JP2000356103A - Gas turbine, disc for gas turbine and heat resisting steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high-temperature strength and to improve the toughness after high-temperature, long-time heating by using a martensite steel having tensile strength at room temperature, creep rupture strength, V-notch Charpy impact value of specified values for the component of a gas turbine. SOLUTION: In this gas turbine having a three-stage blade having closed steam cooling system, its components, for example, turbine discs 11-13, a turbine spacer 18, a compressor disc or the like are formed of a martensite steel having a tensile strength at room temperature of 120 kg/mm2 or more, a 105-hr creep rupture strength at 500 deg.C of 35 kg/mm2 or more and a V-notch Charpy impact value at 25 deg.C after heating at 540 deg.C for 103 hrs of 2 kg-m/cm2 or more. The martensite steel used has the composition consisting of 0.5-0.35 wt.% of C, 0.5 wt.% or more of Si, 0.5 wt.% or more of Mn, 8-13 wt.% or more of Cr, 1.5-4 wt.% of Mo, 2-3.5 wt.% of Ni, and 0.50-0.35 wt.% of V.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel gas turbine, a disk for a gas turbine, and a high-strength heat-resistant steel.

[0002]

2. Description of the Related Art Currently, gas turbine disks include C
r-Mo-V steel and 12Cr-Mo-Ni-VN steel are used.

In recent years, it has been desired to improve the thermal efficiency of gas turbines from the viewpoint of energy saving. High-efficiency power generation can save fossil fuels and reduce the amount of exhaust gas generated, contributing to global environmental conservation. Increasing gas temperature and pressure is the most effective means for improving thermal efficiency. By increasing the gas temperature from the 1300 ° C. class to the 1500 ° C. class, a significant improvement in efficiency can be expected.

However, with the increase in temperature and pressure, conventional Cr-Mo-V steel and 12Cr-Mo-Ni-VN
Steel lacks strength and requires stronger materials.
Creep rupture strength, which greatly affects high temperature properties, is required as strength. Creep rupture strength is Cr-Mo-V
Austenitic steel, Ni-based alloy, Co-based alloy, martensitic steel and the like are generally known as structural materials higher than steel. N in terms of hot workability, machinability and vibration damping characteristics
i-based alloys and Co-based alloys are undesirable. Further, 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, Japanese Patent Application Laid-Open Nos.
Japanese Patent Publication No. 138054 and Japanese Patent Publication No. 46-279 are known. However, these materials do not always provide high creep rupture strength at 400 to 450 ° C., have low toughness after long-time heating at high temperatures, cannot be used as turbine disks, and cannot improve the efficiency of gas turbines. Tokuhei 5-63
No. 544 and Japanese Unexamined Patent Publication No.
A heat-resistant steel having a 0 ° C. creep rupture strength and a reduced toughness after heating at a high temperature for a long time is provided.
At 00 ° C, high creep rupture strength is not necessarily obtained,
It cannot be used as a more efficient hot gas turbine disk.

[0005]

As described above, the gas temperature cannot be increased simply by using a conventional high-strength material for increasing the temperature and pressure of a gas turbine. Generally, increasing the strength lowers the toughness.

It is an object of the present invention to provide a gas turbine capable of coping with higher temperatures, a disk for the turbine, and a heat-resistant steel having high strength and high toughness after high-temperature heating for a long time.

[0007]

SUMMARY OF THE INVENTION The present invention comprises a turbine tub shaft, a plurality of turbine rotors connected to the shaft by turbine stacking bolts via turbine spacers, and a combustor implanted in the rotor. A turbine blade that is rotated by the generated high-temperature combustion gas, a distant piece connected to the rotor, a plurality of compressor rotors connected to the distant piece, and a compressor that is implanted in the rotor and compresses air A gas turbine comprising a blade and a compressor stub shaft connected to the compressor rotor, wherein the turbine disk,
At least one of the distant piece, the turbine spacer, the final stage of the compressor rotor, and the turbine stacking bolt has a room temperature tensile strength of 120 kg / mm ² or more, and a creep rupture strength of 35 kg / cm ² at 500 ° C. for 10 ⁵ hours.
mm ² or more and V at 25 ° C after heating at 540 ° C for 10 ³ hours
A gas turbine comprising a martensitic steel having a notch Charpy impact value of 2 kg-m / cm ² or more.

According to the present invention, at least one of the turbine rotor, the distant piece, the turbine spacer, the final stage compressor rotor and the turbine stacking bolt is C 0.15 to 0.35%, and Si 0.5%.
Below, Mn 0.5% or less, Cr 8-13%, Mo 1.5-
4%, Ni2-3.5%, V0.05-0.35%, Nb
And the total amount of one or two of Ta includes 0.02 to 0.3% and N 0.02 to 0.1%, and the (C / Nb) ratio (y) is the same as the Nb amount (x). (Y = −20x +
It is characterized by being composed of a martensitic steel having a value not less than the value obtained in 3.5).

According to the present invention, at least one of the turbine rotor, the distant piece, the turbine spacer, the last stage of the compressor rotor and the turbine stacking bolt is C 0.15 to 0.35% by weight and Si 0.5.
%, Mn 0.5% or less, Cr 8-13%, Mo 1.5
-4%, Ni2-3.5%, V 0.05-0.35%, N
The total amount of one or two of b and Ta is 0.02 to 0.3% and N is 0.02 to 0.1%, W1% or less, Co0.5 or less, Cu0.5% or less, B0.01. % Or less, Ti 0.5% or less, Al 0.3 or less, Zr 0.1% or less, Hf 0.1% or less, Ca 0.01% or less, Mg 0.01 or less, Y 0.01 or less
% Or less and rare earth elements of 0.01% or less, and the (C / Nb) ratio (y) is equal to the Nb amount (x).
(Y = −20x + 3.5) or more.

