JPH09287402A - Rotor shaft for steam turbine, steam turbine power plant and steam turbine - Google Patents

Abstract

(57) Abstract: An object of the present invention is to make a steam temperature of 600 to 660 ° C possible by using a ferritic steel, to achieve a high thermal efficiency and a compact rotor shaft for a steam turbine, and steam using the same. Provides turbine and ultra-supercritical steam turbine power plant. According to the present invention, a rotor shaft and a casing exposed to a high temperature part are made of ferritic forged steel and cast steel, and a low pressure turbine final stage blade is made of martensite steel, so that the main steam temperature and the reheat steam temperature are 600 to 600. 6
It is a compact rotor shaft for ultra-supercritical steam turbines at 60 ° C., a steam turbine and its power plant. The final stage blade has a tensile strength of 120 kgf / mm ² or more, the rotor shaft has a creep rupture strength of 100 kgh at each operating temperature of 11 kgf / mm ² or more, and the inner casing has 1
The creep rupture strength of 0,000 hours is 10 kgf / mm ² or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel steam turbine, and more particularly to a final stage rotor blade of a low pressure steam turbine.
The present invention relates to a high temperature steam turbine using% Cr steel.

[0002]

2. Description of the Related Art Currently, 12Cr is used for steam turbine rotor blades.
-Mo-Ni-VN steel is used. In recent years, it has been desired to improve the thermal efficiency of a gas turbine from the viewpoint of energy saving and to downsize the device from the viewpoint of space saving.

For improving the thermal efficiency and downsizing the equipment, making the steam turbine blade longer is an effective means. Therefore, the blade length of the last stage of the low-pressure steam turbine tends to increase year by year. Along with this, the usage conditions of the blades of the steam turbine have become stricter, and the strength of the conventional 12Cr-Mo-Ni-VN steel is insufficient, and a material having higher strength is required. As the strength of the long blade material, tensile strength, which is a basic mechanical property, is required.

From the viewpoint of ensuring safety against fracture, high strength and high toughness are required.

Conventional tensile strength of 12Cr-Mo-Ni-
Ni-based alloys and Co-based alloys are generally known as structural materials higher than VN steels (martensitic steels), but they are inferior in hot workability, machinability and vibration damping characteristics.
Not desirable as a wing material.

As a disk material for gas turbines
-171856 and JP-A-4-120246 are known.

In the conventional steam turbine, the maximum steam temperature is 566 ° C. and the steam pressure is 246 atg.

However, from the viewpoints of depletion of fossil fuels such as oil and coal, energy saving, and prevention of environmental pollution, there is a demand for higher efficiency of thermal power plants. Increasing the steam temperature of the steam turbine is the most effective means to increase power generation efficiency. Japanese Patent Laid-Open Nos. 7-233704 and 8-3697 are known as materials for these high-efficiency ultra-high temperature steam turbines.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to cope with the recent enlargement of low-pressure steam turbine blades, and is disclosed in JP-A-63-171856 and JP-A-4-120246. There is no disclosure of a blade material for a steam turbine.

Further, JP-A-7-233704 and JP-A-8-36
The publication mentioned above in No. 97 discloses a rotor material, a casing material, and the like.
12 as the final stage rotor blade in a power plant with medium and high and medium pressure integrated steam turbines and low pressure steam turbines
The use of% Cr-based martensitic steel is not described.

The object of the present invention is to obtain a steam temperature of 600 to 660.
(EN) It is possible to provide a rotor shaft for a steam turbine having a high heat efficiency that enables a high temperature of ℃ by a ferritic heat-resistant steel, a steam turbine using the same, and a power generation plant thereof.

[0012]

According to the present invention, the rotor journal portion and the low temperature region portion have good weldability of Ta or Mo 0.5%.
Of martensitic steel having a content of more than 1% and a rotor body having a higher T strength than that of the martensitic steel.
A steam turbine rotor shaft is characterized by being made of a martensitic steel containing a or containing Mo described above.

According to the present invention, the rotor journal portion and the low temperature region portion have a weight ratio of C0.06 to 0.14%, Si0.5% or less, Mn2% or less, Cr7 to 12%, Ni0.1 to 1.0.
%, V0.05 to 0.3%, Ta0.01 to 0.20% or Ta and Nb in a total amount of 0.01 to 0.20%, N0.0.
05-0.1%, Mo3.5% or less, W3.5% or less, B
Additive-free or less than 0.015%, preferably less than 0.005%, more preferably less than 0.003% and made of martensitic steel containing 1-10% Co, with the rotor body having a weight ratio of C0.06-0.14%. , Si 0.1% or less, Mn 1% or less, Cr 8 to 12%, Ni 0.1 to 1.0%, V 0.05
~ 0.3%, Ta 0.01 ~ 0.20% or Ta and Nb
In the total amount of 0.01 to 0.20%, N 0.005 to 0.03
5%, Mo 0.5% to 3.5% or less, W 3.5% or less, B0.005 to 0.03% and Co1 to 10% of martensitic steel containing, and the body portion from the journal portion. It is characterized by having an alloy composition with high high temperature strength or low weldability. In the present invention, the journal portion, the low temperature and the body portion are made of martensitic steel containing Mo in an amount of more than 0.5% and less than 1% and Nb of 0.01 to 0.20%.

