JPH07145703A - Moving blade for gas turbine, manufacture thereof, and gas turbine using same - Google Patents

Abstract

PURPOSE:To achieve excellent creep strength and eliminate an intercrystalline crack by constituting a moving blade of an integral casting where a part of a blade unit, a platform and a shank unit is made of monocrystal and a part except for the part made of monocrystal is made of columnar crystal coagulated in one direction. CONSTITUTION:A gas turbine moving blade comprises a blade unit 1, a platform 15 having a flat portion continuous to the blade unit 1, a shank unit 18 continuous to the blade 1 and the platform 15, and fins 14 formed on both sides of the shank unit 18, a dovetail continuous to the shank unit 18. The blade unit 1 is made of monocrystal, and the whole except for the blade unit 1 is an integral casting of columnar crystal coagulated in one direction. The casting is composed of 0-0.20wt.% of C, 2-16wt.% of Cr, 4-7wt.% of Al, 2-15wt.% of W, 0.5-5wt.% of Ti, 0-3wt.% of Nb, 0-6wt.% of Mo, 0-12wt.% of Ta, 0-10.5wt.% of Co, 0-2wt.% of Hf, 0-4wt.% of Re, 0-0.035wt.% of B, 0-0.035wt.% of Zr and the rest of 58wt.% or more of Ni.

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 blade and a gas turbine using the blade.

[0002]

2. Description of the Related Art Ni-based superalloys have been mainly used as the blade material of a gas turbine for power generation, but the combustion gas temperature has been increasing year by year in order to improve the thermal efficiency of the gas turbine. In order to increase the heat-resistant strength of the rotor blades, the structure changes from equiaxed crystal blades made by normal casting to columnar crystal blades made by unidirectional solidification, and complicated cooling holes are provided inside the blades. I have been trying to cool down.

Most of the columnar crystal castings are manufactured by the unidirectional solidification method disclosed in Japanese Patent Publication No. 51-4186. This method is a method in which a mold is pulled out from a heated furnace and gradually solidified upward from the lower end. By this method, elongation is extended in the longitudinal direction where centrifugal stress acts, and <10
A columnar crystal blade having a crystal orientation of 0> orientation has been manufactured, and creep strength characteristics and thermal fatigue strength characteristics have been improved.

Further, as a rotor blade having a higher temperature characteristic than that of a columnar crystal rotor blade, JP-A-60-261659 and JP-A-61-71168 are used.
The publication discloses a method of manufacturing a blade for a combustion turbine in which the blade portion is made of single crystal and the root portion is made of fine crystal.

[0005]

Increasing the combustion gas temperature is the most effective method for achieving higher efficiency, and for that purpose, the internal cooling is further strengthened and the high temperature strength of the material is improved. It has become necessary to raise it.

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 thin. Came. The columnar crystal blades are manufactured by the unidirectional solidification method, but the molten metal solidifies in a state where the core is surrounded by casting, and then cooled to room temperature. Then, heat contraction occurs during cooling. Comparing the thermal expansion coefficients of 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 does not shrink almost as if it is wrapped inside. A large tensile stress will be generated in the process. Therefore, in the cast product, vertical cracks are likely to occur along the grain boundaries where the strength is weak. And
Longitudinal cracking is particularly noticeable in the thin blade portion. Therefore, in the conventional columnar crystal moving blade, the blade portion cannot be thinned, and the cooling cannot be sufficiently performed. In addition, grain boundary cracking occurred during casting and the yield was poor.

A moving blade used in an aircraft jet engine has a maximum blade length of about 10 cm and a weight of several hundred grams, so that single crystallization is easy. However, the blade used in the gas turbine for power generation is not only complicated in shape, but also has a blade length of 15 to 40 cm and a weight of several kg to 10 kg.
Since the size is extremely large, foreign crystals and freckle defects are easily generated by the method disclosed in Japanese Patent Publication No. 4186 / 51-4186, and single crystallization is very difficult.

Japanese Unexamined Patent Publication No. 60-261659 and Japanese Unexamined Patent Publication No. 61-71
Japanese Patent No. 168 describes a manufacturing method in which a blade is made of a single crystal and the remaining portion is made into fine crystal grains by using magnetic stirring.
However, when the conventional single crystal alloy is cast by this method, there is a problem that the strength of the fine crystal grain portion becomes weak. In addition, when casting is performed using an alloy containing a large amount of grain boundary strengthening elements in order to maintain the strength of the fine crystal grains, the eutectic structure formed during solidification and the melting point of the eutectic γ ′ phase are lowered, As a result, the strength of the material could not be improved.

As described above, in the rotor blade according to the prior art, grain boundary cracking is likely to occur when the wall thickness is reduced in order to improve cooling efficiency, and grain boundary strengthening elements are added to prevent grain boundary cracking. If added, there was a drawback that the strength could not be improved, and the efficiency of the gas turbine could not be improved.

Further, a single crystal blade excellent in high temperature strength has a very low yield because foreign crystals are easily generated, and a large product cannot be manufactured. Therefore, it cannot be applied as a blade of a gas turbine for power generation. The efficiency of the gas turbine could not be improved.

It is an object of the present invention to provide a columnar crystal blade for a gas turbine which is free from intergranular cracks during casting and which is excellent in creep strength, a method for producing the same, and a gas turbine using the same.

[0012]

DISCLOSURE OF THE INVENTION According to the present invention, a wing portion exposed to high-temperature and high-pressure gas, a platform which is a bulging portion connected to the wing portion for shutting off high-temperature and high-pressure gas, and the wing portion which is connected to the platform Between the disc and the disc, a shank portion having a distance for obtaining a sufficient temperature gradient, a seal fin provided on the shank portion for blocking high-temperature high-pressure gas, and a disc connected to the shank portion. With a dovetail which is an embedded portion, the wing portion is a single crystal at least the outer surface thereof, 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, A balance is a blade for a gas turbine, which is made of an integral casting made of unidirectionally solidified columnar crystals continuously formed from the single crystal.

That is, in the gas turbine rotor blade according to the present invention, the blade portion is a single crystal and the rest is a unidirectionally solidified columnar crystal. However, the blade from the blade portion is formed in the remaining platform and shank portion. Crystals continue to form.

In particular, in the rotor blade for a gas turbine according to the present invention, the longitudinal direction of the columnar crystals is within 15 degrees from the <100> orientation with the polycrystalline portion as the columnar crystal structure, and the crystal orientation of the adjacent columnar crystals is It is preferable that the difference is within 15 degrees, particularly within 8 degrees.

Further, if the crystal orientation difference in the single crystal of the blade portion is within 8 degrees, no grain boundary is observed and it is acceptable.

In particular, the orientation difference between the adjacent crystal grains on the outer surface of the blade is within 8 degrees, and the orientation difference between the adjacent crystal grains of a part including the inside of the blade other than the outer surface of the blade is Within 8 degrees,
The orientation difference between the remaining adjacent crystal grains is preferably within 15 degrees.

Further, it is preferable that the maximum difference in crystal orientation between the crystal grains of the blade portion and other portions is within 8 to 15 degrees.

Further, in order to obtain the above-mentioned gas turbine rotor blade, it is effective to provide a solidification promoting passage between at least one location of the single crystal and the seal fin which is a projection.