Further, the present invention resides in a gas turbine disk comprising the above-mentioned martensitic steel and a heat-resistant steel comprising the steel.

[0011] The present invention relates to a method for producing C 0.15 to 0.35 by weight.
%, Si 0.5% or less, Mn 0.5% or less, Cr 8-13
%, Mo 1.5 to 4%, Ni 2 to 3.5%, V 0.05 to 5%
0.35%, the total amount of one or two of Nb and Ta is 0.0
Martensitic steel containing 2 to 0.3% and N 0.02 to 0.1%, further containing W 1% or less, Co 0.5 or less, Cu 0.5 or less.
5% or less, B 0.01% or less, Ti 0.5% or less, Al
0.3 or less, Zr 0.1% or less, Hf 0.1% or less, Ca
A martensitic steel containing at least one of 0.01% or less, Mg 0.01 or less, Y 0.01% or less and a rare earth element 0.01% or less, and has the above-described tensile strength, creep rupture strength and after heat embrittlement. Gas turbine, gas turbine disk, and heat-resistant steel, characterized by having an impact value of: The invention is based on C 0.21-0.3 by weight.
5%, Si 0.5% or less, Mn 0.5% or less, Cr 8-1
3%, Mo 1.5 to 4%, Ni 2 to 3.5%, V 0.05
~ 0.35%, the total amount of one or two of Nb and Ta is 0.3%.
Martensitic steel containing 0.2-0.3% of N and 0.02-0.1% of N, and further containing 1% or less of W, 0.5% or less of Co, C
u 0.5% or less, B 0.01% or less, Ti 0.5% or less, A
l0.3% or less, Zr 0.1% or less, Hf 0.1% or less,
Ca 0.01% or less, Mg 0.01% or less, Y 0.01%
And a martensitic steel containing at least one kind of rare earth element of 0.01% or less, preferably having the above-mentioned tensile strength, creep rupture strength and impact value after heat embrittlement or the above-mentioned C A gas turbine, a gas turbine disk, and heat-resistant steel having a specific relationship between the amount of Nb and the amount of Nb.

A gas turbine disk must have high tensile strength and high fatigue strength in order to withstand high centrifugal stress and vibration stress due to high-speed rotation. For this reason, the metal structure of the gas turbine disk material preferably has a fully tempered martensitic structure, since the presence of harmful δ ferrite significantly reduces the fatigue strength.

The steel according to the present invention has a Cr content calculated by the following equation:
Equivalent Cr equivalent = Cr + 6Si + 4Mo + 1.5W + 11V +
5Nb-40C-30N-30B-2Mn-4Ni-2
It is preferable that the components are adjusted so that CO + 2.5 Ta becomes 10 or less and that the δ ferrite phase is not substantially contained.

The tensile strength of the gas turbine disk material is 12
0 kgf / mm ² or more, preferably 123kgf / mm ² or more and 5
00 ° C., 10 ⁵ h creep rupture strength is 42kgf / mm ² or more.

The reason for limiting the component range of the material of the present invention will be described. C is required to be 0.15% or more in order to obtain high tensile strength. If C is too large, the toughness is reduced, so the content is made 0.35% or less. In particular, it is preferably from 0.17 to 0.33%, more preferably from 0.20 to 0.30%. Furthermore,
0.221 to 0.30% is preferred.

Si is a deoxidizing agent, and Mn is a desulfurizing and 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 0.55% or less is preferable. In addition, according to the carbon vacuum deoxidation method, the electroslag re-dissolution method, or the like, there is no need to add Si, and it is preferable to add no Si. In particular,
0.10% or less, more preferably 0.05% or less.

The addition of a small amount of Mn improves the toughness, but the addition of a large amount decreases the toughness.
It is preferably at most 3%. In particular, since Mn is effective as a desulfurizing agent, 0.30% or less, especially 0.25%, from the viewpoint of improving toughness.
% Or less, more preferably 0.20% or less. It is preferable to contain 0.05% or more, preferably 0.1% or more from the viewpoint of toughness.

[0018] Cr enhances the corrosion resistance and tensile 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, so that C
r is preferably 8 to 13%. Especially 10.5 from the point of strength
１２12.8%, more preferably 11-12.5%.

Mo has the effect of increasing the creep rupture strength by solid solution strengthening and carbide / nitride precipitation strengthening.
If the Mo content is less than 1.5%, the effect of improving the creep rupture strength is insufficient, and if the Mo content is more than 4%, δ ferrite is formed. In particular, 1.7 to 3.
5%, more preferably 1.9 to 3.0%. Note that W and C
o also has the same effect as Mo, and can be contained up to the same content at the upper limit for higher strength.

V and Nb precipitate carbides to increase tensile strength and also have an effect of improving toughness. V 0.05%, Nb
If the content is less than 0.02%, the effect is insufficient.
%, Nb 0.3% or less is preferable from the viewpoint of suppressing the formation of δ ferrite. In particular, V is 0.15 to 0.30%, more preferably 0.20 to
0.30%, Nb is 0.10% to 0.30%, more than 0.12%
0.22% is preferred. Ta can be added in exactly the same manner as in place of Nb, and the total content can be made the same in the case of composite addition.

Ni enhances the low-temperature toughness and has the effect of preventing the formation of δ ferrite. This effect is insufficient when Ni is less than 2%, and the effect is saturated when added over 3.5%. In particular, 2.3 to 3.2% is preferable.