The present invention relates to a steam turbine power plant equipped with a high pressure turbine, an intermediate pressure turbine and a low pressure turbine or a high intermediate pressure turbine and a low pressure turbine, wherein the high pressure turbine and the intermediate pressure turbine or the high intermediate pressure turbine have steam for the first stage rotor blades. The inlet temperature is 610 to 660 ° C., and the low pressure turbine has a steam inlet temperature to the first stage moving blades of 380 to 475.
° C, the rotor shaft exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine, or the rotor shaft and at least one of the rotor blades, the stator blades, and the inner casing, have a Cr content of 8 to 13% and a Ta content of 0.01 to 0. .20%
Or Nb 0.01-0.2% and Mo 0.5% over 1.
Made of high strength martensitic steel containing less than 0%,
The bearing portion of the rotor shaft is made of martensitic steel having lower strength or higher welding than the body portion.

The present invention has a rotor shaft, a rotor blade planted in the rotor shaft, a stator vane for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the stator vane. The temperature of steam flowing into the first stage of the moving blade is 60
0-660 ° C and pressure 250 kg / cm ² or more or 150-
A steam turbine comprising a high-pressure, medium-pressure or high-medium pressure turbine having a pressure of 200 kg / cm ² , wherein the rotor shaft or the rotor shaft and at least the first stage of moving blades and stationary blades have a temperature of steam flowing into the first stage of the moving blade. At a temperature corresponding to
0 Cr9~13% ⁵ hours creep rupture strength by weight is 10 kgf / mm ² or more and containing less Ta0.01～0.20% or Nb0.01～0.2% and 1% exceed Mo0.5% fully tempered made of a high strength martensite steel having a martensitic structure, containing Cr8~13 wt% 10 ⁵ hours creep rupture strength of 10 kgf / mm ² or more at a temperature which the inner casing corresponding to the steam temperature to Made of martensitic cast steel, and specifically, the rotor shaft is C0.05-0.20% by weight, Si
0.15% or less, Mn 0.03 to 1.5%, Cr 9.5 to 1
3%, Ni 0.05-1.0%, V 0.05-0.35%,
Ta 0.01 to 0.20% or Ta and Nb in the total amount of 0.01 to 0.20%, N 0.005 to 0.06%, Mo1
% Or less, W3.5% or less, Co1 to 10%, B0.00
05-0.03% included, or Nb 0.01-0.20%
And a high-strength martensitic steel containing Mo in an amount of more than 0.5% and less than 1.0% and having Fe of 78% or more, wherein the bearing portion of the rotor shaft has a lower strength or a higher weldability than the body portion. It is characterized by consisting of.

According to the present invention, a high-pressure turbine, an intermediate-pressure turbine, a low-pressure turbine, and a low-pressure turbine, or a high-pressure turbine, a low-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine are connected, or a high-intermediate-pressure integrated steam turbine and one unit or tandem. In a steam turbine power plant in which two low-pressure turbines are connected to each other, the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure turbine have a steam inlet temperature of 6
00 to 660 ° C (preferably 600 to 620 ° C, 620
630 ° C., 630 ° C. to 640 ° C.), the low pressure turbine has a steam inlet temperature of 350 to 4 to the first stage moving blades.
For the range of 00 ° C., at least one of the rotor shaft or rotor shaft exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure turbine, at least one of the moving blades and the stationary blades, and at least one of the inner casings has a weight. Cr of 8 to 13% and Ta of 0.01 to 0.20% or Nb of 0.01 to 0.20% and Mo of more than 0.5% and less than 1.0.
And (the blade length (inch) of the final stage rotor blade of the low-pressure turbine
X number of revolutions (rpm)] is 125,000 or more and is made of martensitic steel.

Further, the present invention has a rotor shaft, a rotor blade embedded in the rotor shaft, a stator vane for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the stator vane. , The temperature of the steam flowing into the first stage of the moving blade is 600 to 660 ° C., and the pressure is 250 kgf / cm ² or more (preferably 246 to 316 kgf / cm ² ) or 170 to
A steam turbine of 200 kgf / cm ² , wherein the rotor shaft or the rotor shaft and at least the first stage of the moving blade and the stationary blade have respective steam temperatures (preferably 610 ° C., 62
5 ℃, 640 ℃, is 650 ℃, 660 ℃) 10 ⁵ h creep rupture strength at a temperature corresponding to the 10 kgf / mm ² or more (preferably 17 kgf / mm ² or more) Cr9.5～1
3% by weight (preferably 10.5 to 11.5% by weight) of the aforementioned high-strength martensitic steel having a fully tempered martensitic structure, wherein the inner casing has a temperature corresponding to each of the steam temperatures. 10 ⁵ hour creep rupture strength of 10 kgf / mm ² or more (preferably 10.5 kgf / mm ^2
2 or more), which is made of a martensitic cast steel containing 8 to 9.5% by weight of Cr. In the high-to-medium pressure integrated steam turbine that is sent to the medium pressure turbine.

In the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure integrated steam turbine, at least the first stage of the rotor shaft or the moving blades and the stationary blades has a weight of C0.0.
5 to 0.20%, Si 0.15% or less, Mn 0.05 to
1.5%, Cr 9.5-13%, Ni 0.05-1.0%,
V0.05 to 0.35%, Nb0.01 to 0.20%, N
0.01-0.1%, Mo 0.5% over 3.5% or less,
W3.5% or less, Co1-10%, B0.0005-0.
03% or Ta 0.01 to 0.20% or Ta and Nb in a total amount of 0.01 to 0.20% and made of high strength martensitic steel having 78% or more of Fe, and 620 to 64
It preferably corresponds to a steam temperature of 0 ° C., and the inner casing has a weight of C 0.06 to 0.16%, Si 0.5% or less, Mn 1% or less, Ni 0.2 to 1.0%, Cr 8 to 12%.
%, V0.05 to 0.35%, Nb0.01 to 0.15%,
N0.01-0.8%, Mo1% or less, W1-4%, B
Fe containing 0.0005 to 0.003% and 85% or more
It is preferably made of high strength martensitic steel having

In the high-pressure steam turbine according to the present invention,
The rotor blade has 9 stages or more, preferably 10 stages or more, the first stage has a double flow, and the rotor shaft has a bearing center distance.
(L) is 5000 mm or more (preferably 5100 to 65)
00 mm) and the minimum diameter (D) at the portion where the stationary vanes are provided is 660 mm or more (preferably 680 to 740 mm).
It is preferable that the high strength martensitic steel contains 9 to 13% by weight of Cr having the (L / D) of 6.8 to 9.9 (preferably 7.9 to 8.7).