The gas turbine rotor blade of the present invention may be provided with a refrigerant passage for cooling the rotor blade inside 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 Cr, Al, Y and containing Co or Ni 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 rotor blade for a gas turbine according to the present invention has a C content of 0.03% or more, a B content of 0.005% or more and 0.0 by weight.
Containing one or more elements of Zr of 05% or more,
Moreover, the alloy is cast from a Ni-base superalloy capable of forming a solid solution of 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%, one or two of B and Zr is 0.005 to 0.025%, and more preferably B.
The content of 0.002 to 0.02% and Zr of 0.02% or less is suitable for preventing cracking.

The gas turbine blade according to the present invention has a weight%
And is cast from a Ni-base superalloy having the following preferable composition.

The castings are in% by weight, C0 to 0.20%, Cr
2-16%, Al4-7%, W2-15%, Ti0.5
~ 5%, Nb0-3%, Mo0-6%, Ta0-12
%, Co0 to 10.5%, Hf0 to 2%, Re0 to 4
%, B0 to 0.035%, Zr0 to 0.035%, and the balance being 58% or more of Ni.

According to the present invention, a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, and fins including protrusions provided on both sides of the shank portion are provided. In a turbine blade for a gas turbine having a dovetail continuous with the shank portion, the blade portion is a single crystal, and a portion excluding the blade portion and the fin is a unidirectionally solidified columnar crystal from an integral casting It is characterized by

According to the present invention, a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, and fins including protrusions provided on both sides of the shank portion are provided. In a gas turbine rotor blade having a dovetail continuous with the shank portion, the blade portion is a single crystal, and all except the blade portion are made of an integral casting which is a unidirectionally solidified columnar crystal. To do.

The moving blade in the present invention has a refrigerant passage integrally connected to the inside thereof.

In the present invention, C0 to 0.20% by weight, C
r2-16%, Al4-7%, W2-15%, Ti0.
5-5%, Nb0-3%, Mo0-6%, Ta0-1
2%, Co0-10.5%, Hf0-2%, Re0-4
%, B0 to 0.035%, Zr0 to 0.035%, and the balance of Ni of 58% or more, and the C content and B and Z.
One or both of the r amount is A (C 0.20%, B + Zr0
%), B (C0.05%, B + Zr0%), C (C0%,
B + Zr 0.01%), D (C0%, B + Zr 0.035)
%) And E (C0.1%, B + Zr0.025%), and the difference in crystal orientation is 2 to 8 degrees.

According to the present invention, C0.03-0.1% by weight,
Cr 5.5-7.0%, Co 8.5-9.5%, W8-9
%, Re 2.5 to 3.5%, Mo 0.3 to 1.0%, Ta3
~ 4%, Al 5-6%, Ti 0.5-1.0%, Hf 0.
5 to 1.0%, one or both of B and Zr 0.005
0.025%, and the balance Ni and inevitable impurities,
The rotor blade for a gas turbine is characterized in that the difference in crystal orientation is 8 degrees or less.

The moving blade of the present invention is used for any stage of a three-stage or four-stage gas turbine, and is particularly suitable for the first stage having the highest temperature. From the second stage onward, a polycrystalline one having columnar crystals or equiaxed crystals as a whole is particularly preferable.

The following composition is particularly 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: 0.0 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 kinds of B and Zr. : 0.005-0.025 balance: Ni and unavoidable impurities Further, the gas turbine blade according to the present invention has a temperature range of 2 to 2 in the temperature range from the solid solution temperature of the γ'phase of the cast alloy to the initial melting temperature. Solution-treated for 60 hours, and further 1000 to 1150 ° C
The heat treatment is preferably performed for 4 to 20 hours and at 800 to 920 ° C. for 8 to 100 hours.

The method for manufacturing a gas turbine rotor blade according to the present invention includes the steps of setting a mold having a ceramic core on a water-cooled chill plate, and casting a molten metal in a heated mold after melting the casting raw material. And a step of pulling out the mold relatively from the high-temperature heating furnace, gradually unidirectionally solidifying from the tip side of the blade to the root side to form the blade into a single crystal, and the drawing speed of the mold of the blade. It is a method of manufacturing a gas turbine rotor blade, which is characterized in that the root portion is unidirectionally solidified by pulling out at a higher speed.

The mold moving speed in producing a single crystal is 15 cm.
/ H or less, and the moving speed in columnar crystal production is preferably 20 to 45 cm / h. In particular, the former is better as long as a single crystal can be produced, but 10 cm from the viewpoint of yield. / H is preferable, and in the latter case, the crystal orientation between the columnar crystals exceeds 10 degrees and equiaxed crystals are obtained when it exceeds 50 cm / h, so 45 cm / h or less is preferable.
Since it is better to use a faster speed to reduce the temperature to less than 30 degrees, 30 to 45
cm / h is preferred.

The present invention comprises a unidirectionally solidified casting of a single crystal and a columnar crystal, and the difference in crystal orientation between the single crystal and the columnar crystal in a direction perpendicular to the solidification direction is 8 degrees or less. It is an article characterized in that it can be used in addition to a blade for a gas turbine.

According to the present invention, a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, and fins including protrusions provided on both sides of the shank portion, In a gas turbine blade having a dovetail continuous with the shank part, the vane part is a single crystal, and all but the vane part is an integrally cast product which is a unidirectionally solidified columnar crystal. From the end to the tip of the blade, a continuous refrigerant passage is provided inside, and the casting has a weight of C0 to 0.20%, Cr2.
~ 16%, Al4 ~ 7%, W2 ~ 15%, Ti0.5 ~
5%, Nb0-3%, Mo0-6%, Ta0-12
%, Co0 to 10.5%, Hf0 to 2%, Re0 to 4,
B0-0.035%, Zr0-0.035%, and the balance being Ni of 58% or more, and one or both of the C amount and the B and Zr amounts are A (C0.20%, B + Zr0%),
B (C 0.03%, B + Zr 0%), C (C 0%, B + Z
r0.01%), D (C0%, B + Zr0.035%) and E (C0.1%, B + Zr0.025%), with a structure in which the γ ′ phase is dispersed in a γ phase matrix. The difference in the crystal orientation of the γ phase is 2 to 6 degrees.

The present invention relates to a gas turbine in which combustion gas compressed by a compressor is caused to collide with a moving blade planted on a disk through a stationary blade to rotate the moving blade,
The moving blade has three or more stages, and the first stage of the moving blade is provided with a wing portion, a platform having a flat portion connected to the wing portion, a shank connected to the platform, and both sides of the shank. From a single casting having fins composed of protrusions and dovetails connected to the shank, the wing portion is a single crystal, and all but the wing portion and the fin are unidirectionally solidified columnar crystals. Gas turbine characterized by becoming.

According to the present invention, in the above-described gas turbine, the combustion gas temperature is 1,500 ° C. or higher, the moving blade has three or more stages, and the combustion gas temperature at the first stage inlet of the moving blade is 1, The temperature is 300 ° C or higher, and the total length of the first stage of the blade is 2
It is characterized in that it has a diameter of at least 00 mm and its blade portion is a single crystal, and that the root portion excluding the blade portion is an integrally cast product which is unidirectionally solidified columnar crystal, and has a power generation capacity of 50,000 kW or more.