N is effective in improving the creep rupture strength and preventing the formation of δ ferrite, but if it is less than 0.02%, the effect is not sufficient, and if it exceeds 0.15%, the toughness is reduced. In particular, excellent characteristics can be obtained in the range of 0.04 to 0.10%.

B has the effect of increasing the grain boundary strength and has the effect of increasing the creep rupture strength. If the content is less than 0.001%, this effect is insufficient, and if the content exceeds 0.01%, the toughness decreases. In particular, 0.002 to 0.008% is desirable.

The reduction of Si, P and S has the effect of increasing the low-temperature toughness without impairing the creep rupture strength, and it is desirable to reduce as much as possible. From the viewpoint of improving low-temperature toughness, Si 0.5
0% or less, preferably 0.1% or less, P 0.015% or less, and S0.015% or less. In particular, Si 0.0
5% or less, P0.010% or less, S0.010% or less are 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.
n is limited to 0.01% or less and As is 0.02% or less.
In particular, Sb 0.001 or less, Sn 0.005%, and As 0.005%.
01% or less is desirable.

Further, in the present invention, the Mn / Ni ratio is set to 0.11 or less, and one, two, three or four types of MC carbide forming elements such as Ti, Zr, Hf and Ta are used. It is preferable that each combination contains not more than 0.5% in total.

In the heat treatment of the material of the present invention, the material is first uniformly heated to a temperature sufficient to transform into austenite at a minimum of 1000 ° C. and a maximum of 1150 ° C., quenched (preferably oil-cooled or sprayed with water), and then 540-500 ° C. It is preferable to heat and hold and cool to a temperature of 600 ° C (first tempering), and then heat and hold and cool to a temperature of 550 to 650 ° C (second tempering) to obtain a fully tempered martensite structure. The second tempering is performed at a temperature higher than the first tempering temperature. In quenching, it is preferable to stop the temperature just above the Ms point in order to prevent quenching cracks. The specific temperature is 1
It is better to stop at 50 ° C or higher. The first tempering heats from that temperature.

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. It has an air cooling system for cooling over, and the turbine disk is made of the aforementioned 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, a steam cooling system for cooling the turbine disk with steam from the trunk to the turbine blades, The turbine disk is made of the aforementioned martensite 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. And an air cooling system for cooling the second and third stage turbine nozzles with air, wherein the turbine disk is made of the aforementioned 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. Wherein the turbine disk is made of the aforementioned martensitic steel.

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 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. Are point A (515 ° C, 1200 ° C), point B (538 ° C, 1200 ° C), point C (593 ° C, 1650 ° C).
C) and point D (557 ° C., 1650 ° C.), and the gas turbine includes a compressor, a combustor,
Three or more stages of turbine blades fixed to a turbine disk, and three turbine blades provided corresponding to the turbine blades.
An air cooling system or a steam cooling system for cooling the first stage turbine nozzle and the first stage and the second stage turbine blades with air cooled by a cooler, or a steam cooling system for cooling the first stage and the second stage turbine blades with a cooler. It has an air cooling system for cooling 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 made of the aforementioned martensitic steel.

The last stage blade of the above-mentioned high / low pressure integrated steam turbine has a blade length (inch) × rotation speed (rpm) of 12
Preferably, it is composed of 0000 or more and a martensitic steel or a Ti-based alloy.

In the present invention, at least one of the first-stage blade and the first-stage nozzle of the gas turbine may be a single crystal or a columnar crystal Ni-based with the above-mentioned gas inlet temperature of 1400 to 1650 ° C. and the above-mentioned temperature of 1300 to 1395 ° C. Preferably, it is made of an alloy. In the gas turbine, it is preferable that the second and third stage turbine blades are made of a unidirectionally solidified columnar crystal Ni-based alloy at the above-mentioned temperature of 1400 to 1650 ° C. The gas turbine is operated at the temperature 1 described above.
For 400 to 1650 ° C., the first-stage turbine blade and the first-stage turbine nozzle are made of a single crystal Ni-based alloy,
Preferably, at least one of the stage and third stage turbine blades is made of a unidirectionally solidified columnar crystal Ni-based alloy, and the second and third stage turbine nozzles are made of an equiaxed crystal Ni-based alloy. (A) Gas turbine The gas turbine for power generation is from the 1300 ° C class to the next generation 150.
In the 0 ° C class gas turbine, the metal temperature of the first stage turbine blade is increased from 700 ° C
Since the temperature is 0 ° C or higher, the service temperature of the material itself is 10 ⁵
It is necessary that the temperature be higher than the metal temperature by 20 ° C. or more at a time of 14 kgf / mm ² . The blades in the second and subsequent stages have a gas temperature of 50-100 ° C. lower than that of the first stage, but their metal temperature is higher than that of a gas turbine having a combustion temperature of 1300 ° C., and the material characteristics are 10 ⁵ hours 14 kgf /
A service temperature of 600 ° C. or more to 800 ° C. or more in 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 16 ° C.
At 50 ° 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 Cr6
８8%, Mo0.5 １1%, W6〜8%, Re1４4
%, 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 blade by weight: Cr 5 to 18%, Mo 0.3 to 5%, W2 to 1
0%, Al 2.5-6%, Ti 0.5-5%, C 0.05-
A columnar crystal Ni-base 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 to 24% Cr, 18 to 23% Co, and 0.00% 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 blade material The long blade material according to the present invention has a blade length of 30 inches or more, preferably 40, made of a Ti-based alloy or martensitic stainless steel. It is preferable to use a diameter of not less than 43 inches, more preferably not less than 43 inches, as the last 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 aforementioned martensitic stainless steel,
It is preferable to use a steam turbine of 33 inches or more, more preferably 35 inches or more, for a high-low pressure or high-medium-low pressure integrated steam turbine for 60-cycle power generation.