In the medium-pressure steam turbine according to the present invention,
The rotor blade has a symmetrical structure having six or more stages each, and the rotor shaft has a double-flow structure in which the first stage is implanted in the center portion of the rotor shaft. The rotor shaft has a bearing center distance (L) of 5000 mm or more (preferably 5100). ~ 6500 mm) and the minimum diameter (D) in the portion where the vanes are provided is 630 mm or more (preferably 650 to 710 mm), and (L / D) is 7.0 to 9.2 (preferably 7). Cr9 which is 0.8 to 8.3)
It is preferably composed of high strength martensitic steel containing ~ 13% by weight.

In a low-pressure steam turbine having a high-pressure turbine and a medium-pressure turbine separately, the moving blades have a symmetric structure of 6 or more stages each, and a double-flow structure in which the first stage is planted in the center of the rotor shaft. The rotor shaft has a bearing center distance (L) of 6500 mm or more (preferably 6600 mm).
７7100 mm) and the minimum diameter (D) at the portion where the stator vanes are provided is 750 mm or more (preferably 760 to 900 mm).
mm), and wherein the (L / D) is 7.8 to 10.2 (preferably 8.0 to 8.6), and 3.25 to 4.25% by weight of Ni.
And the final stage rotor blade has a value of [blade length (inch) × rotation speed (rpm)] of 1
It is preferably composed of high strength martensitic steel of 25,000 or more.

Further, according to the present invention, a high-pressure turbine, an intermediate-pressure turbine, a low-pressure turbine, and a low-pressure turbine, or a high-pressure turbine, a low-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine are connected, or a high-intermediate-pressure turbine and one unit or tandem. In a steam turbine power plant in which two low-pressure turbines are connected, the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure turbine have a steam inlet temperature of 600 to a first-stage rotor blade.
660 ° C., the low-pressure turbine has a steam inlet temperature to the first-stage rotor blade of 350 to 400 ° C., and the metal temperature of the first-stage rotor blade implanted portion of the rotor shaft of the high-pressure turbine and the metal temperature of the first-stage rotor blade are lower than that of the high-pressure turbine. 40 ° C. or more from the steam inlet temperature to the first stage blade (preferably 20 to
35 ° C.) and the metal temperature of the first stage rotor blade installation part of the rotor shaft of the medium pressure turbine and the first stage rotor blade is 75 ° C. or more than the steam inlet temperature to the first stage rotor blade of the medium pressure turbine. (Preferably from 50 to 50
The rotor shaft of the high-pressure turbine and the intermediate-pressure turbine and at least the first-stage rotor blades are made of the above-mentioned martensitic steel containing Cr in an amount of 9.5 to 13% by weight. It is preferable that the step blade be made of high-strength martensitic steel having a value of [blade length (inch) × rotational speed (rpm)] of 125,000 or more.

Furthermore, the present invention provides a coal-fired boiler, a steam turbine driven by the steam obtained by the boiler, and a single machine or two driven by the steam turbine.
In a coal-fired thermal power plant equipped with a generator having a power generation output of 1,000 MW or more, preferably two or more, the steam turbine is a high-pressure turbine, a medium-pressure turbine, a low-pressure turbine and a low-pressure turbine, or a high-pressure turbine and a low-pressure turbine And a medium-pressure turbine and a low-pressure turbine are connected, or a high-intermediate-pressure turbine and one low-pressure turbine or two low-pressure turbines are connected in tandem, and the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure turbine are steam to the first-stage rotor blades. The inlet temperature is 600 to 660 ° C., the steam inlet temperature to the first-stage moving blade of the low-pressure turbine is 350 to 400 ° C., and the steam inlet temperature to the first-stage moving blade of the high-pressure turbine is 3 ° C. or more due to the superheater of the boiler. (Preferably 3 to 10 ° C,
More preferably, the steam heated to a high temperature (3 to 7 ° C.) flows into the first-stage moving blade of the high-pressure turbine, and the steam leaving the high-pressure turbine is fed to the first-stage moving blade of the intermediate-pressure turbine by the reheater of the boiler. 2 ° C or more (preferably 2 to 10 ° C, more preferably 2 to 5 ° C) higher than the steam inlet temperature of the above, and the steam that flows into the first stage moving blade of the intermediate pressure turbine and exits from the intermediate pressure turbine Is preferably 3 ° C. or more (preferably 3 to 10) from the steam inlet temperature to the first-stage moving blades of the low-pressure turbine by the boiler economizer.
C., more preferably 3-6.degree. C.) and heated to a higher temperature to flow into the first-stage rotor blade of the low-pressure turbine, and the final-stage rotor blade of the low-pressure turbine is [blade length (inch) × rotation speed]
(rpm)] is preferably 125,000 or more and is made of high-strength martensitic steel.

Further, in the low-pressure steam turbine according to the present invention, the steam inlet temperature to the first stage moving blade is 350 to 400.
C. (preferably 360 to 380.degree. C.), and the rotor shaft has C0.2-0.3% and Si0.05% by weight.
Below, Mn 0.1% or less, Ni 3.25-4.25%, C
r 1.25 to 2.25%, Mo 0.07 to 0.20%, V
It is preferably made of a low alloy steel having a content of 0.07 to 0.2% and Fe of 92.5% or more.

