JP2000204447A - High strength martensitic steel, turbine disk for gas turbine using the same, gas turbine for power generation and combined power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbine excellent in high temp. strength using steel in this invention and suitable for high efficiency power generation by specifying the contents of C, Si, Mn, Ni, Cr, Mo, V, Nb, Co and N in the steel compsn. and specifying creep rupture strength therein. SOLUTION: The compsn. of martensitic steel for a turbine disk is composed of, by weight, 0.05 to 0.20% C, <=0.5% Si, <=0.6% Mn, 0.5 to 4.0% Ni, 8 to 13% Cr, <=4% Mo, 0.1 to 0.4% V, 0.06 to 0.25% Nb, and the balance substantial Fe. Moreover, the creep rupture strength at 450 deg.C for hundred thousand times is >=50 kg/mm2, and, to this creep rupture strength, the creep rupture strength at 500 deg.C for hundred thousand times is controlled to >=70% thereof. When this martensitic steel is adopted to a turbine disk for a gas turbine of about 1400 to 1650 deg.C nozzle inlet temp., a high efficiency turbine of >=37% by an LHV display can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel gas turbine for high-efficiency power generation and a combined power generation system having a turbine inlet temperature of 1200 ° C. or higher, and more particularly to a turbine disk used in the gas turbine and a novel martensitic steel used in the turbine disk.

[0002]

2. Description of the Related Art In recent years, it has been desired to improve the thermal efficiency of a gas turbine from the viewpoint of energy saving. Raising the gas temperature and pressure is the most effective means for improving the thermal efficiency, but increasing the gas temperature from 1200 ° C. to 1650 ° C.
By increasing the compression ratio to around 15, the conventional 1200
An improvement in efficiency of about 3% or more can be expected as compared with a gas turbine at a temperature of not more than ℃.

However, with these high-temperature / high-pressure ratios, materials having higher strength are required. In addition, creep rupture strength that greatly affects high-temperature characteristics is required. Austenitic steel and N as structural materials with high creep rupture strength
Although i-base alloys, Co-base alloys, martensitic steels and the like are generally known, Ni-base alloys and Co-base alloys are not desirable in terms of hot workability, machinability and vibration damping characteristics. In addition, austenitic steel does not have high strength at high temperatures around 400 to 450 ° C., which is undesirable from the viewpoint of the entire gas turbine system. On the other hand, martensitic steel has good matching with other components, and has sufficient high-temperature strength. As martensitic steels, JP-A-63-60262,
Japanese Patent Application Laid-Open No. 5-263657 is known. However, these materials do not necessarily have high creep rupture strength at 400 to 500 ° C., and cannot be used as they are in a gas turbine for a higher temperature as a turbine disk or the like.

[0004]

SUMMARY OF THE INVENTION The high temperature of a gas turbine
The gas temperature cannot be increased simply by using a material having high strength with respect to the high pressure ratio. In order to increase the temperature of a gas turbine, heat-resistant steel having both high strength at high temperatures and high toughness must be used. However, generally, increasing the strength decreases the toughness.

[0005] Therefore, it is difficult for martensitic steel to sufficiently satisfy both properties.

An object of the present invention is to provide a martensitic steel excellent in high-temperature strength, a gas turbine disk using the same, a gas turbine for power generation, and a combined power generation system combining the same with a steam turbine.

[0007]

SUMMARY OF THE INVENTION The present invention provides a C
0.05 to 0.20%, Si 0.5% or less, Mn 0.6% or less, Ni 0.5 to 4.0%, Cr 8 to 13%, Mo 4% or less, V 0.1 to 0.4%, Nb 0. 06-0.25% and C
consisting of martensitic steel containing 1-5% o
High strength martensitic steel characterized in that the creep rupture strength at 100 ° C. for 100,000 hours is 50 kg / mm ² or more and the creep rupture strength at 500 ° C. for 100,000 hours is 70% or more of the creep rupture strength. It is in.

[0008] The present invention relates to a method for preparing C05 to 0.20 by weight.
%, Si 0.5% or less, Mn 0.6% or less, Ni 0.5 to 0.5%
4.0%, Cr 8-13%, Mo 4% or less, V0.1-
A high-strength martensitic steel comprising 0.4%, Nb 0.06 to 0.25%, Co 1 to 5%, oxygen 0.020% or less and hydrogen 0.003% or less.

The present invention relates to a method for preparing C 0.05 to 0.20 by weight.
%, Si 0.5% or less, Mn 0.6% or less, Ni 0.5 to 0.5%
4.0%, Cr 8-13%, Mo 4% or less, W1-5%,
V 0.1-0.4%, Nb 0.06-0.25% and Co1
High-strength martensitic steel, wherein the ratio (W / Mo) is 2-5.

[0010] The present invention relates to a method for preparing C05 to 0.20 by weight.
%, Si 0.5% or less, Mn 0.6% or less, Ni 0.5 to 0.5%
4.0%, Cr 8 to 13%, Mo 0.2 to less than 1.0%,
V 0.1-0.4%, Nb 0.06-0.25% and Co1
High-strength martensitic steel, characterized by having

[0011] The present invention further relates to the invention as defined in the claims.
-5% and B0.0005-0.01%.

The present invention resides in a turbine disk for a gas turbine, comprising the martensitic steel according to any one of the claims.

[0013] The present invention provides a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk,
In a gas turbine for power generation having a turbine nozzle provided corresponding to the turbine blade, the turbine disk is a gas turbine for power generation constituted by the turbine disk described in the claims.

The present invention provides a gas turbine driven by combustion gas flowing at a high speed, an exhaust heat recovery boiler that obtains steam by the energy of exhaust gas from the gas turbine, and a high / low pressure integrated steam turbine and a generator using a gas turbine. In the combined power generation system to be driven, the gas turbine includes a power generation gas turbine according to the present invention.

[0015] The present invention provides a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk,
In a gas turbine for power generation having three or more stages of turbine nozzles provided corresponding to the turbine blades, the turbine disk is moved from the body of the turbine disk to the turbine blade by air compressed by the compressor. Preferably, the turbine disk has an air cooling system for cooling over the turbine disk, and the turbine disk is made of martensitic steel.

The present invention provides a compressor, a combustor, three or more turbine blades fixed to a turbine disk,
In a gas turbine for power generation having three or more stages of turbine nozzles provided corresponding to the turbine blades, a steam cooling system for cooling the turbine disk with steam from the trunk to the turbine blades, The turbine disk is preferably made of martensitic steel.

The present invention provides a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk,
In a gas turbine for power generation having three or more stages of turbine nozzles provided corresponding to the turbine blades, the gas inlet temperature to the first stage turbine nozzle is from 1200 to 1200
1650 ° C., an air cooling system for cooling the first stage turbine nozzle and the turbine disk with air cooled by the cooler from the body to the first stage and the second stage turbine blades, and the air compressed by the compressor. Preferably, the turbine disk has an air cooling system for cooling the second and third stage turbine nozzles with air, and the turbine disk is made of martensitic steel.

The present invention provides a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk,
In a gas turbine for power generation having three or more stages of turbine nozzles provided corresponding to the turbine blades, the gas inlet temperature to the first stage turbine nozzle is from 1200 to 1200
1650 ° C., having a steam cooling system for cooling the first stage turbine nozzle and the turbine disk from the body of the first stage and the second stage turbine blades with steam. It is preferable that the turbine disk has an air cooling system for cooling by cooling.

In the gas turbine for power generation described above, the gas inlet temperature of the turbine nozzle of the combustion gas is 1200 ° C. to 1295.
The above-mentioned martensitic steel for a turbine disk is 0.05 to 0.20% C, 0.15% or less Si, 1.0% or less Mn, 0.50 to 3.0% Ni, Cr
8.0-13.0%, Mo 1.0-4.0%, V0.10
It preferably has 0.40% and N 0.025 to 0.125%.

The aforementioned gas inlet temperature is 1300 ° C. to 13 ° C.
At 95 ° C., the above-mentioned martensitic steel for turbine disks is C 0.05 to 0.20% by weight and Si 0.15% by weight.
% Or less, Mn 1.0% or less, Ni 0.50 to 3.0%, C
r 8.0 to 13.0%, Mo 1.0 to 4.0%, V0.10
0.40%, Nb 0.01-0.20% and N 0.025-
Preferably it has 0.125%.

The aforementioned gas inlet temperature is 1400 ° C. to 16 ° C.
It is preferable that the martensitic steel for a turbine disk described in the claims be used at 50 ° C. The turbine disk temperature with respect to this gas temperature rises to about 500 ° C. in the first stage, and can withstand it sufficiently. The temperature drops slightly in the second and third stages, but is 450 ° C. or higher.

The martensitic steel according to the present invention is used for at least one of a distant piece, a turbine spacer, a final stage of a compressor disk, a turbine stacking bolt, and a compressor stacking bolt for each corresponding temperature. it can.

Further, it is preferable that the (Mn / Ni) ratio of any of the above-mentioned martensitic steels be 0.11 or less. The content of Mn + Ni + Co is preferably 2.0 to 7.0%, and the content of Mo + 0.5W is preferably 1.0 to 2.0%. Cr + 6Si + 4Mo + 1.5W + 11V + 5Nb
The Cr equivalent obtained from -40C-30N-2Mn-4Ni-2Co is preferably 8 or less.

The present invention provides a gas turbine driven by a combustion gas flowing at a high speed, an exhaust heat recovery boiler for obtaining steam by the energy of exhaust gas from the gas turbine, and a high / low pressure integrated steam turbine and a generator using a gas turbine. In the driven combined power generation system, it is preferable that the gas turbine is constituted by the gas turbine for power generation described above.

According to the present invention, there is provided a combined power generation system in which a generator is driven by a high / low pressure integrated steam turbine and a gas turbine, wherein a steam temperature at a first stage nozzle inlet of the steam turbine and a gas temperature at a first stage nozzle inlet of the gas turbine are provided. Point A (515 ° C, 1200 ° C), point B (5
38 ° C, 1200 ° C), Point C (593 ° C, 1650 ° C)
And point D (557 ° C., 1650 ° C.), wherein the gas turbine includes a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk, and a turbine blade. Three or more stages of turbine nozzles corresponding to the first stage turbine nozzle and the first stage and the second stage
An air cooling system that cools the stage turbine blades with air that has been compressed by the compressor and air cooled by the cooler, or a steam cooling system that cools with steam.
It is preferable to have an air cooling system that cools the second and third stage turbine nozzles with air.

According to the present invention, there is provided a combined power generation system in which a generator is driven by a high-low pressure integrated steam turbine and a gas turbine, wherein the steam temperature at the inlet of the first stage nozzle of the steam turbine is 500 ° C. or more, and The gas turbine has a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk, and three or more stages provided corresponding to the turbine blades. And a turbine nozzle, wherein the turbine disk is preferably made of the martensitic steel described in the claims.

The last stage blade of the high / low pressure integrated steam turbine has a blade length (inch) × rotation speed (rpm).
It is preferable to be composed of 120,000 or more and martensite steel. At least one of the first-stage blade and the first-stage nozzle of the gas turbine in the present invention is made of a single crystal or a columnar crystal Ni-based alloy with the above-mentioned gas inlet temperature of 1400 to 1650 ° C and the above-mentioned temperature of 1300 to 1395 ° C. Is preferred. The gas turbine is operated at the temperature 1 described above.
For 400 to 1650 ° C., it is preferable that the second and third stage turbine blades be made of a directionally solidified columnar crystal Ni-based alloy. The gas turbine has a temperature of 1400 to 1400.
For 1650 ° C., the first-stage turbine blade and the first-stage turbine nozzle are made of a single-crystal Ni-based alloy, and at least one of the second-stage and third-stage turbine blades is made of a unidirectionally solidified columnar-crystal Ni-based alloy. The three-stage turbine nozzle is preferably made of an equiaxed Ni-based alloy. (A) Gas Turbine In the present invention, martensitic steel is used for at least the turbine disk, and it can be used for at least one of the other distant pieces, turbine spacers, last-stage compressor disk, and turbine stacking. The reason for limiting the component range of the martensitic steel will be described.

C is used in order to obtain high tensile strength and proof stress.
It is preferably at least 05%. However, if the amount of C is too large, the metal structure becomes unstable when exposed to a high temperature for a long time, and the 10 ⁵ h creep rupture strength is reduced.
0.20% or less is preferable. Most preferably, it is 0.07 to 0.15%. More preferably, it is 0.10 to 0.14%.

Si is added as a deoxidizing agent and Mn is added as a deoxidizing / desulfurizing agent when dissolving steel, and even a small amount is effective. Si is a δ-ferrite-forming element, and a large amount thereof causes the formation of δ-ferrite, which deteriorates fatigue and toughness. In addition, according to the carbon vacuum deoxidation method, the electroslag melting method, or the like, there is no need to add Si, and the addition of Si is preferable. In particular, the content is preferably 0.2% or less from the viewpoint of embrittlement, and 0.05% or less when Si is not added.

Since Mn promotes embrittlement by heating,
0.6% or less is preferable. In particular, since Mn is effective as a desulfurizing agent, it is used in an amount of 0.01 to 0.4% so as not to cause heat embrittlement.
Is preferred. Further, 0.02 to 0.25% is most preferable.
From the viewpoint of preventing embrittlement, the amount of Si + Mn is preferably set to 0.3% or less.

Cr enhances corrosion resistance and high-temperature strength.
% Or more causes formation of a δ ferrite structure.
If it is less than 8%, the corrosion resistance and high temperature strength are insufficient,
Cr is preferably 8 to 13%. Especially from the point of strength 10.
It is preferably from 5 to 12.5%. Mo has the effect of increasing the creep rupture strength by the action of solid solution strengthening and precipitation strengthening and at the same time has the effect of preventing embrittlement. 4. To obtain high creep rupture strength
0% or less is preferable. If it exceeds 4.0%, δ ferrite may be formed. The amount of Mo is determined by the relationship with the amount of W. When W is not contained, the amount is preferably 1.5 to 2.5%. Further, when the content of Mo is more than 2.1%, as the content of Mo increases, the creep rupture strength increases as the content of Mo increases. In particular, the effect is more significant when the content of Mo is 2.0% or more. Further, when W described later is included, the content is set to 0.2 to less than 1.0%, preferably 0.3 to 0.7%.

Since V and Nb precipitate carbides to increase high-temperature strength and also have an effect of improving toughness, V and Nb are preferably at least 0.1% and Nb at 0.01%, and are preferably at least 0.4% and Nb.
If it is 0.2% or more, δ ferrite is formed, and the creep rupture strength tends to decrease. In particular, V 0.15 to 0.25%, Nb 0.04 to 0.10
% Is preferred. Ta can be added in exactly the same manner as in place of Nb, and can be added in combination.

Ni has an effect of increasing the toughness after heating at a high temperature for a long time and has an effect of preventing the formation of δ ferrite. Therefore, Ni is preferably not less than 0.5%, and if it is not less than 3%, the long-term creep rupture strength is undesirably lowered. Especially 2.0 to 3.0% is preferable. More preferably, the amount is more than 2.5%.

Although Ni is effective in preventing heat embrittlement, Mn
Harms the other way around. Therefore, there is a close correlation between these elements, and by setting the ratio of Mn / Ni to 0.11 or less, the embrittlement due to heating is extremely remarkably prevented.
0.10 or less is preferable, and 0.04 to 0.10 is preferable.