The above-mentioned martensitic stainless steel is
By weight ratio, C: 0.08 to 0.18%, Si: 0.25% or less, Mn: 1.00% or less, Cr: 8.0 to 13.0%, Ni
1.5-3%, preferably more than 2.1 and less than 3%, Mo
1.5 to 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 N0.
Containing 02 to 0.10%, or C 0.03 to 0.1%
%, Si 0.5% or less, Mn 0.5% or less, Ni 2-6
%, Cu 2-6%, Nb 0.2-0.45% and N 0.06%
Those containing the following are preferred.

The above-mentioned Ti-based alloy preferably contains 5 to 8% of Al and 3 to 6% of V by weight.

Further, according to the present invention, C 0.18 to 0.1
28%, Si 0.1% or less, Mn 0.1-0.3%, C
r 1.5-2.5%, Ni 1.5-2.5%, Mo 1-2%
And V of 0.1 to 0.35%, 538 ° C.
⁵ h smooth and notched creep rupture strength of 13 kg / mm ² or more,
The above-mentioned long wing having a tensile strength of 120 kg / mm ² or more was attached to a rotor shaft made of heat-resistant steel having a bainite structure with a tensile strength of a low-pressure part of 84 kg / mm ² or more and a fracture transition temperature of 35 ° C. High, medium and low pressure or high and low pressure integrated steam turbines are preferred.

It is preferable that an erosion prevention layer is provided at the leading edge of the blade at the last stage. Specific wing lengths are 33.5 ", 40",
46.5 "etc. The erosion preventing layer is, by weight, C0.5-1.5%, Si 1.0% or less, Mn 1.0% or less, Cr 25-30%, W2.5-2.5%.
It is preferable to use a Co-based alloy containing 6.0%.

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 caused by high-speed rotation.
For this reason, the metal structure of the blade material is preferably a fully tempered martensite structure in which the Cr equivalent is 10 or less, since the presence of harmful δ ferrite significantly reduces the fatigue strength.

It is preferable that the composition of the steel of the present invention is adjusted so that the Cr equivalent calculated by the above-mentioned formula becomes 10 or less, and the steel does not substantially contain a δ ferrite phase.

The long wing material has a tensile strength of 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.

Further, in order to obtain a uniform 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 portion 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, it is a 3000 rpm steam turbine for power generation of 50 cycles, 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.

(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 produced 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 is good. Especially 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 at 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.

Cr improves the hardenability at 1.5 to 2.5% and 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 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 the tempering treatment, and has an effect of improving high-temperature strength and toughness. Especially 0.20 to 0.30%, more preferably 0.2%
The range of more than 5 and 0.30% or less is preferable.

When a low alloy having the above composition is melted, the toughness is improved by adding a rare earth element, Ca, Zr or Al. The rare earth element is 0.
0.5-0.4%, 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, 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.

W is preferably added 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) +2.7
8] or more, the whole is heat-treated under the same conditions to obtain a high creep rupture strength of 12 kg / mm ² or more at 538 ° C. for 10 ⁵ hours.

The present invention relates to 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 13 kg / mm ² or more at 538 ° C. and 10 ⁵ h. 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: cooling after heating and holding to 930 to 970 ° C. Tempering: Slow cooling after heating and holding to 570 to 670 ° C. (Tempering twice is preferable, of which one is heated and held at 650 to 670 ° C. once) The low-pressure part or the medium-low pressure part of the rotor shaft: high tensile strength and low-temperature toughness are obtained.

○ Quenching: Rapid cooling after heating and holding at 880 to 910 ° C. Tempering: Slow cooling after heating and holding at 570 to 640 ° C. (preferably twice tempering, one of which is heated and held at 615 to 635 ° C. once) That is, in the present invention, the quenching of the high pressure side at a quenching temperature higher than that of the low pressure side is carried out so that a creep rupture time of 180 hours or more at 550 ° C. and 30 kg / mm ² is obtained at the high pressure side. It is preferable to increase the strength and perform a gradient heat treatment on the low-pressure side such that the transition temperature at the center hole is 10 ° C. or lower than 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.

[0069]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Table 1 shows the chemical composition (% by weight) of a 12% Cr steel for a gas turbine disk material, with the balance being Fe. Each sample was melted in a vacuum arc of 150 kg, heated to 1150 ° C. and forged to obtain an experimental material. This material was heated at 1050 ° C. for 2 hours and then subjected to blast cooling. The cooling temperature was stopped at 150 ° C.
After heating at 0 ° C for 2 hours, air-cooled primary tempering was performed.
After heating at 80 ° C. for 5 hours, furnace-cooled secondary tempering was performed.

[0070]

[Table 1]

From the material after the heat treatment, a creep rupture test piece,
Tensile test pieces and V-notch Charpy impact test pieces were collected and used for the experiment. The impact test was performed on the as-heat treated material and 54
The test was performed on the embrittled material heated at 0 ° C. for 1000 hours. This embrittlement material is 1 degree at 500 ° C according to Larson-Miller parameter.
0 is ⁵ hours heated ones equivalent conditions.