In the above-mentioned high-pressure steam turbine, the moving blades have 7 or more stages (preferably 9 to 12 stages) and the blade length is 25 to 180 mm from the upstream side to the downstream side of the steam flow, and the rotor shaft The diameter of the implanted portion of the moving blade is larger than the diameter of the portion corresponding to the stationary blade, and the axial width of the implanted portion is stepwise in the downstream side as compared with the upstream side in three steps or more (preferably 4 to 7 steps). The ratio to the length of the wing is 0.2 to 1.6 (preferably 0.30 to).
It is preferably 1.30, more preferably 0.65 to 0.95) and becomes smaller from the upstream side to the downstream side.

Further, in the high pressure steam turbine described above,
In the present invention, the moving blade has 7 stages or more (preferably 9 stages or more) and the blade length is 25 to 25 from the upstream side to the downstream side of the steam flow.
It has 180mm, and the ratio of the length of the wings of adjacent stages is 2.3.
In the following, it is preferable that the ratio is gradually increased on the downstream side and the blade portion length on the downstream side is larger than that on the upstream side.

Furthermore, in the above-mentioned high-pressure steam turbine,
In the present invention, the moving blade has 7 stages or more (preferably 9 stages or more) and the blade length is 25 to 25 from the upstream side to the downstream side of the steam flow.
180 mm, and the axial width of the portion of the rotor shaft corresponding to the stationary blade portion is smaller on the downstream side in two or more steps (preferably 2 to 4 steps) than on the upstream side, It is preferable that the ratio is gradually reduced toward the downstream side within a range where the ratio to the side wing portion length is 4.5 or less.

In the above-mentioned medium-pressure steam turbine, the moving blade has a double-flow structure having six or more stages (preferably 6 to 9 stages) symmetrically and the blade length is 60 to 300 mm from the upstream side to the downstream side of the steam flow. The rotor shaft has a diameter of an implanted portion of the moving blade larger than a diameter of a portion corresponding to the stationary blade, and an axial width of the implanted portion is two or more stages (preferably 2) in the downstream side as compared with the upstream side. .About.6 steps), and the ratio to the blade length is 0.
It is preferably 35 to 0.80 (preferably 0.5 to 0.7) and becomes smaller from the upstream side to the downstream side.

Further, in the above-mentioned medium-pressure steam turbine according to the present invention, the moving blade has a double-flow structure having six or more stages symmetrically and the blade length is 60 from the upstream side to the downstream side of the steam flow.
The length of the adjacent blades is larger on the downstream side than on the upstream side, and the ratio is 1.3 or less (preferably 1.1 to 1.2) gradually on the downstream side. It is preferably large.

Further, in the above-mentioned medium-pressure steam turbine according to the present invention, the moving blade has a double-flow structure having six or more stages symmetrically and the blade length is 60 from the upstream side to the downstream side of the steam flow.
.About.300 mm, and the axial width of the portion of the rotor shaft corresponding to the stationary vane portion is stepwise smaller than the upstream side by two steps or more (preferably 3 to 6 steps), The ratio of the blade to the downstream blade length is 0.
In the range of 80 to 2.50 (preferably 1.0 to 2.0), it is preferable that the ratio gradually decreases toward the downstream side.

The present invention is a low-pressure steam turbine in a power plant in which the high-pressure turbine and the intermediate-pressure turbine are separately provided, and the moving blades have six or more stages (preferably 8 to 10 stages) symmetrically in the left and right directions. The double flow structure and the blade length are 80 to 1300 depending on the upstream side to the downstream side of the steam flow.
mm, the diameter of the rotor blade of the rotor blade is larger than the diameter of the portion corresponding to the stationary blade, and the axial width of the rotor portion is preferably three stages or more in the downstream side compared to the upstream side ( More preferably, it is gradually increased in 4 to 7 stages, and the ratio to the blade length is 0.2.
.About.0.7 (preferably 0.3 to 0.55), it is preferable that it becomes smaller from the upstream side to the downstream side.

Further, according to the present invention, in the low-pressure steam turbine in the case where the high-pressure turbine and the medium-pressure turbine are separately provided, the moving blade has a double-flow structure having symmetrically six or more stages each and the blade length is equal to that of the steam flow. It has 80 to 1300 mm from the upstream side to the downstream side, and the blade length of each adjacent stage is larger on the downstream side than on the upstream side, and the ratio thereof is 1.2 to 1.8 (preferably 1. It is preferable that the ratio is gradually increased on the downstream side in the range of 4 to 1.6).

Furthermore, in the low-pressure steam turbine according to the present invention, the moving blade has a double-flow structure having symmetrically 6 stages or more, preferably 8 stages or more, and blade lengths from the upstream side to the downstream side of the steam flow. 80 to 1300 mm, and the axial width of a portion of the rotor shaft corresponding to the stationary vane portion is stepwise larger than the upstream side by 3 steps or more (more preferably 4 to 7 steps) as compared with the upstream side. The ratio of the moving blades to the length of the adjacent downstream blades is 0.2 to 1.4 (preferably 0.25 to 1.25, especially 0.2).
In the range of 5 to 0.9), it is preferable that the ratio gradually decreases toward the downstream side.

