JP3164972B2 - Moving blade for gas turbine, method of manufacturing the same, and gas turbine using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel blade for a gas turbine, and more particularly to a blade having excellent creep strength, a method for manufacturing the same, a gas turbine using the same, and a combined power plant system.

[0002]

2. Description of the Related Art Ni-based superalloys have been mainly used as the blade material of gas turbines for power generation, but the combustion gas temperature has been increasing year by year in order to improve the thermal efficiency of gas turbines. And, in order to increase the heat resistance of the rotor blades, the structure changes from an equiaxed crystal blade by ordinary casting to a columnar crystal blade by unidirectional solidification, and a complicated cooling hole is provided inside the blade, Has been cooled.

Most columnar crystal castings are produced by a unidirectional solidification method disclosed in Japanese Patent Publication No. 51-4186. In this method, a mold is drawn downward from a heated furnace and gradually solidified upward from a lower end. By this method, it is elongated in the longitudinal direction where the centrifugal stress acts, and <10
Columnar crystal blades having a crystal orientation of 0> have been manufactured, and creep strength characteristics and thermal fatigue strength characteristics have been improved.

Further, Japanese Patent Application Laid-Open Nos. 60-261659 and 61-71168 disclose blades having higher temperature characteristics than columnar blades.
Japanese Patent Application Publication No. JP-A-2005-64139 discloses a method of manufacturing a blade for a combustion turbine in which a wing portion is made of single crystal and a root portion is made of microcrystal.

[0005]

In order to further increase the efficiency, it is most effective to increase the temperature of the combustion gas, and for that purpose, the internal cooling is further enhanced and the high-temperature strength of the material is increased. It has become necessary to increase.

The internal cooling holes of the blade for a gas turbine are formed by using a ceramic core. To further enhance the cooling, the number of cooling paths is increased and the blade itself is made thinner. Have been. The columnar blades are manufactured by a one-way solidification method, in which the molten metal solidifies in a state where the core is cast and then cooled to room temperature. Then, heat shrinkage occurs during cooling. When comparing the coefficient of thermal expansion between the core and the cast metal, the core shows a value that is about an order of magnitude smaller than the metal, so the metal shrinks with the core that hardly shrinks as it is cast inside. In the process, a large tensile stress is generated. For this reason, in the casting, a vertical crack is likely to occur along a crystal grain boundary having a low strength. And
Longitudinal cracks are particularly remarkable in the thin wings. For this reason, the conventional columnar blades cannot be made thinner in the blade portion, and cannot be sufficiently cooled. Grain boundary cracking occurred during casting, and the yield was poor.

A rotor blade used in an aircraft jet engine has a blade length of at most about 10 cm and a weight of several hundred grams, so that single crystallization is easy. However, the moving blade used for the gas turbine for power generation not only has a complicated blade shape, but also has a blade length of 15 to 40 cm and a weight of several kg to 10 kg.
In the method described in Japanese Patent Publication No. 51-4186, a foreign crystal or a freckle defect is liable to occur, and it is very difficult to form a single crystal.

[0008] JP-A-60-261659 and JP-A-61-71
Japanese Patent Publication No. 168 describes a production method in which a blade portion is made of a single crystal, and the remaining portion is made into fine crystal grains by using magnetic stirring.
However, when a conventional single crystal alloy is cast by this method, there has been a problem that the strength of the fine crystal grain portion is weakened. In addition, when casting is performed using an alloy containing a large amount of grain boundary strengthening elements to maintain the strength of the fine crystal grains, the eutectic structure formed during solidification and the melting point of the eutectic γ 'phase decrease, and As a result, the strength of the material could not be improved.

As described above, in the moving blade according to the prior art, when the thickness is reduced in order to improve the cooling efficiency, grain boundary cracks are likely to occur, and in order to prevent the grain boundary cracking, a grain boundary strengthening element is added. When added, there is a disadvantage that the strength cannot be improved, and the efficiency of the gas turbine cannot be improved.

In addition, a single-crystal blade having excellent high-temperature strength has a very low yield because foreign crystals are easily generated, and cannot be manufactured as a large-size blade. Therefore, it cannot be used as a blade of a gas turbine for power generation. Gas turbine efficiency could not be improved.

An object of the present invention is to provide a moving blade for a gas turbine which is free from grain boundary cracks during casting and has excellent creep strength, a method for manufacturing the same, a gas turbine using the same, and a combined cycle power plant system. is there.

[0012]

SUMMARY OF THE INVENTION The present invention provides a wing exposed to a high-temperature and high-pressure gas, a platform connected to the wing and serving as an overhang for shutting off the high-temperature and high-pressure gas, and a wing connected to the platform and connected to the wing. A shank portion having a distance for obtaining a sufficient temperature gradient between the disk and the disk, a seal fin provided on the shank portion for blocking high-temperature and high-pressure gas, and a disk connected to the shank portion. Having a dovetil as an embedding portion, the wing portion is a single crystal at least on its outer surface, and has a single crystal formed continuously from the wing portion to a part of the shank portion, including the inside of the wing portion, The remainder consists of an integral casting consisting of unidirectionally solidified columnar crystals formed continuously from the single crystal and, by weight, C0.
03 to 0.15%, Cr 5.5 to 9.0%, Al 4 to 7%,
W2 to 15%, Ti 0.5 to 1.5%, Mo 0.3 to 1.0
%, Ta 2 to 7%, Co 8.0 to 10.5%, Hf 0.5 to
A gas turbine rotor blade made of a Ni-based alloy having a total amount of 1.0%, Re1 to 4%, one or two of B and Zr of 0.002 to 0.02%, and Ni of 58% or more. .

That is, the blade for a gas turbine according to the present invention has a blade portion made of a single crystal and the rest made of a unidirectionally solidified columnar crystal, but a single platform from the blade portion in the remaining platform and shank portion. Crystals are subsequently formed.

In particular, in the blade for a gas turbine according to the present invention, the γ phase orientation in the longitudinal direction of the columnar crystal is within 15 degrees from the <100> orientation, and the crystal orientation difference of the γ phase of the adjacent columnar crystal is reduced. It is preferable that the angle be 15 degrees, particularly 8 degrees or less.

Further, if the difference in crystal orientation of the γ phase in the single crystal of the blade portion is within 8 degrees, no particular grain boundary is observed, which is acceptable.

In particular, the azimuthal difference of the γ phase between adjacent crystal grains on the outer surface of the wing portion is within 8 degrees, and a part of the portion including the inside of the wing portion other than the outer surface of the wing portion may have a difference It is preferable that the orientation difference of the γ phase be within 8 degrees and the orientation difference of the γ phase between the remaining adjacent crystal grains be within 15 degrees.

Further, the difference between the crystal orientations of the γ phase in the wing portion and the other portions is preferably within 8 to 15 degrees.

In order to obtain the above-mentioned gas turbine blade, it is effective to provide a solidification promoting passage between at least one portion of the single crystal and the seal fin as a projection.

The gas turbine blade of the present invention may be provided with a refrigerant passage for cooling the blade from the dovetail to the blade portion.

In the gas turbine rotor blade of the present invention, the blade surface may be coated with an alloy layer containing Co, Ni containing Cr, Al and Y as a main component.

Further, the gas turbine rotor blade of the present invention may have a thermal barrier coating made of a ceramic layer on the outermost surface of the blade portion and its periphery.

The blade for a gas turbine according to the present invention has a C content of 0.03% or more, a B content of 0.002% or more, and 0.0% by weight.
Containing 02% or more of one or more elements of Zr,
Further, the alloy is cast with a Ni-based superalloy capable of dissolving the precipitated γ 'phase in the γ phase without causing initial melting due to local melting at the grain boundaries of the alloy.

In particular, C is 0.05 to 0.1%, and one or two of B and Zr are 0.005 to 0.02%, more preferably B
0.002% to 0.02% and Zr 0.02% or less are suitable for preventing cracking.

The moving blade for a gas turbine according to the present invention has a weight percentage of
And is cast with a Ni-base superalloy having the following suitable composition.

According to the present invention, a fin comprising a wing, a platform having a flat portion connected to the wing, a shank connected to the platform, and projections provided on both sides of the shank, In a gas turbine rotor blade having a dovetil connected to the shank portion, the blade portion is a single crystal, and a portion excluding the blade portion and the fins is a one-way solidified columnar crystal integrated casting. It is characterized by becoming.