N is effective in improving the creep rupture strength and preventing the formation of δ ferrite, so N is preferably at least 0.025%, and if it exceeds 0.125%, the toughness is reduced.
In particular, excellent characteristics can be obtained in the range of 0.03 to 0.08%.

Since Co enhances the strength at higher temperatures, it is preferable to increase the content in accordance with the higher temperature.
５5.0%, preferably 2-4%.

Since W contributes to strengthening like Mo, 1
~ 5%, and (W / M
o) The ratio is 2-5.

In particular, the amount of Mo + 0.5W is preferably set to 1 to 2%.

B has a remarkable effect on strengthening, with 0.000
5 to 0.01% is preferred. Al 0.3% or less, Ti 0.5
%, Zr 0.1% or less, Hf 0.1% or less, Ca 0.1% or less.
The high-temperature strength can be improved by containing 0.01% or less, Mg 0.01% or less, Y 0.01% or less, rare earth 0.01% or less, and Cu 0.5% or less.

In the heat treatment of the steel according to the present invention, first, the steel is uniformly heated to a temperature sufficient to transform completely to austenite, at least 900 ° C. and at most 1150 ° C., thereby obtaining a martensitic structure. Rapid cooling at a rate of 100 ° C./h or more
It is preferable to heat and maintain at a temperature of ６００600 ° C. (first tempering), and then heat and hold at a temperature of 550 to 650 ° C. to perform second tempering. During quenching, it is preferable to stop the temperature just above the Ms point in order to prevent quenching cracking. The specific temperature is preferably kept at 150 ° C. or higher. The quenching is preferably performed by quenching in oil or water spray quenching. First
The next tempering heats from that temperature.

At least the last stage or the whole of the compressor disk can be made of the above-mentioned heat-resistant steel, but since the gas temperature is low from the first stage to the central part,
Other low alloy steels can be used, and the above-mentioned heat-resistant steel can be used from the center to the final stage. The upstream side from the first stage on the gas upstream side to the center is C0.15-0.1.
30%, Si 0.5% or less, Mn 0.6% or less, Cr1
2%, Ni 2.0 to 4.0%, Mo 0.5 to 1%, V 0.0
Ni-Cr-Mo-V having a tensile strength of 80 kg / mm ² or more at room temperature and a V-notch Charpy impact value of 20 kg-m / cm ² or more at room temperature consisting of 5 to 0.2% and the balance substantially Fe.
Steel is used, and C is 0.2 to 0.4%, Si is 0.1 to 0.5%, and Mn is 0.2% by weight except for at least the last stage from the center.
5 to 1.5%, Cr 0.5 to 1.5%, Ni 0.5% or less, M
o 1.0 to 2.0%, V 0.1 to 0.3%, and the balance substantially consisting of Fe, a tensile strength at room temperature of 80 kg / mm ² or more, an elongation of 18% or more, and a drawing ratio of 50% or more Cr with
-Mo-V steel can be used.

The compressor stub shaft is C by weight.
0.15 to 0.3%, Si 0.5% or less, Mn 0.6% or less, Ni 2 to 4%, Cr 1 to 2%, Mo 0.5 to 1%,
Ni-Cr-Mo-V steel containing 0.05 to 0.2% V and turbine stub shafts are 0.2 to 0.4% by weight, S
i 0.1 to 0.5%, Mn 0.5 to 1.5%, Cr 0.5 to
1.5%, Ni 0.5% or less, Mo 1-2%, V 0.1-
Cr-Mo-V steel containing 0.3% can be used.

As an example of a compressor disk, 1
In the case of seven stages, the first stage to the twelfth stage are the aforementioned N
i-Cr-Mo-V steel, the 13th to 16th stages are Cr-
The Mo-V steel and the 17th stage can be constituted by the aforementioned martensitic steel. The first-stage and last-stage compressor disks have a rigid structure both in the first stage and the next stage or in the last stage in the preceding stage. Further, this disk has a structure in which the thickness is gradually reduced from the initial stage to reduce the stress due to high-speed rotation.

The compressor blades and nozzles are
0.5-0.2%, Si 0.5% or less, Mn 1% or less, C
r 10 to 13% or Mo0.5% or less and Ni
It is preferable that the steel be comprised of a martensitic steel containing 0.5% or less, with the balance being Fe.

The initial stage of the ring-shaped shroud which comes into sliding contact with the tip of the turbine blade has a weight of 0.05 to 0.2%, less than 2% Si, less than 2% Mn, 17 to 27% Cr, Co5% or less, Mo5-15
%, Fe 10 to 30%, W 5% or less, B 0.02% or less, and the balance is substantially Ni.
In other parts, by weight, C 0.3 to 0.6%, Si 2% or less, Mn 2% or less, Cr 20 to 27%, Ni 20 to 30
%, Nb 0.1-0.5%, Ti 0.1-0.5%, and a cast alloy substantially composed of Fe is used. These alloys are formed in a ring shape by a plurality of blocks.

In the diaphragm for fixing the turbine nozzle, the first stage turbine portion has a C weight of 0.05% or less,
1% or less, Mn 2% or less, Cr 16 to 22%, Ni 8 to
15% and the balance substantially consist of Fe, and other turbine nozzle portions are made of a high C-high Ni-based steel casting.

A plurality of combustors are provided around the turbine, and have a double structure of an outer cylinder and an inner cylinder. The inner cylinder has a weight of 0.05 to 0.2%, less than 2% of Si, less than 2% of Mn. , Cr 20-25%, Co 0.5-5%, Mo 5-1
5%, Fe 10 to 30%, W 5% or less, B 0.02%
The following and the remainder are substantially made of Ni, formed by welding a plastically processed material having a plate thickness of 2 to 5 mm, provided with a crescent-shaped louver hole for supplying air over the entire circumference of the cylindrical body, and provided with a solution having an all austenite structure. Chemical treatment material is used.

The temperature of the turbine blade at the inlet of the combustion gas turbine nozzle is from 0.07 to 0.25%, Si 1% or less, Mn 1% or less, Cr 12 to 20%, Co 5 to 15%, Mo1.0-
5.0%, W 1.0 to 5.0%, B 0.005 to 0.03
%, Ti 2.0 to 7.0%, Al 3.0 to 7.0%, and Nb
1.5% or less, Zr 0.01 to 0.5%, Hf 0.01 to
0.5%, V 0.01 to 0.5% or more, and the balance is substantially Ni, and an ordinary cast alloy in which a γ ′ phase and a γ ″ phase are precipitated on an austenite phase matrix is used. In the nozzle, C 0.20 to 0.60%, Si 2% or less, Mn 2% or less, Cr 25 to 35%, Ni 5 to 15
%, W3 to 10%, B0.003 to 0.03% and the balance substantially consists of Co, or further Ti0.1 to 0.3%,
It is composed of a cast alloy containing at least one of Nb 0.1 to 0.5% and Zr 0.1 to 0.3% and containing eutectic carbide and secondary carbide in an austenite phase matrix. All of these alloys are subjected to aging treatment after solution treatment,
The aforementioned precipitates are formed and strengthened.

The turbine blade is made of Al, Cr or Al + Cr to prevent corrosion by high temperature combustion gas.
A diffusion coating can be applied. The coating layer has a thickness of 30 to 150 μm, and is preferably provided on the wing in contact with the gas.

In the gas turbine for power generation from the 1300 ° C. class to the next generation 1500 ° C. class gas turbine, the metal temperature of the first stage turbine blade is further increased from 700 ° C. or more to 900 ° C. or more even if cooling technology is taken into consideration. The service temperature must be 14 kgf / mm ² for 10 ⁵ hours and must be 20 ° C. or more higher than the metal temperature. The second and subsequent blades have a lower gas temperature of 50-100 ° C. than the first stage, but have a higher metal temperature and a material characteristic of 10 ⁵ as compared with a gas turbine having a combustion temperature of 1300 ° C. class.
A service temperature of 600 ° C. or more to 800 ° C. or more at a time of 14 kgf / mm ² is required. The use of a lower strength material not only increases the probability of blade breakage during operation, but also reduces the efficiency of the gas stream due to the inability to sufficiently convert the energy of the gas flow into rotational force.

The first stage nozzle is exposed to the highest temperature because it receives the combustion gas first, and receives a remarkable thermal stress and thermal shock due to repeated start and stop of the gas turbine. In 1500 ° C. class gas turbine from the combustion gas temperature 1300 ° C. class, service temperature at 10 ^{for 5} hours 6 kgf / mm ² even considering the cooling capacity is further used 900 ° C. or more alloys from 700 ° C. or higher. The turbine nozzles of the second and subsequent stages are not so severe in temperature as compared with the first stage nozzle, but have a combustion temperature of 1
The metal temperature is higher than that of a gas turbine of 300 ° C. class, and a material having a service temperature of 14 kgf / mm ^{2 for} 10 ⁵ hours of 600 ° C. or more to 800 ° C. is used.

According to the present invention, the gas temperature at the inlet of the first stage turbine nozzle is 1400 to 1650 ° C., preferably 1500 to 1650 ° C.
For 1650 ° C., the first-stage turbine blade and the first-stage turbine nozzle are made of a single-crystal Ni-based alloy and have a thermal barrier coating layer, and the second-stage turbine blade and the second-stage turbine nozzle have an alloy coating layer. And the single crystal Ni heavy metal is C
r 6-8%, Mo 0.5-1%, W 6-8%, Re 1-4
%, Al 4-6%, Ta 6-9%, Co 0.5-10%
And a Ni-based alloy containing 0.03 to 0.13% of Hf, and the single crystal Ni heavy alloy is made of a Ni-based alloy containing 0.1 to 2% of one or both of Ti and Nb. Is preferred. In the present invention, the above-mentioned temperature is 1
For 400 to 1495 ° C, the first stage blade and the first stage nozzle, or for 1500 ° C or higher, the second stage turbine blades by weight: Cr 5 to 18%, Mo 0.3 to 5%, W2 to 10
%, 2.5 to 6% of Al, 0.5 to 5% of Ti, 0.05 to 5% of C
A columnar crystal Ni-based alloy containing 0.21% and B 0.005 to 0.025%;
%, Co 10% or less, Hf 0.03 to 0.2%, Zr 0.
001-0.05%, Re 0.1-5% and Nb 0.1-0.1%
Unidirectionally solidified columnar crystal N containing at least 3%
i-base alloys are preferred. In particular, it can be used not only for the second stage blade but also for the third or fourth stage blade.

The second and third stage turbine nozzles are, by weight, 21-24% Cr, 18-23% Co, and 0.00.0% C.
5 to 0.20%, W1 to 8%, Al1 to 2%, Ti2
A polycrystalline Ni-based alloy containing 3%, 0.5 to 1.5% Ta and 0.05 to 0.15% B is preferred.

In order to improve the thermal efficiency of the gas turbine, it is most effective to raise the temperature of the combustion gas as described above. Considering the combination of advanced blade, nozzle cooling technology and thermal barrier coating technology, if the metal temperature of the first stage turbine blade is 920 ° C or higher, the gas inlet temperature to the first stage turbine nozzle will be 1450-1550 ° C.
It becomes possible to. Thereby, the power generation efficiency of the gas turbine can be made 37% or more. The power generation efficiency in this case is represented by the LHV method. At that time, if the turbine exhaust gas temperature is 590 ° C. to 650 ° C.,
The total power generation efficiency of a combined power generation system with a steam turbine can be 50% or more, preferably 55% or more, and an excellent high efficiency power generation system can be provided.

According to the present invention, it is possible to achieve a gas turbine having a higher efficiency and a still higher temperature. At a turbine inlet temperature of 1500 ° C. to 1650 ° C., 37% in LHV is displayed.
The above high efficiency is obtained.

(B) High / Low Pressure Integrated Steam Turbine (1) Long Wing Material The long wing material according to the present invention has a blade length of 30%, which is made of martensitic stainless steel containing 8 to 13% by weight of chrome.
It is preferable to use a diameter of at least 40 inches, preferably at least 40 inches, and more preferably 43 to 46 inches as the final stage rotor blade of a 50-cycle high / low or high / medium / low pressure integrated steam turbine.

The present invention further provides a final stage rotor blade comprising at least 30 inches of the above-mentioned martensitic stainless steel,
Preferably 33 inches or more, more preferably 35-38
It is preferable to use the inch type for a high / low pressure or high / medium / low pressure integrated steam turbine for 60 cycle power generation. 46 inches for 50 cycles, 38 inches for 60 cycles
For those exceeding inches, Al 4-8%, V3-7% by weight
Is preferred.

The aforementioned martensitic stainless steel is:
C. 0.08% to 0.18%, Si 0.25% or less, Mn with respect to the rotation speed and the blade length of 129000rpm • in.
1.00% or less, Cr 8.0-13.0%, Ni 1.5-3
%, Preferably more than 2.1 and 3% or less, Mo 1.5 to 3.3%.
0%, V 0.05 to 0.35%, the total amount of one or two of Nb and Ta is 0.02 to 0.20%, and N 0.02 to 0.25%
Those containing 0.10% are preferred. Higher rpm
For those over inches, martensitic steels having the same composition but containing 0.19 to 0.25% C are preferred.

Further, according to the present invention, C0.18 to 0.1% by weight.
28%, Si 0.1% or less, Mn 0.1-0.3%, Cr 1.
5~2.5%, Ni1.5~2.5%, Mo1~2% and has a V0.1~0.35%, of the high-pressure portion 538 ℃ · 10 ⁵ h
Smooth and notched creep rupture strength of 13 kg / mm ² or more, tensile strength of low-pressure part of 84 kg / mm ² or more, fracture surface transition temperature of 3
A high / medium / low pressure or high / low pressure integrated steam turbine in which a long shaft having a tensile strength of 120 kg / mm ² or more is attached to a rotor shaft made of martensitic heat-resistant steel at 5 ° C.

It is preferable that an erosion prevention layer is provided on the leading edge of the blade at the last stage. The erosion-preventing layer is C0.5-1.5 by weight.
%, Si 1.0% or less, Mn 1.0% or less, Cr 25-3
It is preferable to use a Co-based alloy containing 0% and 2.5 to 6.0% W.

The long blade of the steam turbine must have high tensile strength and high cycle fatigue strength in order to withstand high centrifugal stress and vibration stress due to high-speed rotation.
Therefore, the metal structure of the blade material must be a fully tempered martensitic structure, since the presence of harmful δ ferrite significantly reduces the fatigue strength.

The steel of the present invention is preferably adjusted so that the Cr equivalent calculated by the above-mentioned formula becomes 10 or less, and is substantially free of a δ ferrite phase.

The tensile strength of the long wing material is 120 kg / mm ² or more,
It is preferably at least 128 kgf / mm ² , more preferably 12 kgf / mm ² or more.
8.5 kgf / mm ² or more. The proof stress is 80 kg / mm ² or more, preferably 88 kg / mm ² or more. The elongation is 10% or more in the length direction, 5% or more in the circumferential direction, and the impact value is 3.45kgf
-M or more is preferable.