In the above-described high-pressure steam turbine, the moving blade has 7 stages or more, preferably 9 stages or more, and the rotor shaft has a diameter of a portion corresponding to the stationary blade of a portion corresponding to the moving blade implanting portion. The diameter is smaller than the diameter, and the axial width of the diameter corresponding to the stationary blade is gradually increased in two or more stages (preferably 2 to 4 stages) in the upstream side of the steam flow compared to the downstream side, The width between the last stage of the rotor blade and the front stage thereof is 0.75 to 0.95 times the width between the second stage and the third stage of the rotor blade (preferably 0.8 to 0.9). It is more preferably double 0.82 to 0.88), and the width of the rotor shaft in the axial direction of the moving blade portion is 3 stages or more (preferably 4 to 4) in the downstream side of the steam flow compared to the upstream side. 7
The axial width of the final stage of the moving blade is 1 to 2 with respect to the axial width of the second stage.
It is preferably doubled (preferably 1.4 to 1.7 times).

In the above-mentioned medium-pressure steam turbine, the moving blade has six stages or more, and the rotor shaft has a diameter corresponding to the stationary blade smaller than a diameter corresponding to the moving blade embedded portion. The axial width of the diameter corresponding to the stationary vane is increased stepwise on the upstream side of the steam flow as compared to the downstream side by preferably 2 steps or more (more preferably 3 to 6 steps). The width between the last stage of the blade and its front is 0.5 to 0.5 of the width between the first stage and the second stage of the moving blade.
0.9 times (preferably 0.65 to 0.75 times), and the width of the rotor shaft in the axial direction of the moving blade portion is preferably two stages in the downstream side of the steam flow compared to the upstream side. The axial width of the final stage of the moving blade is 0.8 to 2 times (preferably 1 to 3 times) (preferably 3 to 6 stages). .2-1.5
2 times) is preferable.

In the above-mentioned low-pressure steam turbine, the moving blade has a double-flow structure having symmetrically eight stages or more, and the rotor shaft has a diameter corresponding to the stationary blade and a portion corresponding to the moving blade implanting portion. And the axial width of the diameter corresponding to the stationary vanes is stepwise larger in the upstream side of the steam flow than in the downstream side, preferably by 3 steps or more (more preferably 4 to 7 steps). The width between the last stage of the rotor blade and the front stage thereof is 2 times that of the first stage of the rotor blade.
1.5 to 3.0 times the width between the steps (preferably 2.0 to
2.7 times), and the width of the rotor shaft in the axial direction of the moving blade portion is preferably 3 stages or more (more preferably 4 to 7 stages) in the downstream side of the steam flow compared to the upstream side. The width in the axial direction of the final stage of the moving blade is 5 to 8 times (preferably 6.2 to 7.0 times) the axial width of the first stage. preferable.

The structures of the high-pressure, medium-pressure or high-medium-pressure integrated turbine and the low-pressure turbine described above can be the same for any of the steam temperatures used of 610 to 660 ° C.

In the rotor material of the present invention, in order to obtain high temperature strength, low temperature toughness, and high fatigue strength as a fully tempered martensite structure, the Cr equivalent calculated by the following formula should be adjusted to 4 to 8 components. Is preferred.

In the high-intermediate-pressure integrated steam turbine of the present invention, the high-pressure side moving blades have 7 stages or more, preferably 8 stages or more, and the intermediate-pressure side moving blades have 5 stages or more, preferably 6 stages or more, and the rotor shaft is The bearing center-to-center distance (L) is 6000 mm or more (preferably 6100 to 7000 mm), and the minimum diameter (D) at the portion where the vanes are provided is 660 mm or more (preferably 620 to 760 mm). D) is 8.0
It is preferably made of a high-strength martensitic steel containing 9 to 13% by weight of Cr as described above, which is 〜11.3 (preferably 9.0 to 10.0).

The low pressure steam turbine for the high and medium pressure integrated turbine of the present invention has the following requirements.

In the low-pressure steam turbine, the rotor blades are symmetrically provided with five or more stages, preferably six stages or more, and have a double-flow structure in which the first stage is planted in the center of the rotor shaft. Bearing center distance (L) is 65
00 mm or more (preferably 6600 to 7500 mm) and the minimum diameter (D) at the portion where the stationary blade is provided is 750 mm or more
(Preferably 760 to 900 mm), and the (L / D)
Is 7.2 to 10.0 (preferably 8.0 to 9.0)
Ni-Cr-Mo containing 3.25 to 4.25% by weight
-V low alloy steel, the last stage blade is [wing length (inch)
X rotational speed (rpm)] is preferably 125,000 or more.

In the rotor shaft, the diameter (D) of the vane portion is 750 to 1300 mm, the bearing center distance (L) is 5.0 to 9.5 times the D, and the weight is C0.2 to C0.2. 0.
3%, Si 0.05% or less, Mn 0.1% or less, Ni3.
0-4.5%, Cr 1.25-2.25%, Mo 0.07-
It consists of a low alloy steel with 0.20%, V0.07-0.2% and Fe 92.5% or more.

The moving blade has a double-flow structure having 5 or more stages, preferably 6 or more stages symmetrically, and the blade length is in the range of 80 to 1300 mm from the upstream side to the downstream side of the steam flow, and The diameter of the implanted portion of the moving blade is larger than the diameter of the portion corresponding to the stationary blade, the width of the axial root portion of the embedded portion is wider than the width of the blade embedded portion, and the width from the downstream side to the upstream side is increased. It is gradually reduced, and the ratio to the blade length is 0.
25-0.80.

The moving blade has a double-flow structure having 5 or more stages, preferably 6 or more stages symmetrically, and the blade length is in the range of 80 to 1300 mm from the upstream side to the downstream side of the steam flow, and each adjacent stage The length of the blade of the blade is larger on the downstream side than on the upstream side, and the ratio is 1.2 to 1.7.
In the range, the wing portion length is gradually increased on the downstream side.

