature of gas turbines is high even for ground use, and the alloys for blades are also ordinary cast alloys.
The transition to single crystal alloys has become necessary. Since the continuous operation time of the ground type is much longer than that of the aircraft type, the inspection interval is long and the progress rate of corrosion when the coating is peeled off is particularly important. Therefore, although it is necessary that the corrosion resistance and the oxidation resistance in a combustion gas atmosphere are better than those for aircraft, the present situation is that a single crystal alloy aiming at such high corrosion resistance has not yet been put to practical use.

Further, the greatest bottleneck in improving the efficiency of the gas turbine is the service temperature of the first-stage blade and nozzle, and a high corrosion resistance and high strength superalloy that solves the above problems and single crystal casting using this superalloy. If the product can be manufactured, the combustion temperature of the gas turbine is raised, and the efficiency of the gas turbine can be improved. Furthermore, if this high-efficiency gas turbine can be manufactured, an exhaust heat recovery boiler that obtains steam by the energy of the exhaust gas of this gas turbine, a steam turbine driven by the steam, and a generator driven by the gas turbine and the steam turbine It is possible to obtain a highly efficient combined cycle power generation system in which the thermal efficiency of the entire plant is 50% or more, which cannot be achieved by the conventional technology, in the complex plant including the above.

[0007]

The corrosion products contained in the combustion gas of a gas turbine for ground power generation are mainly Na products.
Cl and Na ₂ SO ₄ are known. Generally, the corrosion resistance is evaluated by a burner rig test containing these mixed salts, a coating heating test, a molten salt total immersion test, and the like. When using a single crystal alloy for terrestrial power generation, Rene 80 (60Ni-14Cr-9.5Co-4Mo-4), which has been widely used as a polycrystalline alloy, has been used.
W-3Al-5Ti-0.17C-0.015B-0.03Zr) must have corrosion resistance equivalent to or close to that. Furthermore Re
When considering use at a temperature higher than ne80, Rene80
It is also necessary to have better oxidation resistance than.

The inventors of the present invention conducted a comparative examination of the corrosion resistance of various existing single-crystal alloys with Rene 80 by a molten salt coating heating test shown in Examples described later as a means for evaluating the corrosion resistance. Among the above single crystal alloys (Alloy 444 was not evaluated because it is too low for the target level strength of the present invention), SC-83K and TUT-31D were used.
Although TUT-95 and TUT-95 are currently known as the alloys with the highest creep rupture strength in the world, their corrosion resistance is far inferior to that of René80 in the evaluation by this experiment, and in terms of corrosion resistance, they are gas turbines for ground use. It was found that they do not have sufficient corrosion resistance for blades. On the other hand, PWA1484 and CMSX-4 have a thermal efficiency of 5
In order to provide a highly efficient combined cycle power generation system exceeding 0%, not only corrosion resistance but also strength was insufficient.

The object of the present invention is to provide conventional blades (moving blades) and nozzles (static blades) for gas turbines for aircraft or ground power generation, which require high creep rupture strength in a high temperature combustion gas atmosphere. A superalloy with high corrosion resistance and high strength suitable for single crystal parts that has both high corrosion and oxidation resistance equivalent to cast alloys and creep rupture strength equivalent to conventional single crystal alloys.
A single crystal casting made by using the master ingot and the alloy thereof, and a gas turbine blade and a gas turbine nozzle made by using the single crystal casting, and further by using these gas turbine blades and a gas turbine nozzle. It is possible to provide a high-efficiency gas turbine and a high-efficiency combined cycle power generation system that exceeds 50% in thermal efficiency that can be achieved by using the gas turbine.

[0010]

Means for Solving the Problems As a preliminary study for the development of a high-corrosion-resistant high-strength single crystal alloy, the present inventors examined the influence of various additive elements on the improvement of corrosion resistance. As a result, conventionally, only sulfurization has been regarded as a problem in the corrosion of gas turbines for ground power generation, but in the higher temperature range where oxidation resistance is also important, it is one of the most effective elements for improving high temperature strength. It has been found that excessive addition of some Ti is prohibited. This is because when the addition amount of Ti is too large, works effectively in environments sulfide oxidation by coexistence with Cr ₂ O ₃ is superimposed, Al ₂ O ₃
This is because it prevents the formation of a uniform layer of the protective film. The feature of the present invention is to find out the optimum addition amount of Ti for achieving both excellent corrosion resistance and high creep rupture strength. By adding Re and a suitable amount of Ti in combination, excellent corrosion resistance and high temperature strength can be obtained. It was found that

Another feature of the present invention is to find an optimum amount of Co added. In conventional alloys, Co was regarded only as an impurity level, or conversely, about 5 to 10% was added for the purpose of improving strength. It has been clarified that this excessive Co is an unsuitably large amount with respect to the alloys of the present invention in terms of oxidation resistance, corrosion resistance and strength. This carefully controlled amount of Co
Combined with the addition of a small amount of Hf, had a remarkable effect on the improvement of the oxidation resistance, corrosion resistance and high temperature strength of the alloy of the present invention.

Of the conventional alloys, US Pat. No. 4,719,
No. 080 (Japanese Patent Laid-Open No. 61-284545) describes PWA1.
Although it is an alloy having a composition containing 484, in this alloy, Ti is included only in a wide composition range and deviates from the preferable range. Further, the invention of this U.S. Patent is 3360 in a wide composition range in the P value of the formula (1) shown below.
To 4850, more preferably 3800 to 44
It is claimed to be 00 (the values in the formula (1) are all values by weight). P = -200Cr + 80Mo-20Mo ² -250Ti ² -50 (TixTa) + 15Nb + 200W-14W ² + 30Ta-1.5Ta ² + 2.5C o + 1200Al-100Al ² + 100Re + 1000Hf-2000Hf ² + 700Hf ^3- 2000V-500C-15000B-500Zr… (1)

The P value is considered to represent the contribution rate of each alloy element to the strength. For reference, the P value was calculated also for the alloys of the present invention shown in the examples, but sufficient high temperature strength was obtained despite the values being below 3360. The main reason why the P value of the alloy of the present invention is lower than 3360 is that the Ti amount and the Cr amount are relatively high and the Ta amount is relatively low.
Independent of the value, a sufficiently high high temperature strength can be obtained by adding a suitable amount of Ti, and the formula (1) is completely unsuitable for deriving the high temperature strength. Therefore, it can be said that this invention is a different invention from the alloy of the present invention.