In addition, in order to obtain a homogeneous and high-strength steam turbine long blade material, a refining heat treatment is performed after melting and forging.
00 ° C to 1100 ° C (preferably 1000 to 1070
C.) for 0.5 to 3 hours, and then quenched by quenching to room temperature (particularly oil quenching is preferred), followed by tempering at 550 to 620.degree.
C. for 1 to 6 hours, followed by primary tempering to cool to room temperature and 560 to 590.degree. C., preferably 1 to 6 hours.
It is preferable to perform two or more tempering heat treatments of a secondary tempering of cooling to room temperature after heating and holding for a time. The secondary tempering temperature is preferably higher than the primary tempering temperature.
Preferably, the temperature is increased by 0 to 30 ° C, more preferably by 15 to 20 ° C.

The length of the last stage blade section of the low pressure turbine according to the present invention is 914 mm (36 ″) or more, preferably 965 mm (3 ″).
8 ") 3600 rpm steam turbine for 60 cycle power generation and low pressure turbine final stage blade length 1041 mm
(41 ") or more, preferably 1092 mm (43") or more,
More preferably, the steam turbine is a 3000 rpm steam turbine for 50-cycle power generation having a length of 1168 mm (46 ") or more, and the value of [wing length (inch) × rotation speed (rpm)] is 125,000 or more, preferably 138000 or more.

In the long wing material according to the present invention, in order to obtain a high strength, a low temperature toughness, and a fatigue strength by adjusting the alloy composition so as to have the entire martensite structure, the content of each element of the following formula is adjusted. The Cr equivalent calculated as% by weight is 4 to
It is preferable to adjust the components to 10.

Cr equivalent = Cr + 6Si + 4Mo + 1.5
W + 11V + 5Nb-40C-30N-30B-2Mn
The content of -4Ni-2Co + 2.5TaC is preferably 0.08% or more in order to obtain high tensile strength, and 0.2% or less so as not to lower the toughness. In particular, 0.
10 to 0.18% is preferred. From 0.12 to 0.16
% Is preferred.

Si is a deoxidizing agent, and Mn is a desulfurizing / deoxidizing agent added during melting of steel, and is effective even in a small amount. Si is a δ-ferrite forming element, and if added in a large amount, causes harmful δ-ferrite formation which deteriorates fatigue and toughness, so is preferably not more than 0.25%. In addition,
According to the carbon vacuum deoxidation method, the electroslag melting method, or the like, there is no need to add Si, and it is preferable to add no Si. In particular, it is preferably 0.10% or less, more preferably 0.07% or less.

Addition of Mn of 0.9% or less improves toughness. In particular, since Mn is effective as a deoxidizing agent, it is 0.6% or less, more preferably 0.1% to 0.5%, most preferably 0.2%, from the viewpoint of improving toughness.
~ 0.4% is preferred.

Cr enhances corrosion resistance and tensile strength.
% Or more causes formation of a δ ferrite structure.
If it is less than 8%, the corrosion resistance and tensile strength are insufficient, so that C
r is preferably 8 to 13%. Especially 10.5 from the point of strength
１２12.5% is more preferable.

Mo has the effect of increasing the tensile strength by the action of solid solution strengthening and precipitation strengthening. Mo has an insufficient effect of improving the tensile strength, and if it is 3% or more, it causes the formation of δ ferrite. Therefore, Mo is preferably 1.5 to 3.0%. Especially 1.8 ~
2.7%, more preferably 2.0-2.5%. Note that W and Co have the same effect as Mo.

V and Nb have the effect of precipitating carbide and increasing the tensile strength, and at the same time have the effect of improving the toughness. V 0.05%, Nb
At 0.02% or less, the effect is insufficient, and V0.40
%, Nb 0.2% or more causes the formation of δ ferrite. Especially V is 0.20 to 0.36%, more preferably 0.25 to 0.31.
%, Nb is 0.04 to 0.16%, more preferably 0.06 to 0.14.
% Is preferred. Ta can be added in exactly the same manner as in place of Nb, and can be added in combination.

Ni has an effect of improving low-temperature toughness at a content of 2 to 3% and preventing the formation of δ ferrite. In particular, 2.3
~ 2.9% is preferred. More preferably, 2.4 to 2.8%
It is. N is 0.02 to 0.1%, which is effective for improving toughness and tensile strength and preventing the formation of δ ferrite. In particular, 0.
Excellent characteristics can be obtained in the range of 04 to 0.08%, more preferably 0.045 to 0.08%.

The reduction of Si, P and S has the effect of increasing the low-temperature toughness without impairing the tensile strength, and it is desirable to reduce as much as possible. From the viewpoint of improving low-temperature toughness, Si 0.1% or less,
P is preferably 0.015% or less, and S is preferably 0.015% or less. In particular, Si 0.05% or less, P 0.010% or less, S
0.010% or less is desirable. The reduction of Sb, Sn and As also has the effect of increasing the low temperature toughness, and it is desirable to reduce it as much as possible. However, from the point of the current steelmaking technology level, Sb0.
0015% or less, Sn 0.01% or less, and As 0.02%
Limited to the following. In particular, Sb 0.001% or less, Sn0.
005% and As0.01% or less are desirable.

Further, in the present invention, the Mn / Ni ratio is preferably set to 0.11 or less.

In the heat treatment of the material of the present invention, first, the material is uniformly heated to a temperature sufficient to transform completely into austenite, at least 1000 ° C. and at most 1100 ° C., and rapidly cooled (preferably oil-cooled).
Next, it is preferable to heat and hold at a temperature of 550 to 570 ° C. and cool (first tempering), and then to heat and hold at a temperature of 560 to 680 ° C. to perform second tempering to obtain a fully tempered martensitic structure.

(2) The rotor shaft C for a high / low pressure or high / medium / low pressure integrated steam turbine is an element necessary for improving hardenability and ensuring toughness and strength at 0.15 to 0.4%. In particular, C is 0.20 to 0.2.
A range of 8% is preferred.

Conventionally, Si and Mn have been added as deoxidizing agents. However, according to steelmaking techniques such as vacuum C deoxidizing method and electroslag remelting method, a sound rotor can be melted and manufactured without any particular addition. is there. From the point of embrittlement due to long use,
Si and Mn should be low, each 0.1%
And 0.5% or less. In particular, Si 0.05% or less, M
n 0.05 to 0.25%, more preferably 0.01% or less for the former and 0.20% or less for the latter.

On the other hand, the addition of a very small amount of Mn has the effect of fixing harmful S, which deteriorates hot workability, as sulfide MnS. Therefore, the addition of a very small amount of Mn reduces the aforementioned harm of S. Therefore, the content is preferably 0.01% or more in the production of a large forged product such as a rotor shaft for a steam turbine. However, if S can be reduced on steelmaking, the addition of Mn lowers toughness and high-temperature strength.
If it is possible to reduce the amount of super clean, zero is good, and 0.
It is preferably from 0.01 to 0.2%.

Ni improves the hardenability by 1.5 to 2.7% and improves the creep rupture strength and toughness. Especially 1.
The range is preferably from 6 to 2.0% to 1.7 to 1.9%. Further, by setting the Ni content to a range higher than the Cr content by 0.20% or lower than the Cr content by 0.30% or less, characteristics having both high-temperature strength and toughness can be obtained.

When Cr is 1.5 to 2.5%, hardenability is improved, and it is effective in improving toughness and creep rupture strength. It also improves corrosion resistance in steam. In particular, it is preferably 1.7 to 2.3%, more preferably 1.9 to 2.1%.

Mo is in the range of 0.8 to 2.5% and precipitates fine carbides in the crystal grains during the tempering treatment, thereby improving the high-temperature strength and preventing temper embrittlement. Particularly, from the viewpoint of strength and toughness, it is 1.0.
-1.5%, more preferably 1.1-1.3%.

V is 0.15 to 0.35%, and precipitates fine carbides in crystal grains during tempering, and has an effect of improving high-temperature strength and toughness. In particular, 0.20 to 0.30%, more preferably 0.2%
The range of more than 5 and 0.30% or less is preferable.

In addition, when a low alloy having the above composition is melted, toughness is improved by adding any of the rare earth elements, Ca, Zr and Al. The rare earth element is 0.
0.05-0.4%, Ca is 0.0005-0.01%, Zr
Is preferably 0.01 to 0.2%, and Al is preferably 0.001 to 0.02%.

Further, oxygen contributes to the high-temperature strength, and in the steel of the present invention, a higher creep rupture strength can be obtained by controlling O ₂ in the range of ₅ to 25 ppm.

At least one of Nb and Ta is 0.00
It is preferable to add 5 to 0.15%. If these contents are less than 0.005%, a sufficient effect for improving the strength cannot be obtained, while if it exceeds 0.15%, these large carbides are formed in large structures such as a rotor shaft for a steam turbine. 0.005 to 0.15% because of lowering strength and toughness
And Especially 0.01 to 0.05% is preferable.

It is preferable to add W in an amount of 0.1% or more in order to increase the strength. However, if it exceeds 1.0%, the strength of a large steel ingot is reduced, for example, a problem of segregation occurs.
It is preferably set to 0%. Preferably it is 0.1-0.5%.

The Mn / Ni ratio or (Si + Mn) / Ni ratio is preferably 0.13 or 0.18 or less, respectively. Thereby, the heat embrittlement in the Ni-Cr-Mo-V low alloy steel having the bainite structure can be significantly prevented, and it can be applied as a high / low pressure or high / medium / low pressure integrated rotor shaft. Also,
(Ni / Mo) ratio is 1.25 or more and (Cr / Mo) ratio is 1.1 or more, or (Cr / Mo) ratio is 1.45 or more and (Cr / Mo) ratio is [−1.11 × (Ni / Mo) +
2.78] or more, the whole is heat-treated under the same conditions, so that
High strength with a ^5- hour creep rupture strength of 12 kg / mm ² or more can be obtained.

Further, by including the Ni content in a specific range with respect to the Cr content, a material having both higher strength on the high pressure side and higher toughness on the low pressure side can be obtained.

The present invention provides a rotor shaft for a high / low pressure or high / medium / low pressure integrated steam turbine, in which the high pressure portion or the high / medium pressure portion has a smooth and notched creep rupture strength of 538 ° C. and 10 ⁵ h of 13 kg / mm ² or more. Alternatively, it is preferable that the tensile strength of the middle and low pressure part is 84 kg / mm ² or more and the fracture surface transition temperature is 35 ° C. or less. In order to obtain such excellent mechanical properties, it is preferable to perform the following gradient refining heat treatment. Before performing this tempering heat treatment, 65
It is preferable to perform a pearlite treatment at 0 ° C. to 710 ° C. for 70 hours or more.

High pressure part or high medium pressure part of rotor shaft: High high temperature strength is obtained.

○ Quenching: heating and holding at 930 to 970 ° C. followed by cooling ○ Tempering: heating and holding at 570 to 670 ° C. and slow cooling (preferably twice tempering, one of which is 650 to 670 ° C.)
It is preferable to heat and hold the rotor shaft at a low pressure portion or a medium / low pressure portion of the rotor shaft: high tensile strength and low-temperature toughness are obtained.

○ Quenching: Rapid cooling after heating and holding to 880 to 910 ° C. Tempering: Slow cooling after heating and holding to 570 to 640 ° C. (Tempering twice is preferable, and one time is 615 to 635 ° C.
That is, in the present invention, by quenching the high-pressure side at a higher quenching temperature than the low-pressure side, a creep rupture time of 180 hours or more at 550 ° C. and 30 kg / mm ² can be obtained on the high-pressure side. It is preferable that the high-temperature strength be higher than that of the low-pressure side and that the gradient heat treatment be performed so that the transition temperature of the low-pressure side is 10 ° C. or less at the center hole from the high-pressure side. Even at the tempering temperature, it is preferable to temper the high pressure side at a higher temperature than the low pressure side.

As described above, it is possible to obtain steel having both characteristics of high creep rupture strength and high impact value, and as a final stage rotor blade in the high / low pressure integrated rotor shaft of the present invention, particularly for 50 cycle power generation. It is preferable to plant a plant having a length of 40 inches or more, preferably 43 inches or more, and a length of 33 inches or more, preferably 35 inches or more for 60 cycle power generation.

(3) Other moving blades, stationary blades, and other high-pressure side blades in the steam turbine of the present invention, the first stage or the first to third stages are weighted at C0.
2 to 0.3%, Si 0.5% or less, Mn 1% or less, Cr1
0 to 13%, Ni 0.5% or less, Mo 0.5 to 1.5%, W
Martensitic steel containing 0.5 to 1.5%, V 0.15 to 0.35%, and other low pressure side blades of less than 26 inches by weight are C 0.05 to 0.15%, Si 0.5 %, Mn 1% or less, preferably 0.2 to 1.0%, Cr
A martensitic steel containing 10 to 13%, Ni 0.5% or less, and Mo 0.5% or less is preferable.

The stationary blade according to the present invention has a weight of C0.05.
0.15%, Si 0.5% or less, Mn 0.2-1%, C
It is preferable to use a tempered all martensitic steel containing 10 to 13% of r, 0.5% or less of Ni, and 0.5% or less of Mo.

In the present invention, the casing is C by weight.
0.10 to 0.20%, Si 0.75% or less, Mn 1% or less, Cr 1 to 2%, Mo 0.5 to 1.5%, V 0.05 to 0.5
It is preferable to use a Cr-Mo-V cast steel having a bainite structure containing 0.2% or less and 0.05% or less of Ti.

[0098]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 shows a case where the martensitic steel according to the present invention is used for a turbine disk, the first and second stage blades and the first stage nozzle are cooled by steam, and the second stage is cooled. It is a combined power generation cycle system diagram which cools a stage and a 3rd stage stationary blade by air. In a combined power generation cycle that generates power by combining a steam turbine and a gas turbine, steam generated by an exhaust heat recovery boiler can be used,
In addition, steam can be separately generated and used.

A. Gas Turbine FIG. 2 is a cross-sectional view of the upper half of a gas turbine having three stages of blades having a closed steam cooling system using martensitic steel for a turbine disk. As shown by the arrow in the figure, the steam cooling passage 6 enters the first-stage blade 51 and the second-stage blade 52 from between the disk and the spacer through the center of the turbine rotor 1 and cools each blade. Also flows out of the outer periphery of the steam inlet of the turbine rotor 1 through the space between the disk and the spacer. For the steam cooling of the first stage nozzle 81, it flows out through the casing 80 and the outside through the same path as the inlet.

On the other hand, the cooling passage 6 for air cooling of the second-stage and third-stage nozzles extracts air from the air extraction units 31 and 32 of the air compressor as shown by arrows in the figure. Since the compression ratio is slightly lower, it is used to cool the third stage nozzle. The air from the bleed portion 32 has a slightly higher compression ratio than the bleed portion 31 and has a higher cooling capacity, and is used for cooling the two-stage stationary blade.

As shown in FIG. 2, the gas turbine of this embodiment comprises a casing 80, a compressor comprising a compressor rotor 2 and a cascade of outer peripheral portions, a combustor 84, nozzles 81 to 83, and blades 51 to 53. It is constituted by gas paths 85, turbine rotors 1 and the like formed alternately.

The turbine rotor 1 comprises three turbine disks 11, 12, 13 and a stub shaft 34.
It is closely bonded as a high-speed rotating body. Blades 51 to 53 are implanted on the outer periphery of each disk, and are connected to the compressor rotor 2 via a distant piece 33, and are rotatably supported by bearings.