The present invention relates to a gas turbine in which combustion gas compressed by a compressor is caused to collide with a moving blade planted on a disk through a stationary blade to rotate the moving blade,
The combustion gas temperature is 1,500 ° C. or higher, the moving blade has three or more stages, the combustion gas temperature at the inlet of the first stage of the moving blade is 1,300 ° C. or higher, and the first stage of the moving blade is A total length of 200 mm or more, the first stage of the moving blade is a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, and protrusions provided on both sides of the shank portion. In a gas turbine moving blade having a fin made of and a dovetail connected to the shank portion, the blade portion is a single crystal, and is made of an integral casting which is a unidirectionally solidified columnar crystal except for the fin, The casting is by weight C0.0-0.1%, Cr5.5-9.0%,
Co 8.5-10.5%, W8-11%, Re 1.0-
3.5%, Mo 0.3-1.0%, Ta 3-4%, Al5
~ 6%, Ti 0.5-1.0%, Hf 0.5-1.0%, B
One or both of Zr and 0.005 to 0.025%, and the balance Ni and unavoidable impurities, and a structure in which a γ ′ phase is precipitated in a γ phase matrix. The difference in the crystal orientation of the γ phase of the columnar crystal is 8 degrees or less, and the power generation capacity is 50,000 KW or more.

The present invention is directed 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 the steam turbine. In the combined power generation plant system including a generator driven by, the gas turbine has three or more moving blades, the combustion blade first stage inlet temperature of the combustion gas is 1,300 ° C. or more, and the turbine outlet combustion is performed. The exhaust gas temperature is 560 ° C or higher, and the exhaust heat recovery boiler causes
Steam of 30 ° C. or higher is obtained, 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 higher, and the power generation capacity of the gas turbine is 50,000 KW or higher; Power generation capacity of steam turbine is 30,000 kW
The above is the total thermal efficiency of 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 power generation driven by the gas turbine and the steam turbine. In the combined power generation plant system including a gas turbine, the gas turbine has three or more stages of moving blades, and the combustion gas has a first-stage inlet temperature of 1,30.
At 0 ° C or higher, the combustion exhaust gas temperature at the turbine outlet is 560
C. or higher, steam is obtained at 530.degree. C. or higher by the exhaust heat recovery boiler, the steam turbine is a high-low pressure integrated type, and the steam temperature to the first stage of the steam turbine moving blade is 53.degree.
Above 0 ℃, the power generation capacity of the gas turbine is 50,000K
W or more and a steam turbine power generation capacity of 30,000 kW or more, total thermal efficiency of 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 has a blade portion,
A platform having a flat portion connected to the wing portion,
A shank portion connected to the platform, fins formed of protrusions provided on both sides of the shank portion, and a dovetail connected to the shank portion, the wing portion being a single crystal, and the fin Except for the unidirectionally solidified columnar crystals, the casting is composed of C0.0.
3 to 0.1%, Cr 5.5 to 9.0%, Co 8.5 to 10.
5%, W8-11%, Re1.0-3.5%, Mo0.3
~ 1.0%, Ta3-4%, Al5-6%, Ti0.5-
1.0%, Hf 0.5 to 1.0%, one or both of B and Zr 0.005 to 0.025%, and the balance Ni and inevitable impurities, and the γ'phase is contained in the γ phase matrix. Is precipitated, and the difference in crystal orientation between the γ phase of the single crystal and the γ phase of the columnar crystal is 8 degrees or less.

The rotor blade for a gas turbine according to the present invention has a C content of not more than 0.20% by weight, a B content of 0.002 to 0.02%, and
It contains one or two or more elements of 0.002% or more Zr and 0.5% or more Hf, and about 6% by volume without initial melting due to local melting by about 5% or more by volume.
It is cast from a Ni-base superalloy that can dissolve 0% or more of the precipitated γ'phase in the γ phase.

In particular, 0.03 to 0.1% of C, 0.002 to 0.20% of one or two kinds of B and Zr, and 0.1% of Hf.
5 to 1.1% prevents cracking, and does not cause initial melting of about 5% or more by volume ratio, and about 60% by volume ratio.
It is suitable for solid-dissolving the above precipitated γ ′ phase in the γ phase, and the C content and B + Zr content are A (C 0.20%, B + Zr
0%), F (C 0.04%, B + Zr 0.002%), C (C
0%, B + Zr0.01%), G (C0%, B + Zr0.0)
2%) and H (C 0.10%, B + Zr 0.20%).

In order to satisfy all of the intergranular cracks during casting, creep strength, corrosion resistance, oxidation resistance and heat fatigue resistance, Cr 6.0-9.0%, Al 5-6%,
W7-10%, Ti 0.5-1%, Mo 0.3-0.7
%, Ta 3.0 to 7.0%, Re 1 to 3.4%, Co 8 to 1
0.5%, C 0.03 to 0.1%, B 0.002 to 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.

Further, the moving blade of the present invention can be used in any of gas turbines having three or four stages of turbines, and is particularly suitable for the first stage turbine having the highest metal temperature. From the second stage onward, columnar crystals or equiaxed crystals are often used as a whole.

The gas turbine blade of the present invention is subjected to solution heat treatment within a range from the solid solution temperature of the precipitated γ'phase of the alloy after casting to the initial melting temperature thereof for 2 to 60 hours, and further 1000 to 1150.
It is preferable that the heat treatment is performed for 4 to 20 hours and 800 to 920 ° C. for 8 to 100 hours.

The gas turbine moving blade of the present invention includes the step of setting a mold for forming the moving blade on a water-cooled chill plate, and heating the mold to a predetermined temperature in a vacuum heating furnace. A step of melting the casting raw material in the same vacuum chamber as the mold and casting the molten metal into the heated mold, and pulling out the mold containing the molten metal from the heating furnace, and removing the dovetail from the blade. Direction unidirectionally solidified to form a single crystal in the wing portion, and then the platform and subsequent parts are pulled out at a speed higher than the drawing speed of the wing portion, and a part of the portion other than the wing portion is continuously formed from the wing portion. Then, the unidirectionally solidified single crystal and the rest are continuously cast from the single crystal into a unidirectionally solidified columnar crystal to form an integral casting.

The above-mentioned drawing speed of the template is preferably 15 cm / h or less in the production of single crystals, and 20 to 45 cm / h in the production of columnar crystals. Each of these is better if it can be manufactured, but from the viewpoint of yield, 10 cm /
About h is preferable. For columnar crystals, when it exceeds 50 cm / h, the difference in crystal orientation between columnar crystals exceeds 20 degrees and becomes equiaxed crystals, so 45 cm / h or less is preferable, and the crystal orientation difference between adjacent columnar crystals is good. In order to obtain a good columnar crystal having a crystallinity of 15 degrees or less, it is not preferable that the drawing speed is too slow, and preferably 30 to 45 cm / h.

[0050]

The blade of the gas turbine according to the present invention is made of a single crystal, and the crystal orientation difference in the single crystal is within 8 degrees. The unidirectionally solidified columnar crystal other than the wing portion is used to minimize the crystal orientation difference between the adjacent columnar crystals, and particularly the difference is set to be within 15 degrees, more preferably within 8 degrees. Even if the addition amount of the strengthening element is reduced, it is possible to obtain a columnar crystal blade in which grain boundary cracking does not occur during casting, and it is possible to maintain strength equivalent to that of 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 rises and the solution heat treatment temperature can be raised. It became possible to perform a heat treatment to form a solid solution in. Therefore, the columnar crystal blade having high creep strength can be obtained. On the contrary, when the difference in crystal orientation exceeds 10 degrees, the strength of the single crystal is rapidly reduced to about 10 to 20%.

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

However, the alloy used in the conventional columnar crystal blade has a grain boundary strengthening element such as B, C, Zr and Hf in order to prevent vertical cracks along the grain boundaries during casting. It is necessary to contain a large amount. The crystal grain boundary strengthening element improves the strength of the crystal grain boundary, and partly segregates between the dendrite arms to significantly lower the melting point of the segregated portion. In the case of a Ni-base superalloy, the segregation part forms a eutectic structure and produces a coarse eutectic γ'phase during solidification. The eutectic structure and the eutectic γ'phase formed at this time have the lowest melting points in the alloy, and when the temperature is raised to perform the solution heat treatment, the eutectic structure causes initial melting. Therefore, the alloy used in the conventional columnar crystal blade cannot raise the solution heat treatment temperature, and the solution treatment was insufficient, so that the strength of the material could not be improved as a result.