According to the present invention, there is provided a fin comprising a wing, a platform having a flat portion connected to the wing, a shank connected to the platform, and projections provided on both sides of the shank. A gas turbine rotor blade having a dovetil connected to the shank portion, wherein the blade portion is a single crystal, and the entire portion other than the blade portion is formed of an integral casting that is a columnar crystal solidified in one direction. I do.

The rotor blade according to the present invention has a refrigerant passage integrally connected inside.

The present invention comprises the above-mentioned Ni-based alloy, and the amount of C and one or both of the amounts of B and Zr are A (C0.2).
0%, B + Zr0%), F (C0.04%, B + Zr0.
002%), C (C0%, B + Zr 0.01%), G (C
0%, B + Zr 0.02%), H (C 0.1%, B + Zr
0.02%) and the point A described above, and the difference in crystal orientation is 2 to 8 degrees.

The gas turbine blade of the present invention has a C
0.03-0.1%, Cr 5.5-7.0%, Co 8.5-9.5.
5%, W 8-9%, Re 2.5-3.5%, Mo 0.3-
1.0%, Ta 3-4%, Al 5-6%, Ti 0.5-
1.0%, Hf 0.5 to 1.0%, one or both of B and Zr are 0.005 to 0.025%, and the balance is Ni and inevitable impurities, and the difference in crystal orientation is 8 degrees or less. Is preferred.

The blade of the present invention is used in any of three-stage or four-stage gas turbines, and is particularly suitable for the first stage having the highest temperature. The second and subsequent stages are particularly preferably polycrystalline in which the whole is columnar or equiaxed.

Particularly, the following composition is preferable (% by weight).

C: 0.03 to 0.1 Cr: 5.5 to 7.0 Co: 9 to 10.5 W: 8.0 to 11.0 Re: 1.0 to 3.5 Mo: 0.5 3 to 1.0 Ta: 3.0 to 4.0 Al: 5.0 to 6.0 Ti: 0.5 to 1.0 Hf: 0.5 to 1.0 One or two of B and Zr : 0.005 to 0.02 Remainder: Ni and unavoidable impurities The blade for a gas turbine according to the present invention has a temperature in the range of not less than the solid solution temperature of the γ 'phase of the alloy after casting and not more than the initial melting temperature. Solution solution for 60 hours, 1000-1150 ° C
For 4 to 20 hours and at 800 to 920 ° C. for 8 to 100 hours.

The method of manufacturing a moving blade for a gas turbine according to the present invention comprises the steps of: setting a mold having the above-described structure and alloy composition and having a ceramic core on a water-cooled chill plate; Step of pouring the molten metal into the post-heated mold, and relatively withdrawing the mold from the high-temperature heating furnace,
A gas characterized by a step of gradually unidirectionally solidifying the wing from the wing tip to the end of the dovetil to make the wing into a single crystal, and extracting the wing at a speed higher than the drawing speed of the mold to unidirectionally solidify the dovetil. In the method of manufacturing turbine blades.

The moving speed of the mold in the production of a single crystal was 15 cm.
/ H or less, and the moving speed in the production of columnar crystals is preferably 20 to 45 cm / h. In particular, the former is better as long as it can produce a single crystal, but it is better, but from the viewpoint of yield, 10 cm / H is preferable, and the latter is more than 50 cm / h, the crystal orientation between the columnar crystals exceeds 10 degrees and becomes equiaxed.
30 ~ 45
cm / h is preferred.

According to the present invention, there is provided a refrigerant passage integrally connected from the dovetail portion to the tip of the blade portion.
The phase matrix has a structure in which a γ 'phase is dispersed, and a difference in crystal orientation of the γ phase is 2 to 6 degrees.

According to the present invention, there is provided a gas turbine for rotating a moving blade by causing combustion gas compressed by a compressor to impinge on a moving blade implanted on a disk through a stationary blade.
A gas turbine comprising three or more stages of the moving blades, wherein the first stage of the moving blades comprises the above-described gas turbine moving blade.

According to the present invention, in the above-described gas turbine, the combustion gas temperature is 1,500 ° C. or more, the rotor has three or more stages, and the combustion gas temperature at the first stage inlet of the blade is 1,500. 300 ° C or higher, and the first stage of the rotor blade has a total length of 2
It is characterized in that the wing portion is a single crystal, the root portion excluding the wing portion is a unidirectionally solidified columnar crystal, and the power generation capacity is 50,000 KW or more.

According to the present invention, there is provided a gas turbine for rotating a moving blade by causing combustion gas compressed by a compressor to collide with a moving blade implanted on a disk through a stationary blade.
The combustion gas temperature is 1,500 ° C. or more, and the rotor blade has three or more stages, the combustion gas temperature at the first stage inlet of the rotor blade is 1,300 ° C. or more, and the power generation capacity is 50,000 KW or more. The first stage of the moving blade has a total length of 200 mm or more, and the first stage of the moving blade includes the above-described moving blade for a gas turbine. The casting is C 0.03 to 0.1% by weight and Cr 5.5 to 9%. 0.0%,
Co 8.5 to 10.5%, W 8 to 11%, Re 1.0 to 1.0
3.5%, Mo 0.3-1.0%, Ta 3-4%, Al5
６6%, Ti 0.5-1.0%, Hf 0.5-1.0%, B
And one or both of Zr and 0.005 to 0.025%, and the balance consists of Ni and unavoidable impurities, and has a structure in which a γ ′ phase is precipitated in a γ phase matrix, and It is preferable that the difference in the crystal orientation of the γ phase of the columnar crystal is 8 degrees or less.

The present invention provides a gas turbine driven by combustion gas flowing at high speed, an exhaust heat recovery boiler that obtains steam from combustion exhaust gas of the gas turbine, a steam turbine driven by the steam, the gas turbine and the steam turbine. And a generator driven by the turbine, wherein the gas turbine has three or more moving blades, and the temperature of the first stage of the moving blade of the combustion gas is 1,300 ° C. or more, and the combustion at the turbine outlet The exhaust gas temperature is 560 ° C. or higher, and the exhaust 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 ° C or more, and the power generation capacity of the gas turbine is 50,000 KW or more. The power generation capacity of the steam turbine is 30,000 KW
That is, the overall thermal efficiency is 45% or more.

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, and a power generator driven by the gas turbine and the steam turbine The gas turbine has three or more stages of moving blades, and the temperature of the first stage of the moving blade of the combustion gas is 1,30.
At 0 ° C or higher, the temperature of the flue gas at the turbine outlet is 560
° C or higher, and steam having a temperature of 530 ° C or higher is obtained by the exhaust heat recovery boiler. The steam turbine is of a high / low pressure integrated type, and the steam temperature to the first stage of the steam turbine blade is 53 ° C.
0 ° C or higher, and the power generation capacity of the gas turbine is 50,000K
W and the power generation capacity of the steam turbine is 30,000 KW or more, the total thermal efficiency is 45% or more, the first stage of the moving blade has a total length of 200 mm or more, and the first stage of the moving blade is It is characterized by consisting of wings.

The blade for a gas turbine according to the present invention has at least one kind of C of 0.15% or less by weight, B of 0.002 to 0.02%, and Zr of 0.002% to 0.02%. And 0.5 to
It contains about 1.0% of Hf, and does not cause initial melting due to local melting of about 5% or more by volume, and has a volume fraction of about 60%.
% Of the precipitated γ 'phase in the γ phase.

In particular, C is 0.03 to 0.1%, one or two of B and Zr are 0.002 to 0.02%, and Hf is 0.0 to 0.1%.
The content of 5 to 1.0% prevents cracks, and the initial melting does not occur at about 5% or more by volume, and about 60% by volume.
The above-mentioned precipitated γ ′ phase is suitable for solid solution in the γ phase, and the C amount and B + Zr amount are determined by A (C 0.20%, B + Zr
0%), F (C 0.04%, B + Zr 0.002%), C (C
0%, B + Zr 0.01%), G (C 0%, B + Zr 0.0
2%) and H (C 0.10%, B + Zr 0.20%).

In order to satisfy all of grain boundary cracking, creep strength, corrosion resistance, oxidation resistance, and thermal fatigue resistance during casting, it is particularly preferable to use Cr 6.0 to 9.0%, Al 5 to 6%,
W7 to 10%, Ti 0.5 to 1%, Mo 0.3 to 0.7
%, Ta 3.0 to 7.0%, Re 1 to 3.4%, Co 8 to 1
0.5%, C 0.03-0.1%, B 0.002-0.02
%, Hf 0.5 to 1.1%, Zr 0.02% or less, and a composition in which the balance is Ni and inevitable impurities.