In this configuration, the high-temperature and high-pressure working gas generated in the combustor 84 using the air compressed by the compressor flows while expanding the gas path, thereby rotating the turbine rotor and generating power. You.

The pressure of the working gas at the outlet of the combustor is 22 to 25.
ata, when the temperature is 1500 ℃, the rotor outer diameter is 2.5
Although the power of 400 MW or more can be generated even with a gas turbine of about m 2, the relative gas total temperature at the blade entrance is about 125 in the first stage.
0 to 1300 ° C, the two stages gently exceed the allowable temperature of the blade (850 to 900 ° C for normal wing material) at about 950 to 1000 ° C, and the heat load is about 1.5% (about 6000
kW) and 1.2% (5000 kW).

In order to set the pressure of the working gas at 22 to 25 at, it is necessary to set the compression ratio to 22 or more. In this case, the discharge temperature of the compressor becomes about 500 ° C. and the normal rotor material (allowable temperature) (450 ° C.), it is necessary to cool the outer periphery of the compressor rotor 2.

In this embodiment, other turbine stacking bolts 54, compressor discs, compressor blades 17, compressor stacking bolts,
And a compressor stub shaft. The gas turbine of this embodiment has three stages of turbine blades and turbine nozzles.

The first-stage nozzle 81 and the first-stage blade 51 of the gas turbine in this embodiment are single crystal castings of a Ni-base superalloy, and are Cr 4 to 10% by weight, Mo 0.5 to 1.5.
%, W4-10%, Re1-4%, Al3-6%, Ta
4-10%, Co 0.5-10% and Hf 0.03-0.2
% Ni-based alloy. The first stage blade has a wing length of 130 mm solidified in the dove-til direction from the wing tip,
Its total length is about 220 mm. 10% of this single crystal casting
The service temperature of 14 kgf / mm ² for ⁵ hours is 930 to 940 ° C. All of them have complicated steam cooling holes inside and cool with compressed steam during operation. The cooling system is a closed system, and has a path for entering by a dovetil and returning to the dovetil again through a plurality of passages provided inside the wing portion. This single crystal casting is 1250-135
After solution treatment at 0 ° C., 1000 to 1100 ° C. and 850
A two-stage aging treatment at ~ 950 ° C is performed to precipitate a γ 'phase having a length of 1 µm or less on one side at 50-70% by volume.

The first stage nozzle 81 has a C
The amount of Cr was increased by 1 to 3%, and the amount of Cr was increased by 6 to 10%.
%.

Although the first stage blade 51 in this embodiment is a single crystal as a whole, the shank and the dovetail other than the wing portion may be columnar crystals. In the present embodiment, in the one-way solidification, solidification is performed from the wing side and solidified into a shank and a dovetail, and the whole is made a single crystal, or when the solidification reaches the shank portion, the cooling rate is increased to increase the columnar crystal. It can be.

The first stage nozzle 81 in this embodiment has a vane, a sidewall on the outer peripheral side, and a sidewall on the inner peripheral side.

The first stage blade 51 has a wing portion, one end of which is rounded on the upstream side and a crescent shape on the downstream side, a platform, a shank, a Christmas tree type dovetil, and two seal fins on each side. Each of the seal fins has a projection on the wing side.
The dovetail is provided with a sealing projection on the bottom thereof. The shank is concave at the center. A plurality of cooling holes are provided inside, and have a passage through which the refrigerant enters and exits from the dovetail side. The seal fins prevent leakage of the combustion gas.

Second Stage Blade 52 and Third Stage Blade 5
No. 3 is Cr 5 to 18% by weight, Mo 0.3 to 6
%, W2 to 10%, Al 2.5 to 6%, Ti 0.5 to 5
%, Ta 1-4%, Nb 0.1-3%, Co 0-10%,
C 0.05-0.21%, B 0.005-0.025%, Hf
It is made of a unidirectionally solidified columnar Ni-base superalloy having 0.03 to 2% and Re of 0.1 to 5%. These blades all have a columnar structure obtained by solidification in one direction from the tip to the dovetail direction. The second stage blade has the same internal cooling hole as the first stage blade, and has a structure to enter from the dovetil and return to the dovetil, and is cooled by high-pressure steam. The service temperature of 14 kgf / mm ² for 10 ⁵ hours of these materials is preferably 840 to 860 ° C. On these blade surfaces, Al2-5% by weight, Cr20-30
% And an alloy layer made of a Ni-based or Ni + Co-based alloy containing 0.1 to 1% of Y and having a thickness of 50 to 150 μm by plasma spraying in a non-oxidizing reduced-pressure atmosphere to enhance corrosion resistance. The alloy layer is provided on the side of the wing and the platform that contacts the flame. Dovetil has seal fins. The third stage blade is solid and has no cooling holes.

The first stage nozzle in this embodiment is formed of a single crystal Ni-based alloy in which two vanes are integrated between an outer side wall and an inner side wall, and has a crescent shape with one end rounded and cooling water vapor inside. A plurality of cooling holes are formed in the vane portion so that cooling air flows in from the outer peripheral side wall side and returns to the outer peripheral side wall side again in the vane portion.

In the present embodiment, single crystal Ni of the first stage nozzle was used.
The service temperature of 6 kgf / mm ² for 10 ⁵ hours of the base alloy is 920 to 9
40 ° C. The cooling flow path has a closed type and has a structure in which the cooling blade enters the outer peripheral side wall side where a plurality of cooling holes are provided in the blade portion, and returns to the outer peripheral side wall through the plurality of cooling holes. A thermal barrier coating layer is provided on the wing portion and the platform, and the wing portion and the sidewall, which are in contact with the flame on the outer surface of the first stage blade and the first stage nozzle. This is composed of fine columnar crystals in the direction of deposition, and a fine columnar crystal having a diameter of 10 to 200 μm.
stabilized zirconia layer comprising Y ₂ O ₃ 10% or less having a columnar double structure crystal structure having the columnar crystal μm by vapor deposition provided to a thickness of 100-200 [mu] m, between the base metal and zirconia layer And a bonding layer. The bonding layer is composed of Al 2 to 5%, Cr 20 to 30%, Y 0.1 to 1% by weight.
Is a thermal sprayed layer made of an alloy composed of Ni or Ni + Co. The alloy layer also has the effect of improving corrosion resistance. This cast material after solution treatment at 1150-1200 ° C,
Heat treatment of a one-stage aging treatment is performed at 820 to 880 ° C.

The second stage nozzle and the third stage nozzle are, by weight, 21 to 24% of Cr, 18 to 23% of Co, and 0.05% of C.
~ 0.20%, W1 ~ 8%, Al ~ 2%, Ti2 ~ 3
%, 0.5 to 1.5% of Ta and 0.05 to 0.15% of B. These nozzles have an equiaxed structure obtained by ordinary casting. Although it is not particularly necessary to provide a thermal barrier coating layer, a diffusion coating of Cr or Al is applied to the second stage nozzle in order to enhance corrosion resistance. A similar diffusion coating layer can be provided on the third stage nozzle. Each has an internal cooling hole, and is cooled by compressed air through a path that enters from the leading side and exits from the trailing side. The service temperature of 6 kgf / mm ² of these materials for 10 ⁵ hours is 840 ° C.
860 ° C. The same heat treatment is applied to the cast material. The two-stage and three-stage nozzles are arranged such that each center is located substantially at the center between the blades.

The overall structure of the two-stage turbine nozzle is substantially the same as that of the first-stage nozzle. In this embodiment, the two-stage turbine nozzle has two vanes and has a cooling structure using cooling air. The cooling structure enters from the outer sidewall,
A cooling hole that flows out from the inner side wall side and flows out from the trailing edge downstream of the vane is provided at the vane tip. The inside of the vane is hollow, and the vane is constituted by a thin member having a thickness of 0.5 to 3 mm. In the present embodiment, two vanes are provided, but any one to three vanes can be used.

The third-stage nozzle has substantially the same structure as the second-stage nozzle. Cooling air flows from the outer peripheral side wall and passes through the inside of a vane made of a thin member having a thickness of about 0.5 to 3 mm. And flows out from the trailing edge on the downstream side of the combustion gas. In the present embodiment, two vanes are formed integrally between the sidewalls, but one nozzle may be any of one, two or three vanes.

In the first stage blade, a wax model having the same product shape is formed around a core having a hollow structure for a cooling hole. Further, after forming a coating layer of molding sand described later on the outer layer, dewaxing and firing were performed to obtain a mold. Next, the master ingot having the above-described composition is cast into the mold in a vacuum unidirectional solidification furnace, and is unidirectionally solidified from the starter portion to the wing portion, platform, shank portion and dovetil at a pulling rate of 5 to 30 cm / h. And a single crystal casting made of a Ni-based alloy using a selector. Subsequently, the core was removed with an alkali, and the starter portion, the selector, the hot water portion, and the like were cut to obtain a gas turbine blade having a predetermined shape.

The two-stage and three-stage gas turbine blades are made of Ni
It is made of a unidirectionally solidified columnar crystal casting made of a base alloy, and has a lower pulling speed than that of a single crystal by a similar manufacturing method.
It can be obtained by unidirectional solidification at 0 to 50 cm / h.

The obtained blade is subjected to a solution treatment and an aging treatment in a non-oxidizing atmosphere to control the structure in order to exhibit a predetermined strength.

In the first stage nozzle of this embodiment, a wax model provided around a core having a hollow structure for a cooling hole is immersed in a liquid obtained by dissolving an acrylic resin in methyl ethyl ketone, air-dried, and then slurried (zircon flower + colloidal). A stack (first layer zircon sand, second layer and subsequent chamotte sand) is sprayed by dipping in silica + alcohol, and this is repeated several times to form a mold. The mold was fired at 900 ° C. after dewaxing.

Next, this mold is provided in a vacuum furnace, and the master ingot is melted by vacuum melting, cast into a mold in a vacuum, and the outer peripheral side wall, the vane and the inner peripheral side are moved from the starter portion in the same manner as the blade. A nozzle formed by single crystal casting made of a Ni-based alloy was sequentially unidirectionally solidified into side walls. This nozzle has a wing portion between the sidewalls of about 74 mm in width, 110 mm in length, 25 mm in the thickest part, 3 to 4 mm in thickness, and about 0.7 mm in the tip.
It has a thickness.

The obtained nozzle is subjected to a solution treatment and an aging treatment in a non-oxidizing atmosphere to control the structure in order to exhibit a predetermined strength.

Hereinafter, No. 1 to No. 4 in Table 1 indicate specific single-crystal Ni of the first-stage blade and the first-stage nozzle in this embodiment.
This is an example of a base alloy (single crystal: SC, columnar crystal: DS, equiaxed crystal: CC).

Cr improves the oxidation resistance and corrosion resistance of the alloy. Al is a main strengthening element that forms a γ ′ phase, which is an intermetallic compound that precipitates and strengthens a Ni-base superalloy. The basic composition of the γ 'phase is represented by Ni ₃ Al.
It is further strengthened by dissolving elements such as i, Ta, W, Mo, and Nb. Further, Nb is an important additive element together with Re to enhance the corrosion resistance of the alloy. Addition of Co improves corrosion resistance and oxidation resistance. In terms of strength,
The addition of Co lowers the stacking fault energy of the alloy,
It has the effect of improving the creep strength in a relatively low temperature range and the effect of increasing the solid solubility of the γ 'phase in the high temperature range, weakening the precipitation strengthening and making the creep strength in the high temperature range insufficient. Due to the opposing effects of both, Co has an optimum addition amount in terms of strength. Hf is an important element for improving the oxidation resistance and high-temperature strength of the alloy, and its effect appears only in a very small amount. However, excessive addition lowers the melting point of the alloy and sufficiently reduces the eutectic γ 'phase. Can not be dissolved. R
e forms a solid solution in the γ phase and strengthens the matrix, and enhances the corrosion resistance of the alloy.
It causes precipitation of harmful phases such as W, Re-Mo and Re-Ta.

Nos. 5 and 6 in Table 1 are examples of the unidirectionally solidified columnar crystal Ni-base alloys of the second and third stage blades in this embodiment.

[0127]

[Table 1]

The materials used for the second-stage and third-stage nozzles used in the gas turbine for power generation according to the present invention are as follows.
Table 2 shows the alloy composition (% by weight), the casting method when casting, the service temperature of 6 kgf / mm ² for ⁵ hours, and the weldability.
The function of each alloy component is substantially as described above, but the alloy of the present embodiment has a composition in which the weldability is more important than the Ni-based alloy described above. In Table 2,
No. 8 is inferior to Nos. 7 and 8 in weldability which is excellent in high-temperature strength. 2N2 has the best weldability among them, but is inferior in high-temperature strength. Therefore, in consideration of the balance between weldability and high-temperature strength, it can be said that No. 7 is the most excellent. This is A
This is the effect of strict control of the l + Ti amount and the addition of W. In addition,
Weldability is evaluated by a 1 pass TIG with a length of 80 mm and a width of 8 mm.
The reference was based on whether the preheating temperature at which cracks did not occur in the bead formed by welding was 400 ° C. or less.

In this embodiment, the turbine disks 11, 12,
13 by weight, C 0.05 to 0.20%, Si 0.5% or less, Mn 0.6% or less, Cr 8 to 13%, Ni 0.5 to 0.5%
4.0%, Mo 4.0% or less, V 0.1 to 0.4%, Nb
Forgings of all martensitic steels containing 0.06 to 0.25%, N 0.025 to 0.125% and 1.0 to 5.0% Co are used. Table 3 shows the specific martensitic steel.
(% By weight). The balance is Fe.

Table 4 shows the creep rupture strength at 450 ° C. and 500 ° C. for 10 ⁵ h and the (500 ° C. strength / 450 ° C. strength) ratio.

[0131]

[Table 2]

[0132]

[Table 3]

[0133]

[Table 4]

These martensite steels were prepared by melting 150 kg steel ingot in a high-frequency induction melting furnace, casting it by deoxidizing with vacuum carbon, heating it to 1150 ° C., and forming it into a plate by hot forging. Thereafter, the plate material was melted at 1050 ° C. and quenched by air cooling. After cooling to room temperature, 570 ° C
Alternatively, primary tempering was performed at 590 ° C. From these samples, a smooth creep rupture test specimen (JIS Z 2272, ASTM E292), a tensile test specimen (JIS G 0567), and a Charpy impact test specimen (JIS Z 2202) were sampled and subjected to an experiment.

FIG. 3 is a diagram showing the creep rupture times at 450 ° C. and 500 ° C. according to the Larson-Miller parameter. From this diagram, the intensity of 100,000 hours shown in Table 4 was obtained. The martensitic steel according to the invention has a 50
kg / mm ² or more, have at 500 ℃ 40kg / mm ² or more, 500 ° C. strength in each sample was as high strength showing a 70% or more strength to 450 ° C. strength.

Further, the tensile strength at room temperature is 107.5 kg / mm ^2.
The above and the 0.2% proof stress were 86.5 kg / mm ² or more.

FIG. 4 is a diagram showing the relationship between FATT (° C.) and the amount of Ni. As shown in the figure, when the Ni content is 0.5% or more, it is required as FATT 26.
It can be seen that the temperature is below 6 ° C.