The rotor blade has a double-flow structure having five or more stages, preferably six or more stages symmetrically, and the blade portion length increases from the upstream side to the downstream side of the steam flow, from 80 to 130.
0 mm, and the axial width of the root portion of the implanted portion of the rotor blade of the rotor shaft is larger at at least three stages on the downstream side than on the upstream side. It is getting bigger.

The high-intermediate-pressure integrated steam turbine according to the present invention has the following configuration.

The moving blade on the high-pressure side has seven stages or more and the blade portion length is 40 to 200 mm from the upstream side to the downstream side of the steam flow, and the diameter of the rotor blade on the rotor shaft is equal to that of the stationary blade. It is larger than the diameter of the corresponding portion, the width of the axial root portion of the implant portion is gradually larger on the upstream side than on the downstream side, and the ratio to the blade length is 0.20 to 1.
60, preferably 0.25 to 1.30, which increases from the upstream side to the downstream side, the intermediate pressure side moving blades have 5 or more stages symmetrically, and the blade length is the upstream side of the steam flow. From 100 to 350 mm on the downstream side of the rotor shaft, the diameter of the rotor blade of the rotor blade is larger than the diameter of the portion corresponding to the stationary blade, and the axial width of the root portion of the rotor portion is the same except for the final stage. The downstream side is larger than the upstream side, and the ratio to the blade length is 0.35 to 0.8.
It is 0, preferably 0.40 to 0.75, and decreases from the upstream side to the downstream side.

The moving blade has 7 stages or more and the blade length is 25 to 200 mm from the upstream side to the downstream side of the steam flow, and the ratio of the blade lengths of adjacent stages is 1.05 to 1.35. The blade length is gradually increased on the downstream side compared to the upstream side, the intermediate pressure portion of the moving blade has five stages or more, and the blade length is 100 from the upstream side to the downstream side of the steam flow. ~ 350 mm
The length of the adjacent wings is greater on the downstream side than on the upstream side, and the ratio is 1.10 to 1.30, and gradually increases on the downstream side.

The moving blade on the high-pressure side has 6 or more stages, preferably 7 or more stages, and the rotor shaft has a diameter of a portion corresponding to the stationary blade smaller than a diameter of a portion corresponding to the moving blade implanting portion, The axial width of the root portion of the implanting portion of the moving blade is largest at the first stage, and gradually increases in two or more stages, preferably three or more stages from the upstream side to the downstream side of the steam flow, and the intermediate pressure side. The rotor blade has five or more stages, and the rotor shaft has a diameter of a portion corresponding to the stationary blade smaller than a diameter of a portion corresponding to the rotor blade implanting portion, and an axial direction of a root portion of the implanting portion of the rotor blade. The upstream side of the steam flow is preferably stepwise different from the downstream side in four stages or more, and the first stage of the moving blade is larger than the second stage and the last stage is larger than the other stages. The steps are widened toward the end.

The long blade for a steam turbine according to the present invention has a weight ratio of C0.08 to 0.18%, Si of 0.25% or less, and Mn.
0.90% or less, Cr 8.0-13.0%, Ni 2-3%
Below, Mo1.5-3.0%, V0.05-0.35%, N
The total amount of one or two of b and Ta is 0.02 to 0.20
%, And a martensitic steel containing 0.02 to 0.10% N.

This steam turbine long blade must have high tensile strength and high cycle fatigue strength at the same time in order to withstand high centrifugal stress and vibration stress due to high speed rotation.
Therefore, the metal structure of the blade material must be a fully tempered martensite structure because the fatigue strength is significantly reduced in the presence of harmful δ-ferrite.

It is necessary that the composition of the steel of the present invention is adjusted so that the Cr equivalent calculated by the above-mentioned formula is 10 or less so that it does not substantially contain the δ ferrite phase. The tensile strength of the long blade material is 120 kgf / mm ² or more, preferably 1
It is 28.5 kgf / mm ² or more.

Further, in order to obtain a homogeneous and high-strength steam turbine long blade material, as a heat treatment for refining, after melting and forging, 10
After heating and holding at 00 ° C to 1100 ° C, preferably for 0.5 to 3 hours, quenching is performed by rapidly cooling to room temperature.
Primary tempering in which the material is heated and held at 570 ° C. for preferably 1 to 6 hours and then cooled to room temperature and at 560 to 590 ° C., preferably 1
After heat-holding for up to 6 hours, the tempering heat treatment is performed twice or more, that is, secondary tempering of cooling to room temperature.

The length of the last stage low-pressure turbine blade portion according to the present invention is 914 mm (36 ") or more, preferably 965 mm (3").
8 ″) or higher 3600 rpm steam turbine and low pressure turbine The final stage blade length is 1092 mm (43 ″) or more, preferably 1168 mm (46 ″) or more 3000 rpm steam turbine, and [blade length (inch) × rotation speed ( rpm)] value is 125,000 or more, preferably 138,000 or more.

In the casing material made of the heat-resistant cast steel of the present invention, tempered martensite (δ
Ferrite 5% or less) In order to adjust the alloy composition so as to obtain a high temperature high temperature toughness and low temperature toughness and high fatigue strength, the Cr equivalent calculated as the content of each element in the following formula by weight% is 4 It is preferable to adjust the components to 10.

Cr equivalent = Cr + 6Si + 4Mo + 1.5
W + 11V + 5Nb-40C-30N-30B-2Mn
-4Ni-2Co + 2.5Ta In the 12Cr heat-resisting steel of the present invention, especially when used in steam at 621 ° C or higher, creep rupture strength at 625 ° C, 10 ⁵ h, 10 kgf / mm ² or more, room temperature impact absorption energy 1 kgf. It is preferably −m or more.