The moving blade of the present invention can be used for any gas turbine having three or four stages, and is particularly suitable for the first stage turbine having the highest metal temperature. After the second stage, a columnar crystal or equiaxed crystal is often used.

The blade for a gas turbine according to the present invention is solution-solutioned in a range from the solid solution temperature of the precipitated γ 'phase of the alloy after casting to the initial melting temperature for 2 to 60 hours, and further from 1000 to 1150.
It is preferable to carry out a heat treatment at 4% to 20 hours and at 800 to 920 ° C for 8 to 100 hours.

Further, the moving blade for a gas turbine of the present invention has the above-mentioned structure and alloy composition, and includes a step of setting a mold for forming the moving blade on a water-cooled chill plate; A step of heating the casting raw material to a predetermined temperature in a heating furnace, a step of melting the casting raw material in the same vacuum chamber as the mold and casting the molten metal in the heated mold, and a step of heating the mold containing the molten metal to the heating furnace. From the wings, solidified sequentially in the direction of dovetails from the wings to form a single crystal of the wings, and then withdrawn from the platform and beyond at a speed higher than the drawing speed of the wings. It is manufactured by a process in which a part of the part is a single crystal continuously and unidirectionally solidified from the wing portion, and the remaining part is a columnar crystal continuously and unidirectionally solidified from the single crystal to form an integrated casting.

The drawing speed of the mold is preferably 15 cm / h or less in the production of a single crystal, and is preferably 20 to 45 cm / h in the production of a columnar crystal. These are better as soon as they can be manufactured, respectively, but from the viewpoint of yield, 10 cm / cm
h is preferred. With respect to the columnar crystals, if it exceeds 50 cm / h, the difference in the crystal orientation between the columnar crystals exceeds 20 degrees and becomes an equiaxed crystal. Therefore, the crystal orientation difference between the adjacent columnar crystals is preferably 45 cm / h or less. In order to obtain a good columnar crystal having a particle diameter of 15 ° or less, it is not preferable that the drawing speed is too slow, and it is preferably 30 to 45 cm / h.

[0048]

In the blade for a gas turbine according to the present invention, the blade portion is a single crystal, and the crystal orientation difference in the single crystal is set to within 8 degrees. Then, the unidirectionally solidified columnar crystals other than the wing portion are used, and the crystal orientation difference between adjacent columnar crystals is made as small as possible. Particularly, the difference is made within 15 degrees, more preferably within 8 degrees, thereby obtaining a crystal grain boundary. Even if the addition amount of the reinforcing element is reduced, it is possible to obtain a columnar blade in which grain boundary cracks do not occur during casting, and it is possible to maintain the same strength as a single crystal. In addition, since the addition amount of the grain boundary strengthening element is reduced, the melting point of the eutectic structure formed during casting increases, and the solution heat treatment temperature can be increased. A heat treatment for forming a solid solution in the alloy has become possible. Therefore, a columnar blade having high creep strength can be obtained. Conversely, if the difference between the crystal orientations exceeds 10 degrees, the strength of the single crystal drops sharply to about 10 to 20%.

In order to improve the high-temperature strength of the material, solution heat treatment after casting is effective. The solution heat treatment can optimize the size and shape of the precipitated γ 'phase in the subsequent aging heat treatment by completely dissolving the precipitated γ' phase in the mother phase after solidification, and can improve the high-temperature strength .

However, the alloys used in the conventional columnar blades do not have a grain boundary strengthening element such as B, C, Zr, or Hf in order to prevent vertical cracks along the grain boundaries during casting. It is necessary to contain a large amount. The grain boundary strengthening element improves the strength of the grain boundary, and partially segregates between the dendrite arms, remarkably lowering the melting point of the segregated portion. In the case of a Ni-based superalloy, the segregated portion forms a eutectic structure and generates a coarse eutectic γ 'phase upon solidification. The eutectic structure and the eutectic γ 'phase formed at this time have the lowest melting point in the alloy, and when the temperature is raised to perform the solution heat treatment, the eutectic structure causes initial melting. For this reason, the alloys used in the conventional columnar blades could not have a high solution heat treatment temperature and were insufficiently solution-treated, and as a result, the strength of the material could not be improved.

In the case of a single crystal alloy containing no grain boundary strengthening element, the melting point of the eutectic γ 'phase increases because the grain boundary strengthening element is treated as an impurity element and its content is minimized. It enables complete solution heat treatment. For this reason, single crystal alloys exhibit excellent high-temperature characteristics that are 40 to 50 ° C. higher than conventional materials, and are used as moving blades for aircraft jet engines. However, single crystal alloys have as few grain boundary strengthening elements as possible, so they are very weak when grain boundaries are formed, and if there are foreign crystals with different crystal orientations, cracks can easily occur at those grain boundaries. enter. If there is a crystal grain boundary, it usually becomes weak enough to crack only by cooling after casting. Therefore, a rotor blade cast using a single crystal alloy needs to be a complete single crystal without any foreign crystal.

Also, an alloy containing the above-mentioned grain boundary strengthening element,
Of course, it is also possible to make the entire moving blade a single crystal. This blade has a lower creep strength at high temperatures than a single crystal blade cast with a single crystal alloy containing no grain boundary strengthening element. Since the azimuth difference can be allowed up to 15 degrees, the crystal azimuth measurement using X-rays, which is required for the conventional single crystal blade, can be greatly simplified. Further, there is no effective inspection means for crystal defects inside the blade, and the blade is usually cut and inspected by a sampling test. However, in the case of a moving blade for a power generation gas turbine whose blades are large, it is difficult to ensure reliability in a sampling test, and this has been a major bottleneck in applying a single crystal blade to a power generation gas turbine. However, in the present invention, since the orientation difference between adjacent crystal grains can be allowed up to 15 degrees, the reliability of the moving blade can be greatly improved, and the high-strength moving blade can be applied to a gas turbine for power generation.

The role of each element contained in the Ni-base superalloy constituting the moving blade for the gas turbine will be described below.

C forms a carbide while forming a solid solution in the matrix or especially at the grain boundaries, and improves the high-temperature tensile strength. However, if added excessively, it lowers the melting point of the grain boundaries and lowers the high-temperature strength and toughness. Is appropriate in a range of 0.15% or less, particularly 0.05 to 0.15%, and more preferably 0.03 to 0.1%.

Co forms a solid solution in the matrix to improve the high-temperature strength and contributes to the improvement of the corrosion resistance. However, if added excessively, it promotes the precipitation of harmful intermetallic compounds and lowers the high-temperature strength. The addition amount should be 10.5% or less,
In particular, 8 to 10.5% is appropriate. In particular, the lower limit is 4
% Or more, more preferably 8.5% or more.

Cr improves corrosion resistance, but when added excessively, it causes harmful σ phase precipitation and coarsening of carbides, and lowers the high-temperature strength. The addition amount is 5.5 to 9
% Range.

Al and Ti precipitate the γ ′ phase, ie, Ni ₃ (Al, Ti), which is a precipitation strengthening factor of the Ni-based alloy, thereby contributing to improvement in high-temperature strength. The addition amount is Al: 4.
The ranges of 0 to 7.0 and Ti: 0.5 to 1.5% are appropriate, and in particular, Al of 5 to 6% and Ti of 0.5 to 1.0% are preferable.

Nb, Ta, and Hf form a solid solution in the γ 'phase, which is a strengthening factor, and improve the high-temperature strength. However, if added excessively, they segregate at the crystal grain boundaries and lower the strength. The addition amount is Nb 3% or less, Ta 2 to 7%, Hf 0.5.
１1.0% is appropriate, especially Nb: 0.2 to 3.0%,
Ta3-4%, Hf0.5-1.0% are preferred. In particular,
Hf has the effect of preventing longitudinal cracks during solidification and improves ductility at high temperatures. However, if it exceeds 1%, the eutectic structure at the time of solidification increases, making effective solution treatment difficult.

Zr and B prevent vertical cracks during solidification, strengthen grain boundaries, and improve high-temperature strength. However, if added excessively, ductility and toughness are reduced, and the melting point of grain boundaries is lowered and high-temperature strength is reduced. Let it. As the addition amount, Zr: 0 to 0.035%, B:
0-0.035% is appropriate. Particularly, A (C 0.20%, B + Zr 0%), B (C 0.05%,
B + Zr 0%), C (C 0%, B + Zr 0.01%),
D (C 0%, B + Zr 0.035%), E (C 0.1%, B
+ Zr 0.025%), F (C 0.04%, B + Zr 0.0
02%), G (C0%, B + Zr 0.02%), H (C0.
1%, B + Zr 0.02%), A, F, C, G,
A range surrounded by H and A is preferable.