Table 2 shows the mechanical properties of these samples. The material of the present invention (sample Nos. 1, 2 and 8) has a room temperature tensile strength (> 1) required as a high-temperature and high-pressure gas turbine disk material.
20kgf / mm ^2), it is 500 ° C., 10 ⁵ h creep rupture strength (> 42kgf / mm ²⁾ and the embrittlement process 20 ° C. V-notch Charpy impact value after ^{(> 5kgf-m / cm 2} ) that is fully satisfactory confirmed. On the other hand, the material (sample No. 7) used in the current gas turbine cannot satisfy the mechanical properties required for the high-temperature / high-pressure gas turbine disk material at the same time. Although the notch Charpy impact value at 20 ° C after embrittlement treatment satisfies the required value, the C content is low, and the tensile strength and the creep rupture strength at 500 ° C for 10 ⁵ hours are low. Furthermore, the comparative material samples Nos. 3 to 6 cannot simultaneously satisfy the mechanical properties required for the high-temperature and high-pressure gas turbine.

[0073]

[Table 2]

As is clear from the relationship between the Mn / Ni ratio and the V-notch Charpy impact value after embrittlement, the higher the Mn / Ni ratio (> 0.25), the lower the V-notch Charpy impact value after embrittlement. There is a tendency. In addition, the sample N having a large amount of Mo and C
In o.5 and 6, the Mn / Ni ratio was low, but the V-notch Charpy impact value after embrittlement was low. Mn, Mo, C
Although has the effect of increasing the strength, it is clear that it promotes embrittlement.

FIG. 1 is a graph showing the relationship between the amount of W, the creep rupture strength at 500 ° C. for 10 ⁵ hours, and the impact value after heating at 540 ° C. for 1000 hours. As shown in FIG. 1, the creep rupture strength hardly changes up to around W0.5%, but decreases slightly above W0.5%. Heat embrittlement is promoted by adding W.

FIG. 2 is a graph showing the relationship with the B amount. B addition is the same as W addition, and B0.00
No significant effect is seen up to around 3%.

The martensitic steel according to the present invention has a (C / N
b) When the ratio is shown on the vertical axis (y) and the Nb amount is shown on the horizontal axis (x), y is equal to or more than the value obtained by y = −20x + 3.5, and y = −20x + 4.2. It is preferable that y is equal to or larger than the required value.

Samples having the chemical compositions shown in Table 3 were produced by melting and forging, and subjected to the same heat treatment and subjected to experiments. Table 4 shows the test results.

[0079]

[Table 3]

As shown in Table 4, Sample No. 9 to which B was added in an amount of 0.01% or less had higher high-temperature strength than Nos. 1, 2, and 8, and also had a lower impact value after embrittlement. Although the decrease is small and high toughness is obtained, B is more than 0.01%.
A value of 0 increases the high-temperature strength, but significantly reduces the impact value after embrittlement.

Sample No. 11 to which W was added at 1% or less has high temperature strength and a small decrease in impact value after embrittlement, and high toughness can be obtained. The strength is greatly improved, the creep rupture strength is reduced, and the reduction in impact value after embrittlement is significantly reduced.

[0082]

[Table 4]

Embodiment 2 FIG. 3 is a diagram of a combined power generation cycle system in which first and second stage blades and first stage nozzles are cooled by steam, and second and third stage vanes are cooled by air. It is. 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, or steam can be separately generated and used.

A. Gas Turbine FIG. 4 is a sectional view of the upper half of a gas turbine having three stages of blades having a closed steam cooling system. 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. 4, the gas turbine of the present 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 gradually exceed the permissible temperature of the blade at about 950 to 1000 ° C (850 to 900 ° C for normal blade material), and the heat load is about 1.5% (about 6000k
W) and 1.2% (5000 kW).

Further, in order to set the pressure of the working gas to 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 is about 500 ° C. (450 ° C.), it is necessary to cool the outer periphery of the compressor rotor 2.

In the present embodiment, another turbine stacking bolt 54, a compressor disk, a compressor blade 17, a compressor stacking bolt, and a compressor stub shaft are provided. 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 930-940 ° C,
In each case, a complicated steam cooling hole is provided inside, and during operation, it is cooled by compressed steam. 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 1250-1350 ° C
After the solution treatment at 1000 to 1100 ° C and 850 to 950
A two-stage aging treatment was carried out at 50 ° C. to precipitate a γ ′ phase having a length of 1 μm or less on one side at 50 to 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 24 and the dovetail 26 other than the wing portion 21 may be columnar crystals. In the present embodiment, in the one-way solidification, solidification is performed from the wing side and solidified into the shank 24 and the dovetail 26 to form a single crystal as a whole, or when the solidification reaches the shank 24, the cooling rate is increased. Columnar crystals.

The first stage nozzle 81 in this embodiment has the vane 36, the outer peripheral side wall 38, and the inner peripheral side wall 37.

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 dovetail, 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 composed of a unidirectionally solidified columnar Ni-based 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, Cr20-3
An alloy layer made of a Ni-based or Ni + Co-based alloy containing 0% and Y 0.1-1% is provided with a thickness of 50-150 [mu] m by plasma spraying under 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 the outer side wall and the 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 almost 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 shape as the product is formed around a core having a hollow structure for cooling holes. 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 solution in which an acrylic resin is dissolved in methyl ethyl ketone, dried by ventilation, 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 described above. 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 5 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 5 are examples of the unidirectionally solidified columnar crystal Ni-based alloys of the second and third stage blades in this embodiment.

[0112]

[Table 5]

The materials used for the second and third stage nozzles used in the gas turbine for power generation according to the present invention are as follows.
Alloy composition (wt%), the useful temperature of the casting process 10 ⁵ hours 6 kgf / mm ² in the case of casting, and the weldability are shown in Table 6.
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 6,
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, 1
The forged material of martensitic steel having the entire martensite structure described in Example 1 is used in Examples 2 and 13. This specific martensitic steel was sufficiently satisfactory as the material for the high-temperature gas turbine described in the present embodiment as described in the first embodiment.