The high corrosion resistance and high strength superalloy of the present invention can be single crystallized by the unidirectional solidification casting method. Since single crystal parts such as blades and nozzles of a gas turbine made by using this single crystal superalloy have high corrosion resistance and high temperature strength, the current gas turbine whose combustion efficiency is limited by the performance of these parts is the present invention. By using the single crystal superalloy blades and nozzles described above, it becomes possible to manufacture a highly efficient gas turbine that has never been achieved. Further, by manufacturing this highly efficient gas turbine, a combined cycle power generation system having a high efficiency of 50% or more can be obtained in cycle power generation with a steam turbine.

The first invention of the present invention obtained as a result of the above-mentioned detailed examination is, by weight%, Cr 5.5 to 12%,
Al4.5-6.5%, Ti0.1-5%, W2-12
%, Ta 2.5 to 10%, Mo 5.8% or less, Co 0.
It is a high corrosion resistant high strength superalloy characterized by comprising 1 to 3%, Re 0.1 to 4%, Hf 0.3% or less and the balance unavoidable impurities and Ni. Above all, it is the weight% that Cr, 7.3 to 12%, and Al that have higher corrosion resistance and higher strength.
4.5-6.5%, Ti 0.35% or more and less than 1%, W2
~ 12%, Ta2.5-10%, Mo3% or less, Co
0.1-3%, Re0.1-3.2%, Hf0.13%
It is a high-corrosion and high-strength superalloy consisting of the following and the unavoidable impurities and Ni. Furthermore, as a means for further improving the corrosion resistance of these alloys, 3% or less of Nb can be added. And, more preferably, Ti is more than 0.7% by weight and 1
% Of the above-mentioned high corrosion-resistant high-strength superalloy, and more preferable is the above-mentioned high corrosion-resistant high-strength superalloy having a Ti content of more than 0.7% and 0.9% or less by weight.

The highest corrosion resistance and high strength are
% By weight, Cr 7.3 to 9%, Al 4.5 to 5.5%,
Ti more than 0.7% and 0.9% or less, W5.5 to 7.5
%, Ta 6.5 to 9%, Mo 0.5 to 2% or less, Co
0.5-1.5%, Nb1-2%, Re1-2%, Hf
It is a high corrosion resistant high strength superalloy consisting of 0.1 to 0.13% and the balance unavoidable impurities and Ni. If only high temperature strength and corrosion resistance are important and oxidation resistance is not important, Co
And Hf may not be added intentionally.

A second aspect of the present invention is a rod-shaped master ingot made of the above alloy. A third aspect of the present invention is a high-corrosion-resistant, high-strength single crystal casting that is formed by unidirectionally solidifying the above alloy and has substantially no grain boundaries. Furthermore, this high corrosion-resistant high-strength single crystal casting has a volume ratio of the undissolved eutectic γ ′ phase existing after the solid solution treatment of 5% or less, and a volume ratio of the γ ′ phase after solid solution + aging is 50 to 50%. 70%,
Also, the γ'phase precipitated after solution treatment + aging treatment is adjusted to have a cubic or rectangular parallelepiped shape with a side length of 1 μm or less, whereby excellent high temperature strength and corrosion resistance can be obtained. In addition, a part of this high corrosion resistant high strength single crystal casting is
Creep rupture time at 4 kgf / mm ² is 1000 hours or more, and 75 wt% Na ₂ SO ₄ -25 wt% NaC
l Mixed salt application heating test, 900 ° C, 20 hours ×
The characteristic that the maximum erosion depth after 5 cycles is 0.5 mm or less can be obtained.

A fourth invention of the present invention is a gas turbine blade characterized by comprising the high corrosion resistant high strength single crystal casting of the third invention. When the gas turbine blade is used for power generation, a blade portion against which high-temperature gas collides, a platform portion and a seal fin that seal the high-temperature gas, a shank portion that supports the both portions, and a dovetail portion that has a role of being planted in a disk, Is effective in improving thermal efficiency.

Furthermore, when these gas turbine blades are used for power generation with an output of about 25,000 KW or more, the total length in the longitudinal direction must be 150 mm or more. A gas turbine blade according to the present invention includes a dovetail portion which is a fixed portion to a disc, and a shank portion which is connected to the dovetail portion and which is provided with a single or a plurality of seal fins integrally projecting on a side surface thereof, And a wing portion connected to the portion, and in weight%, Cr 5.5 to 12%, Al 4.5 to
6.5%, Ti 0.1 to 5%, W 2 to 12%, Ta2.
5 to 10%, Mo 5.8% or less, Re 0.1 to 4%, and Ni-based alloy which is Ni with the balance unavoidable impurities, or Nb 3% or less, Co 0.1 to 3% or Hf.
A Ni-based alloy containing one or more of 0.3% or less, and a bypass mold communicating with the seal fin for a main mold corresponding to the blade, shank and dovetail, and It can be obtained by a manufacturing method including a step of gradually solidifying the melt of the Ni-based alloy in the main mold and the bypass mold in one direction at the same speed and casting it into a single crystal structure.

A fifth aspect of the present invention is a gas turbine nozzle characterized by comprising the above-mentioned high corrosion-resistant and high-strength single crystal casting. When the gas turbine nozzle is used for power generation with an output of about 25,000 kW or more, it has one blade portion and sidewalls formed at both ends of the blade portion,
A structure in which the distance between the sidewalls at both ends of the blade is 70 mm or more and the length from the combustion gas inlet side to the outlet side is 100 mm or more is effective for improving thermal efficiency.

A gas turbine nozzle according to the present invention comprises a blade portion and sidewalls provided at both ends of the blade portion,
% By weight, Cr 5.5 to 12%, Al 4.5 to 6.5
%, Ti 0.1 to 5%, W 2 to 12%, Ta 2.5 to 1
0%, Mo 5.8% or less, Re 0.1 to 4%, and Ni-based alloy which is Ni with the balance unavoidable impurities, or Nb 3% or less, Co 0.1 to 3% or Hf 0.3%.
Consisting of a Ni-based alloy containing one or more of the following,
The main mold corresponding to the wing has a bypass mold in communication with the sidewall, and the melt of the Ni-based alloy in the main mold and the bypass mold is gradually solidified in one direction at the same speed to obtain a single crystal structure. It can be obtained by a manufacturing method including a step of casting. A sixth aspect of the present invention is to burn the air compressed by a compressor, pass the high temperature gas through a gas turbine nozzle, and collide with the fourth gas turbine blade of the present invention which is planted in each of a plurality of disks. And a gas turbine that rotates the blade.

A seventh invention of the present invention is to combust air compressed by a compressor, and let its high-temperature gas pass through a gas turbine nozzle of the fifth invention of the present invention, and gas turbine blades are respectively planted in a plurality of disks. It is a gas turbine that causes the blades to rotate by colliding with. An eighth aspect of the present invention is the fourth aspect of the present invention in which the air compressed by the compressor is burned, and the high temperature gas is passed through the gas turbine nozzle of the fifth aspect of the present invention and is implanted in a plurality of disks. A gas turbine that collides with a gas turbine blade to rotate the blade.