W and Mo form a solid solution in the γ phase of the matrix to strengthen them, and are particularly effective in improving long-term strength. However, if added in excess, it promotes the precipitation of harmful phases such as the σ phase, and on the contrary, lowers the strength. The addition amount is W2
-15%, especially W7.0-11.0%, Mo0.3-1.0%
Is preferred. W8 to 10% is more preferable.

Re improves the high-temperature corrosion resistance, but the effect is saturated when it is added to a certain amount or more, and on the contrary, the ductility and the toughness are reduced. The addition amount is preferably 1 to 4%, more preferably 2.5 to 3.5%.

[0062]

Embodiment 1 FIG. 1 is a perspective view of a single crystal blade for a gas turbine according to the present invention, and FIG. 2 is a schematic view of an apparatus showing a method for manufacturing a blade according to the present invention.

In FIG. 2, first, a ceramic mold 8 containing alumina as a main component is fixed on a cold water copper chill plate 11, and the ceramic mold 8 is set in a mold heating furnace 4. Heat to above the melting point of the base superalloy. Next, the melted Ni-base superalloy was cast into the ceramic mold 8, and then the water-cooled copper chill plate 11 was pulled out downward and solidified in one direction. In directional solidification, many crystals are generated in the starter 10 at first. Next, only one crystal is grown by the selector 9. Further, the crystal is enlarged in the enlarged portion, and the wing portion is solidified at a withdrawal speed of 10 cm / h to form a single crystal. After the wings were solidified and single-crystallized, the platform 15 was used to increase the mold withdrawal speed to 40 cm / h, thereby forming columnar crystals without growing single crystals. By this method, a columnar crystal blade having a single crystal structure in the blade portion and a columnar crystal structure in other than the blade portion was obtained. In this case, since the columnar crystal was grown using the single crystal of the blade portion as a seed, the difference in orientation between the columnar crystals could be set to about 5 degrees. The mold heating furnace 4 was kept at a high temperature until the ceramic mold 8 was completely drawn out and solidification was completed. In addition, the steps of dissolving and coagulating,
All performed in vacuum. Table 1 shows the casting conditions of the single crystal blade and Table 2 shows the chemical composition of the Ni-based superalloy used for casting. In addition, the columnar crystal blade cast by the above method is
A solution treatment is performed in a vacuum at 60 to 1280 ° C. for 2 to 60 hours to change a precipitated γ ′ phase formed in a cooling process after solidification into a γ phase.
Aging heat treatment was performed at 0 to 950 ° C. for 8 to 100 hours to precipitate a γ ′ phase having an average of 0.3 to 2 μm, more preferably 0.1 to 0.5 μm, in the γ phase of the matrix.

[0064]

[Table 1]

[0065]

[Table 2]

With respect to the mold withdrawal speed, a thermocouple was inserted into a portion of the mold 8 corresponding to the platform 15, the temperature of the portion was measured, and when the solidification point was reached, the withdrawal speed was changed. In addition, a graphite partition plate was provided at the lower part of the heating furnace 4, and a water-cooled copper pipe was spirally wound at the lower part to cool the mold.

In the rotor blade obtained in the above manner, the blade portion 1 was a single crystal, and the portion 2 below the platform 15 was a columnar crystal. The air-cooled fin 14 has a diameter of 10 which is hardly a columnar crystal.
The crystal grains were about mm. Columnar crystals were formed on the surface of the shank 18, but gradually smaller columnar crystals were formed inside the shank 18 from large columnar crystals on which the single crystal of the wing 1 was grown. The width of the columnar crystals on the surface was 5 to 10 mm, and the average width was 5 to 6 mm. The wings were confirmed to be all single crystals on the outer surface by etching. Therefore, it can be seen that the difference in crystal orientation in the wing is within 8 degrees.

FIG. 3 is a plan view of the core of the moving blade, showing the positional relationship with the moving blade. The rotor blades in this embodiment are hollow so that the inside can be cooled. Although air is used as a cooling medium, steam cooling can also be applied. The refrigerant is supplied from the core 21 of the dovetail 16,
It flows into a part discharged from the wing and a part discharged from the trailing edge 23 of the wing. The cores 20 and 22 are holes, and the two wings are integrated with each other by protrusions formed corresponding to the holes. The outlet of the refrigerant at the trailing edge 23 is formed in a slit shape. Has become. The core 22 is a hole and is formed integrally with the molten metal buried in this portion.

The length of the wing 1 in this embodiment is about 100
mm, and the length after the platform has a size of 120 mm.

FIG. 4 shows the obtained creep rupture strength of the rotor blade using the Larson-Miller parameter P.
The comparative material used was a columnar crystal of a commercial CM186LC alloy. By performing solution heat treatment and aging heat treatment after single crystallization,
As compared with the conventional columnar crystal structure subjected to only the aging heat treatment, the service temperature at a stress of 14.0 kgf / mm ² and creep for 100,000 hours was improved by about 20 ° C. The commercially available alloy compositions are the alloy compositions shown in Table 2 with B 0.016%, Zr 0.016%,
It has a C of 0.15%.

[Example 2] C, B, and Z were subjected to solution heat treatment on the rotor blade of the present invention.
This is because the amounts of added r and Hf were controlled to increase the melting point of the eutectic structure. Hereinafter, a method for increasing the melting point of the eutectic structure will be described.

Conventional alloys containing a grain boundary strengthening element include C,
It contained a large amount of B, Zr, Hf, etc., and could not be subjected to solution heat treatment. Therefore, by weight, Cr: 5.0 to 14.0% Co: 0 to 12.0% W: 5.0 to 12.0% Re: 0 to 3.5% Mo: 0.5 to 3.0% % Ta: 3.0 to 7.0% Al: 4.0 to 6.0% Ti: 0.5 to 3.0% Hf: 0 to 2.0% Quantity and (Zr +
The relationship between the melting point of the eutectic structure and the solid solution temperature of the precipitated γ 'phase was examined by changing the proportion of B). As a result, it was found that if the content of C was 0.1% or less and the content of B + Zr was 0.025% or less, the precipitated γ ′ phase could be dissolved in the parent phase without initial melting of the eutectic structure. However, C: 0.1% or less, B +
When a unidirectionally solidified columnar blade of Ni-base superalloy having a composition range of Zr: 0.025% or less was cast, grain boundary cracking occurred. FIG. 5 shows a sketch of a grain boundary crack of a columnar blade manufactured by conventional directional solidification. That is, when the columnar crystal blade is manufactured by the conventional directional solidification method using an alloy of C: 0.1% by weight or less and B + Zr: 0.025% by weight or less, cracks occur at the grain boundaries and the product can be used as a product. Did not.

Therefore, the difference in crystal orientation between the columnar crystals and the C
When the relationship between the amount and the (Zr + B) amount and the grain boundary cracking was examined, when the crystal orientation difference of the columnar crystal was within 8 degrees,
When C: 0.03% or more and (Zr + B): 0.005% or more, a sound columnar blade without grain boundary cracks can be obtained, but when the crystal orientation difference of the columnar crystal is 8 degrees or more, C : 0.03%
As described above, grain boundary cracking occurred even when (Zr + B) was 0.005% or more. When the C content was 0.03% or less, grain boundary cracking occurred even when the crystal orientation difference of the columnar crystals was within 8 degrees. The above results are shown in FIG. When the crystal orientation difference is within 6 degrees, A (C 0.20%, B + Zr 0%) and B (C0.
05%, B + Zr0%), C (C0%, B + Zr0.01)
%), D (C 0%, B + Zr 0.035%) and E (C
(0.1%, B + Zr 0.025%), a material having no initial melting and no grain boundary cracking can be obtained.

C: 0.1% by weight or less, B + Zr: 0.02
In order to prevent grain boundary cracks from occurring in alloys of 5% by weight or less, it is necessary to keep the difference in crystal orientation within 8 degrees. However, in the conventional unidirectional solidification method, the lateral crystal orientation of each columnar crystal is used. Was random and could not be controlled within 8 degrees. However, in the method of the present invention, the difference in the orientation of the columnar crystals could be kept within 8 degrees by making the wings a single crystal and growing the columnar crystals by using this single crystal as a seed. That is, as in the present invention, the wing portion is made of a single crystal, and the other portions are made of columnar crystals having a misorientation of 8 degrees or less, so that C: 0.1% by weight or less,
Even with Zr: 0.025% by weight or less, a sound columnar blade free of grain boundary cracks was obtained. B and Zr showed the same effect in either one or both.