FIG. 5 is a graph showing the relationship between FATT (° C.) and the amount of Ni. As shown in the figure, the Ni content is around 3%, and it is understood that the Ni content is not so related to the W content.

FIGS. 6 and 7 are diagrams showing the relationship between the impact value and the amounts of Ni and W. FIG. As shown in the figure, the impact value significantly exceeds the required value of 4.14 kg · m or more, which is satisfactory.

As is apparent from the above experimental results, the material of the present invention is used for stacking bolts, distant pieces, and spacers in this embodiment, in addition to the gas turbine disk of the 1500 ° C. class at the inlet of the first stage turbine nozzle as the combustion gas temperature. Was.

The gas inlet temperature of the first stage nozzle of the gas turbine of the present invention is 1500 ° C., the gas inlet temperature of the second stage nozzle is 1100 ° C., and the gas inlet temperature of the third stage nozzle is 8 ° C.
The temperature is 50 ° C., and the metal temperature of the first stage nozzle is 900 ° C. or more even when cooling is considered. Since the strength of the Co-based alloy exceeds the strength of the Ni-based alloy for the nozzle at the temperature received by the first-stage nozzle, the first-stage nozzle has excellent weldability.
Base alloys are most desirable. On the other hand, the metal temperature of the second and subsequent nozzles is 800 ° C. or less, but in that temperature range, Co
The creep strength of the Ni base for the nozzle is higher than that of the base. Therefore, it is desirable to use a polycrystalline Ni-based alloy for the second and subsequent nozzles. In a gas turbine having a turbine inlet temperature of 1500 ° C., a single-crystal Ni-based alloy is used for the first nozzle and a polycrystalline Ni is used for the second and subsequent nozzles. The material composition to be a Ni-based alloy is optimal.

The compressor blades have 17 stages and the resulting air compression ratio is 18.

As the fuel used, natural gas and light oil are used.

With the above structure, the compressor disk, the distant piece, the turbine disk, and the spacer, which are the shafts of the rotating part, are made of martensitic steel, so that a ferrite-based iron-based member is used as a structural member for holding the entire gas turbine. Since the coefficient of thermal expansion is the same, the efficiency at the time of start-up is high, so that steady operation can be reached in a short time, and a gas turbine with higher reliability as a whole as a whole as a whole can be obtained. In addition, the gas inlet temperature to the first stage turbine nozzle is 1500 ° C, the metal temperature of the first stage turbine blade is 920 ° C, the exhaust gas temperature of the gas turbine is 650 ° C, and the power generation efficiency is 37% or more in LHV display. Can be achieved.

In this embodiment, the turbine has three stages, but the present invention can be similarly applied to the four stages in combination with the steam turbine of this embodiment. For the fourth stage, the blades and nozzles of the first stage and the second stage perform the material and cooling in the same manner as in the present embodiment, and the third and fourth stages perform the material and cooling in the same manner as the third stage in the present embodiment. it can.

B. FIG. 8 shows a partial cross-sectional view of a reheat-type high-medium-low pressure integrated steam turbine according to the present invention. The steam turbine according to the present invention includes 14 stages of a high-pressure section, a middle-pressure section, and a low-pressure section having four stages of blades 4 implanted on a reheat-type high-low pressure integrated rotor shaft 3. In other steam turbines, the high pressure section is 7 stages,
The same structure is also provided for the 18-stage having 6 stages of the medium pressure section and 5 stages of the low pressure section. An internal casing is provided in the high pressure section and the medium pressure section. In this embodiment, the temperature of the exhaust gas discharged from the gas turbine is 650 ° C. as described above, and the exhaust gas is sent to an exhaust heat recovery boiler (HRSG) to obtain high-pressure steam at 538 ° C. The high-pressure steam passes through the steam control valve 55 and is supplied from the steam inlet 121 at 538 ° C. and 169 at, as described above.
g flows into the high temperature and high pressure side. The steam flows leftward from the inlet, exits from the high-pressure steam outlet 122, is heated again to 538 ° C., and is sent from the reheat steam inlet 123 to the medium-pressure turbine section. The steam that has entered the medium-pressure turbine section is sent to the low-pressure turbine section, and is also sent from the low-pressure steam inlet 124. Then, the steam temperature becomes 33 ° C. and 722 mmHg, and is discharged from the blade 4 at the final stage. The high-low pressure integrated rotor shaft 3 according to the present invention is heated from 538 ° C steam to 33 ° C.
To the temperature of Ni-Cr
Forged steel of -Mo-V low alloy steel is used. The implanted portion of the blade 4 of the high / low pressure integrated rotor shaft 3 has a disk shape, and is manufactured by being integrally cut from the high / low pressure integrated rotor shaft 3. The length of the disk portion increases as the length of the blade decreases, so that vibration is reduced. The blades 4 on the high pressure side with respect to the steam inlet have six stages of five or more stages, and are arranged at the same intervals after the second stage.
The interval between the steps is 1.5 to 2.0 times the interval after the second step, and the axial width of the blade implantation section is the thickest in the first step, and gradually increases gradually from the second step to the final step. Thick, the thickness of the first stage is 2 to 2.6 times the thickness of the second stage.

The blade 4 on the medium pressure side with respect to the steam inlet
There is a step, and the axial width of the blade implantation portion is the same at the first stage and the last stage at the same thickness and is the thickest, and increases toward the second stage and the third stage toward the downstream side. The low pressure part has four stages, and the axial width of the blade implantation part is 2.7 to 3.3 of the thickness just before the last stage.
Double, the thickness immediately before the last stage is 1.1 to
It is 1.3 times. The intervals between the centers of the blades from the first stage to the fourth stage of the medium pressure part are almost the same, and the intervals of the low pressure part become larger from the first stage to the last stage. In addition, the ratio of the interval of the first stage to the interval of the previous stage is 1.1 to 1.2 times, and the ratio of the interval between the last stage and the previous stage to the interval of the previous stage is 1.5 to 1.7 times. .

The length of the blade gradually increases from the first stage to the last stage on the medium pressure / low pressure side, and the length of each stage with respect to the preceding stage is 1.2 to 2.1 times. 1.35
The second stage of the low pressure section is 1.5 to 1.7 times, the third stage and the fourth stage are 1.9 to 2.1 times respectively.

In this embodiment, the length of each step is 2.5 ", 3", 4 ", 5", 6.3 ", 10", 20.7 "from the intermediate pressure part.
And 40 ".

Reference numeral 14 denotes an inner casing, and 15 denotes an outer casing.

(1) Rotor Shaft Table 5 shows the chemical composition of a representative sample subjected to the toughness and creep rupture tests of the high, medium and low pressure integrated steam turbine rotor according to the present invention. The sample was melted and formed in a vacuum high-frequency melting furnace and hot forged into a 30 mm square at a temperature of 850 to 1150 ° C. Samples No. 3 to No. 12 are materials according to the present invention.
Samples Nos. 1 and 2 were melted for comparison.
No. 1 is a material equivalent to ASTM standard A470 class 8, and No. 2 is a material equivalent to ASTM standard A470 class 7. These samples were simulated under the conditions at the center of the high, middle and low pressure integrated steam turbine rotor shaft, heated to 950 ° C., austenitized, and then cooled and quenched at a rate of 100 ° C./h. Then, it was heated at 665 ° C. for 40 hours, cooled in a furnace, and tempered. The Cr-Mo-V steel according to the present invention did not contain a ferrite phase and had an all-bainite structure.

The rotor shaft in this embodiment has a C value of 0.05 to 0.30% by weight, preferably 0.18 to 0.2%.
5%, Si 0.1% or less, preferably 0.06% or less, M
n 0.3% or less, preferably 0.02 to 0.20%, Ni
1.0 to 2.5%, preferably 1.5 to 2.0%, Cr
8 to 3.0%, preferably 1.5 to 2.5%, Mo 0.5 to 0.5%
2.5%, preferably 0.8-1.5%, V0.10-0.1.
Forged steels having a fully tempered bainite structure containing 35%, preferably 0.15 to 0.30%, are preferred. Furthermore, this steel has an Nb of 0.01 to 0.10%, preferably 0.015 to 0.15%.
It is preferable to contain one or more of 0.050% and W0.1 to 0.5%.

[0153]

[Table 5]

The austenitizing temperature of the steel according to the present invention needs to be 900-1000 ° C. If the temperature is lower than 900 ° C., high toughness can be obtained, and the creep rupture strength decreases. If the temperature exceeds 1000 ° C., a high creep rupture strength is obtained, but the toughness is lowered. The tempering temperature needs to be 630 ° C to 700 ° C. If the temperature is lower than 630 ° C, high toughness cannot be obtained, and if the temperature exceeds 700 ° C, high creep rupture strength cannot be obtained.

Table 6 shows the results of the tensile, impact and creep rupture tests. Toughness was expressed as V-notch Charpy impact energy tested at a temperature of 20 ° C. The creep rupture strength was represented by a strength of 538 ° C. and 10 ⁵ h determined by the Larson-Miller method. As is clear from the table, the material according to the present invention has a room temperature tensile strength of 88 kg / mm ² or more and a 0.2% proof stress of 70 kg / mm 2.
² or more, FATT of 40 ° C. or less, impact absorption energy before and after heating of 2.5 kg-m or more, and creep rupture strength of about 11 kg / mm ² or more, which can be said to be extremely useful as a high-medium-low pressure integrated turbine rotor. In particular, 3
A 3.5-inch long blade implanted turbine rotor material preferably has a strength of about 15 kg / mm ² or more.

[0156]

[Table 6]

Nos. 7 to 12 are rare earth elements (La-Ce), Ca, Zr, Ta and Al additive materials, respectively, and the toughness is improved by adding these elements. In particular, the addition of rare earth elements is effective for improving toughness. La-Ce
In addition, Y additives were also examined, and it was confirmed that there was a remarkable toughness improving effect.

By setting O ₂ to 100 ppm or less, a high strength of about 12 kg / mm ² or more can be obtained.
15 kg / mm ² or more at pm or less, and 18 kg at 40 ppm or less
/ Mm ² or higher creep rupture strength is obtained.

The creep rupture strength at 538 ° C. for 10 ⁵ hours shows a tendency to decrease as the amount of Ni increases.
When the Ni content is 2% or less, the strength is about 11 kg / mm ² or more. In particular, if it is 1.9% or less, it has a strength of 12 kg / mm ² or more.

Although the amount of Ni contained 1.52 to 2.0%, M
As a result of examining the relationship with n / Ni or (Si + Mn) / Ni ratio, it was found that Mn / Ni ratio was 0.12 or less, and Si + Mn / Ni ratio
It was found that a high impact value of 2.5 kg-m or more was exhibited at a ratio of 0.04 to 0.18.

The austenitizing temperature of the steel according to the present invention is preferably from 870 to 1000 ° C. In order to obtain high toughness and high creep rupture strength, 870 to 1000 ° C is preferable.
The tempering temperature is 61 to obtain high toughness and creep rupture strength.
0 ° C to 700 ° C is preferred. From the results of the tensile, impact and notch creep rupture tests, the toughness was indicated by the V-notch Charpy impact energy tested at a temperature of 20 ° C. Creep rupture strength was 538 ° C., 10 ⁵ determined by the Larson-Miller method.
h Indicated by strength. As is clear from the table, the material of the present invention is:
Tensile strength at room temperature is 88 kg / mm ² or more, 0.2% 70k
g / mm ² or more, FATT 40 ° C. or less, shock absorption energy before and after heating is 2.5 kg-m or more and creep rupture strength is as high as about 12 kg / mm ² or more, making it extremely useful as a high-medium-low pressure integrated turbine rotor. It can be said. In particular, a turbine rotor material on which a 33.5 inch long blade is to be implanted preferably has a strength of about 15 kg / mm ² or more.

Further, the (Ni / Mo) ratio is 1.25 or more and the (Cr / Mo) ratio is 1.1 or more, or (Cr / Mo)
The ratio is 1.45 or more, and the (Cr / Mo) ratio is [-1.1.
1 × (Ni / Mo) +2.78] or more so that the same heat treatment can be performed to obtain a high creep rupture strength of 538 ° C. for 10 ⁵ hours of 12 kg / mm ² or more.

FIG. 9 shows the shape of the high, medium and low pressure integrated rotor shaft 3 according to the present invention. The rotor shaft of this embodiment was prepared by melting a forged steel having an alloy composition shown in Table 7 in an arc melting furnace.
The molten metal was poured into a ladle, and then Ar gas was blown from the lower part of the ladle to perform vacuum refining to form an ingot. Then, 900-1150
Forged to a maximum diameter of 1.7m and a length of about 8m at ℃, high pressure side 1
6 at 950 ° C for 10 hours, medium pressure / low pressure side 17 at 880
After heating and holding for 10 hours at about 100 ° C / h at the center
While cooling the shaft, water spray cooling or immersion in water was performed. Then, the high pressure side 116 is set to 650 ° C.
For 40 hours, and tempering by heating and holding the medium pressure / low pressure side 117 at 625 ° C. for 40 hours. A test piece was cut out from the center of the rotor shaft and subjected to a creep rupture test, a V-notch impact test (cross-sectional area of the test piece: 0.8 cm ² ), and a tensile test.
Table 8 shows the test results. As shown in the figure, the axial width and spacing of the implanted portion 18 of each blade on the high pressure side 116 and the medium pressure / low pressure side 117 are as described above.
19 is a bearing part, and 20 is a coupling.

[0164]

[Table 7]

[0165]

[Table 8]

The diameter of the moving blade portion and the stationary blade portion of the high pressure portion is the same in each stage, and the diameter gradually increases in the moving blade portion from the intermediate pressure portion to the low pressure portion.
The diameter at the stationary blade portion is the same up to the stage. The diameter at the stationary blade portion between the 4th stage and the 6th stage is the same. The diameter at the stationary blade portion from the 6th stage to the 8th stage is the same. The diameter has increased.

The axial width of the last stage blade implant is 0.3 times the length of the blade, preferably 0.28 to 0.35 times.

The rotor shaft has the largest blade diameter at the last stage, and the diameter is 1.72 times the length of the blade, preferably 1.60 to 1.85 times.

Further, the length between the bearings is 1.65 times the diameter between the blade tips in the final stage blade, and
Preferably it is 1.75 times.

In this embodiment, 100,000 to 200,000 K
W power can be generated. The distance between the bearings 32 of the rotor shaft in this embodiment is about 520 cm, and the outer diameter of the last stage blade is 316 cm.
It is. The length between these bearings is 0,000 per 10,000 kW of power output.
52m2.

In this embodiment, when a 40-inch blade is used as the last stage blade, the outer diameter is 365 cm, and the bearing ratio to this outer diameter is 1.43. As a result, a power generation output of 200,000 KW is possible, and the distance between bearings per 10,000 KW is 0.26 m.

The ratio of the length of these last stage blades to the outer diameter of the blade implant portion of the rotor shaft is 33.
1.70 for 5 "blades and 1.7 for 40" blades
1.

This embodiment can be applied to a steam temperature of 566 ° C., and can be applied to a case where the pressure is set to 121, 169 and 224 atg.