A ninth aspect of the present invention is a gas turbine driven by a high-temperature gas flowing at a high speed, an exhaust heat recovery boiler for obtaining steam by the energy of exhaust gas of the gas turbine, and steam driven by the steam. In a combined power generation plant including a turbine and a generator driven by the gas turbine and the steam turbine, by using the gas turbine according to any one of the sixth to eighth aspects of the present invention for the gas turbine, the thermal efficiency of the entire plant Is 50% or more, which is a combined cycle power generation system.

In particular, the present invention relates to a gas turbine driven by combustion gas flowing at a high speed, an exhaust heat recovery boiler for obtaining steam from combustion exhaust gas of the gas turbine, a steam turbine driven by the steam, the gas turbine and steam. In a combined power generation plant including a generator driven by a turbine, the gas turbine has three or more blades, the first stage blade inlet temperature of the combustion gas is 1300 ° C. or more, and the combustion exhaust gas temperature at the turbine outlet is 560. ℃ or more, obtain steam of 530 ℃ or more by the waste heat recovery boiler, the steam turbine is a high-low pressure integrated type, the steam temperature to the first stage of the steam turbine blade is 530 ℃ or more, the gas If the power generation capacity of the turbine is 50,000 kW or more and the power generation capacity of the steam turbine is 30,000 kW or more Ri, characterized in that total thermal efficiency is 50% or more, in which a single crystal alloy mentioned above is used in the first stage blade and the first stage nozzle.

[0025]

The reason for limiting the components of the alloy of the present invention will be described below. Since Cr has an effect of improving the oxidation resistance and corrosion resistance of the alloy, it needs to be at least 5.5%, but excessive addition thereof causes harmful precipitation phases such as σ phase and reduces creep rupture strength and ductility. Therefore, it is limited to 5.5 to 12%. It is preferably 7.3 to 12%. The most preferable range is 7.3.
~ 9%.

Al is an important element for forming a film of Al ₂ O _{3 which} contributes most to the improvement of the high temperature oxidation characteristics of the Ni-base superalloy, and in this respect, it is desirable that the amount of Al is large. At the same time, Al is also a main strengthening element that forms a γ'phase, which is an intermetallic compound that precipitation strengthens the Ni-base superalloy. Although the basic composition of the γ'phase is represented by Ni ₃ Al, it is further strengthened by solid-dissolving elements other than Al, such as Ti, Ta, W, Mo and Nb. The action of these elements will be described in detail below. A single crystal alloy usually contains a large amount of γ'phase of 50% or more in volume ratio, but at the end of solidification, a coarse γ'phase called a eutectic γ'phase exists in the final solidification part. A solution treatment is performed at a high temperature to once form a solid solution in the (γ phase). The γ'phase solid-solved by the solution treatment strengthens the alloy by uniformly and finely precipitating during the cooling treatment and the subsequent aging treatment.

Therefore, Al needs to be at least 4.5%, but excessive addition exceeding 6.5% causes too much γ'phase, and the eutectic γ'phase is completely solidified by solution treatment. Since it cannot be melted, the strength decreases. Also, A
The amount of 1 is relatively high with respect to the solid solution strengthening elements of the γ'phase such as Ta, W, Mo and Nb described above.
It also means that the phases are not solution strengthened. Therefore, in the present invention, Al is limited to the range of 4.5 to 6.5%. The most preferable range is 4.5 to 5.5%.

Ti is an element for which the addition amount must be controlled very carefully in order to achieve both excellent corrosion resistance and high creep rupture strength. The finding of the optimum Ti addition amount for achieving both corrosion resistance and high temperature strength
This is one of the most characteristic features of the present invention.

Ti mainly forms a solid solution in the γ'phase, contributes to solid solution strengthening of the γ'phase, and stabilizes the γ'phase.
Also in terms of corrosion resistance, when the casting is used in an actual corrosive environment, Ti forms a sulfide near the surface of the casting, prevents S from entering the inside, and improves the sulfidation resistance. To obtain these effects, Ti needs to be added at a minimum of 0.1%. On the other hand, excessive addition of Ti in excess of 5% leads to an increase in the eutectic γ'phase, and further significantly lowers the initial melting temperature of the alloy. Therefore, the difference between the initial melting temperature and the complete solution temperature of the γ'phase, that is, the heat treatment window is narrowed, so that the γ'phase is not solidly dissolved by the solution treatment, resulting in a decrease in strength. At the same time, excessive addition hinders the formation of a uniform layered Al ₂ O ₃ protective film and reduces the oxidation resistance. Therefore, in the present invention, Ti is limited to the range of 0.1 to 5%. A preferred range is 0.35% or more and less than 1%, and more preferably more than 0.7% and less than 1%. Further, in order to achieve both excellent corrosion resistance and high creep rupture strength, the most preferable range is more than 0.7% and 0.9.
% Or less.

W is an element that forms a solid solution in the γ phase and the γ'phase to strengthen both phases, and at least 2% is required. However, excessive addition causes precipitation of the α-W phase and the Re-W phase and lowers the strength, and further lowers the corrosion resistance at high temperatures and increases the specific gravity. Therefore, W is limited to the range of 2 to 12%. The most preferable range is 5.5 to 7.5%. Mo is also W
Similarly to, is an element that forms a solid solution in the γ phase and the γ ′ phase to strengthen both phases and is an essential additional element. However, excessive addition causes precipitation of an α-Mo phase or a Re-Mo phase to lower the strength and further lowers the corrosion resistance at high temperatures. Therefore, Mo
Is limited to a range of 5.8% or less. However, oxidation resistance,
From the viewpoint of corrosion resistance, the lower the better, the Mo is preferably 3% or less. The most preferable range is 0.5 to 2%.

Co is an element that plays an important role in the alloy of the present invention, and there is an optimum addition amount that clearly improves the corrosion resistance and the oxidation resistance with respect to the alloy of the present invention. In terms of strength, the addition of Co lowers the stacking fault energy of the alloy and improves the creep strength in a relatively low temperature range, while it also increases the solid solubility of the γ'phase in a high temperature range, resulting in precipitation strengthening. And weakens the creep strength in the high temperature range. Because of the conflicting effects of both
There is an optimum addition amount of Co in terms of strength. Due to such effects, Co requires a minimum addition of 0.1%. However, the addition of more than 3% is no longer effective for oxidation resistance and corrosion resistance, and the high temperature strength also decreases. In addition, TCP phase (topologically close-packed
C) because it is easy to generate a harmful phase called phase).
o is limited to 0.1 to 3.0%.