Table 3 compares the characteristics of the columnar crystal blade, the single crystal blade according to the conventional method, and the blade according to the present invention when a blade having a blade length of 22 cm (wing portion 100 mm, root portion 120 mm) was manufactured. Show. A commercially available alloy was used for casting the columnar crystal blade and the single crystal blade.

[0076]

[Table 3]

Since the columnar crystal blade according to the present invention does not cause grain boundary cracking, the yield of the blade is increased by about 5 times from 15% to 70%, and the stress at a stress of 14.0 kgf / mm ² and a creep of 100,000 hours is applied. The service temperature increased by about 20 ° C.

When only the service temperature is compared, it is inferior to a single crystal. However, in the present invention, the casting time was shortened and the mold heating temperature was lowered by using a columnar crystal structure other than the blade portion. As a result, the reaction with the mold is small, the ratio of defects is reduced, and the production yield of the moving blade is improved. Therefore, the present invention is an extremely practical columnar crystal blade and a manufacturing method. In addition,
Although productivity and yield are inferior, it is obvious that there is no actual harm even if the entire blade is made of a single crystal using this alloy.

Example 3 Solution blades of the present invention were subjected to solution heat treatment for C, B, and Z.
This is because the amounts of added r and Hf were controlled to increase the melting point of the eutectic structure. Hereinafter, a method for increasing the melting point of the eutectic structure will be described.

Conventional alloys containing a grain boundary strengthening element include C,
It contained a large amount of B, Zr, Hf, etc., and could not be subjected to solution heat treatment. Therefore, by weight, Cr: 2.0 to 16.0% Co: 4 to 10.5% W: 2.0 to 15.0% Re: 0 to 4.0% Mo: 0 to 6.0% Ta : 2.0 to 12.0% Al: 4.0 to 7.0% Ti: 0.5 to 5.0% For Ni-based alloys containing Hf in the range of 0.5 to 1.1%. The relationship between the melting point of the eutectic structure and the solid solution temperature of the precipitated γ 'phase was examined by changing the ratio between the C content and the (Zr + B) content of the alloy.
As a result, it was found that when B + Zr: 0.020% or less, the precipitated γ ′ phase can be dissolved in the parent phase without initial melting of the eutectic structure. However, Hf: 0.5 to 1.
When a unidirectionally solidified columnar blade of Ni-base superalloy having a composition range of 1%, C: 0.2% or less and B + Zr: 0.020% or less was cast, grain boundary cracking was observed as shown in FIG. Occurred. That is, Hf: 0.5 to 1.1% by weight, C: 0.5%.
When a columnar crystal blade with a random crystal orientation is manufactured by a conventional one-way solidification method using an alloy having a weight ratio of 2% by weight or less and B + Zr: 0.020% by weight or less, cracks occur at grain boundaries and the product can be used as a product. Did not.

Then, when the relationship between the crystal orientation difference of the columnar crystals, the C content and the (Zr + B) content of the alloy with 0.5% Hf, and the grain boundary cracking was examined, the crystal orientation difference of the columnar crystals was within 15 degrees. At the time of, C: 0.03% or more by weight, (Zr + B):
When the content is 0.002% or more, a sound columnar blade without grain boundary cracks can be obtained. However, when the crystal orientation difference of the columnar crystals is 15 degrees or more, C: 0.03% or more, and (Zr + B): 0. .002
% Or more, grain boundary cracking occurred. When the Zr + B content was less than 0.002%, grain boundary cracking occurred even when the crystal orientation difference of the columnar crystal was within 15 degrees.

When the C content is 0.1% or more, 1040 ° C., 1%
In some cases, the creep rupture time of 4 kgf / mm ² was less than 400 hours. In addition, less than 400 hours did not allow complete solution treatment due to initial melting. Further, when Hf is 0.5 to 1.1% and the crystal orientation difference of the columnar crystal is 15%.
The relationship between the amount of C and the amount of Zr + B in the case of the degree is A (0.2
%, 0%), F (0.04%, 0.002%), C (0%,
0.01%), G (0%, 0.02%), H (0.1%, 0.0
2%) within the range surrounding each point. Hf:
0.5 to 1.1%, C: 0.2% by weight or less, B + Zr: 0.2%
In order to prevent grain boundary cracks from occurring in alloys of 020% by weight or less, it is necessary to keep the difference in crystal orientation within 15 degrees. Was random and could not be controlled within 15 degrees. However, in the method of the present invention, the difference in the orientation of the columnar crystals could be kept within 15 degrees by using a single crystal for the blade portion and growing the columnar crystals using this single crystal as a seed. That is, as in the present invention, the wing portion is made of a single crystal, and the other portions are made of columnar crystals having a misorientation difference of 15 degrees or less, so that Hf: 0.5 to 1.5.
1% by weight, C: 0.2% by weight or less, B + Zr: 0.02
Even at 0% by weight or less, a sound columnar blade without grain boundary cracks was obtained. B and Zr showed the same effect in either one or both.

Table 4 shows the casting conditions and alloy compositions (% by weight). The balance is Ni.

[0084]

[Table 4]

Since the blade of the present invention does not cause grain boundary cracking,
Compared with the conventional columnar blades, the yield is increased by about 5 times from 15% to 70%, and at 1040 ° C.-14 kgf / mm ^2.
Creep rupture time of wings from 193h to 456
h and improved within 2 times. Although the shank portion of the blade of the present invention is columnar, the creep rupture time of the columnar portion was twice or more as compared with the conventional columnar blade by performing the solution treatment.

When the blade of the present invention is compared with the single crystal blade, the blade of the present invention is inferior to the single crystal blade in high temperature creep strength.
However, the rotor blade of the present invention has columnar crystals other than the wing portion,
The casting time could be shortened and the mold heating temperature could be reduced. As a result, the reaction with the mold and the deformation of the core are reduced, the ratio of defects is reduced, and the production yield is improved. Therefore, the present invention is an extremely practical high-strength blade.
Furthermore, the tensile strength of the columnar crystal part of the blade of the present invention at around 700 ° C. was about 10% higher than that of the single crystal blade. This is thought to be due to the subgrains of columnar crystals contributing to the improvement in tensile strength, but what is required for the shank is not the creep strength at high temperatures but the tensile strength at temperatures around 700 ° C. Therefore, it can be said that the rotor blade of the present invention in which the blade portion is a single crystal and the other portion than the blade portion is a columnar crystal is an excellent rotor blade having two characteristics required for the rotor blade.

Example 4 N of the composition (% by weight) shown in Table 5 was obtained by the method described in Example 1.
An i-base superalloy was cast to produce a columnar blade in which the blade portion was a single crystal and the other portions were almost completely columnar. In the mold of the present embodiment, a straight mold was formed so as to bypass the protruding portion of the air-cooled fin portion from the enlarged single crystal portion in FIG. 2 so that the air-cooled fin portion became a columnar crystal. No grain boundary cracks were found on the blade after casting. In addition, 1
Solution treatment in vacuum at 270 to 1285 ° C. for 2 to 60 h,
4 to 20 h at 1000 to 1150 ° C and 800 to 95
The aging heat treatment was performed at 0 ° C. for 8 to 100 hours. And 10
4 ~ 20h at 00 ~ 1150 ° C and 8 ~ at 800 ~ 950 ° C
A sample subjected to only the aging heat treatment for 100 hours and a stress of 14.
When the service temperature after creeping at 0 kgf / mm ² and 100,000 hours was compared, the service temperature increased by about 15 ° C. In this example, the crystal orientation difference between the columnar crystals was about 5 degrees.

[0088]

[Table 5]

Example 5 The compositions shown in Table 6 were cast by the method described in Example 1, and a blade for a gas turbine in which the blade portion was a single crystal and the column except for the blade portion was almost completely columnar was cast. In the mold in this embodiment, a straight mold which is bypassed from the single crystal enlargement portion to the fin which is the protrusion in FIG. 2 is added as a solidification promoting passage so that the fin becomes a columnar crystal having good crystallinity. did. As a result, no grain boundary cracks were found in the blade after casting, and the fins were sound columnar crystals with a misorientation of less than 5 degrees.