(1) Ferrite heat-resisting steel constituting the high-pressure and intermediate-pressure or high-intermediate-pressure integrated rotor, blade, nozzle, inner casing fastening bolt, and intermediate-pressure section first-stage diaphragm of the 600-660 ° C. steam turbine in the present invention The reasons for limiting the composition will be described. C secures hardenability,
It is an element indispensable for increasing the high-temperature strength by precipitating carbides during the tempering heat treatment process. In addition, 0.05% or more is necessary to obtain high tensile strength, but 0.20%
If it exceeds, the metal structure becomes unstable when exposed to high temperature for a long time, and the creep rupture strength is reduced for a long time.
It is limited to 0.05 to 0.20%. Desirably 0.08 ~
0.13%, and particularly preferably 0.09 to 0.12%.

Mn is added as a deoxidizing agent and the like, and its effect is achieved by adding a small amount, and addition of a large amount exceeding 1.5% lowers the creep rupture strength, which is not preferable. Especially 0.03 to 0.20% or 0.3 to 0.7%
Is preferable, and more preferably 0.35 to 0.65%. Higher strength is obtained with less Mn. In addition, the higher the Mn content, the better the workability.

Although Si is also added as a deoxidizing agent, Si deoxidizing is not required according to the steelmaking technology such as the vacuum C deoxidizing method. By lowering Si, it is possible to prevent harmful δ-ferrite structure from being generated and to prevent deterioration of toughness due to segregation of grain boundaries. Therefore, when adding it,
It should be kept below 15%, preferably 0.07%
Or less, and particularly preferably less than 0.04%.

Ni is a very effective element for enhancing the toughness and preventing the formation of δ ferrite, but 0.0
If it is less than 5%, its effect is not sufficient, and if it exceeds 1.0%, the creep rupture strength is lowered, which is not preferable. In particular, it is preferably 0.2 to 0.7%, more preferably 0.4 to 0.65%.

Cr is an indispensable element for enhancing high temperature strength and high temperature oxidation resistance, and at least 9% is necessary, but 13%
If it exceeds 0.1%, a harmful δ-ferrite structure is formed and the high temperature strength and toughness are reduced, so it is limited to 9 to 12%. In particular, it is preferably 10 to 12%, more preferably 10.8 to 11.8%.

Mo is added to improve the high temperature strength. When containing Ta, 3.5% or less, preferably 1%
When Nb is contained below, sufficient toughness and fatigue strength cannot be obtained if it is less than 0.5%, and it is contained more than 0.5% and not more than 3.5%, preferably less than 1.0%. Especially 0.55
~ 0.85% is preferred.

W suppresses the coagulation and coarsening of carbides at high temperatures and strengthens the matrix by solid solution, so that it has the effect of significantly increasing the high temperature long-term strength at 620 ° C. or higher. 620
1 to 1.5% below ℃, 1.6 to 2.30% below 630 ° C.
0%, 2.1-2.5% below 640 ° C, 2.6-3.0% below 650 ° C, 3.1-3.5 below 660 ° C.
% Is preferable. When W exceeds 3.5%, δ
Since ferrite is formed and toughness is reduced, the content is limited to 3.5% or less, preferably 1 to 3.5%. Particularly preferably, it is 1 to 3%, more preferably 1.5 to 3.0%, and further preferably 2.0 to 2.7%.

V has the effect of precipitating carbonitrides of V to increase the creep rupture strength, but if it is less than 0.05% the effect is insufficient, and if it exceeds 0.3%, δ ferrite is formed and the fatigue strength is increased. Lower. Particularly, 0.1 to 0.25% is preferable, and 0.15 to 0.23% is more preferable.

Nb and Ta are very effective elements for precipitating NbC and TaC carbides and increasing the high temperature strength. However, if added in a too large amount, coarse eutectic NbC and TaC carbides especially in large steel ingots. Occurs, which rather causes reduction in strength or precipitation of δ-ferrite that reduces fatigue strength. Therefore, it is necessary to suppress the content to 0.20% or less singly or in combination. Further, if it is less than 0.01%, the effect is insufficient. Especially 0.02 to 0.15%, more 0.04 to 0.
10% is preferable.

Co is an important element that distinguishes and characterizes the present invention from the conventional invention. In the present invention, addition of Co significantly improves high temperature strength and also enhances toughness. This is thought to be due to the interaction with W, and W
Is a characteristic phenomenon in the alloy of the present invention containing 1% or more. In order to realize such Co effect, the lower limit of Co in the alloy of the present invention is 1.0%, but even if it is excessively added, not only a larger effect cannot be obtained, but also the ductility decreases. , The upper limit is 10%. Preferably 600
1-3% for 620 ° C, 3.5-4.5% for 630 ° C, 5-6% for 640 ° C, 650
6.5 to 7.5% for ℃, 8 to 660 ℃
9% is desirable.

N is also an important element for distinguishing and characterizing the present invention from the conventional invention. N is effective in improving creep rupture strength and preventing the formation of δ ferrite structure, but 0.0
If it is less than 1%, the effect is not sufficient, and if it exceeds 0.05%, the toughness is lowered and the creep rupture strength is also lowered. In particular, 0.01 to 0.03% is more preferable to 0.015 to 0.03.
025% is preferable.

[0068] B is a solid solution in the grain boundary strength effects and M ₂₃ C ₆ carbide is effective to increase the high-temperature strength by the action preventing the aggregation and coarsening of M ₂₃ C ₆ type carbide, added in excess of 0.001% Is effective, but if it exceeds 0.03%, the weldability and forgeability are impaired, so it is limited to 0.001 to 0.03%. Desirably 0.001 to 0.01%, or 0.01 to 0.01%
0.02% is preferred.