Specifically, as a gas turbine disk, a 150 kg steel ingot is melted in a high-frequency induction melting furnace, vacuum carbon deoxidized and cast, heated to 1150 ° C., and formed into a plate by hot forging. did. After that, the plate material is
After cooling to room temperature, it was subjected to primary tempering at 570 ° C, and secondary tempering at 590 and 620 ° 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 collected.

[0116]

[Table 6]

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 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
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 configuration, the compressor disk, the distant piece, the turbine disk, and the spacer, which are the shafts of the rotating part, are made of martensite 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. I can do it.

B. High / Medium / Low Pressure Integrated Steam Turbine FIG. 5 is a partial 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 medium pressure section 6
The same structure is also provided for 18 stages including 5 stages 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 flows through the steam control valve 55 from the steam inlet 121 to the high-temperature high-pressure side of 538 ° C. and 169 atg as described above. 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. Since the high / low pressure integrated rotor shaft 3 according to the present invention is exposed from steam at 538 ° C. to a temperature of 33 ° C., the Ni—Cr—Mo—
Forged steel of 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 blade 4 on the high pressure side with respect to the steam inlet
There is a step, and it is arranged at the same interval after the second step, the interval between the first step and the second step is 1.5 to 2.0 times the interval after the second step, and the axial width of the blade implantation part is the first step It is the thickest, gradually increasing in thickness from the second stage to the final stage, and 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 times, the thickness immediately before the final stage is 1.1 to 1.1
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 medium pressure part.
And 40 ".

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

(1) Rotor Shaft Table 7 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.
Nos. 1 and 2 were melted for comparison.
Is ASTM A470 class 8 equivalent material, No. 2 is AS
It is equivalent to TM standard A470 class7. 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.

In this embodiment, the rotor shaft has a C weight of 0.05 to 0.30%, 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%.

[0130]

[Table 7]

The austenitizing temperature of the steel according to the present invention needs to be 900 to 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 8 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 tensile strength at room temperature 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, shock 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.

[0133]

[Table 8]

Nos. 7 to 12 are rare earth elements (La-Ce), Ca, Zr, Ta and Al additives, respectively. 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%,
As a result of examining the relationship with the n / Ni or (Si + Mn) / Ni ratio, a high impact of 2.5 kg-m or more when the Mn / Ni ratio is 0.12 or less and the Si + Mn / Ni ratio is 0.04 to 0.18. Value was found.

[0138] 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 the (Cr / Mo) ratio is 1.45 or more, and the (Cr / Mo) ratio is [−1.11 ×
(Ni / Mo) +2.78] or more, so that the same heat treatment is applied to the whole to obtain 53
8 ° C., 10 ⁵ h creep rupture strength of 12 kg / mm ² or more high strength can be obtained.

The rotor shaft of this embodiment was prepared by melting a forged steel having an alloy composition shown in Table 9 in an arc melting furnace, pouring it into a ladle, then blowing Ar gas from the lower part of the ladle to vacuum refining. Lumped. Next, forging to a maximum diameter of 1.7 m and a length of about 8 m at 900 to 1150 ° C.
After heating and holding the medium / low-pressure side 17 at 880 ° C. for 10 hours at 10 ° C. for 10 hours, water spray cooling or immersion in water was performed while rotating the shaft at about 100 ° C./h at the center. . Next, the high pressure side 116 was heated at 650 ° C. for 40 hours,
The medium- and low-pressure side 117 was tempered by heating and holding 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 10 shows the test results.

[0141]

[Table 9]

[0142]

[Table 10]

The diameters of the moving blade portion and the stationary blade portion of the high pressure portion are the same in each stage. From the intermediate pressure portion to the low pressure portion, the diameter gradually increases in the moving blade 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, preferably 0.28 to 0.35 times, the length of the blade.

The rotor shaft has the largest blade diameter at the final 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 the present 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 the present embodiment, the outer diameter when using 40 inches as the last stage blade is 365 cm, and the ratio between 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 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 121, 169 and 224 atg.

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 center part, and quenching with a difference in cooling rate (uniform heating / deviation cooling). (B) The turbine rotor body is heated to 970 ° C in the high pressure part and the medium pressure part or 930 ° C in the low pressure part or the medium pressure / low pressure part in the same manner as in (a),
After that, the actual turbine rotor body is cooled at a cooling rate of 50 ° C./h assuming a cooling rate at the center when the body is cooled by fountain or water, and then quenched (deviation heating / uniform cooling).

(C) The parts corresponding to the high-pressure part and the medium-pressure part or the high-pressure part are replaced by 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.

From 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 length of the medium pressure portion gradually increases as the pressure decreases, and the C value is 0.05 to 0.15% by weight and Mn 1
% Or less, Si 0.5% or less, Cr 10 to 13%, Mo
Forging of martensitic steel consisting of 0.5% or less, Ni 0.5% or less, and the balance Fe.

The final stage wing length should be 33.5 inches or more for 60 cycles and 40 for 50 cycles.
Inch or more, there are about 90 per round, and C.O.
15 to 0.35%, Mn 1% or less, Si 0.25% or less, Cr 8 to 13%, Ni 2.0 to 3.5%, Mo 1.5
３3.0%, V 0.05 to 0.35%, N 0.02 to 0.1
0%, one or more of Nb and Ta in a total amount of 0.02 to 0.2.
It was constituted by forging a martensitic steel containing 30%. In particular, in the present embodiment, the alloys shown in Tables 1 and 2 of Embodiment 1 were used. Also, in this final stage, C1.0% by weight,
Si 0.6%, Mn 0.6%, Cr 28%, W 1.0%,
An erosion-preventing shield plate made of a stellite plate made of the remainder Co is provided at the leading edge by electron beam or TIG welding at the leading edge portion. In addition, a partial quenching process can be performed on a part other than the shield plate.