After casting, the rotor blades were provided with 1250 to 1285
A sample subjected to solution heat treatment at −2 to 60 ° C. and aging heat treatment at 1080 ° C. for 4 h and 871 ° C. for 20 h;
Samples were prepared only for the aging heat treatment at 0 ° C-4h and 871 ° C-20h. As a result, the samples subjected to the solution heat treatment showed that all the alloys shown in Table 4 had a stress of 14 kgf / mm ² and a service temperature under creep of 100,000 hours improved by about 15 ° C. as compared with the samples subjected to the aging heat treatment alone.

[0091]

[Table 6]

Example 6 Using the alloy of the present invention shown in Table 7, a rotor blade for a gas turbine was cast in accordance with the method shown in Example 1. However, in this case, the entire mold was cast at a mold withdrawal speed of 10 cm / h without changing the mold withdrawal speed even after passing through the platform 15. After casting, the same heat treatment as in Example 1 was performed, and several miniature samples having two crystal grains were cut out from the rotor blade, and the difference in crystal orientation in the direction perpendicular to the solidification direction of the two crystal grains and the creep strength were measured. Investigated the relationship. The sample was taken in a direction parallel to the grain boundary. In addition, a special alloy for single crystal
The alloy shown in 3-75619 was evaluated as a comparative alloy. The comparative alloy was cast under the same casting conditions as the alloy of the present invention, subjected to the heat treatment described in Japanese Patent Publication No. 3-75619, and then subjected to a test. Table 8 shows the results. from this result,
The creep strength of the alloy of the present invention at 1040 ° C. and 14 kgf / mm ² is hardly affected by the difference in crystal orientation as long as the difference in crystal orientation is within 15 degrees. In contrast, it can be seen that the comparative alloy dedicated to single crystals cannot tolerate even a slight difference in crystal orientation.

[0093]

[Table 7]

[0094]

[Table 8]

[Embodiment 7] FIG. 7 is a cross-sectional view of a rotating part of a gas turbine having a gas turbine rotor blade according to Embodiment 2 of the present invention.

Reference numeral 30 denotes a turbine stub shaft; 33, a turbine rotor blade; 43, a turbine stacking bolt;
Is a turbine spacer, 49 is a distant piece, 40
Is a nozzle, 36 is a compressor disk, 37 is a compressor blade, 38 is a compressor stacking bold, 39 is a compressor stub shaft, 34 is a turbine disk, and 41 is a hole. The gas turbine of the present invention has seventeen stages of compressor disks 36 and three 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 of this embodiment is mainly composed of a heavy tuty type, a single-shaft type, a horizontally split casing, and a stacking type rotor. The compressor is a 17-stage axial flow type, the turbine is a 3-stage impulse type, and , Two-stage air-cooled stationary blades and combustor of berth flow type, 16 cans, slot cool type.

The distant pieces 39, the turbine disk 34, the spacers 38, and the stacking bolts 33 are C 0.06 to 0.15%, Si 1% or less, and Mn 1.5 by weight.
% Or less, Cr 9.5 to 12.5%, Ni 1.5 to 2.5
%, Mo 1.5 to 3.0%, V 0.1 to 0.3%, Nb 0.0
A fully tempered martensitic steel consisting of 3 to 0.15%, N 0.04 to 0.15% and the balance Fe is used. As a characteristic in this embodiment, the tensile strength is 90 to 120 kg / m.
m ² , 0.2% yield strength 70-90 kg / mm ² , elongation 10
25%, drawing ratio 50-70%, V-notch impact value 5-9.
5kg-m / cm ² , 450 ° C 10 ⁵ h Creep rupture strength 4
It was 5~55kg / mm ^2.

The turbine blade 33 has three stages, the first stage being the one manufactured in Example 1 and having a compressor pressure of 14.7.
, Temperature 400 ℃, first stage rotor blade inlet temperature 1,300 ℃,
The temperature of the combustion gas from the combustor was set at 1450 ° C. In the second stage of the turbine rotor blade 33, a blade length of 280 mm (160 mm in blade portion, 120 mm in length after the platform portion) made of a polycrystal having the same alloy composition, and the same alloy composition in the third stage are used. Used, same polycrystalline wing length 350mm
A solid wing (wing section 230 mm, other 120 mm) was manufactured. The manufacturing method was a precision casting method using a conventional lost wax method.

For the turbine nozzle 40, a known Co-based alloy is used, and the first to third stages formed with one blade portion by vacuum precision casting are used. The wing has a length corresponding to the length of the moving blade, and has a pin fin cooling, impingement cooling and film cooling structure. The first stage nozzle is constrained at both ends of the sidewall, while the second and third stages are constrained on one side of the sidewall outer peripheral side. The gas turbine is provided with an intercooler.

The power output obtained by this embodiment is 50
MW is obtained, and a high thermal efficiency of 33% or more is obtained.

Eighth Embodiment FIG. 8 is a schematic diagram showing a single-shaft combined cycle power generation system using the gas turbine of the seventh embodiment in combination with a steam turbine.

When power is generated using a gas turbine,
In recent years, a gas turbine is driven by using liquefied natural gas (LNG) as a fuel, and a steam turbine is driven by steam obtained by recovering exhaust gas energy of the gas turbine, and a generator is driven by the steam turbine and the gas turbine. There is a tendency to adopt a so-called combined power generation system.
In this combined power generation system, the following system configuration enables high thermal efficiency of about 45% or more as compared with the thermal efficiency of 40% in the case of the conventional steam turbine alone. In such a combined cycle power plant, recently, it has been further promoted to use both liquefied natural gas (LNG) and liquefied petroleum gas (LPG), and to realize co-firing of LNG and LPG, thereby facilitating plant operation and economy. The goal is to improve

First, the air passes through the intake filter and the intake siren and enters the air compressor of the gas turbine.
Compress air and send compressed air to low NOx combustor. In the combustor, fuel is injected into the compressed air and burned to produce a high-temperature gas of 1400 ° C. or higher, and the high-temperature gas works in a turbine to generate power.

Exhaust gas of 530 ° C. or higher discharged from the turbine is sent to an exhaust heat recovery boiler through an exhaust silencer,
530 ° C by recovering thermal energy in gas turbine exhaust
The above high-pressure steam is generated. This boiler is provided with a denitration device by dry ammonia catalytic reduction. Exhaust gas is discharged outside from a three-legged chimney with a length of several hundred meters. The generated high-pressure and low-pressure steam is sent to a steam turbine comprising a high-low pressure integrated rotor.

The steam that has exited the steam turbine flows into the condenser, is degassed in a vacuum, and becomes condensed water. The condensed water is pressurized by the condensate pump and supplied as water to the boiler. Then, the gas turbine and the steam turbine each drive a generator from both shaft ends to generate power. For cooling the gas turbine blades used in such combined power generation, steam used in a steam turbine may be used as a cooling medium in addition to air. Generally, air is used as a cooling medium for the blades. However, steam has a much higher specific heat than air, and has a large cooling effect because of its light weight.

The combined power generation system can generate a total of 80,000 KW of power of 50,000 KW by the gas turbine and 30,000 KW by the steam turbine. The steam turbine in this embodiment is compact, and It is possible to manufacture economically with the same power generation capacity as compared with the above, and there is obtained a great merit that it can be operated economically with respect to fluctuations in power generation.

The steam turbine according to the present invention is a high / low pressure integrated steam turbine, and the single steam output of the turbine is increased by increasing the steam pressure at the main steam inlet of the high / low pressure integrated steam turbine to 100 atg and the temperature to 538 ° C. Can be achieved. Increasing the output of a single unit increases the blade length of the last stage rotor blade by three.
It needs to be increased to 0 inches or more, and the steam flow rate needs to be increased. The steam turbine according to the present invention has 13 or more stages of blades installed on a high / low pressure integrated rotor shaft, and steam flows through the steam control valve from the steam inlet at a high temperature and pressure of 538 ° C. and 88 atg as described above. I do. The steam flows in one direction from the inlet, reaches a steam temperature of 33 ° C. and 722 mmHg, and is discharged from the outlet through the blade at the last stage. The high-low pressure monolithic rotor shaft according to the present invention is Ni-Cr-M.
Forged steel of oV low alloy steel is used. The implanted portion of the blade of the rotor shaft has a disk shape, and is manufactured by being integrally cut from the rotor shaft. The length of the disk portion increases as the length of the blade decreases, so that vibration is reduced.