It is one of the characteristics of the present invention that the single crystal alloy containing Ti or Re contains such a limited amount of Co, and the most preferable range is 0.5-.
It is 1.5%. Ta mainly solid-solution strengthens the γ'phase. Therefore, a minimum of 2.5% is required, but excessive addition of more than 10% raises the solid solution temperature of the eutectic γ'phase and Re-.
It induces the precipitation of Ta phase, and conversely reduces the high temperature strength. Therefore, Ta is limited to the range of 2.5 to 10%. The most preferred range is 6.5-9%.

Nb is an element belonging to the same group as Ta. From the viewpoint of corrosion resistance, Nb has an action superior to that of Ta, so Nb can be added to the alloy of the present invention. However, in order to improve the high temperature creep rupture strength, Ta is better than Nb as a γ'solid solution strengthening element, so Nb is limited to 3% or less. The most preferred range is 1-2%.

Re has the effects of forming a solid solution in the γ phase to strengthen the matrix and enhance the corrosion resistance of the alloy. However, the effect becomes a level that can withstand use at high temperature for a long time such as a gas turbine for power generation only when it coexists with a suitable amount of Ti, and therefore, Re required is at least 0.1%. On the other hand, Re is a very expensive element, and excessive addition of more than 4% not only unnecessarily raises the price of the alloy but also causes precipitation of harmful phases such as Re-W, Re-Mo and Re-Ta. Therefore, Re is set to the range of 0.1 to 4.0%. More preferably, it is 0.1 to 3.2%, and the most preferable range is 1 to 2%. Hf is an important element for improving the oxidation resistance and high temperature strength of the alloy, and is an essential additional element. The effect appears from a very small amount of addition. However, excessive addition of Hf lowers the melting point of the alloy, lowers the solution treatment temperature, and the eutectic γ ′ phase cannot be sufficiently dissolved. Therefore, the addition amount should be as small as possible. Therefore, Hf should be 0.3% or less,
Therefore, the more preferable range is 0.13% or less, and the most preferable range is 0.01 to 0.13%.

Among the elements other than the above, C, Si, M
If n, P, S, B, Zr, Y, REM, and Cu are within the ranges shown below, there is no particular problem in terms of characteristics, but it is desirable that they are as low as possible. C ≦ 0.015% Si ≦ 0.05% Mn
≤0.5% P ≤0.005% S ≤0.003% B
≤0.003% Zr≤0.02% Y ≤0.2% REM
≤0.2% Cu ≤0.1%

The above alloy composition group is made into a master ingot by the method described below, and further becomes a single crystal cast product. Here, the matrix γ phase (austenite phase) and γ '
Although it is a phase different from the phase, it is usually called a single crystal because it is a matched phase with the same crystal orientation. First of all, the master ingot of the above alloy composition has individual alloy elements in advance,
Or, after refining the scrap of the single crystal casting described below and using a return material with a reduced impurity level to a level where it can be reused, it is vacuum melted into a master ingot, then remelted in vacuum and then unidirectional. It can be solidified to obtain a single crystal casting. At this time, a master ingot having a purity as high as possible is suitable for manufacturing a single crystal cast.

The single crystal cast product can be industrially used by being subjected to heat treatment such as solution treatment, aging treatment and surface coating treatment. This single crystal casting is
The heat treatment and the alloy composition are preferably adjusted so as to have the structure shown below. First of all, if the eutectic γ'phase generated during solidification cannot be sufficiently dissolved by the solution treatment, this undissolved eutectic γ'phase portion becomes the starting point of creep fracture.
Therefore, the undissolved eutectic γ ′ existing after the solution treatment
The phase volume ratio is preferably 5% or less. Secondly, the amount of γ'phase present after solid solution + aging treatment also has a great influence on the strength and ductility of the casting. If the volume ratio of the γ'phase is less than 50%, sufficient high temperature strength cannot be obtained. On the contrary, if it exceeds 70%, undissolved eutectic γ'phase becomes excessively left in the solution treatment. . Therefore, the volume ratio of the γ ′ phase after solid solution + aging treatment is limited to 50 to 70%. Therefore, a more preferable volume ratio of the γ'phase is 55 to 65%.

Thirdly, it is desirable that the γ'phase precipitated during the aging treatment has a lattice constant sufficiently matching with the austenite phase which is the matrix, and causes fine precipitation in a regular cubic or rectangular parallelepiped shape. If the austenite phase and the γ'phase are not sufficiently matched, the length of one side exceeds 1 μm, the corners of a cube or a rectangular parallelepiped are deformed, and spherical precipitation occurs, resulting in sufficient high temperature strength. You won't get it. Therefore, it is necessary that the γ'phase precipitated during the aging treatment has a cubic shape or a rectangular parallelepiped shape with a side length of 1 μm or less. Therefore, the desirable side length of the γ ′ phase is 0.02 to 0.7 μm. Further, this single crystal cast product has characteristics of 1040 ° C., 1
Creep rupture time at 4 kgf / mm ² is 1000 hours or more, and 75 wt% Na ₂ SO ₄ -25 wt% NaC
It is preferable that the maximum erosion depth after 900 cycles at 900 ° C. for 20 hours × 5 cycles is 0.5 mm or less in the medium salt application heating test.

The high corrosion-resistant high-strength single-crystal cast product obtained by unidirectionally solidifying the above-mentioned novel material is used as an article for use in a harsh environment requiring high creep rupture strength and excellent corrosion resistance and oxidation resistance. It is suitable. Gas turbine blades and gas turbine nozzles made of the above-mentioned high-corrosion and high-strength single crystal castings have high creep rupture strength and excellent corrosion resistance and oxidation resistance, so that the combustion gas temperature of the gas turbine will be higher than at present. It is possible to increase the temperature, and as a result, the thermal efficiency of the gas turbine is significantly improved. In the combined cycle power generation system using the above-described gas turbine, the combustion gas temperature of the gas turbine is higher than that of the conventional one, so that the thermal efficiency of the entire system is 50% or more.

[0040]

EXAMPLES Example 1 Table 1 shows the chemical compositions of samples used for comparing the properties of the alloys of the present invention and comparative alloys and the alloy compositions described in US Pat. No. 4,719,080. And the P value of Equation 1 is shown to show that the effect is quite different. Inventive alloy No. 1 to 10 and comparative alloy No. For 21 to 28, a 5 kg master ingot was prepared by vacuum induction melting. All conventional alloys were melted aiming at the same composition as the published composition. N among comparative alloys
o. 23 is SC-83K, No. 23. 24 is PWA148
4, No. 25 is CMSX-4, No. 26 is TUT-
31D, No. No. 27 is TUT-95, No. 27. 28 is Re
ne80 is shown.