In the single crystal alloy containing no grain boundary strengthening element, the grain boundary strengthening element is treated as an impurity element, and the content is minimized, so that the melting point of the eutectic γ'phase increases. Enables complete solution heat treatment. Therefore, the single crystal alloy exhibits excellent high temperature characteristics of 40 to 50 ° C. higher than that of conventional materials, and is used as a blade of an aircraft jet engine. However, since the single crystal alloy contains as few crystal grain boundary strengthening elements as possible, the crystal grain boundaries are very weak when they are formed, and if there are different crystals with different crystal orientations, cracks easily occur at the crystal grain boundaries. enter. If there is a grain boundary, it is usually weak enough to cause cracking only by cooling after casting. Therefore, it is necessary for the rotor blade cast using a single crystal alloy to be a complete single crystal without foreign crystals.

An alloy containing the grain boundary strengthening element described above,
Of course, it is possible to make the whole moving blade a single crystal. This blade is inferior in creep strength at high temperatures to a single crystal blade cast with an alloy for single crystals that does not contain grain boundary strengthening elements, but between the adjacent crystal grains other than the outer surface of the blade where the temperature becomes high. Since the azimuth difference can be allowed up to 15 degrees, the crystal orientation measurement by X-ray, which was necessary in the conventional single crystal blade, can be greatly simplified. Further, there is no effective inspection means for crystal defects inside the blade, and normally the blade is cut and inspected by a sampling test. However, it is difficult to secure reliability in a sampling test for a turbine blade for a power generation gas turbine, which has a large blade, and it has been a major obstacle in applying the 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 rotor blade can be significantly improved, and the application to the gas turbine for power generation of the high-strength rotor blade becomes possible.

The role of each element contained in the Ni-based superalloy constituting the rotor blade for a gas turbine is shown below.

C forms a solid solution with the matrix or especially the grain boundaries and forms carbides to improve the high temperature tensile strength. However, if added in excess, the melting point of the grain boundaries is lowered and the high temperature strength and toughness are lowered. Is appropriately 0.20% or less, particularly preferably in the range of 0.05 to 0.2%, and more preferably 0.03 to 0.1%.

Co dissolves 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, resulting in the reduction of the high temperature strength. The addition amount is 10.5% or less,
Especially, 8 to 10.5% is appropriate. In particular, the lower limit is 4
% Or more, and more preferably 8.5% or more.

Cr improves the corrosion resistance, but when added in excess, it causes harmful σ-phase precipitation and coarsening of carbides, which lowers the high temperature strength. Addition amount is 2-16
%, Preferably 5 to 14%, and more preferably 5.5 to 9%.

Al and Ti precipitate the γ'phase which is the precipitation strengthening factor of the Ni-based alloy, that is, Ni ₃ (Al, Ti), and contribute to the improvement of the high temperature strength. The added amount is Al: 4.
The range of 0 to 7.0, Ti: 0.5 to 5.0% is appropriate, and Al is preferably 5 to 6% and Ti is 0.5 to 1.0%.

Nb, Ta, and Hf are solid-solved in the γ'phase, which is a strengthening factor, to improve the high temperature strength, but if added in excess, they segregate at the crystal grain boundaries to lower the strength. The addition amount is Nb 3% or less, Ta 12% or less, Hf 2%
The following is appropriate, especially Nb: 0.2-3.0%, Ta2
-7%, more preferably 3-4%, Hf 0.5-1.0% is preferable. In particular, Hf has the effect of preventing vertical cracking during solidification and improves the ductility at high temperatures, but if it exceeds 2%, it increases the eutectic structure during solidification, making effective solution treatment difficult.

Zr and B prevent vertical cracking during solidification, strengthen grain boundaries and improve high temperature strength. However, if added excessively, ductility and toughness are lowered, melting point of grain boundaries is lowered and high temperature strength is lowered. Let The addition amount is Zr: 0 to 0.035%, B:
0 to 0.035% is appropriate. In particular, from the relationship with the amount of C, A (C 0.20%, B + Zr 0%), B (C 0.05%,
B + Zr0%), C (C0%, B + Zr0.01%),
D (C0%, B + Zr 0.035%), E (C0.1%, B
+ Zr 0.025%), or 0.005 to 0.025% of 1 or 2 kinds of B and Zr is preferable. The range surrounded by A, F, C, G, H and A is more preferable.

W and Mo are solid-solved in the γ phase of the matrix and strengthened, and are particularly effective in improving the long-term strength. However, if added excessively, precipitation of a harmful phase such as σ phase is promoted and the strength is rather lowered. The amount added is W2
〜15%, Mo 6.0% or less is appropriate, especially W7.
0 to 11.0% and Mo 0.3 to 1.0% are preferable. W8 to 10% is more preferable.

Re improves the high temperature corrosion resistance, but when it is added in a certain amount or more, the effect is saturated and rather the ductility and toughness are deteriorated. The addition amount is Re 4% or less, particularly 1 to 4%, and more preferably 2.5 to 3.5%.

[0064]

【Example】

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

In FIG. 2, first, the set ceramic mold 8 containing alumina as a main component was fixed on the cold water copper chill plate 11, which was set in the mold heating furnace 4, and the ceramic mold 8 was set to Ni. Heat above the melting point of the base superalloy. Next, the melted Ni-base superalloy was cast into a ceramic mold 8, and then the water-cooled copper chill plate 11 was drawn out downward and solidified in one direction. In directional solidification, many crystals are first generated in the starter 10. Then, only one crystal is grown by the selector 9. Further, the crystal is enlarged in the enlarged portion, and the blade portion is solidified at a drawing speed of 10 cm / h to form a single crystal. After the wing portion solidified and became a single crystal, the extraction speed of the mold was set to 40 cm / h on the platform 15 to form a columnar crystal without growing the single crystal in the remaining portion. By this method, a columnar crystal blade having a single crystal structure in the blade portion and a columnar crystal structure in the portions other than the blade portion was obtained. In this case, since the columnar crystals were grown using the single crystal of the blade portion as a seed, the difference in orientation between the columnar crystals could be about 5 degrees. Further, 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 melting and solidifying are
Everything was done in vacuum. Table 1 shows the casting conditions for the single crystal moving blade, and Table 2 shows the chemical composition of the Ni-based superalloy used for casting. The columnar crystal blades cast by the above method are
Solution treatment is performed in vacuum at 60 to 1280 ° C. for 2 to 60 hours to change the precipitated γ ′ phase formed in the cooling process after solidification to the γ phase, and then at 1000 to 1150 ° C. for 4 to 20 hours and 80 hours.
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.