The high / low pressure integrated rotor shaft according to this embodiment has a C of 0.18 to 0.30%, a Si of 0.1% or less, and a Mo of 0.1%.
3% or less, Ni 1.0 to 2.0%, Cr 1.0 to 1.7%,
Mo is 1.0 to 2.0%, V is 0.20 to 0.3%, and the balance is Fe. After quenching at 900 to 1050 ° C by water spray cooling, it is tempered at 650 to 680 ° C.

The plant has a single-shaft type in which six sets of a power generation system including a gas turbine, an exhaust heat recovery boiler, a steam turbine, and a generator are combined. On the other hand, steam can be obtained by exhaust gas after combining one generator and combining these six sets, so that a multi-shaft type having one steam turbine and one generator can be obtained.

The combined power generation is realized by a combination of a gas turbine that can be easily started and stopped in a short time and a small and simple steam turbine. Therefore, the output can be easily adjusted, and the intermediate load that can respond to a change in demand can be easily obtained. Ideal for thermal power.

The reliability of gas turbines has been dramatically increased due to the recent development of technology. In addition, since a combined cycle power plant has a system composed of a combination of small-capacity machines, a failure should occur. Even so, the effects can be localized, and the power supply is highly reliable.

[0113]

According to the present invention, a moving blade for a gas turbine having a high creep strength can be obtained, so that the life of the moving blade is prolonged and the combustion gas temperature is increased, and a gas turbine and a combined cycle power plant system using the same are provided. This has a remarkable effect of improving the thermal efficiency of the device.

Further, according to the method for manufacturing a moving blade for a gas turbine according to the present invention, the yield rate in manufacturing the moving blade can be improved.

[Brief description of the drawings]

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

FIG. 2 is a schematic view showing the outline of a method for manufacturing a moving blade for a gas turbine according to the present invention.

FIG. 3 is a diagram showing a plan view of a core shown in the present embodiment and a positional relationship between the rotor blades.

FIG. 4 is a comparison diagram showing the high-temperature strength of a columnar crystal blade obtained by the present invention and a conventional columnar crystal blade.

FIG. 5 is a sketch diagram showing a state of grain boundary cracks observed in a columnar crystal blade manufactured by a unidirectional solidification method.

FIG. 6 is a characteristic diagram showing a relationship between the amount of C and the amount of (B + Zr) capable of forming a precipitated γ ′ phase in a γ phase without causing initial melting of an alloy, and a relationship of grain boundary cracking.

FIG. 7 is an overall configuration diagram of a gas turbine according to the present embodiment.

FIG. 8 is an overall system diagram of the combined cycle power plant according to the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wing part, 2 ... Root part, 3 ... Melting furnace, 4 ... Mold heating furnace,
5: molten metal, 6: casting, 7: core, 8: ceramic mold,
9 selector, 10 starter, 11 water-cooled copper chill plate, 12 vacuum pump, 13 furnace hearth, 14 air-cooled fins, 15 platform, 16 dubtil, 18
... shank, 33 ... rotor blade, 34 ... turbine disk, 3
6 ... Compressor disk, 38 ... Spacer, 40 ... Static blade.

Continued on the front page (72) Inventor Saito New Year 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Mitsuru Kobayashi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratory Co., Ltd. (72) Inventor Akemi Iijima 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratory Co., Ltd. No. 1 Co., Ltd.Hitachi, Ltd.Hitachi Plant (72) Inventor Kimio Kano 3-7-1 Ichibancho, Aoba-ku, Sendai, Miyagi Prefecture Inside Tohoku Electric Power Co., Inc. 3-7-1 Ichibancho Inside Tohoku Electric Power Co. (56) References JP-A-4-124237 (JP, A) JP-A-4-187363 (JP, A) JP-A-58-57005 (JP, A) JP-A-59-113205 (JP, A) JP-A-61-71168 (JP, A) JP-A-60-261659 (JP, A) A) JP-A-5-113131 (JP, A) JP-B-45-40661 (JP, B1) JP-B-51-4186 (JP, B2) Jiko-sho 52-32739 (JP, Y1) (58) Survey Field (Int.Cl. ⁷ , DB name) F01D 5/28 B22D 27/04 C22C 19/05 F01D 5/18 F02C 7/00

Claims (14)