[0041]

[Table 1]

Table 2 shows the characteristic test results of each alloy. Left
1040 ° C-14kgf / mm ²Cree under the conditions
Rupture time and elongation at that time, 75 wt% Na₂SO_Four-2
900 ℃, 20 in 5wt% NaCl mixed salt application test
Maximum erosion depth after 5 times time cycle. 110 in the crucible
After heating at 0 ° C for 16 hours, repeat the heat cycle of air cooling 10 times.
Oxidation weight loss value after returning. And, a simulated combustion at 900 ℃
After descaling when exposed to burning gas for 7 hours x 7 cycles
Corrosion weight loss order. Where the maximum erosion depth is the test
Minimum excluding scale after test from thickness of previous test piece
The thickness was reduced to 1/2.

[0043]

[Table 2]

The various tests shown in Table 2 are conducted for Re of polycrystalline alloys.
Except for ne80, the above master ingot was redissolved, single-crystallized in a pull-down type directional solidification furnace, and then subjected to the heat treatment shown below. The creep rupture test is
A test piece having a parallel part diameter of 6.35 mm and a score distance of 25.4 mm was used to perform the test under the above conditions based on the ASTM method. Mixed salt application heating test is 12mm in diameter and 2mm in height
A disc-shaped test piece of No. 7 was used for the oxidation resistance test of the crucible.
A disc-shaped test piece having a size of 4 mm and a height of 4 mm was used, and each test was performed under the above conditions. Actual machine simulated combustion test is 9 mm in diameter and 50 in length
The test was carried out under the above conditions using a round bar test piece of mm.

The heat treatment conditions are the alloy of the present invention and the comparative alloy 2
1,250 and 1350 ° C for 1, 26 and 27
The structure which was heated in the range of 4 hours and then air-cooled was examined in advance. Basically, for all alloys, the temperature at which the γ'phase was completely solid-solved was selected as the solution treatment temperature, and the alloy was kept at that temperature for 4 hours and then air-cooled. A solution treatment was carried out. As for the aging condition after the solution treatment, heating at 1080 ° C. for 4 hours, air cooling and subsequent 870
After heating at 0 ° C. for 20 hours, a two-stage aging treatment of air cooling was performed. For other comparative alloys, No. 23 (SC-83K) was heated at 1320 ° C. for 4 hours and then air-cooled, heated at 1080 ° C. for 5 hours and then air-cooled, and heated at 870 ° C. for 20 hours and then air-cooled. No. 24 (PWA1484) is 1316 ℃
After heating for 4 hours at 80 ° C. and air cooling, heat treatment was performed at 1080 ° C. for 4 hours and then air cooling, and further heating at 870 ° C. for 20 hours and then air cooling.

No. 25 (CMSX-4) is Cannon-M
Recommended heat treatment conditions by uskegon (Source: “Single crystallization of latest nickel-base superalloy and its high temperature strength characteristics”, Yoshio Ota)
Others; 12 according to iron and steel, vol.76, (1990), pp940-947)
Hold at 72 ° C for 2 hours, raise temperature at 1288 ° C for 2 hours, raise temperature at 1296 ° C for 3 hours, raise temperature at 1304 ° C for 3 hours
After 6 hours of continuous solution treatment of temperature rise after holding for 3 hours, hold at 1313 ° C. for 3 hours, hold at 1316 ° C. for 2 hours and air cooling, hold for 4 hours at 1080 ° C. and air cooling and 871 ° C.
After maintaining at 20 ° C. for 20 hours, air cooling aging treatment was performed. The comparative alloy No. used in the polycrystalline state in the comparative alloy. 28 (Re
ne80) is obtained by remelting a master ingot and heating it at 1220 ° C. for 2 hours and then air cooling, 1096 ° C. for 4 hours and then air cooling, and 1050 ° C. for 16 hours and then air cooling.
After heating at 45 ° C. for 16 hours, air-cooled heat treatment was performed.

From Table 1, the P-values calculated by the above formula (1) for the alloys of the present invention are shown in US Pat. No. 4,719,08.
It is lower than 3360 specified in No. 0, and it is clear that the present invention is different from the present invention. It can be seen that all of 1 to 10 have good creep rupture life, creep rupture elongation, corrosion resistance and oxidation resistance. Especially for corrosion resistance,
No. in the coating heating test. Although it is slightly inferior to that of the No. 28 (Rene 80), it is clearly better than other single crystal alloys. It clearly has better corrosion resistance than 28. No. 1 also for oxidation resistance. 28 (Rene 80) is far superior. Also, in terms of creep rupture life, the alloy of the present invention is comparative alloy No. 1 having poor corrosion resistance. 23 (SC-83
Although shorter than K), the shortest one has a life equivalent to that of other comparative alloys, and this strength is at a satisfactory level as a single crystal alloy.

On the other hand, some of the comparative alloys have individual characteristics comparable to those of the alloy of the present invention, but not all the characteristics are well balanced as in the alloy of the present invention. From these, it is clear how the alloys within the composition range of the present invention exhibit excellent properties in a well-balanced manner.

Of the comparative alloys, No. 21 is Ti, Co
And strength as compared with the alloy of the present invention because it does not contain Hf
Both have poor corrosion resistance. In addition, No. 23 (SC-
83K) has excellent creep rupture strength, and a small amount of Co
And Hf, the oxidation resistance is good, but since Re and Ti are not contained, the corrosion resistance is poor. No. 24 (PWA148
4) contains Re but does not contain Ti, and contains Cr and Co.
Since the amount is out of the composition range of the present invention, the corrosion resistance is inferior to that of the alloy of the present invention, and the creep rupture life is also short. N
o. No. 25 (CMSX-4) is No. Since the amount of Co is large as in No. 24, the creep rupture life is short. No. 26, 2
Although No. 7 has a good creep rupture property, it does not have a combined addition of Co and Hf, and thus is inferior in oxidation resistance and corrosion resistance in a simulated combustion test to the alloy of the present invention. No. which is a polycrystalline material.
No. 28 (Rene 80) has a good corrosion resistance in the mixed salt coating heating method, but the corrosion resistance under the simulated combustion gas of an actual machine is significantly inferior to that of the alloy of the present invention, while the creep rupture strength is extremely low and the oxidation resistance is also high. bad. In addition, in the alloy of the present invention, a high corrosion resistance and high strength alloy having a creep rupture time of 1000 hours or more in a P value range of 2350 to 3280 and a maximum erosion depth of 0.5 mm or less in a coating heating test can be obtained. It was

(Example 2) Inventive alloy N in Example 1
o. 1 was used to manufacture the gas turbine blade shown in FIG. 1 and the gas turbine nozzle shown in FIG. FIG. 3 shows a front view of a core for a gas turbine blade, and FIG. 4 shows a front view of a core for a gas turbine nozzle. In gas turbines of recent years, it is common to provide cooling holes of complicated shapes inside the blades and nozzles in order to lower the temperature on the metal surface and inside as the combustion gas temperature rises. In order to manufacture such a hollow structure blade and nozzle, a core made of a refractory material containing silica as a main component and having the shapes shown in FIGS. 3 and 4 was used. A wax model was formed around this core, and a ceramic shell was formed on the outside with a refractory material such as alumina, zircon, and yttria, and dewaxed and fired to obtain a mold.