To increase the output of a single machine, it is necessary to increase the blade length of the final stage rotor blade and increase the steam flow rate. For example, if the blade length of the last stage rotor blade is set to 33.5 inches longer than 26 inches, the annulus area increases by about 1.7 times. Therefore, if the blade length is increased from the conventional output of 100 MW to 170 MW, and further to 40 inches, the output of a single unit can be increased more than twice.

When using a long wing of a class of 30 inches or more and 40 inches or more, a material having a tensile strength of 88 kg / mm ² or more is preferable.

Further, as a high-medium-low pressure integrated steam turbine rotor material on which a long blade of 30 inches or more is mounted, 538 ° C., 10 ° C.
⁵ h The creep rupture strength is preferably 15 kg / mm ² or more, and the impact absorption energy at room temperature is preferably 2.5 kg-m (3 kg-m / cm ² ) or more from the viewpoint of ensuring safety against brittle fracture on the low pressure side. The method of hardening the rotor shaft can be performed by the following method. (A) After uniformly heating each element body to 940 ° C., a portion corresponding to a high pressure portion and a medium pressure portion in an 18-stage steam turbine or a high pressure portion in a 14-stage steam turbine is
Cooling at a cooling rate of 25 ° C / h assuming the cooling rate of the central part when the actual turbine rotor body is forcibly air-cooled, and the low-pressure part or the part corresponding to the medium-pressure / low-pressure part is cooled with fountain or water Cooling at a cooling rate of 50 ° C./h assuming the cooling rate of the central part, and quenching with a different cooling rate (uniform heating / deviation cooling).

(B) As in (a), the turbine rotor body is replaced with a portion corresponding to the high pressure portion and the medium pressure portion or a high pressure portion of 97%.
0 ° C, 930 parts corresponding to low pressure part or medium pressure / low pressure part
° C, and then the cooling rate at the center is assumed to be 50 when the actual turbine rotor body is cooled by fountain or water.
Cooling at a cooling rate of ° C./h and quenching (deviation heating / uniform cooling).

(C) The parts corresponding to the high-pressure part and the medium-pressure part or the high-pressure part are 97
0 ° C, 930 parts corresponding to low pressure part or medium pressure / low pressure part
℃, and further cools the part corresponding to the high / medium pressure part or the high pressure part at a cooling rate of 25 ° C./h assuming a central part cooling rate when the actual turbine rotor element is forcibly air-cooled. A method of cooling a low pressure part or a part corresponding to a medium pressure / low pressure part at a cooling rate of 50 ° C./h assuming a central part cooling rate in the case of fountain cooling (deviation heating / deviation cooling). Each element can be cooled by immersing it in a water bath and stirring the water. After the quenching, the element is tempered at 650 ° C. for 20 hours.

According to the material test results of the test steel after the heat treatment, according to the method of the present invention, the high-temperature creep strength is improved in the high-pressure part and the toughness is improved in the low-pressure part, as compared with the conventional method. Further, in the method of the present invention, the method using the deviation heating / uniform cooling has a more remarkable effect than the deviation heating / deviation cooling and the uniform heating / deviation cooling.

(2) Blade The length of the three steps on the high temperature and high pressure side is about 40 mm, and the weight is C0.2.
0 to 0.30%, Cr 10 to 13%, Mo 0.5 to 1.5
%, W 0.5 to 1.5%, V 0.1 to 0.3%, Si 0.5
%, Mn 1% or less and the balance Fe.

The medium pressure portion gradually increases in length as it goes to the low pressure side, and has a C weight of 0.05 to 0.15% and a Mn of 1%.
Below, Si0.5% or less, Cr10-13%, Mo0.5.
Forging of martensitic steel consisting of 5% or less, Ni 0.5% or less, and the balance Fe.

As the final stage, when the wing length is 35 inches for 60 cycles, there are about 90 wings per round, and the weight is C
0.08 to 0.18%, Mn 1% or less, Si 0.25% or less, Cr 8 to 13%, Ni 2.0 to 3.5%, Mo 1.5 to 1.5
3.0%, V 0.05 to 0.35%, N 0.02 to 0.10
%, Nb and / or Ta in a total amount of 0.02 to 0.2.
It was constituted by forging a martensitic steel containing 0%.
In particular, in this embodiment, the alloy No. 2 shown in Table 1 of Embodiment 1 was used. In addition, a shield plate of stellite plate for preventing erosion is welded at the tip of this last stage,
Provided in the leading edge section. In addition to the shield plate, a partial quenching process is performed. In addition, a forging of martensitic steel having a wing length of 43 inches or more is used for 50 cycles.

Each of these blades is fixed by a shroud plate made of the same material by caulking four to five blades at each end by a protruding tenon.

Table 9 shows the chemical composition (% by weight) of 12% Cr steel for the long blade material for the high / low pressure integrated steam turbine. Samples No. 1 to No. 6 were each subjected to high-frequency vacuum melting of 150 kg, heated to 1150 ° C. and forged to obtain experimental materials. Sample No. 1 was cooled to room temperature by oil quenching (cooling rate of 100 ° C./min or more) after heating at 1000 ° C. for 1 hour,
Next, the mixture was heated to 570 ° C., kept at room temperature for 2 hours, and air-cooled to room temperature. No. 2 was heated at 1050 for 1 h, cooled to room temperature by oil quenching, then heated to 570 ° C., held for 2 h and air-cooled to room temperature. Samples No. 3 to No. 7 were heated at 1050 ° C. for 1 hour, cooled to room temperature by oil quenching,
After heating to 60 ° C. and holding for 2 hours, it was air-cooled to room temperature (primary tempering), further heated to 580 ° C., and kept for 2 hours and furnace-cooled to room temperature (secondary tempering).

[0185]

[Table 9]

In Table 9, Nos. 3, 4 and 7 are materials of the present invention, Nos. 5 and 6 are comparative materials, and Nos. 1 and 2 are current long wing materials.

Table 10 shows the mechanical properties of these samples at room temperature. The materials of the present invention (Nos. 3, 4 and 7) have the tensile strength (120 kgf / mm ² or more or 128.5 kgf / mm ² or more) and low temperature toughness (20 ° C.
Notch Charpy impact value of 4 kgf-m / cm ² or more) was confirmed to be sufficiently satisfied.

On the other hand, the comparative materials No. 1, No. 5 and No. 6 have low values of both or any of the tensile strength and the impact value for use in long blades for steam turbines. Comparative material No. 2 has low tensile strength and toughness. No.5 is impact value 3.8kgf-m / cm ² and slightly lower, for 43 "or more is slightly deficient in 4kgf-m / cm ² or more requests.

[0189]

[Table 10]

In this embodiment, the Ni and Mo contents are contained in the same content to increase both low-temperature strength and toughness, and the strength decreases as the difference between the two contents increases. Show the trend. When the amount of Ni is less than 0.6% or less than the amount of Mo, the strength is sharply reduced, and conversely, when the amount of Ni is more than 1.0%, the strength is sharply reduced. Therefore, the (Ni-Mo) amount is -0.6.
１1.0% indicates high strength. (Ni-Mo) amount is -0.0.
The impact value decreases around 5%, but shows a high value before and after that. 0.1-0.5% is preferable.

Looking at the effects of heat treatment conditions (quenching temperature and secondary tempering temperature) on the tensile strength and impact value of Sample No. 3, the quenching temperature was 975 to 1125 ° C, and the tempering was performed at 550 to 560 ° C for 1 hour. After that, the secondary tempering temperature is 560
５590 ° C. As shown in the table, it was confirmed that the characteristics required for the long blade material (tensile strength ≧ 128.5 kgf / mm ² , notch Charpy impact value at 20 ° C. ≧ 4 kgf-m / cm ² ) were satisfied.

The 12% Cr steel according to the present invention is particularly suitable for C + N
The amount of b is 0.18 to 0.35% and the (Nb / C) ratio is 0.45.
1.00 and (Nb / N) ratio of 0.8 to 3.0 are preferred. The amount of C + Nb is 0.19 to 0.29%, more preferably 0.21 to 0.29%.
0.27% or the amount of C + V / 2 + Nb is 0.33 to 0.43.
%, More preferably 0.35 to 0.41%.

All samples have a fully tempered martensite structure, and the average crystal grain size of each sample is 5.5 to 6.0 in terms of particle size number (GSNo.). The (Nb / C) ratio is 0.5 to
1.0, the (Nb / N) ratio is preferably 1.3 to 2.0. Further, the (Mn / Ni) ratio is 0.11 or less, more preferably from 0.04 to 0.1.
10 is preferred.

From the diagram showing the relationship between the 0.2% proof stress and the tensile strength, the material according to the present invention has a 0.2% proof stress (y) of especially 3%.
Preferably, the value is not less than 6.0 plus a value obtained by multiplying the tensile strength (x) by 0.5. From the diagram showing the relationship between the 0.2% proof stress and the 0.02% proof stress, the material according to the present invention is particularly 0.2%.
The yield strength (y) is 58.4 and the 0.02% yield strength (x) is 0.54.
It is preferable that the value be equal to or more than the value obtained by adding the multiplied values.

FIG. 10 shows that the wing length for 3000 rpm is 10
Fig. 11 is a perspective view of a final stage blade having a diameter of 92 mm (43 "). Fig. 11 is a side view thereof. 41 is a wing portion against which high-speed steam is impinged.
Are pin holes for inserting pins to support the centrifugal force of the wing,
Reference numeral 4 denotes an erosion shield (welding a stellite plate of a Co-based alloy by welding) for preventing erosion due to water droplets in steam, and 47 denotes a cover. In this embodiment, it is formed by cutting after the whole forging. Note that the cover 47 can be formed integrally mechanically.

As shown in FIGS. 10 and 11, the wing implant 42 is of a fork type having eight implants. 11, pin insertion holes 43 for inserting pins into a fork shape are provided in three stages, and corresponding recesses are provided. The diameter of the pin insertion hole 43 is the largest on the wing side and is gradually reduced. The inclination of the wing portion 41 in the width direction is substantially parallel to the axial direction of the axle, and the wing implantation portion 42 is gradually inclined at about 75 degrees at the tip of the wing. In this embodiment, the maximum width of the wing implant 42 is about 2.4 times the width of the tip of the wing, and preferably 2.2 to 2.6.
Reference numeral 48 denotes an extension width of a tangent line to the vicinity of the wing implantation portion 42 of the wing portion 41, which is an effective width of the wing portion 41 and has about 1.79 times the width of the wing tip. 1.6
It is preferably from 0 to 1.85 times.

The 43 ″ long blade was produced by forging and processing after electroslag remelting and forging. The forging was performed at a temperature in the range of 850 to 1150 ° C., and the heat treatment was performed in Example 1. Conditions (quenching: 1050 ° C, primary tempering: 56
(0 ° C., secondary tempering: 580 ° C.). No. 7 in Table 9
Indicates the chemical composition (% by weight) of this long wing material. The metal structure of this long wing was a fully tempered martensite structure.

No. 7 in Table 9 shows room temperature tensile and 20 ° C. V notch Charpy impact values. The mechanical properties of this 43 ”long blade have the required properties, tensile strength of 128.5 kgf / mm ² or more, 20 ° C V notch Charpy impact value of 4 kgf-m / cm ² or more, and can be sufficiently satisfied. confirmed.

The erosion shield in this embodiment (by weight, C 1.0%, Si 0.6%, Mn 0.6%, C
(a stellite alloy composed of 28% r, 1.0% W, and the balance of Co) 44 is joined by electron beam welding or TIG welding. The erosion shield 44 is welded at two places, a front side and a back side. The blade tip is provided with a continuous cover 47 formed integrally with the wing.

[0200]

[Table 11]

Table 11 shows the mechanical properties of the long wing material at 25 ° C.

(3) Martensite steel having the same composition as that of the moving blade is used for the stationary blade 7 up to the third stage of high pressure. .

(4) The inner casing 1
4 and an outer casing 15. The inner casing has a weight of C 0.15 to 0.3%, Si 0.5% or less, Mn 1% or less, Cr 1 to 2%, Mo 0.5 to 1.5%, V 0.05 to 0.5%.
A Cr-Mo-V cast steel of 0.2% or less and 0.1% or less of Ti is used.

The generator can generate 100,000 to 200,000 KW. The distance between the bearings 62 of the rotor shaft in this embodiment is about 520 cm, the outer diameter of the last stage blade is 316 cm, and the ratio of the center to the outer diameter is 1.65. A power generation capacity of 100,000 KW is possible. The distance between the bearings is 0.52 m per 10,000 KW of power output.

In this embodiment, when a 40-inch blade is used as the last stage blade, the outer diameter is 365 cm, and the ratio of bearings to this outer diameter is 1.43. As a result, a power generation output of 200,000 KW is possible, and the distance between bearings per 10,000 KW is 0.26 m.

The ratio of the length of these last stage blades to the outer diameter of the blade implantation portion of the rotor shaft is 33.
1.70 for 5 "blades and 1.7 for 40" blades
1.

According to this embodiment, all the structural members of the rotating part are made of ferrite steel having a small thermal expansion coefficient and are covered with the ferrite steel having the same thermal expansion coefficient as the whole supporting the turbine nozzle and the compressor nozzle. , So that it can respond quickly when starting and stopping,
This contributes to improvement in thermal efficiency.

In this embodiment, the above-described gas turbine and steam turbine are uniaxially connected to generate electric power. A high combined power generation plant having an HHV efficiency of 50% or more for electric power generation was obtained.

In this embodiment, the steam temperature can be applied at 566 ° C., and the pressure can be applied at 121, 169 and 224 atg.

[Embodiment 2] FIG. 12 shows a sectional structure of an upper half of an air compression type three-stage turbine having a closed air cooling system in place of the steam cooling of the embodiment 1. The basic structure and material configuration of the turbine structure in this embodiment are almost the same as those in the first embodiment.

In the air cooling system of this embodiment, the first stage blade 51 and the second stage blade 52 have the same cooling passage as the steam cooling of the first embodiment, and the second stage nozzle 82
The cooling of the third stage nozzle 83 has the same cooling channel as that of the first embodiment. The first stage nozzle is cooled by the same compressor as that of the first stage blade and the second stage blade, is extracted from the inside of the casing 80, is cooled by the cooler 67, and is cooled by the air compressed by the booster 65. First stage nozzle 81 and blade 5
The air that has cooled the first and the second 52 is discharged into the casing 80.

The combustion gas exiting the turbine section is sent to an exhaust heat recovery boiler (HRSG), thereby producing steam.

The first stage nozzle 81 in this embodiment has a cooling hole, and cooling air enters from the outer side wall.
It has a structure in which it is discharged into the casing 80 through a vane provided with a plurality of cooling holes, through an inner peripheral side wall.

In this embodiment, the turbine disks 11, 1
2. The turbine stub shaft and the turbine stacking bolts are made of the fully tempered martensitic steel shown in the first embodiment, and the weight of the turbine disk 13 is 0.05 to 0.5%.
2%, Si 0.5% or less, Mn 1% or less, Cr 8-13
%, Ni 3% or less, Mo 1.5-3%, V 0.05%-
0.3%, Nb 0.02 to 0.2%, N0.02 to 0.1%
A heat-resistant steel having a fully tempered martensite structure substantially consisting of Fe is used. The heat resistant steels shown in Table 10 of Example 5 were used. As described below, 4
50 ° C, 10 ⁵ h Creep rupture strength of 50 kgf / mm ² or more, 20 ° C V Notch Charpy impact value of 7 kgf-m / cm
Thus, the strength required as a material for a high-temperature gas turbine is sufficiently satisfied. These martensitic steels have a ferrite-based crystal structure.
The coefficient of thermal expansion is smaller than that of an austenitic material such as an i-base alloy. This embodiment using heat-resistant steel than using a Ni-based alloy for the turbine disk has higher thermal efficiency,
Further, the thermal stress generated in the disk having a small coefficient of thermal expansion of the disk material can be reduced, and the generation and breakage of cracks can be suppressed. The materials and structures of other parts are the same as in the first embodiment.