[0066]

[Table 1]

[0067]

[Table 2]

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

In the rotor blade obtained by the above method, the blade portion 1 was a single crystal, and the portion 2 below the platform 15 was a columnar crystal. The diameter of the air-cooled fins 14 is 10
The crystal grains were about mm. The shank 18 had columnar crystals on its surface, but inside the shank 18, small columnar crystals gradually formed from large columnar crystals in which the single crystal of the blade portion 1 had grown. The width of the columnar crystals on the surface was 5 to 10 mm, and the average width was 5 to 6 mm. It was confirmed by etching that the wings were all single crystals on the outer surface. Therefore, it can be seen that the difference in crystal orientation in the wings 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 blade in this embodiment is hollow so that the inside can be cooled. Air is used as the cooling medium, but steam cooling can also be applied. The refrigerant is supplied from the core 21 of the dovetail 16, and
It flows separately into the part discharged from the blade and the part discharged from the trailing edge 23 of the blade. The cores 20 and 22 are holes, and the two blades are integrated with each other by the projections formed corresponding to these holes, and the refrigerant outlet of the trailing edge 23 is slit-shaped. Has become. The core 22 is a hole, and the molten metal is filled in this portion to be integrally formed.

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

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

[Example 2] The reason why the solution heat treatment was performed on the rotor blade of the present invention was that the addition amounts of C, B, Zr, and Hf were controlled to raise the melting point of the eutectic structure. The method for raising the melting point of the eutectic structure will be described below.

Conventional alloys containing grain boundary strengthening elements are C,
Since it contained a large amount of B, Zr, Hf, etc., solution heat treatment could not be performed. 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: 3.0-7.0% Al: 4.0-6.0% Ti: 0.5-3.0% Hf: 0-2.0% For Ni-based alloys, the alloy C Quantity and (Zr +
The ratio of the amount B) was changed and the relationship between the melting point of the eutectic structure and the solid solution temperature of the precipitated γ'phase was investigated. As a result, it was found that when the content of C: 0.1% or less and B + Zr: 0.025% or less, the precipitated γ'phase can be solid-solved in the parent phase without causing the initial melting of the eutectic structure. However, C: 0.1% or less, B +
Zr: 0.025% When a unidirectionally solidified columnar blade of Ni-base superalloy having a composition range of not more than 0 was cast, grain boundary cracking occurred. FIG. 5 shows a sketch of grain boundary cracking of a columnar crystal blade manufactured by conventional unidirectional solidification. That is, when a columnar crystal blade is manufactured by the conventional unidirectional 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 grain boundaries and it can be used as a product. There wasn't.

Therefore, the crystal orientation difference of the columnar crystals and the C of the alloy are
When the relationship between the amount of (Zr + B) and the grain boundary cracking was investigated, when the crystal orientation difference of the columnar crystals was within 8 degrees,
When C: 0.03% or more and (Zr + B): 0.005% or more, a healthy columnar crystal blade without grain boundary cracks can be obtained, but when the crystallographic 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): 0.005% or more. When the C content was 0.03% or less, intergranular cracking occurred even when the crystal orientation difference of the columnar crystal was within 8 degrees. The above results are summarized in FIG. Incidentally, if the crystal orientation difference is within 6 degrees, A (C0.20%, B + Zr0%), B (C0.2.
05%, B + Zr0%), C (C0%, B + Zr0.01)
%), D (C0%, B + Zr 0.035%) and E (C
Within 0.1% and B + Zr 0.025%), 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 the occurrence of intergranular cracks in alloys of 5% by weight or less, it is necessary to make the difference in crystal orientation within 8 degrees. However, the conventional unidirectional solidification method uses the crystal orientation in the lateral direction of each columnar crystal. Were random and could not be controlled within 8 degrees. However, in the method of the present invention, the blade portion is made of a single crystal, and the single crystal is used as a seed to grow the columnar crystals, whereby the difference in the orientation of the columnar crystals can be made within 8 degrees. That is, as in the present invention, the blade portion is made of a single crystal and the portion other than the blade portion is made of a columnar crystal having an orientation difference of 8 degrees or less.
Even if Zr: 0.025% by weight or less, a sound columnar crystal blade without grain boundary cracks was obtained. B and Zr showed the same effect with either one or both.

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

[0078]

[Table 3]

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

Compared only in the service temperature, it is inferior to the single crystal. However, in the present invention, the casting time can be shortened and the mold heating temperature can be lowered by forming the columnar crystal structure other than the blade portion. As a result, the reaction with the mold is small, the percentage of defects is reduced, and the manufacturing yield of the moving blade is improved. Therefore, the present invention is a very practical columnar crystal moving blade and 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 the present alloy.

[Example 3] The reason why the solution heat treatment was performed on the rotor blade of the present invention was that the addition amounts of C, B, Zr and Hf were controlled to raise the melting point of the eutectic structure. The method for increasing the melting point of the eutectic structure will be described below.

Conventional alloys containing grain boundary strengthening elements are C,
Since it contained a large amount of B, Zr, Hf, etc., solution heat treatment could not be performed. 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% in a Ni-based alloy 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 investigated by changing the ratio between the C content and the (Zr + B) content of the alloy.
As a result, it was found that if the content of B + Zr: 0.020% or less, the precipitated γ'phase can be solid-solved in the matrix without causing the initial melting of the eutectic structure. However, Hf: 0.5-1.
When a unidirectionally solidified columnar blade of a 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 in. That is, Hf: 0.5 to 1.1% by weight, C: 0.0.
If columnar crystal blades with random crystallographic orientations are manufactured by the conventional unidirectional solidification method using alloys of 2% by weight or less and B + Zr: 0.020% by weight or less, cracks occur at the grain boundaries, and they can be used as products. There wasn't.

Then, the crystal orientation difference of the columnar crystals, the C content and (Zr + B) content of the alloy with Hf of 0.5%, and the relation between the grain boundary cracks were examined, and the crystal orientation difference of the columnar crystals was within 15 degrees. When, by weight, C: 0.03% or more, (Zr + B):
When it is 0.002% or more, a sound columnar crystal blade without grain boundary cracking can be obtained, but when the crystal orientation difference of the columnar crystals is 15 degrees or more, C: 0.03% or more, (Zr + B): 0 .002
Even if the content was more than 100%, intergranular cracking occurred. When the amount of Zr + B was less than 0.002%, intergranular cracking occurred even if the crystal orientation difference of the columnar crystals was within 15 degrees.

When the C content is 0.1% or more, 1040 ° C., 1
The creep rupture time of 4 kgf / mm ² was less than 400 h in some cases. In addition, the number of samples that could not be completely solution-treated due to the initial melting occurred was less than 400 hours. Further, when Hf is 0.5 to 1.1%, the crystal orientation difference of the columnar crystals is 15
The relationship between the amount of C and the amount of Zr + B within the range of A (0.2%,
0%), F (0.04%, 0.002%), C (0%, 0.0)
1%), G (0%, 0.02%), H (0.1%, 0.02)
%) Is obtained within the range enclosing each point. Hf: 0.5-1.1%, C: 0.2% by weight or less, B + Z
r: In order to prevent the occurrence of intergranular cracks in the alloy of 0.020% by weight or less, it is necessary to make the difference in crystal orientation within 15 degrees. The crystallographic orientation was random and could not be controlled within 15 degrees. However, in the method of the present invention, the blade portion is made of a single crystal, and the single crystal is used as a seed to grow the columnar crystal, whereby the difference in the orientation of the columnar crystal can be made within 15 degrees. That is, as in the present invention, Hf: 0.
5 to 1.1% by weight, C: 0.2% by weight or less, B + Z
Even if r: 0.020% by weight or less, a healthy columnar crystal blade without grain boundary cracks was obtained. B and Zr showed the same effect with either one or both.

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

[0086]

[Table 4]

Since the interfacial cracks do not occur in the rotor blade of the present invention,
The yield is 15% to 70%, which is about 5 times higher than that of the conventional columnar crystal blade, and 1040 ° C-14kgf / mm ²
Creep rupture time of wing from 193h to 456
It improved within 2 times with h. Further, although the shank portion of the rotor blade of the present invention is columnar crystal, the creep rupture time of the columnar crystal portion was twice or more as long as that of the conventional columnar crystal blade by the solution treatment.