FIG. 5 is a sectional view of a mold for a gas turbine blade, and FIG. 6 is a sectional view of a mold for a gas turbine nozzle. 5 and 6, the mold 10 was fixed on the water-cooled copper chill 11 and set in the mold heater 13. Next, the alloy No. of the present invention melted by high frequency heating. 1
The master ingot having the composition of No. 1 is cast into the mold 10 heated above the melting point of the alloy, and the pulling speed is 30 cm / h.
Withdraw from the mold heater 13 and starter part 1
One-way solidification was sequentially carried out from No. 4. Although many columnar crystals grow in the starter portion 14, only one crystal in the columnar crystal was grown using the selector portion 15, and the portion above the selector portion 15 was a single crystal cast.

The mold heater 13 was kept at a temperature not lower than the melting point of the alloy until the mold 10 was completely drawn out and the casting was completely solidified. After the steps of setting the mold 10 in the water-cooled copper chill 11 among the above steps, the steps were performed in vacuum. After cooling, the mold 10 is taken out, the core is removed with an alkali, and the starter part, the selector part, the riser part, etc. are cut,
A gas turbine blade having the shape shown in FIG. 1 and a gas turbine nozzle having the shape shown in FIG. 2 were obtained. The gas turbine blade has a total length of about 220 mm, of which the blade part is about 130 mm,
The gas turbine nozzle has approximately 13 between the two sidewalls.
It is 0 mm. Here, the bypass portion 12 is used to single-crystallize a portion of the overhang portion, such as the seal fin 3 and the sidewall 8 where the cross-sectional area changes abruptly with respect to the crystal growth direction. Cut and remove like hot water. By using this, generation of foreign crystals in the overhang portion of the large single crystal cast was suppressed, and the yield was improved.

In the blade, the crystal can be grown so that the <001> direction is the blade longitudinal direction (the direction from the enlarged portion 16 to the dovetail portion 5), that is, the <001> direction is the direction to which the centrifugal force is applied. Desirably, in the nozzle, the <001> direction is the lateral direction of the wing (sidewall 7
To the side wall 8), that is, the <001> direction is preferably the direction in which the thermal stress generated from the thermal cycle accompanying the start and stop of the gas turbine is applied. In each of the examples, single crystal castings were obtained in which the deviation of the crystal growth orientation from the <001> direction was within 5 degrees. Both the gas turbine blade and the gas turbine nozzle were heated in vacuum at 1300 ° C. for 4 hours and then air-cooled for solution treatment, and then the blades were made of CoNiCrAl with a thickness of 100 μm.
A Y alloy layer was formed by a plasma spraying method, and in order to make the alloy layer and the base material compatible with each other, the Y alloy layer was held at 1080 ° C. for 4 hours and then subjected to air cooling diffusion treatment. Next, the thickness of the outer layer is 300μ
m ZrO ₂ -6 wt% Y ₂ O ₃ film was coated by the plasma spraying method. After that, for the purpose of adjusting the shape of the γ'layer, an aging treatment of heating at 870 ° C for 20 hours and then air cooling was performed.

(Third Embodiment) FIG. 7 is a sectional view of a rotating portion of a gas turbine having a gas turbine blade and a nozzle according to the second embodiment of the present invention. 30 is a turbine stub shaft, 33 is a turbine blade, 43 is a turbine stacking bolt, 38 is a turbine spacer, 49 is a distant piece, 40 is a nozzle, 36 is a compressor disk, 37 is a compressor blade, 41 is a compressor stacking bolt, and 39 is The compressor stub shaft 34 is a turbine disk. The gas turbine of the present invention has 17 stages of compressor disks 36 and 3 stages of turbine blades 33. The turbine blade 33 may have four stages, and the alloy of the present invention can be applied to any of them.

The gas turbine in this embodiment is mainly of a heavy tuty type, a single shaft type, and comprises a horizontal split casing and a stacking type rotor, a compressor is a 17-stage axial flow type, a turbine is a 3-stage impulse type, The first and second stages of blades and nozzles are air cooled, and the combustor is a verse flow type, 16 cans, slot cool type. The distant piece 49, the turbine disk 34, the spacer 38, and the stacking bolt 43 are% by weight, and C 0.
06-0.15%, Si 1% or less, Mn 1.5% or less, Cr 9.5-12.5%, Ni 1.5-2.5
%, Mo 1.5 to 3.0%, V 0.1 to 0.3%, N
b 0.03 to 0.15%, N 0.04 to 0.15%,
A fully tempered martensitic steel consisting of the balance Fe is used. Tensile strength of 90 to 1 is a characteristic of this embodiment.
20kg / mm ^2, 0.2% proof stress 70~90kg / mm ^2, elongation
It was 10 to 25%, drawing ratio was 50 to 70%, V notch impact value was 5 to 9.5 kg-m / cm ² , and 450 ° C.-10 ⁶ h creep rupture strength was 45 to 55 kg / mm ² .

The turbine blade 33 is of a three-stage type, the one manufactured in Example 2 is used in the first stage, and the compression pressure of the compressor is 1
4.7, temperature 400 ℃, the first stage blade inlet temperature 1,
The temperature of the combustion gas at 350 ° C and that of the combustor was set to 1500 ° C. The second stage of the turbine blade 33 is Ren.
e80 (Cr 14%, Co 9.5%, Mo 4%, W 4
%, Al 3%, Ti 5%, C 0.17%, B 0.01
A hollow blade having a blade length of 280 mm (wing portion 160 mm, length after the platform portion 120 mm) made of a polycrystalline body of 5%, Zr 0.03%, Ni balance) was used. In the third row, IN
738 (C 0.17%, Cr 16%, Co 8.5%,
Mo 1.75%, W 2.6%, Nb 0.9%, Ti
3.4%, Al 3.4%, Ta 1.75%, B 0.0
A solid blade having a blade length of 350 mm (blade portion 230 mm, other 120 mm) made of a polycrystalline body of 1% and Ni balance was used. The manufacturing method was a precision casting method using the conventional lost wax method.