The compressor blades have 17 stages and the resulting air compression ratio is 18.

As the fuel used, natural gas and light oil are used.

With the above configuration, a more reliable and balanced gas turbine is obtained overall, the gas inlet temperature to the first stage turbine nozzle is 1500 ° C., the metal temperature of the first stage turbine blade is 900 ° C., and the exhaust gas of the gas turbine is exhausted. The temperature is 650 ° C., and a power generation gas turbine having a power generation efficiency of 37% or more in LHV display can be achieved.

FIG. 13 shows a gas turbine 1 similar to the first embodiment.
FIG. 2 is a configuration diagram showing a multi-shaft combined cycle power generation system in which a table, a high-medium / low-pressure integrated steam turbine, and a generator are respectively provided. The gas turbine in the present embodiment is as described above, and the air compressed by the compressor passes through an air pre-cooler (IC) for cooling it, and further a boost compressor (BC) for further compressing the air. Through the above-described path, the blade (rotor blade) and the nozzle (stationary blade) are cooled by the above-described path, and the air used for the cooling is warmed and used in the combustor.
The combustion gas temperature in this embodiment is 1500 ° C. or higher, the exhaust gas temperature is 600 ° C. or higher, and an exhaust heat recovery boiler (HRS) provided with a denitration device (DeNOx) as described above.
G) generates 530 ° C. or higher steam. 530 ° C
The above steam enters the high pressure section (HP) of the high, middle and low pressure integrated steam turbine, and the steam discharged from the high pressure section (HP) again enters the head of the HRSG and is reheated, and is heated to the same temperature as the inlet temperature of the HP. From the medium pressure section (IP) to the low pressure section (L
It has a path into the HP section after flowing into P), entering the condenser, and then entering the latter part of the HRSG and being reheated to 530 ° C. or higher.

The constructions of the gas turbine and the high, medium and low pressure integrated steam turbine in this embodiment are almost the same as those in the first embodiment. In this embodiment, the gas turbine is 20 to 3
100,000 KW and steam turbine has 100,000-200,000 KW,
HHV efficiency of the plant of 50% or more is obtained. In addition, a total of 70 to 70 gas turbines and steam turbines
1,000,000 KW of power generation is possible. In the present embodiment, a multi-shaft type is used. However, a gas turbine and a steam turbine may be directly connected by a single shaft and power may be generated by one generator. In this embodiment, the steam temperature is 538 ° C. (1000 ° C.).
° F) and 566 ° C (1050 ° F), but also for 593 ° C (1100 ° F) used as the high, medium and low pressure integrated rotor shaft for the turbine disk according to the present invention. A martensitic steel containing 5% by weight Cr is preferred.

In this embodiment, the turbine has three stages. However, the present invention can be similarly applied to the four stages in combination with the steam turbine of this embodiment. For the fourth stage, the blades and nozzles of the first stage and the second stage perform the material and cooling in the same manner as in the present embodiment, and the third and fourth stages perform the material and cooling in the same manner as the third stage in the present embodiment. it can.

According to the present embodiment, as in the first embodiment, the gas turbine can be started and stopped quickly, so that a higher thermal efficiency can be obtained, and the HHV efficiency of power generation is 50%.
A combined power plant having the above is obtained.

[Embodiment 3] FIG. 14 shows that exhaust gas from the above-mentioned gas turbine is supplied to an exhaust heat recovery boiler (HRSG) and generated, and the steam is used to cool the gas turbine as described above and to operate as a steam turbine. 1 is a configuration diagram of a combined cycle power generation system including a steam turbine divided into a high-pressure steam turbine (HP), a medium-pressure steam turbine (IP), and a low-pressure steam turbine (LP). This embodiment is different from the first embodiment in that the steam turbine is divided into high-pressure, medium-pressure and low-pressure steam turbines, the high-pressure part and the medium-pressure part are formed as an integral rotor shaft, and the low-pressure part has a different composition. This is the point constituted by the rotor shaft. The inlet temperature of water vapor is 538 ° C with the same temperature of HP and IP
Or 566 ° C., and the inlet temperature of LP is about 3
It will be 00 ° C. The steam discharged from the HP is heated by an exhaust heat recovery boiler and enters the IP. The HP and the IP in the steam turbine are composed of a single shaft and an integral rotor shaft, and the rotor shaft material is different from that of the LP. No. 1 material and LP in Table 3 are used for HP and IP rotor shafts.
No. 2 in Table 3 is used. L in the present embodiment
The last blade of P has a wing length of 43 as in the first embodiment.
An inch of 12% Cr-based martensitic steel is used.
The casing is composed of two compartments, one compartment for HP and IP and one compartment for LP. Water vapor from IP is HRS
Along with the steam of about 300 ° C. that has exited from G, it flows into the center of the LP having a symmetrical turbine structure. The configuration of the gas turbine according to the present embodiment is almost the same as that of the first embodiment. The outputs of the gas turbine and the steam turbine are the same as those of the first embodiment, and the HHV efficiency of power generation is 50% or more.

Embodiment 4 This embodiment has the following requirements in place of the gas turbines of Embodiments 1 to 3.

The first stage blade 51 of the gas turbine is made of Ni
It is a single crystal casting of a base superalloy with Cr 6-8% by weight,
Mo 0.5-1%, W 6-8%, Re 1-4%, Al4
-6%, Ta 6-9%, Co 0.5-10%, Hf 0.0
It is composed of 3 to 0.13%, and an alloy consisting of Ni and impurities inevitable in the balance. The first blade has a wing portion of 130 mm and a total length of about 220 mm. 10 ^{5 of} this single crystal casting
The service temperature of 14 kgf / mm ² is 930 ° C. to 940 ° C., and a complicated air cooling hole is provided inside, so that it is cooled by compressed air during operation. The cooling system is a closed system and the cooling structure is a staggered rib system. On the blade surface, Al 2 to 5%, Cr 20 to 30%, Y0.
An alloy layer containing 1 to 1% and the balance of Ni or Ni + Co is subjected to plasma spraying in a non-oxidizing reduced pressure atmosphere by plasma spraying.
It was provided with a thickness of about 150 μm to enhance corrosion resistance. This single crystal casting is subjected to a solution treatment at 1250 to 1350 ° C.
A two-stage aging treatment at 1100 ° C. and 850-950 ° C. was performed to precipitate a γ ′ phase having a length of 1 μm or less on one side at 50-70% by volume.

The second stage blade 52 and the third stage blade 53 are, by weight, 12 to 16% Cr, 0.5 to 2% Mo,
W2-5%, Al2.5-5%, Ti3-5%, Ta1.
5 to 3%, Co 8 to 10%, C 0.05 to 0.15%,
B is comprised of a Ni-based superalloy consisting of 0.005% to 0.02% and the balance of unavoidable impurities and Ni. These blades have an equiaxed structure obtained by ordinary casting. The second stage blade has an internal cooling hole, and is cooled by compressed air. The service temperature of 14 kgf / mm ² for 10 ⁵ hours for these materials is 840 ° C. to 860 ° C. The blade surface was provided with a diffusion coating of Cr or Al to enhance corrosion resistance. These Ni-based alloys are subjected to heat treatment as described above.

The first stage nozzle 81 has a weight of Cr 24-3.
0%, Ni 8-12%, W 6-9%, Ti 0.1-0.4
%, Co 8 to 10%, C 0.2 to 0.4%, B 0.005
% Or less, Fe 1.0% or less, Zr 1.0% or less, Nb 0.
An ordinary cast material (equiaxed structure) of a Co-based superalloy containing 3% or less, Hf 1.0% or less, Ta 2.0% or less, and Co, which is unavoidable, and Co is used. The service temperature of 6 kgf / mm ² for 10 ⁵ hours of this alloy is 900 ° C. to 910 ° C. The cooling is a closed impingement cooling.
A portion of the outer surface of the first stage nozzle that is in contact with the flame is provided with a thermal barrier coating layer. It consists of fine columnar crystal, a Y ₂ O ₃ stabilized zirconia layer having a columnar crystal structure of the double structure having a columnar crystal macroscopic columnar crystals of the following diameters 10μm in fine diameter 50~200μm It is provided to a thickness of 100 to 200 μm by vapor deposition and comprises a bonding layer between a base metal and a zirconia layer. The tie layer is A
This is a sprayed layer made of an alloy containing 12 to 5%, Cr 20 to 30%, and Y 0.1 to 1%, and the balance being Ni or Ni + Co. The alloy layer also has the effect of improving corrosion resistance. The cast material was subjected to a solution treatment at 1150 to 1200 ° C.
A heat treatment of a one-stage aging treatment is performed at ８880 ° C.

Second Stage Nozzle 82 and Third Stage Nozzle 83
In weight, Cr 21-24%, Co 18-23%, C
0.05 to 0.20%, W1 to 8%, Al1 to 2%, Ti
2-3%, Ta 0.5-1.5%, B 0.05-0.15
%, And alloy Ni consisting of Ni and unavoidable impurities
It is composed of a base superalloy. These nozzles have an equiaxed structure obtained by ordinary casting. Although it is not particularly necessary to provide a thermal barrier coating layer, a diffusion coating of Cr or Al is applied to the second stage nozzle in order to enhance corrosion resistance.
Each has an internal cooling hole and is cooled by compressed air. The service temperature of 6 kgf / mm ² for 10 ⁵ hours for these materials is 840 ° C. to 860 ° C. The same heat treatment is applied to the cast material.

In this embodiment, the turbine disks 11, 12
The fully tempered martensitic steel used in Example 1 was used. The turbine disk 13 has a C.O.
0.5 to 0.2%, Si 0.5% or less, Mn 1% or less, Ni
3% or less, Cr 8 to 13%, Mo 1.5 to 3.0%, V
0.05-0.3%, Nb 0.02-0.10% and N0.02
A fully tempered martensitic steel containing ０0.10% was used. Specific examples of this compound are the same as in Example 2, the characteristics of, 450 ° C., 10 ⁵ h creep rupture strength 50kgf
/ Mm ² or more, which sufficiently satisfies the strength required for high-temperature gas turbine materials. The compressor blades have 17 stages and the resulting air compression ratio is 18. Natural gas and light oil are used as fuels.

With the above configuration, a gas turbine with higher reliability and a higher balance can be obtained overall as described above, and the gas inlet temperature to the first stage turbine nozzle is 150 ° C.
0 ℃, the metal temperature of the first stage turbine blade is 920 ℃,
The exhaust gas temperature of the gas turbine is 650 ° C., and a gas turbine for power generation having a power generation efficiency of 37% or more in LHV display can be achieved, and a high combined power generation plant having an HHV efficiency of power generation of 50% or more can be obtained.

[Embodiment 5] This embodiment has the following requirements in place of the gas turbines of Embodiments 1 to 3.

The first stage blade 51 of the gas turbine according to the present embodiment has substantially the same structure as that of the first embodiment, and is a unidirectionally solidified columnar crystal casting of a Ni-based superalloy.
6%, Mo 0.3-2%, W2-9%, Al 2.5-6
%, Ti 0.5-5%, Ta 1-4%, Co 8-10
%, C 0.05 to 0.15%, B 0.005 to 0.02%,
And a Ni-based superalloy consisting of Ni and the unavoidable impurities. The total length of the first stage blade is about 220 mm.
14 kgf / mm ^{2 of the} unidirectionally solidified columnar casting for 10 ⁵ hours
Since the durable temperature is 890-900 ° C., a thermal barrier coating layer for lowering the metal temperature of the material is provided in the same manner as in Example 1. Unidirectional solidification is performed sequentially over the dovetails from the wing side, and is constituted by columnar crystals. The diameter of the columnar crystals is 2 to 10 mm, the wings are small, and the shanks are large from the shank. 1 directionally solidified casting
After subjecting to a solution treatment at 200 to 1280 ° C, 1000
A two-stage aging treatment is performed at 1150 ° C. and 800-950 ° C., and 50-70% by volume of a γ ′ phase having a side length of 2 μm or less is precipitated. In particular, it is preferable to precipitate 60 to 65% by volume.

Second stage blade 52, third stage blade 53
Is the same as that used in the first embodiment.

The first-stage nozzle 81 uses the same alloy as in Example 1, but the thermal barrier coating layer has the following structure. Sequentially directed from the surface portion to the base material, Y ₂ O ₃ stabilized zirconia thermal sprayed layer, an alloy layer, a mixed layer of ceramic and alloy,
It has a four-layer structure of an alloy layer and has functions of heat shielding, thermal stress relaxation, and corrosion resistance. The tie layer is 2-5% Al, Cr20 by weight.
~ 30%, Y0.1 ~ 1%, balance Ni or Ni + C
o.

Second-stage nozzle 82 and third-stage nozzle 83
Also, as in Example 1, Cr 21 to 24% by weight, Co 1
8-23%, C 0.05-0.20%, W1-8%, Al
1-2%, Ti 2-3%, Ta 0.5-1.5%, B0.
It is composed of a Ni-based superalloy containing 0.5 to 0.15% and the balance of unavoidable impurities and Ni. Although it is not particularly necessary to provide a thermal barrier coating layer, the second-stage nozzle has Al 2 to 5%, Cr 20 to 30%, Y
An alloy layer composed of an alloy containing 0.1 to 1% and the balance being Ni or Ni + Co is provided. Each has an internal cooling hole and is cooled by compressed air. One of these materials
0 tolerable temperature for ⁵ hours 6 kgf / mm ² is 840 ℃ ~860 ℃.

In the present embodiment, the martensitic steel used in the first embodiment is used for the turbine disk 11, the turbine stub shaft 34, and the turbine stacking bolt, and the turbine disks 12, 13 have the same weight as in the second embodiment.
0.05-0.2%, Si 0.5% or less, Mn 1% or less,
Cr 8 to 13%, Ni 3% or less, Mo 1.5 to 3%, V
0.05 to 0.3%, Nb 0.02 to 0.2%, N 0.02
A heat-resistant steel having a fully tempered martensitic structure of about 0.1% and the balance substantially consisting of Fe was used.

The compressor blades have 17 stages and the resulting air compression ratio is 18. Natural gas and light oil are used as fuels.

The martensitic steel of this example has a smaller coefficient of thermal expansion than an austenitic material such as a Ni-based alloy. In this embodiment, in which the heat-resistant steel is used for the turbine disk as compared with the Ni-based alloy, since the thermal expansion coefficient of the disk system is smaller, it is possible to generate power with high thermal efficiency from the start. Further, thermal stress can be reduced, and generation and fracture of cracks can be suppressed.