Comparing the blade of the present invention and the single crystal blade, the blade of the present invention is inferior to the single crystal blade in the high temperature creep strength.
However, the rotor blade of the present invention has columnar crystals other than the blade portion,
The casting time could be shortened and the mold heating temperature could be lowered. As a result, the reaction with the mold and the deformation of the core are reduced, the percentage of defects is reduced, and the manufacturing yield is improved. Therefore, the present invention is a very practical high-strength rotor blade.
Furthermore, the tensile strength of the columnar crystal portion of the rotor blade of the present invention at around 700 ° C. was about 10% higher than that of the single crystal blade. It is considered that the columnar crystal subgrains contribute to the improvement of the tensile strength, but what is required for the shank portion is not the creep strength at high temperature but the tensile strength at a temperature near 700 ° C. Therefore, it can be said that the blade of the present invention in which the blade portion is a single crystal and the portion other than the blade portion is a columnar crystal is an excellent blade having two characteristics required for the blade.

[Embodiment 4] Table 5 is obtained by the method described in Embodiment 1.
A Ni-base superalloy having the composition (% by weight) shown in FIG. 1 was cast to manufacture a columnar crystal blade in which the blade portion was a single crystal and the portions other than the blade portion were columnar crystals. In the mold of this example, a straight mold was formed by bypassing the single crystal expanded portion with respect to the protrusion of the air-cooled fin portion in FIG. 2 so that the air-cooled fin portion became columnar crystals. No intergranular cracks were found in the rotor blade after casting. Further, the alloy was subjected to solution treatment in vacuum at 1270 to 1285 ° C. for 2 to 60 hours, and aging heat treatment at 1000 to 1150 ° C. for 4 to 20 hours and 800 to 950 ° C. for 8 to 100 hours. And 1000 ~ 1150 ℃ 4 ~ 20h
And a sample subjected only to an aging heat treatment at 800 to 950 ° C. for 8 to 100 hours, and a service temperature at a stress of 14.0 kgf / mm ² , 100,000 hours of creep, were compared.
C was rising. In this example, the crystal orientation difference between the columnar crystals was about 5 degrees.

[0090]

[Table 5]

[Embodiment 5] Table 6 is obtained by the method described in Embodiment 1.
By casting the composition shown in (1), a blade for a gas turbine was cast with a single crystal blade and almost completely columnar crystals other than the blade. In the casting mold of this embodiment, a straight casting mold bypassed from the single crystal expanded portion is added to the fin, which is the protrusion in FIG. 2, as a solidification promoting passage so that the fin becomes a columnar crystal with good crystallinity. did. As a result, no intergranular cracks were found in this rotor blade after casting, and the fins were sound columnar crystals with an orientation difference within 5 degrees.

After casting, 1250 to 1285 was added to this rotor blade.
108, a sample subjected to solution heat treatment at -2 to 60 hours and aging heat treatment at 1080 to 4 hours and 871 to 20 hours;
Samples were prepared only by aging heat treatment at 0 ° C-4h and 871 ° C-20h. As a result, the solution-annealed sample was improved in all-alloy alloys in Table 4 by about 15 ° C. in stress of 14 kgf / mm ² and 100,000 hour creep for all alloys in Table 4.

[0093]

[Table 6]

[Example 6] Using the alloys of the present invention shown in Table 7, a blade for a gas turbine was cast according to the method shown in Example 1. However, here, the casting speed was not changed even after passing through the platform 15, and the entire casting was performed at a casting speed of 10 cm / h. After casting, the same heat treatment as in Example 1 was performed, and several miniature samples having two crystal grains were cut out from this blade, and the difference in the crystal orientation of the two crystal grains at right angles to the solidification direction and the creep strength were measured. I investigated the relationship. The sample was taken in a direction parallel to the grain boundary. In addition, the alloy shown in Japanese Examined Patent Publication No. 3-75619, which is an alloy for single crystals, was evaluated as a comparative alloy. The comparative alloy was also cast under the same casting conditions as the alloy of the present invention, subjected to the heat treatment shown in JP-B-3-75619, and then subjected to the test. The results are shown in Table 8
Shown in. From these results, it is found that the alloy of the present invention has
The creep strength of kgf / mm ² is hardly affected by the difference in crystal orientation if the difference in crystal orientation is within 15 degrees. On the other hand, it can be seen that the comparative alloy, which is dedicated to single crystals, cannot tolerate a slight difference in crystal orientation.

[0095]

[Table 7]

[0096]

[Table 8]

[Embodiment 7] FIG. 7 is a sectional view of a rotating portion of a gas turbine having a gas turbine blade of the present invention according to Embodiment 2. As shown in FIG.

Reference numeral 30 is a turbine stub shaft, 33 is a turbine rotor blade, 43 is a turbine stacking bolt, and 38 is 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 bolt, 39 is a compressor stub shaft, 34 is a turbine disk, and 41 is a hole. In the gas turbine of the present invention, the compressor disk 36 has 17 stages and the turbine rotor blades 33 have 3 stages. The turbine rotor 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 composed of a heavy tuty type, a single shaft type, a horizontal split casing, a stacking type rotor, a compressor is a 17-stage axial flow type, and a turbine is a 3-stage impulse type. The two-stage air-cooled stationary blades and combustor have a verse-flow type, 16 cans, and a slot cool system.

The weight of the distant piece 39, the turbine disk 34, the spacer 38, and the stacking bolt 33 is C0.06 to 0.15%, Si 1% or less, and Mn 1.5.
% 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. Tensile strength is 90 to 120 kg / m as a characteristic in this embodiment.
m ² , 0.2%, yield strength 70-90 kg / mm ² , elongation 10-
25%, drawing rate 50-70%, V notch impact value 5-9.
5 kg-m / cm ² , 450 ° C 10 ⁵ h Creep rupture strength 4
It was 5 to 55 kg / mm ² .

The turbine rotor blade 33 has three stages, the one produced in Example 1 is used in the first stage, and the compression pressure of the compressor is 14.7.
, Temperature 400 ℃, first stage rotor blade inlet temperature 1,300 ℃,
The combustion gas temperature by the combustor was set to 1450 ° C. In addition, a blade length of 280 mm (blade portion 160 mm, platform portion and subsequent length 120 mm) made of a polycrystalline body having an equivalent alloy composition is used in the second stage of the turbine blade 33, and an equivalent alloy composition is used in the third stage. Also used, the wings of polycrystal are 350mm
A solid wing (wing 230 mm, other 120 mm) was manufactured. The manufacturing method was a precision casting method using the conventional lost wax method.

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

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

[Embodiment 8] FIG. 8 is a schematic diagram showing a single-shaft combined cycle power generation system using the gas turbine of Embodiment 7 and in combination with a steam turbine.

When generating electricity 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 the so-called combined power generation method.
In this combined power generation system, the following system configuration enables a high thermal efficiency of about 45% or more as compared to the thermal efficiency of 40% in the case of the conventional steam turbine alone. In such a combined cycle power plant, recently, the operation of the plant is facilitated and economically improved by the dual use of liquefied natural gas (LNG) and liquefied petroleum gas (LPG), and the co-firing of LNG and LPG. It is intended to improve the

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

Exhaust gas of 530 ° C. or higher discharged from the turbine is sent to the exhaust heat recovery boiler through the exhaust silencer.
Recovers thermal energy from gas turbine exhaust at 530 ° C
The above high-pressure steam is generated. This boiler is provided with a denitration device by dry ammonia catalytic reduction. Exhaust gas is exhausted to the outside from a stack of several tripods with a length of several hundred meters. The generated high-pressure and low-pressure steam is sent to a steam turbine composed of a high-low pressure integrated rotor.