(57) [Claims] 1. A platform having a wing portion, a flat portion connected to the wing portion, a shank portion connected to the platform, fins comprising projections provided on both sides of the shank portion, and the shank. In a gas turbine rotor blade having a dovetil connected to a part, the blade part and the platform and a part of the shank part are single crystals, and all other than the single crystal, or the single crystal and the fin Except for the part, it is a unidirectionally solidified columnar solid casting, C03-0.15% by weight, Cr
5.5-9.0%, Al 4-7%, W2-15%, Ti
0.5-1.5%, Mo 0.3-1.0%, Ta 2-7%,
Co 8.0-10.5%, Hf 0.5-1.0%, Re1
4%, the total amount of one or two of B and Zr is 0.002
A moving blade for a gas turbine, comprising a Ni-based alloy having a content of 0.02% or more and a Ni content of 58% or more. 2. A platform having a wing portion, a flat portion connected to the wing portion, a shank portion connected to the platform, fins including projections provided on both sides of the shank portion, and the shank. In a gas turbine rotor blade having a dovetil connected to a part, the blade part, the platform, and a part of the shank part are single crystals, and all other than the single crystal, or the single crystal and fins The removed part is a columnar crystal solidified in one direction, consisting of an integral casting solidified from the tip of the wing toward the end of the dovetail, and has a weight of C0.03-0.15%,
Cr 5.5-9.0%, Al 4-7%, W2-15%, Ti
0.5-1.5%, Mo 0.3-1.0%, Ta 2-7%,
Co 8.0-10.5%, Hf 0.5-1.0%, Re1
4%, the total amount of one or two of B and Zr is 0.002
A moving blade for a gas turbine, comprising a Ni-based alloy having a content of 0.02% or more and a Ni content of 58% or more. 3. The moving blade for a gas turbine according to claim 1, wherein a cooling medium passage is provided integrally from the dovetail portion to the tip of the blade portion. 4. The moving blade for a gas turbine according to claim 1, wherein a difference in crystal orientation of the γ phase between the adjacent columnar crystals is 2 to 8 degrees. 5. A fin comprising a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, projections provided on both sides of the shank portion, and the shank. In a gas turbine rotor blade having a dovetil connected to a part, the blade part and the platform and a part of the shank part are single crystals, and all other than the single crystal, or the single crystal and the fin Except for the part, it is a unidirectionally solidified columnar solid casting, C03-0.15% by weight, Cr
5.5-9.0%, Al 4-7%, W2-15%, Ti
0.5-1.5%, Nb0-3%, Mo 0.3-1.0%,
Ta 2 to 7%, Co 8.0 to 10.5%, Hf 0.5 to 1.0.
0%, Re 1-4%, B 0.002-0.02%, Zr
A gas turbine engine comprising a Ni-based alloy of 0.002 to 0.02% and Ni of 58% or more, wherein a difference in crystal orientation of the γ phase between the adjacent columnar crystals is 2 to 8 degrees. Wings. 6. A platform having a wing portion, a flat portion connected to the wing portion, a shank portion connected to the platform, fins comprising projections provided on both sides of the shank portion, and the shank. In a gas turbine rotor blade having a dovetil connected to a part, the blade part and the platform and a part of the shank part are single crystals, and all other than the single crystal, or the single crystal and the fin Except for the part, it is a unidirectionally solidified columnar solid casting, C03-0.15% by weight, Cr
5.5-9.0%, Al 4-7%, W2-15%, Ti
0.5-1.5%, Nb0-3%, Mo 0.3-1.0%,
Ta 2 to 7%, Co 8.0 to 10.5%, Hf 0.5 to 1.0.
0%, Re 1-4%, B 0.002-0.02%, Zr
0.002-0.02% and Ni-based alloy of 58% or more, and the C amount and one or both of B and Zr amounts are A (C 0.20%, B + Zr 0%), F (C 0.04%).
%, B + Zr 0.002%), C (C0%, B + Zr 0.0
1%), G (C 0%, B + Zr 0.02%), H (C 0.1
%, B + Zr 0.02%) and the point A. 7. A platform having a wing portion, a flat portion connected to the wing portion, a shank portion connected to the platform, fins including projections provided on both sides of the shank portion, and the shank. In a gas turbine rotor blade having a dovetil connected to a part, the blade part and the platform and a part of the shank part are single crystals, and all other than the single crystal, or the single crystal and the fin The removed part is made of an integral casting with columnar crystals solidified in one direction, the wing has a single crystal and dovetail has columnar crystals, and C0.03-0.1%, Cr5.5-0.9 by weight. 0
%, Co 8.0-10.5%, W2-15%, Re1
4%, Mo 0.3 to 1.0%, Ta 2 to 7%, Al 4 to
7%, Ti 0.5 to 1.5%, Hf 0.5 to 1.0%, one or both of B and Zr are 0.005 to 0.02%, and the balance is Ni and inevitable impurities. A blade for a gas turbine, wherein a difference in crystal orientation between phases is 8 degrees or less in a single crystal part and 15 degrees or less in a columnar crystal part. 8. A platform having a wing portion, a flat portion connected to the wing portion, a shank portion connected to the platform, fins comprising projections provided on both sides of the shank portion, and the shank. In a gas turbine rotor blade having a dovetil connected to a part, the blade part and the platform and a part of the shank part are single crystals, and all other than the single crystal, or the single crystal and the fin The removed part is an integral casting which is a columnar crystal solidified in one direction, and a refrigerant passage is provided integrally inside from the dovetail part to the tip of the wing part. The casting is C0.03-0.0 by weight. .15%, Cr 5.5
~ 9.0%, Al4 ~ 7%, W2 ~ 15%, Ti0.5 ~
1.5%, Nb 0 to 3%, Mo 0.3 to 1.0%, Ta2
~ 7%, Co 8.0 ~ 10.5%, Hf 0.5 ~ 1.0%,
Re 1-4%, B 0.002-0.02%, Zr 0.00
2 to 0.02% and a Ni-based alloy of Ni 58% or more, and the C amount and one or both of the B and Zr amounts are A
(C 0.20%, B + Zr 0%), F (C 0.04%, B
+ Zr 0.002%), C (C 0%, B + Zr 0.01
%), G (C0%, B + Zr 0.02%), H (C0.1
%, B + Zr 0.02%) and the difference between the crystal orientations of the γ phase between the adjacent columnar crystals is 2 to 8 degrees within the range connecting the points A and A. Wings. 9. A gas turbine in which fuel gas formed using air compressed by a compressor is impinged on a moving blade implanted on a disk through a stationary blade to rotate the moving blade. A fin comprising a platform having a wing portion, a flat portion connected to the wing portion, a shank connected to the platform, and projections provided on both sides of the shank; And a dovetil connected to the shank, wherein the wing portion is a single crystal, and the dovetil is formed of a one-piece solidified columnar solidified casting, and has a weight of C0.03-0.03.
15%, Cr 5.5-9.0%, Al 4-7%, W2-1
5%, Ti 0.5-1.5%, Mo 0.3-1.0%, Ta
2-7%, Co 8.0-10.5%, Hf 0.5-1.0
%, Re1 to 4%, and the total amount of one or two of B and Zr is 0.002 to 0.02% and Ni is 58% or more.
A gas turbine comprising an i-based alloy. 10. A gas turbine in which combustion gas formed using air compressed by a compressor is caused to impinge on a moving blade implanted on a disk through a stationary blade to rotate the moving blade. 1,500 ° C. or more, and has three or more stages of the moving blades, the combustion gas temperature at the first stage inlet of the moving blade is 1,300 ° C. or more, and the power generation capacity is 5 or more.
10,000 KW or more, the first stage of the rotor blade has a total length of 200 mm or more, the first stage of the rotor blade has a wing portion, a platform having a flat portion connected to the wing portion, and a shank connected to the platform. An integral casting comprising a fin comprising protrusions provided on both sides of the shank and a dovetil connected to the shank, wherein the wing is a single crystal, and the dovetil is a columnar crystal solidified in one direction. Consisting of 0.03 to 0.15% of C, 5.5 to 9.0% of Cr,
14-7%, W2-15%, Ti 0.5-1.5%, Mo
0.3 to 1.0%, Ta 2 to 7%, Co 8.0 to 10.5
%, Hf 0.5-1.0%, Re 1-4%, B and Zr
The total amount of one or two of 0.002 to 0.02% and
A gas turbine comprising a Ni-based alloy containing 58% or more of Ni. 11. A gas turbine in which a combustion gas formed by using air compressed by a compressor is caused to collide with a moving blade implanted on a disk through a stationary blade to rotate the moving blade. 1,500 ° C. or more, and has three or more stages of the moving blades, the combustion gas temperature at the first stage inlet of the moving blade is 1,300 ° C. or more, and the power generation capacity is 5 or more.
10,000 KW or more, the first stage of the rotor blade has a total length of 200 mm or more, the first stage of the rotor blade has a wing portion, a platform having a flat portion connected to the wing portion, and a shank portion connected to the platform. And a fin comprising protrusions provided on both sides of the shank portion and a dovetail connected to the shank portion, wherein the blade portion is a single crystal, and the dovetil is unidirectionally solidified. Of a columnar crystal, wherein the weight of the casting is 0.03 to 0.1% C, 5.5 to Cr
9.0%, Co 8.0 to 10.5%, W 2 to 15%, R
e 1-4%, Mo 0.3-1.0%, Ta 2-7%, Al
4-7%, Ti 0.5-1.5%, Hf 0.5-1.0%,
One or both of B and Zr is 0.005 to 0.02%, and the balance is Ni and unavoidable impurities, and has a structure in which a γ 'phase is precipitated in a γ phase matrix; A difference in crystal orientation between the γ phase of the columnar crystal and the columnar crystal is 8 degrees or less. 12. 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, and driven by the gas turbine and the steam turbine A gas turbine having three or more stages of moving blades, wherein the temperature of the first stage of the moving blade of the combustion gas is 1.3.
If the temperature of the exhaust gas at the turbine outlet is
0 ° C. or higher, and steam having a temperature of 530 ° C. or higher is obtained by the exhaust heat recovery boiler. The steam turbine is of a high / low pressure integrated type, and the steam temperature to the first stage of the steam turbine blade is 53 ° C.
0 ° C or higher, and the power generation capacity of the gas turbine is 50,000K
W or more and the power generation capacity of the steam turbine is 30,000 KW or more, the total thermal efficiency is 45% or more, the first stage of the gas turbine rotor blade has a total length of 200 mm or more, and the first stage of the rotor blade has a blade portion, A platform having a flat portion connected to the wing portion, a shank portion connected to the platform, fins formed on both sides of the shank portion, and fins formed on both sides of the shank portion, and a dovetail connected to the shank portion. The wing portion is a single crystal, and the dovetail is a one-piece solidified columnar solid casting, and the casting is C0.03-0.15% by weight, Cr5.5.
~ 9.0%, Co 8.0 ~ 10.5%, W2 ~ 15%, R
e 1-4%, Mo 0.3-1.0%, Ta 2-7%, Al
4-7%, Ti 0.5-1.5%, Hf 0.5-1.0%,
One or both of B and Zr is 0.002 to 0.02%, and the balance is Ni and unavoidable impurities, and has a structure in which a γ 'phase is precipitated in a γ phase matrix; Wherein the difference between the crystal orientations of the γ phase and the columnar crystal is 8 degrees or less. 13. A fin comprising a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, projections provided on both sides of the shank portion, and the shank. And Dovetil connected to the other part, C0.03-0.15% by weight, Cr5.5
~ 9.0%, Al4 ~ 7%, W2 ~ 15%, Ti0.5 ~
1.5%, Mo 0.3-1.0%, Ta 2-7%, Co8.
0-10.5%, Hf0.5-1.0%, Re1-4%, B
And the total amount of one or two of Zr is 0.002 to 0.02.
% And a method for manufacturing a moving blade for a gas turbine comprising an integral casting made of a Ni-based alloy having a Ni content of 58% or more,
Setting the mold forming the rotor blade on a water-cooled chill plate; setting the mold in a heating furnace and heating the mold to a predetermined temperature; Casting the molten metal into the mold, and pulling the mold having the molten metal relatively from the heating furnace to solidify sequentially from the tip of the wing portion to the end of the dovetail to form the wing portion into a single crystal, and then mold the wing portion. Drawing out the dovetil unidirectionally to form columnar crystals by drawing at a speed higher than the drawing speed of the gas turbine. 14. The gas turbine according to claim 13, wherein a difference in crystal orientation of the γ phase of the alloy in a direction perpendicular to the solidification direction between the single crystal and the columnar crystal is 8 degrees or less. Method of manufacturing rotor blades.