In the first stage of the turbine nozzle 40, the second embodiment is used.
Known Co-based alloys are used in the second and third stages obtained in the above. The second stage and the third stage were formed of one blade by vacuum precision casting according to the conventional method. The length of the blade has a length corresponding to the length of the blade of the blade, and has a pin fin cooling, impingement cooling and film cooling structure. The first-stage nozzle is restrained at both ends of the sidewall, but the second-stage nozzle and the third-stage nozzle are restrained at one side on the outer peripheral side of the sidewall. The gas turbine is provided with an intercooler. According to the present embodiment, a power generation output of 60,000 kW can be obtained, and its thermal efficiency can be as high as 33% or more.

(Fourth Embodiment) FIG. 8 is a schematic diagram showing a single-shaft combined cycle power generation system using the gas turbine of the third embodiment and used in combination with a steam turbine. In the case of performing power generation using a gas turbine, in recent years, exhaust gas energy of the gas turbine is recovered, a steam turbine is driven by high temperature steam obtained thereby, and a generator is driven by the steam turbine and the gas turbine. The so-called combined cycle power generation method tends to be adopted. With this combined cycle power generation system,
It is possible to significantly improve the thermal efficiency as compared with the case of using the gas turbine and the steam turbine alone, and using the gas turbine of the present invention, the thermal efficiency of the entire system is 50%.
Reach over%.

In this system, air is first introduced into the air compressor of the gas turbine through the intake filter and the intake silencer, and the compressed air compressed here is sent to the combustor. In the combustor, fuel is injected into this compressed air and burned.
A high temperature gas of 500 ° C. or higher is produced, and this high temperature gas works in a turbine to generate power. Next, the exhaust gas of 500 ° C. or higher discharged from the turbine is sent to the exhaust heat recovery boiler through the exhaust silencer, and the thermal energy in the exhaust gas of the gas turbine is recovered to generate high-pressure steam of 500 ° C. or higher. The generated high pressure and low pressure steam is sent to a steam turbine.

Further, the steam discharged from the steam turbine is guided to a condenser and vacuum deaerated to be condensed water. Condensed water is boosted by the condensate pump and supplied to the boiler. As a result of the above, the gas turbine and the steam turbine drive the directly connected generator from both shaft ends thereof. With the combined cycle power generation system of the present embodiment, a total of 90,000 kW of power could be obtained from the gas turbine, 60,000 kW, and the steam turbine, 30,000 kW. Further, since the steam turbine in this embodiment is compact, it can be economically manufactured for the same power generation capacity as compared with the large steam turbine. The steam turbine according to the present invention is a high-low pressure integrated steam turbine, and the steam pressure at the main steam inlet of this high-low pressure integrated steam turbine is 1
By increasing the temperature to 00 atg and increasing the temperature to 538 ° C., it is possible to increase the single-unit output of the turbine. Due to the increase in single machine output, it is necessary to increase the blade length of the final stage blade to 30 inches or more and increase the steam flow rate.

The steam turbine according to the present invention is provided with 13 or more stages of blades planted in the high and low pressure integrated rotor shaft, and the steam passes through the steam control valve to reach the high temperature of 538 ° C. and 100 atg from the steam inlet as described above. Inflow at high pressure. Steam flows in one direction from the inlet, resulting in a steam temperature of 33
It becomes 722 mHg at ℃ and is discharged from the outlet through the blade at the final stage. For the high-low pressure one-piece rotor shaft according to the present invention, forged steel of Ni-Cr-Mo-V low alloy steel is used. The length of the disk at the blade implant portion of the rotor shaft increases as the length of the blade decreases, thereby reducing vibration. The high / low pressure integrated rotor shaft according to the present embodiment has C 0.18 to 0.30 in weight%.
%, Si 0.1% or less, Mn 0.3% or less, Ni 1.
0-2.0%, Cr 1.0-1.7%, Mo 1.0-
It consists of 2.0%, V 0.20 to 0.3%, and the balance Fe. After quenching by water spray cooling at 900 to 1050 ° C, tempering is performed at 650 to 680 ° C.

The plant is of a single-shaft type in which six sets of a power generation system consisting of a gas turbine, an exhaust heat recovery boiler, a steam turbine, and one generator are combined in parallel. In addition to this, one generator is combined in parallel with one gas turbine, and steam obtained from the exhaust gas of each gas turbine is introduced into one steam turbine. It may be a multi-shaft type composed of a single generator and the six sets of gas turbines. Combined power generation consists of a combination of a gas turbine, which is easy to start and stop in a short time, and a small, simple steam turbine. For this reason, the output can be easily adjusted, and it is most suitable as an intermediate load thermal power that quickly responds to changes in demand, and there is a great merit that it can be economically operated with respect to fluctuations in power generation. The reliability of gas turbines has increased dramatically due to recent technological developments, and the combined cycle power plant has a system composed of a combination of small capacity machines. It is a highly reliable power source that can limit the impact locally.

With this system, it was possible to generate power with a thermal efficiency of approximately 52%, which exceeds the thermal efficiency of conventional thermal power generation. Also, in the case of a power generation system that combines multiple combined cycle power generation systems into one plant,
Even in the case of partial load, by reducing the number of operating gas turbines, it is possible to operate the operating equipment near the rated load with high thermal efficiency, so that it is possible to maintain high thermal efficiency for the entire plant.

[0064]

INDUSTRIAL APPLICABILITY As described above, the alloys of the present invention have superior corrosion resistance to existing single crystal alloys, good oxidation resistance among existing single crystal alloys, and particularly high resistance among existing single crystal alloys. It has a creep rupture strength that is equivalent to or close to that of a strength alloy. As a result, as a single crystal casting for blades and nozzles of high-efficiency gas turbines for terrestrial power generation, which was difficult to apply in the past, it became possible to operate in a severe corrosive environment and high creep stress, which was previously unattainable. A highly efficient combined cycle power generation system with a thermal efficiency of 50% or more can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a gas turbine blade according to the present invention.

FIG. 2 is a perspective view of a gas turbine nozzle according to the present invention.

FIG. 3 is a front view of a core used for manufacturing a gas turbine blade according to the present invention.

FIG. 4 is a front view of a core used for manufacturing the gas turbine nozzle according to the present invention.

FIG. 5 is a vertical cross-sectional view of a gas turbine blade mold showing a method for manufacturing a gas turbine blade according to the present invention.

FIG. 6 is a vertical cross-sectional view of a mold for a gas turbine nozzle showing a method for manufacturing a gas turbine nozzle according to the present invention.

FIG. 7 is a schematic view of a gas turbine according to the present invention.

FIG. 8 is a schematic diagram of a combined cycle power generation system according to the present invention.