Further, the steam exiting the steam turbine flows into the condenser, is vacuum deaerated and becomes condensate, and the condensate is boosted by the condensate pump and supplied to the boiler. Then, the gas turbine and the steam turbine respectively drive a generator from both shaft ends thereof to generate electric power. For cooling the gas turbine blade used for 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, but steam has a significantly larger specific heat than air and has a large cooling effect because of its light weight.

With this combined power generation system, a gas turbine of 50,000 kW and a steam turbine of 30,000 kW can generate a total of 80,000 kW, and the steam turbine of this embodiment is compact, so that a large steam turbine can be obtained. Compared with the above, it is possible to economically manufacture with the same power generation capacity, and there is a great merit that it can be economically operated with respect to fluctuations in power generation.

The steam turbine according to the present invention is a high-low pressure integrated steam turbine. By increasing the steam pressure at the main steam inlet of this high-low pressure integrated steam turbine to 100 atg and a temperature of 538 ° C., the single-unit output of the turbine is increased. Can be achieved. The increase in the single machine output increases the blade length of the final stage rotor blade by 3
It is necessary to increase the steam flow rate to 0 inches or more. The steam turbine according to the present invention has 13 or more blades planted in the high and low pressure integrated rotor shaft, and the steam flows through the steam control valve from the steam inlet at the high temperature and high pressure of 538 ° C. and 88 atg as described above. To do. The steam flows in one direction from the inlet, the steam temperature becomes 33 ° C. and 722 mmHg, and is discharged from the outlet from the blade at the final stage. The high / low pressure one-piece rotor shaft according to the present invention is Ni-Cr-M.
Forged steel of oV low alloy steel is used. The blade of the rotor shaft has a disk-shaped implant portion and is manufactured by integrally cutting the rotor shaft. The shorter the length of the blade, the longer the length of the disk portion, so that vibration is reduced.

The high / low pressure integral type rotor shaft according to the present embodiment has C 0.18 to 0.30%, Si 0.1% or less, Mo 0.1.
3% or less, Ni 1.0 to 2.0%, Cr 1.0 to 1.7%,
It consists of Mo 1.0-2.0%, V 0.20-0.3%, 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 constructed in such a way that six sets of one power generation system each consisting of a gas turbine, an exhaust heat recovery boiler, a steam turbine, and a generator are arranged in a single-shaft type, and one gas turbine is used. On the other hand, it is possible to obtain a steam from the exhaust gas after combining one generator and six sets of these generators, and it is possible to make a multi-shaft type having one steam turbine and one generator.

The combined power generation consists of a combination of a gas turbine, which can be easily started and stopped in a short time, and a small, simple steam turbine. Therefore, the output can be easily adjusted and the intermediate load that responds quickly to changes in demand. Best for firepower.

The reliability of the gas turbine has dramatically increased due to the recent technological development. Further, since the combined cycle power plant constitutes a system with a combination of small capacity machines, a failure should occur. Even so, the effect can be limited to local areas, and it is a highly reliable power source.

[0115]

According to the present invention, since a gas turbine moving blade having high creep strength can be obtained, a gas turbine having a long life of the moving blade and an increase in combustion gas temperature and a combined power generation plant system using the gas turbine can be obtained. There is a remarkable effect of improving the thermal efficiency of.

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

[Brief description of drawings]

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

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

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

FIG. 4 is a comparative diagram showing high temperature strengths 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 intergranular cracks observed in a columnar crystal blade manufactured by a unidirectional solidification method.

FIG. 6 is a characteristic diagram showing the relationship between the amount of C and the amount of (B + Zr) that can dissolve the precipitated γ ′ phase in the γ phase without causing the initial melting of the alloy, and the relationship of intergranular 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 a combined cycle power plant according to the present embodiment.

[Explanation of Codes] 1 ... Wing portion, 2 ... Root portion, 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 shell, 14 ... Air-cooled fins, 15 ... Platform, 16 ... Dovetail, 18
... Shank, 33 ... Moving blade, 34 ... Turbine disk, 3
6 ... Compressor disk, 38 ... Spacer, 40 ... Stator blade.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tosatsu Saito 7-1, 1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Mitsuru Kobayashi 7-chome, Omika-cho, Hitachi-shi, Ibaraki No. 1-1 Hitachi Ltd., Hitachi Research Laboratory (72) Inventor Katsumi Iijima 7-1, 1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Katsuo Wada Hitachi, Ibaraki Prefecture 3-1-1, Saiwaicho, Ichi, Ltd. Hitachi, Ltd., Hitachi Plant (72) Inventor Kimio Kano 3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture Tohoku Electric Power Co., Inc. (72) Inventor Matsuzaki Hiroyuki 3-7-1, Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture Tohoku Electric Power Co., Inc.

Claims (16)