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 provided at the tip thereof.

Each of the long blade materials for the high and low pressure integrated steam turbine was subjected to high frequency melting in a vacuum of 150 kg, heated to 1150 ° C., and forged to obtain experimental materials. The sample is at 1000 ° C. or 105
After heating at 0 ° C for 1 hour, the mixture was cooled to room temperature by oil quenching (cooling rate of 100 ° C / min or more), and then cooled to 570 ° C or 56 ° C.
The mixture was heated to 0 ° C., kept at room temperature for 2 hours, and air-cooled to room temperature. Then
After heating to 560 ° 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 cooled to room temperature (secondary tempering).

(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.

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, and the entire ferrite steel supporting the turbine nozzle and the compressor nozzle has the same thermal expansion coefficient. Therefore, a rapid response at the time of starting and stopping can be performed, which contributes to improvement of thermal efficiency.

In this embodiment, the above-described gas turbine and steam turbine are combined into a single shaft to generate power. A high combined power generation plant having an HHV efficiency of 50% or more for 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 3] FIG. 6 shows an air compression type 3 having a closed air cooling system in place of the steam cooling of the embodiment 2.
It is a cross-sectional structure of the turbine upper half part of the step turbine. The basic structure and material configuration of the turbine structure in this embodiment are almost the same as those in the second 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 second embodiment, and the second stage nozzle 82
The cooling of the third stage nozzle 83 has the same cooling channel as that of the second 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 completely tempered martensitic steel shown in Example 2 was used for the turbine stub shaft and the turbine stacking bolt. Also in this embodiment, the strength required as a material for a high-temperature gas turbine is sufficiently satisfied. Further, these martensitic steels have a ferrite-based crystal structure, but the ferrite-based material has a smaller coefficient of thermal expansion than an austenitic-based material such as a Ni-based alloy. Ni for turbine disk
The present embodiment, which uses heat-resistant steel, has higher thermal efficiency than the base alloy, and further reduces the thermal stress generated in the disk having a small coefficient of thermal expansion of the disk material, and can suppress the generation and fracture of cracks. . The materials and structures of other parts are the same as in the second 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 can be 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. 7 is a configuration diagram showing a multi-shaft combined cycle power generation system in which a single gas turbine, a high, medium and low pressure integrated steam turbine, and a generator are provided in each of them, as in the second embodiment. 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 second 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, 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. I can do it.

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

[Embodiment 4] FIG. 8 shows that the exhaust gas discharged from the above-mentioned gas turbine is supplied to an exhaust heat recovery boiler (HRSG) and is generated. High pressure steam turbine
1 is a configuration diagram of a combined cycle power generation system including a steam turbine divided into (HP), an intermediate-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 at 538 ° C. or 566 ° C. with HP and IP entering at the same temperature, while LP has an inlet temperature of about 30 ° C.
It will be 0 ° C. The steam discharged from the HP is heated by an exhaust heat recovery boiler and enters the IP. HP and I in steam turbine
P is composed of a single shaft integral rotor shaft, and a material different from that of LP is used for the rotor shaft material. HP and I
No. 1 material and LP in Table 3 are used for the rotor shaft of P.
No. 2 material shown in Table 3 is used. The last blade of the LP in this embodiment has a wing length of 4 as in the second embodiment.
A 3 inch 12% Cr martensitic steel is used. The casing is composed of two compartments, one compartment for HP and IP and one compartment for LP. The water vapor from IP is H
The steam of about 300 ° C. from the RSG flows into the center of the LP having a symmetric turbine structure. The configuration of the gas turbine according to the present embodiment is almost the same as that of the second embodiment. The outputs of the gas turbine and the steam turbine are the same as those of the second embodiment, and the HHV efficiency of power generation is 50% or more.

[0177]

According to the present invention, a disk which satisfies the creep rupture strength and the impact value after heat embrittlement required for a disk for a high-efficiency high-temperature gas turbine (gas temperature: 1500 ° C. class) can be obtained. Further, a heat-resistant steel which can be applied to other members exposed to a high temperature in a heating embrittlement region is obtained. According to the present invention, the combustion temperature of a gas turbine power plant can be increased, and fossil fuel can be saved and the amount of generated exhaust gas can be suppressed by performing high-efficiency power generation, thereby contributing to global environmental conservation.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of B, creep rupture strength, and V-notch Charpy impact value after heat embrittlement.

FIG. 2 is a graph showing the relationship between the W content, the creep rupture strength, and the V-notch Charpy impact value after heat embrittlement.

FIG. 3 is a configuration diagram of a combined power generation system using steam cooling.

FIG. 4 is a sectional view of a rotating part of a gas turbine by steam cooling.

FIG. 5 is a cross-sectional view of a high, medium and low pressure integrated steam turbine.

FIG. 6 is a sectional view of a rotating part of a gas turbine by air cooling.

FIG. 7 is a configuration diagram of a combined power generation system using closed air cooling.

FIG. 8 is a configuration diagram of a combined power generation system using steam cooling.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Turbine rotor, 11, 12, 13 ... Turbine disk, 18 ... Turbine spacer, 33 ... Distant piece, 54 ... Turbine stacking bolt.