[Explanation of symbols]

 1 Wing Part 2 Platform Part 3 Seal Fin 4 Shank Part 5 Dovetail Part 6 Wing Part 7, 8 Sidewall 10 Mold 11 Water-cooled Copper Chill 12 Bypass Part 13 Mold Heating Heater 14 Starter Part 15 Selector Part 16 Expanding Part 30 Turbine Stub Shaft 33 Turbine blade 34 Turbine disk 36 Compressor disk 37 Compressor blade 38 Turbine spacer 39 Compressor stub shaft 40 Nozzle 41 Compressor stacking bolt 43 Turbine stacking bolt 49 Distant piece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideki Tamaki, Inventor Hideki Tamaki 7-1, Omika-cho, Hitachi City, Ibaraki Hitachi Ltd. (72) Inventor Akira Yoshinari 7-chome, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Hitachi Ltd., Hitachi Research Laboratory (72) Inventor Mitsuru Kobayashi 7-1, 1-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Noriyuki Watanabe Hitachi City, Ibaraki Prefecture 7-1-1 Omika-cho, Hitachi, Ltd. Hitachi Research Laboratory

Claims (21)

[Claims] 1. Cr in an amount of 5.5 to 12% by weight and Al
4.5-6.5%, Ti0.1-5%, W2-12%,
Ta 2.5-10%, Mo 5.8% or less, Co 0.1
A high corrosion-resistant high-strength superalloy comprising 3%, Re 0.1 to 4%, Hf 0.3% or less, and the balance unavoidable impurities and Ni. 2. Cr in the range of 7.3 to 12% and Al
4.5-6.5%, Ti 0.35% or more and less than 1%, W2
~ 12%, Ta2.5-10%, Mo3% or less, Co
0.1-3%, Re0.1-3.2%, Hf0.13%
A high-corrosion-resistant high-strength superalloy characterized by comprising Ni and the following and the unavoidable impurities. 3. The weight percentage of Nb is 3% or less.
Alternatively, the high corrosion resistance and high strength superalloy according to 2. 4. The high corrosion-resistant high-strength superalloy according to claim 1, which contains Ti in an amount of more than 0.7% and less than 1% by weight. 5. A Ti content of more than 0.7% and 0.9 by weight.
% Or less, the high corrosion resistant high strength superalloy according to claim 1. 6. A weight percentage of Cr 7.3-9%, Al 4.
5 to 5.5%, Ti over 0.7% and 0.9% or less, W
5.5-7.5%, Ta 6.5-9%, Mo 0.5-2
%, Co 0.5-1.5%, Nb 1-2%, Re 1-2
%, Hf 0.01 to 0.13%, and the balance unavoidable impurities and Ni, a high corrosion resistant high strength superalloy. 7. A polycrystalline master ingot made of the alloy according to claim 1. 8. A high-corrosion-resistant high-strength single crystal cast, which is obtained by unidirectionally solidifying the alloy according to claim 1 and has substantially no grain boundaries. 9. The volume ratio of the undissolved eutectic γ ′ phase existing after the solution treatment is 5% or less, the volume ratio of the γ ′ phase after solution + aging is 50 to 70%, and the solution + The high corrosion-resistant high-strength single crystal cast product according to claim 8, wherein the γ'phase precipitated by the aging treatment has a cubic or rectangular parallelepiped shape with a side length of 1 µm or less. 10. 1040 ° C., 14 kgf / creep rupture time in mm ² is 1000 hours or more, and 75 wt% Na ₂ SO ₄ at -25 wt% NaCl mixed salt coating heat test, 900 ° C., 20 hours × 5 cycles The maximum corrosion depth afterwards is 0.5 mm or less, The high-corrosion-resistant high-strength single crystal casting according to claim 8. 11. A gas turbine blade comprising the high-corrosion-resistant high-strength single crystal cast product according to any one of claims 8 to 10. 12. A wing portion against which high temperature gas collides, a platform portion for sealing high temperature gas and a seal fin, a shank portion for supporting both portions, and a dovetail portion having a role of being planted on a disk. Gas turbine blade having. 13. The gas turbine blade according to claim 11, wherein the total length in the longitudinal direction is 150 mm or more. 14. A method of manufacturing a gas turbine blade made of the high corrosion resistant high strength superalloy according to claim 1, wherein the blade is a dovetail portion fixed to a disk and is connected to the dovetail portion. A shank portion having a single or a plurality of seal fins integrally projecting on its side surface, and a wing portion continuous with the shank portion, and for the main mold corresponding to the wing portion, the shank portion and the dovetail portion. A gas having a bypass mold communicating with the seal fins, and including a step of unilaterally gradually solidifying the melt of the Ni-based alloy in the main mold and the bypass mold at the same speed and casting into a single crystal structure. Turbine blade manufacturing method. 15. A gas turbine nozzle comprising the high corrosion resistant high strength single crystal casting according to claim 8. 16. The wing according to claim 15, comprising one wing and sidewalls formed at both ends of the wing, wherein the wing has a distance between the sidewalls of both ends of 70 mm or more and an outlet from a combustion gas inlet side. Gas turbine nozzle whose length to the side is 100 mm or more. 17. A method of manufacturing a gas turbine nozzle made of the high corrosion resistant high strength superalloy according to claim 1, wherein the nozzle comprises a blade portion and sidewalls provided at both ends of the blade portion. And a bypass mold communicating with the sidewall with respect to the main mold corresponding to the blade portion, and a single crystal is obtained by unidirectionally gradually solidifying the melt of the Ni-based alloy in the main mold and the bypass mold at the same speed. A method of manufacturing a gas turbine nozzle, comprising the step of casting into a tissue. 18. Combusting air compressed by a compressor, and passing the hot gas through a gas turbine nozzle,
A gas turbine which collides with the gas turbine blade according to any one of claims 11 to 13, which is planted in a plurality of disks, to rotate the blade. 19. The air compressed by a compressor is burned, and its hot gas is passed through a gas turbine nozzle according to claim 15 or 16 and collided with gas turbine blades respectively implanted in a plurality of disks. A gas turbine that rotates the blades. 20. The gas according to any one of claims 11 to 13, wherein the compressed air is burned by a compressor, and the high temperature gas is passed through the gas turbine nozzle according to any one of claims 15 and 16 and is implanted in a plurality of disks. A gas turbine that collides with a turbine blade to rotate the blade. 21. A gas turbine driven by high-temperature gas flowing at a high speed, an exhaust heat recovery boiler that obtains steam by the energy of the exhaust gas of the gas turbine, a steam turbine driven by the steam, the gas turbine and steam. In a combined power generation plant including a generator driven by a turbine, by using the gas turbine according to any one of claims 18 to 20 for the gas turbine, the thermal efficiency of the entire plant becomes 50% or more. Characteristic combined cycle power generation system.