[Claims] 1. A wing section, a platform having a flat section connected to the wing section, a shank section connected to the platform, fins formed by projections provided on both sides of the shank section, and the shank. In a rotor for a gas turbine having a dovetail connected to a portion, a portion of the blade portion and the platform and the shank portion is a single crystal, and a portion excluding the portion made of the single crystal is unidirectionally solidified. A blade for a gas turbine, which is characterized by being formed of an integral casting that is a columnar crystal. 2. A wing section, a platform having a flat section connected to the wing section, a shank section connected to the platform, fins formed by projections provided on both sides of the shank section, and the shank. In a turbine blade for a gas turbine having a dovetail connected to a portion, the blade portion and a part of the platform and the shank portion are single crystals, and all except the portion made of the single crystal are unidirectionally solidified. A rotor blade for a gas turbine, which is characterized by being formed of an integral casting that is a columnar crystal. 3. The moving blade for a gas turbine according to claim 1 or 2, wherein a refrigerant passage integrally connected to the inside is provided from the dovetail portion to the tip of the blade portion. 4. A gas turbine moving blade having a blade portion and a root portion connected to the blade portion, which is made of an integral casting,
The wing portion and a part of the platform and the shank portion are single crystals, and unidirectionally solidified columnar crystals other than the portion made of the single crystal are solidified from the tip of the wing portion toward the root portion. A blade for a gas turbine, which is characterized in that 5. A moving blade for a gas turbine, which has a blade portion and a root portion connected to the blade portion and is made of an integral casting,
A rotor blade for a gas turbine, wherein a difference in crystal orientation between the blade portion and the root portion is 2 to 8 degrees. 6. A wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, fins formed by projections provided on both sides of the shank portion, and the shank. A gas turbine moving blade having a dovetail connected to a portion, wherein the moving blade is made of an integral casting, and the difference in crystal orientation between the portions is 2 to 8 degrees. 7. The casting according to claim 1, wherein the weight of the casting is C0 to 0.20%, Cr to 2 to 16%, and Al.
4-7%, W2-15%, Ti0.5-5%, Nb0-
3%, Mo0-6%, Ta0-12%, Co0-10.
5%, Hf 0 to 2%, Re 0 to 4%, B 0 to 0.035
%, Zr0 to 0.035%, and the balance being 58% or more of Ni. 8. By weight, C0 to 0.20%, Cr2 to 16
%, Al 4-7%, W 2-15%, Ti 0.5-5%,
Nb0-3%, Mo0-6%, Ta0-12%, Co0
-0.5%, Hf0-2%, Re0-4, B0-0.
035%, Zr0 to 0.035%, and the balance consisting of 58% or more of Ni, and the C amount and one or both of B and Zr amounts are A (C0.20%, B + Zr0%), B (C0.05).
%, B + Zr0%), C (C0%, B + Zr0.01)
%), D (C0%, B + Zr 0.035%) and E (C
0.1%, B + Zr 0.025%), and the difference in crystal orientation is 2 to 6 degrees. 9. A wing portion having a single crystal and a dovetail having a columnar crystal, C0.03 to 0.1% by weight, and Cr 5.5 to 9.0.
%, Co 8.5-10.5%, W 8-11%, Re 1.0
~ 3.5%, Mo 0.3-1.0%, Ta 3-4%, Al
5-6%, Ti 0.5-1.5%, Hf 0.5-1.0%,
One or both of B and Zr are 0.005-0.025%,
The balance is Ni and unavoidable impurities, and the difference in crystal orientation is 8 degrees or less in the single crystal portion and 15 degrees or less in the columnar crystal portion. 10. A wing section, a platform having a flat section connected to the wing section, a shank section connected to the platform, fins formed by projections provided on both sides of the shank section, and the shank. In a turbine blade for a gas turbine having a dovetail continuous with a part, the blade part is a single crystal, and the dovetail is an integral casting made of columnar crystals that are unidirectionally solidified, from the dovetail part to the tip of the blade part. A coolant passage integrally connected to the inside is provided, and the casting is C0 to 0.20% by weight and Cr2 to 16
%, Al 4-7%, W 2-15%, Ti 0.5-5%,
Nb0-3%, Mo0-6%, Ta0-12%, Co0
-0.5%, Hf0-2%, Re0-4, B0-0.
035%, Zr0-0.035%, and the balance 58%
It consists of the above Ni, and the C amount and one or both of the B and Zr amounts are A (C0.20%, B + Zr0%), B (C0.2.
05%, B + Zr0%), C (C0%, B + Zr0.01)
%), D (C0%, B + Zr 0.035%) and E (C
0.1%, B + Zr 0.025%), and has a structure in which the γ ′ phase is precipitated in the γ phase matrix.
A rotor blade for a gas turbine, wherein the crystal orientation difference between the phases is 2 to 6 degrees. 11. A gas turbine for rotating fuel blades by causing fuel gas compressed by a compressor to collide with rotor blades implanted in a disk through stationary blades, wherein the rotor blades have three or more stages. The first stage of the wing has a wing portion, a platform having a flat portion connected to the wing portion, a shank connected to the platform, fins formed by protrusions provided on both sides of the shank, and connected to the shank. A gas turbine, wherein the blade portion is a single crystal, and the dovetail is an integral casting made of unidirectionally solidified columnar crystals. 12. A gas turbine in which combustion gas compressed by a compressor is caused to collide with a moving blade planted in a disk through a stationary blade to rotate the moving blade, and the combustion gas temperature is 1,500 ° C. or higher. , The moving blade has three or more stages, and the combustion gas temperature at the inlet of the first stage of the moving blade is 1,
Above 300 ° C, the first stage of the rotor blade has a total length of 200m
A gas turbine characterized in that the blade portion is a single crystal having a diameter of m or more, the root portion is made of a unidirectionally solidified columnar crystal, and is integrally cast, and has a power generation capacity of 50,000 KW or more. 13. A gas turbine in which combustion gas compressed by a compressor is caused to collide with a moving blade planted in a disk through a stationary blade to rotate the moving blade, and the combustion gas temperature is 1,500 ° C. or higher. , The moving blade has three or more stages, and the combustion gas temperature at the inlet of the first stage of the moving blade is 1,
Above 300 ° C, the first stage of the rotor blade has a total length of 200m
At m or more, the first stage of the moving blade includes a wing portion, a platform having a flat portion connected to the wing portion, a shank portion connected to the platform, and protrusions provided on both sides of the shank portion. In a gas turbine moving blade having a fin and a dovetail connected to the shank part, the vane part is a single crystal, and the dovetail is an integral casting made of columnar crystals that are unidirectionally solidified, and the casting is By weight, C0.03-0.1%, Cr5.5-
9.0%, Co8.5 to 10.5%, W8 to 11%, R
e 1.0-3.5%, Mo 0.3-1.0%, Ta 3-4
%, Al 5-6%, Ti 0.5-1.0%, Hf 0.5-
1.0%, one or both of B and Zr 0.005 to 0.005.
025% and the balance Ni and unavoidable impurities,
It has a structure in which the γ ′ phase is precipitated in the phase matrix, the difference in crystal orientation between the γ phase of the single crystal and the γ phase of the columnar crystal is 8 degrees or less, and the power generation capacity is 50,000 kW or more. Characteristic gas turbine. 14. A gas turbine driven by combustion gas flowing at a high speed, an exhaust heat recovery boiler for obtaining steam by combustion exhaust gas of the gas turbine, a steam turbine driven by the steam, and driven by the gas turbine and the steam turbine. In the combined power generation plant system including the generator, the gas turbine has three or more moving blades, and the combustion blade first stage inlet temperature of the combustion gas is 1,3.
Above 00 ° C, the combustion exhaust gas temperature at the turbine outlet is 56
0 ° C or higher, 530 ° C by the exhaust heat recovery boiler
The above steam is obtained, the steam turbine is of a high-low pressure integrated type, and the steam temperature to the first stage of the steam turbine rotor blade is 5
The temperature is 30 ° C. or higher, the power generation capacity of the gas turbine is 50,000 KW or higher, the power generation capacity of the steam turbine is 30,000 KW or higher, the total thermal efficiency is 45% or higher, and the first stage of the moving blade has a total length of 200 mm or more. The first stage of the moving blade is a fin including a blade portion, a platform having a flat portion connected to the blade portion, a shank portion connected to the platform, and protrusions provided on both sides of the shank portion. And a dovetail continuous with the shank portion, the wing portion is a single crystal, and the dovetail is an integrally cast product that is a unidirectionally solidified columnar crystal, and the cast product is C0.03 in weight. ~ 0.1%, Cr 5.5-
9.0%, Co8.5 to 10.5%, W8 to 11%, R
e 1.0-3.5%, Mo 0.3-1.0%, Ta 3-4
%, Al 5-6%, Ti 0.5-1.0%, Hf 0.5-
1.0%, one or both of B and Zr 0.005 to 0.005.
025% and the balance Ni and unavoidable impurities,
A composite power plant system having a structure in which a γ'phase is precipitated in a phase matrix, and a difference in crystal orientation between the γ phase of the single crystal and the γ phase of a columnar crystal is 8 degrees or less. 15. A method for manufacturing a gas turbine moving blade having a blade portion and a root portion connected to the blade portion, the casting blade forming mold being a water-cooled chill plate. , A step of setting the mold in a heating furnace and heating the mold to a predetermined temperature, a step of melting a casting raw material in vacuum and then pouring a molten metal into the heated mold, and a mold having the molten metal. Is relatively extracted from the heating furnace and sequentially solidified from the blade tip to the root side end to make the blade a single crystal, and then the blade is extracted at a speed faster than the mold drawing speed. And a step of unidirectionally solidifying the root portion to form columnar crystals. 16. A unidirectionally solidified casting of a single crystal and a columnar crystal, wherein a difference in crystal orientation between the single crystal and the columnar crystal in a direction perpendicular to the solidification direction is 8 degrees or less. Characterized articles.