Continuation of the front page (72) Inventor Masao Shiga 3-10-2 Bentencho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Kyowa Engineering Co., Ltd. (reference) 3G002 EA06

Claims (7)

[Claims] 1. A turbine tab shaft, and a plurality of turbine disks connected to each other by a turbine stacking bolt via a turbine spacer.
A turbine blade implanted in the disk and rotated by hot combustion gas generated by a combustor; a distant piece connected to the disk; a plurality of compressor rotors connected to the distant piece; A compressor blade implanted in the compressor and a compressor stub shaft connected to the compressor rotor, wherein the turbine disk, the distant piece, the turbine spacer, the last stage of the compressor disk and the turbine at least one tensile strength at room temperature is 120 kg / mm ² or more, 10 ⁵ h creep rupture strength at 500 ° C. has a V-notch Charpy impact value of 25 ° C. after 10 ³ hours heating at 35 kg / mm ² or more and 540 ° C. 2kg-
A gas turbine comprising a martensitic steel having a m / cm ² or more. 2. A turbine tub shaft, and a plurality of turbine disks connected to the shaft by turbine stacking bolts via a turbine spacer.
A turbine blade implanted in the disk and rotated by hot combustion gas generated by a combustor; a distant piece connected to the disk; a plurality of compressor rotors connected to the distant piece; A compressor blade implanted in the compressor and a compressor stub shaft connected to the compressor rotor, wherein the turbine disk, the distant piece, the turbine spacer, the last stage compressor disk and the turbine At least one is by weight, C0.
15 to 0.35%, Si 0.5% or less, Mn 0.5% or less, Cr 8 to 13%, Mo 1.5 to 4%, Ni 2 to 3.5
%, V 0.05 to 0.35%, one or two of Nb and Ta
The total amount of seeds is 0.02-0.3% and N 0.02-0.1%
Wherein the (C / Nb) ratio (y) is the Nb amount (x)
Characterized by the following relationship (y = −20x + 3.5). 3. A turbine tub shaft, and a plurality of turbine disks connected to the shaft by turbine stacking bolts via a turbine spacer.
A turbine blade implanted in the disk and rotated by hot combustion gas generated by a combustor; a distant piece connected to the disk; a plurality of compressor rotors connected to the distant piece; A compressor blade implanted in the compressor and a compressor stub shaft connected to the compressor rotor, wherein the turbine disk, the distant piece, the turbine spacer, the last stage of the compressor disk and the turbine At least one is by weight, C
0.15 to 0.35%, Si 0.5% or less, Mn 0.5% or less, Cr 8 to 13%, Mo 1.5 to 4%, Ni 2 to 3.5
%, V 0.05 to 0.35%, the total amount of one or two of Nb and Ta is 0.02 to 0.3% and N 0.02 to 0.1%
And W 1% or less, Co 0.5% or less, Cu 0.5% or less,
B 0.01% or less, Ti 0.5% or less, Al 0.3% or less, Zr 0.1% or less, Hf 0.1% or less, Ca 0.01
% Or less, 0.01% or less of Mg, 0.01% or less of Y, and 0.01% or less of rare earth elements, and the (C / Nb) ratio (y) is related to the Nb amount (x) ( y
= -20x + 3.5). A gas turbine comprising a martensitic steel having a value equal to or greater than a value determined by: 4. The composition according to claim 1, wherein C is 0.15 to 0.35% by weight and Si is 0.1%.
5% or less, Mn 0.5% or less, Cr 8 to 13%, Mo 1.
5-4%, Ni 2-3.5%, V 0.05-0.35%,
The total amount of one or two of Nb and Ta is 0.02 to 0.3%
And the (C / Nb) ratio (y) is related to the Nb amount (x) (y = −20x + 3.
A gas turbine disk comprising a martensitic steel having a value not less than the value obtained in 5). 5. The composition according to claim 1, wherein C is 0.15 to 0.35% by weight and Si is 0.1%.
5% or less, Mn 0.5% or less, Cr 8 to 13%, Mo 1.
5-4%, Ni 2-3.5%, V 0.05-0.35%,
The total amount of one or two of Nb and Ta is 0.02 to 0.3%
And N 0.02 to 0.1%, W 1% or less, Co 0.5%
Hereinafter, Cu 0.5% or less, B 0.01% or less, Ti 0.5
% Or less, Al 0.3% or less, Zr 0.1% or less, Hf 0.3%.
1% or less, Ca 0.01% or less, Mg 0.01% or less,
At least one of Y 0.01% or less and a rare earth element 0.01% or less, wherein the (C / Nb) ratio (y) is Nb
A gas turbine disk comprising a martensitic steel having a value equal to or greater than a value determined by a relationship with an amount (x) (y = −20x + 3.5). 6. 0.15 to 0.35% by weight of C.O.
5% or less, Mn 0.5% or less, Cr 8 to 13%, Mo 1.
5-4%, Ni 2-3.5%, V 0.05-0.35%,
The total amount of one or two of Nb and Ta is 0.02 to 0.3%
And the (C / Nb) ratio (y) is related to the Nb amount (x) (y = −20x + 3.
A heat-resistant steel comprising a martensitic steel having a value not less than the value obtained in 5). 7. 0.15% to 0.35% by weight of Si, 0.3% by weight.
5% or less, Mn 0.5% or less, Cr 8 to 13%, Mo 1.
5-4%, Ni 2-3.5%, V 0.05-0.35%,
The total amount of one or two of Nb and Ta is 0.02 to 0.3%
And N 0.02 to 0.1%, W 1% or less, Co 0.5 or less, Cu 0.5% or less, B 0.01% or less, Ti 0.5%
Below, Al 0.3 or less, Zr 0.1% or less, Hf 0.1%
Below, Ca 0.01% or less, Mg 0.01 or less, Y0.0
1% or less and at least 1 of rare earth element 0.01% or less
The (C / Nb) ratio (y) is equal to the Nb amount (x).
A heat-resistant steel comprising a martensitic steel having a value not less than the value determined by the relationship (y = −20x + 3.5).