With the above configuration, a gas turbine having higher overall reliability and a higher balance can be obtained as described above, the gas inlet temperature to the first stage turbine nozzle is 1350 ° C., and the metal temperature of the first stage turbine blade is lower. The gas turbine exhaust gas temperature is 850 ° C and the exhaust gas temperature of the gas turbine is 600 ° C. The time required for steady operation is short, and the slight reduction of the time is extremely important for improving the thermal efficiency of a gas turbine with a frequent start / stop. .

A gas turbine for power generation having a power generation efficiency of 37% or more in LHV display can be achieved.

Further, a combined power plant having an HHV efficiency of power generation of 50% or more can be obtained.

[Embodiment 6] FIG. 15 is a sectional view of an air cooling system and a turbine rotating section of a gas turbine according to the present invention. The configuration of the turbine rotating section is almost the same as that of FIG. Although not shown, the main configuration of the gas turbine in this embodiment has an air compressor, a combustor, and a turbine. Furthermore, detailed parts include a turbine stub shaft, a turbine stacking bolt, a turbine spacer, a distant piece, a compressor disk, a compressor blade, a compressor stacking bolt, a compressor stub shaft, and a turbine disk. There are three stages. The same can be applied to four stages.

In this embodiment, as shown by the flow of air shown by the arrow in FIG. 15, each component is cooled using the air compressed by the compressor. First stage nozzle 81, second stage nozzle 8
In 2, air flows in from the outer side wall and is discharged from the wing. The two-stage nozzle is cooled over the inner sidewall. In the third stage nozzle 83, air flows in from the outer side wall, exits from the inner side wall, and is discharged outside the spacer portion. First stage blade 5
Numeral 1 indicates that compressed air passes from the center of the turbine disk 11 through the side wall thereof, passes through the spacer 18, passes through cooling holes provided inside the blade, and is discharged from the trailing portion of the tip and the blade. This cools both the blade and the disk. In the blade, air is flown from the seal fin so that combustion gas does not flow into the inside. Similarly, the second stage blade 52 is discharged from the tip portion through the cooling hole provided in the blade through the spacer 18 from the turbine disk 12 and is cooled. Although the third stage blade 53 has no cooling holes, it passes through the side wall of the turbine disk 13 from the center thereof, passes through the seal fins, cools them, and enters the exhaust heat recovery boiler together with the combustion gas, where steam is formed. , Power source of the steam turbine.

In this embodiment, the turbine disk 11,
20 kg of each sample having the composition (% by weight) shown in Table 12 was dissolved as a material used in 12 and 13, and heated to 1150 ° C. and cast to obtain an experimental material. This material was heated at 1150 ° C for 2 hours and then subjected to impingement cooling, the cooling temperature was stopped at 150 ° C, the temperature was heated at 580 ° C for 2 hours, then air-cooled, and then tempered at 605 ° C for 5 hours, followed by furnace cooling. Was subjected to secondary tempering.

From the material after the heat treatment, a creep rupture test piece,
Tensile test pieces and V-notch Charpy impact test pieces were sampled and used for the experiment. In the impact test, the material was heat treated 500
The test was performed on the embrittled material heated at 1000C for 1000 hours. The embrittlement material is 10 ° C at 450 ° C according to Larson-Miller parameters
The conditions are the same as those heated for ⁵ hours.

[0245]

[Table 12]

Table 13 shows the mechanical properties of these samples.
Nos. 1 and 6 have the following requirements: 450 ° C, 10 ⁵ h creep rupture strength (> 50 kg / mm ² ) and 25 ° C V notch Charpy impact value [4 kg- m (5 kg-mcm ² ) or more]. Looking at the mechanical properties of a high steel having an Mn / Ni ratio of 0.12 or more (sample numbers 3 to 7), the creep rupture strength can satisfy the value required for a high-temperature / high-pressure gas turbine disk material, The subsequent V notch Charpy impact value was as low as 3.5 kg-m or less.

[0247]

[Table 13]

When the (Mn / Ni) ratio is 0.11 or less, the embrittlement is sharply improved, becomes 4 kg-m (5 kg-m / cm ² ) or more, and when it is 0.10 or less, 6 kg-m (7.5 kg). −m / cm ² )
It was the most preferable one that provided the above excellent characteristics. However, Mn is indispensable as a deoxidizing agent and a desulfurizing agent, and is preferably 0.05 to 0.20%.
Also, the impact value after embrittlement is Mn when the Ni content is 2.1% or less.
Although the impact value is slightly improved by reducing the amount, the effect of reducing the Mn by setting the Ni amount to more than 2.1% is remarkable. In particular, the Ni content is 2.4%
As described above, the effect is great.

Further, when the Mn content is around 0.7%, no improvement in the impact value is obtained regardless of the Ni content, but the Mn content is reduced to 0.6%.
If the amount of Mn is lower, a Ni content of 2.4% or more and a higher impact value can be obtained. Particularly, when the amount of Mn is 0.15 to 0.4%, the amount of Ni is more than 2.2%.
6 kg-m (7.5 kg-m / cm ² ) at 4% or more, and 2.
With a Ni content of 5% or more, a high value of (7 kg-m / cm ² ) or more can be obtained.

The creep rupture strength at 450 ° C. × 10 ⁵ h was as follows:
The strength is hardly affected until the Ni content is around 2.5%, but when it exceeds 3.0%, the strength is less than 50 kg / mm ² and the target strength cannot be obtained. The smaller the Mn, the higher the strength. When Mn is near 0.15 to 0.25%, the Mn is most strengthened, and a high strength is obtained.

Dissolution of steel having almost the same chemical composition as No. 1 in Table 12 was performed by carbon vacuum deoxidation, and after forging,
After heating at 0 ° C. for 2 hours, it was quenched in oil at 150 ° C., then heated at 520 ° C. for 5 hours, air-cooled, and heated at 590 ° C. for 5 hours, and then tempered by furnace cooling. This disk had an outer diameter of 1000 mm and a thickness of 200 mm, and was machined into the shape shown in the figure after heat treatment. This disk was used for turbine disks 11, 12, and 13. A through hole through which the refrigerant passes is provided at the center, and a hole for inserting the stacking bolt 54 is further provided. As for the characteristics of this disk, the impact value after embrittlement was 8.0 kg-m (10 kg / c
m ² ) and creep rupture strength at 450 ° C. × 10 ⁵ hours
It was 5.2 kg / mm ² and had excellent properties.

Table 14 shows the material composition (% by weight) used for each member of the gas turbine of this embodiment. Table 1
The material shown in 2 can be used for the distant piece, the last stage of the compressor disk, the turbine spacer, and the turbine stacking bolt. All steels were smelted by the electroslag remelting method and forged and heat-treated. The casting was performed within a temperature range of 850 to 1150 ° C., and the heat treatment was performed under the conditions shown in Table 14. The microstructures of these materials are as follows: No. 10 to 15 are all tempered martensite structures;
No. 14 and No. 15 were all tempered bainite structures. No.10 is used for the distant piece and the final stage compressor disk of No.11. The former is 60mm thick.
× width 500mm × length 1000mm, the latter 1000m in diameter
m, thickness 180mm, No.7 is 1000mm diameter disk
× 180mm in thickness, No. 12 has an outer diameter of 10 as a spacer
No. 13 has a diameter of 40 mm, length of 500 mm and steel of No. 13 as a stacking bolt for either a turbine or a compressor. Bolts were also manufactured. Nos. 14 and 15 were forged to a diameter of 250 mm and a length of 300 as a turbine stub shaft and a compressor stub shaft, respectively. Further, the alloy of No. 14 was added to the compressor disk 6
No. 15 was used for the compressor disk 6 from the first stage to the 12th stage. These were all manufactured to the same size as the turbine disk. After heat treatment, the test piece was No. 13 from the center of the sample.
, Except in the direction perpendicular to the axis (longitudinal) direction.
In this example, a test piece was taken in the longitudinal direction.

[0253]

[Table 14]

Table 13 shows the results of room temperature tensile, 20 ° C. V notch Charpy impact and creep rupture test. 450 ° C. × 10 ⁵ h Creep rupture strength was determined by a generally used Larson-Miller method.

Looking at Nos. 10 to 13 (12Cr steel) of the present invention, the creep rupture strength at 450 ° C. for 10 ⁵ h was 51 kg.
/ Mm ² or more, is 20 ° C. V-notch Charpy impact value 7kg-
m / cm ² or more, and it was confirmed that the strength required as a material for a high-temperature gas turbine was sufficiently satisfied.

Next, the stub shaft Nos. 14 and 15
(Low alloy steel) has low creep rupture strength at 450 ° C,
Tensile strength of 86 kg / mm ² or more, 20 ° C V notch Charpy impact value of 7 kg-m / cm ² or more, strength required for stub shaft (tensile strength ≧ 81 kg / mm ² , 20 ° C notch Charpy impact value ≧ 5 kg-m / cm ² ).

[0257]

[Table 15]

The temperature of the distant piece and the temperature of the final stage compressor disk are 450 ° C. at the maximum. The former preferably has a thickness of 25 to 30 mm, and the latter has a thickness of 40 to 70 mm. Each of the turbine and the compressor disk is provided with a through hole at the center. A compressive residual stress is formed in the through hole in the turbine disk.

The alloys shown in Table 16 were used for the turbine blade, nozzle, combustor liner, compressor blade, nozzle, shroud segment, and diaphragm.

As described above, by cooling the turbine disk, it is possible to use a martensitic steel in which the content of alloying elements is reduced to a low level for strengthening, so that the steel has high toughness. Stopping can be performed, and the time when starting and stopping can be reduced.

The gas turbine of the present invention constituted by a combination of the above materials has a rated output of 150 MW, a rated rotational speed of 3600 rpm, a compression ratio of 3.7, a gas temperature of about 1260 ° C. at the inlet of the first stage nozzle, and a 34.5% Thermal efficiency (LHV) is obtained.

[0262]

[Table 16]

Further, for the turbine disk 13 of this embodiment, martensitic steel shown in Table 17 can be used.

[0264]

[Table 17]

With the combined use of the gas turbine described in the present embodiment and the high / low pressure integrated steam turbine described in the first embodiment, the power generation end thermal efficiency was about 47%. The main specifications of the high and low pressure integrated steam turbine are a steam temperature of 538 ° C. and a blade length of the last stage rotor blade of 33.5 inches.

[0266]

According to the present invention, high-strength martensitic steel can be obtained, and the inlet temperature of the turbine nozzle is 1400 to 16
By adopting the turbine disk for a gas turbine at various temperatures of 50 ° C., a highly efficient gas turbine having an LHV display of 37% or more can be obtained. Further, a combined power generation system with an HHV heat efficiency of 50% or more for power generation can be achieved by combining with a high, medium and low pressure integrated steam turbine composed of a combination of a rotor shaft made of an appropriate material and a final stage blade.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a combined power generation system using steam cooling.

FIG. 2 is a sectional view of a rotating part of a gas turbine by steam cooling.

FIG. 3 is a diagram showing creep rupture strength.

FIG. 4 is a diagram showing the relationship between FATT and Ni content.

FIG. 5 is a diagram showing a relationship between FATT and W amount.

FIG. 6 is a diagram showing a relationship between an impact value and an amount of Ni.

FIG. 7 is a diagram showing a relationship between an impact value and an amount of Ni.

FIG. 8 is a plan view of a high, medium and low pressure integrated steam turbine.

FIG. 9 is a plan view of a rotor shaft for a high, medium and low pressure integrated steam turbine.

FIG. 10 is a perspective view of a long blade for a steam turbine.

FIG. 11 is a side view of the long blade for the steam turbine of FIG. 10;

FIG. 12 is a configuration diagram of a combined power generation system using closed air cooling.

FIG. 13 is a sectional view of a rotating part of a gas turbine by air cooling.

FIG. 14 is a configuration diagram of a combined power generation system using steam cooling.

FIG. 15 is a sectional view of a rotating part of a gas turbine by air cooling.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Turbine rotor, 2 ... Compressor rotor, 11, 12,
13: turbine disk, 18: spacer, 51: first stage blade, 52: second stage blade, 53: third stage blade, 81: first stage nozzle, 82: second stage nozzle, 83: third stage nozzle.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeyoshi Nakamura 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Ryo Hiraga 4-6-Kanda Surugadai, Chiyoda-ku, Tokyo Address Hitachi, Ltd. (72) Inventor Takeshi Onoda 3-1-1, Sachimachi, Hitachi-shi, Ibaraki F-term in Hitachi, Ltd. Hitachi Plant F-term (reference) 3G002 AA02 AA11 AB00 EA06

Claims (9)

[Claims] (1) 0.05 to 0.20% by weight of C, 0.2% by weight of Si
5% or less, Mn 0.6% or less, Ni 0.5 to 4.0%, C
r 8 to 13%, Mo 4% or less, V 0.1 to 0.4%, Nb
0.06 to 0.25%, Co 1 to 5% and N 0.025 to 0.2.
Consists of martensitic steel containing 125%
High strength martensitic steel having a creep rupture strength at 100 ° C. for 100,000 hours of 50 kg / mm ² or more and a creep rupture strength at 500 ° C. for 100,000 hours of 70% or more of the creep rupture strength. . 2. 0.05 to 0.20% of C, 0.2% of Si by weight.
5% or less, Mn 0.6% or less, Ni 0.5 to 4.0%, C
r 8 to 13%, Mo 4% or less, V 0.1 to 0.4%, Nb
0.06 to 0.25%, Co 1 to 5%, N 0.025 to 0.1
A high-strength martensitic steel comprising 25%, oxygen of 0.020% or less and hydrogen of 0.003% or less. 3. The composition according to claim 1, wherein the content of C is 0.05 to 0.20% and the content of Si is 0.2.
5% or less, Mn 0.6% or less, Ni 0.5 to 4.0%, C
r8-13%, Mo4% or less, W1-5%, V0.1-
0.4%, Nb 0.06 to 0.25%, Co 1 to 5% and N 0.025 to 0.125%, and the (W / Mo) ratio is 2 to 5. Strength martensitic steel. 4. The composition according to claim 1, wherein the content of C is 0.05 to 0.20% and the content of Si is 0.2%.
5% or less, Mn 0.6% or less, Ni 0.5 to 4.0%, C
r8 to 13%, Mo 0.2 to less than 1.0%, W1 to 5%,
V0.1-0.4%, Nb0.06-0.25%, Co1-
High strength martensitic steel characterized by having 5% and N 0.025-0.125%. 5. The method according to claim 1, wherein W1 to W1 is used.
A high-strength martensitic steel having at least one of 5% and B 0.0005 to 0.01%. 6. The method according to claim 3, wherein B is 0.0005 to 0.0.
High strength martensitic steel characterized by having 1% by weight. 7. A turbine disk for a gas turbine, comprising the martensitic steel according to any one of claims 1 to 6. 8. A gas turbine for power generation comprising a compressor, a combustor, three or more stages of turbine blades fixed to a turbine disk, and turbine nozzles provided corresponding to the turbine blades. A gas turbine for power generation comprising a turbine disk according to claim 7. 9. A gas turbine driven by combustion gas flowing at a high speed, an exhaust heat recovery boiler for obtaining steam by the energy of exhaust gas from the gas turbine, and a generator driven by a high / low pressure integrated steam turbine and the gas turbine. A combined power generation system, wherein the gas turbine includes the gas turbine for power generation according to claim 8.