The addition of Ti and Zr has the effect of increasing the toughness, and Ta of 0.15% or less, Ti of 0.1% or less, and Z
Sufficient effect can be obtained by adding r 0.1% or less alone or in combination.

The heat-resistant steel according to the present invention contains rare earth elements such as La and Ce, Ca, Mg, and Y alone or in a combination of 0.001.
０0.03%. These elements are particularly strong deoxidizers, have a desulfurization action, and can improve toughness. Preferably 0.003-0.010%
It is.

In the present invention, at least the first stage of the rotor shaft and the moving blades and the stationary blades have C0.09 to 0.20% and Si of 0.15% or less for a steam temperature of 620 to 630 ° C.
Mn 0.05-1.0%, Cr 9.5-12.5%, Ni
0.1-1.0%, V0.05-0.30%, N0.01-
0.06%, Ta 0.02 to 0.08% or the total amount of Ta and Nb 0.02 to 0.08%, Mo 3.5% or less, preferably 1.0% or less, or Nb 0.02 to 0.02. 08%, Mo
More than 0.5% and less than 3.5%, preferably less than 1.0%,
W3.5% or less, preferably 2-3.5%, Co2-4.
Fe of 5%, B0.001-0.030%, 77% or more
What is constituted by steel having a fully tempered martensite structure having Also, 635-660 ° C
With respect to the steam temperature of
It is preferably constituted by a steel having a fully tempered martensitic structure with 8% or more Fe. In particular, high strength can be obtained by reducing the Mn amount to 0.03 to 0.2% and the B amount to 0.001 to 0.01% with respect to both temperatures.

The Cr equivalent calculated by the equation described below is preferably 4 to 10.5, particularly 6.5 to 9.5 for the rotor shaft, and the same is true for the others.

In the high-pressure and medium-pressure rotor materials for the steam turbine of the present invention, if the δ-ferrite structure is mixed, the fatigue strength and toughness are lowered, so that the structure is preferably a tempered martensite structure. In order to obtain a tempered martensite structure, the Cr equivalent calculated by the above formula must be adjusted to 10 or less by adjusting the composition. If the Cr equivalent is too low, the creep rupture strength will decrease, so it must be 4 or more. In particular, a Cr equivalent of 5 to 8 is preferable.

In the rotor of the present invention, an alloy raw material having a target composition is melted in an electric furnace, carbon vacuum deoxidized, cast in a metal mold and forged to form an electrode rod. The electrode rod is remelted by electroslag and forged into a rotor shape. This forging must be performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. Also, after this forged steel is annealed, it can be used in steam at 620 ° C or higher by quenching by heating to 1000 to 1100 ° C and quenching, and then tempering twice in the order of 550 to 650 ° C and 670 to 770 ° C. A steam turbine rotor can be manufactured.

The blades, nozzles, inner casing tightening bolts and intermediate pressure part first stage diaphragm in the present invention are melted by vacuum melting and cast in a mold under vacuum to manufacture an ingot. The ingot is hot forged into a predetermined shape at the same temperature as described above, heated at 1050 to 1150 ° C and then water-cooled or oil-quenched, and then tempered at 700 to 800 ° C, and a blade having a desired shape by cutting. Become. Vacuum melting is performed under 10 ^-1 to 10 ^-4 mmHg. In particular, the heat-resistant steel in the present invention can be used in all stages of the blade and nozzle in the high pressure region and the medium pressure region, but it is particularly necessary in the first stage of both.

(2) The reason for limiting the composition range of the 12% Cr steel used for the final stage blade of the low pressure steam turbine in the present invention will be described.

C is at least 0.0 in order to obtain high tensile strength.
8% is required. If too much C is added, the toughness will be reduced, so it must be 0.20% or less. Particularly, 0.10 to 0.18% is preferable. From 0.12 to 0.
16% is preferable.

Si is a deoxidizing agent, and Mn is a desulfurizing / deoxidizing agent, which is added when melting steel, and is effective even in a small amount. Si is a δ-ferrite forming element, and the addition of a large amount thereof causes harmful δ-ferrite formation that reduces fatigue and toughness, so it must be made 0.25% or less. According to the carbon vacuum deoxidizing method and the electroslag melting method, it is not necessary to add Si, and Si is not added. Particularly, it is preferably 0.10% or less, more preferably 0.05% or less.

Since a large amount of Mn lowers the toughness,
Should be no more than 9%. In particular, Mn is effective as a deoxidizer, so from the viewpoint of improving toughness, it is 0.4% or less, more preferably 0.2
% Or less is preferable.

Cr enhances corrosion resistance and tensile strength, but 13
If it is added in an amount of not less than%, it will cause the formation of δ ferrite structure.
If it is less than 8%, the corrosion resistance and tensile strength are insufficient, so C
The r was determined to be 8-13%. Especially in terms of strength 10.
5 to 12.5% is more preferable, 11 to 12%.

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

V and Nb have the effect of improving the toughness while precipitating carbides to increase the tensile strength. V0.05%, Nb
If it is less than 0.02%, the effect is insufficient, and V0.35
%, Nb of 0.2% or more causes the formation of δ ferrite. Especially V is 0.15-0.30%, and more preferably 0.25-0.30
%, Nb is 0.04 to 0.15%, more preferably 0.06 to 0.12.
% Is preferred. Ta can be added in exactly the same manner as Nb instead of Nb, and composite addition can be performed.

Ni has the effect of increasing the low temperature toughness and preventing the formation of δ ferrite. This effect is insufficient if Ni is 2% or less, and is saturated by addition if Ni exceeds 3%. In particular, 2.3 to 2.9% is preferable. More preferably 2.4
~ 2.8%.

N has an effect of improving the tensile 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 0.1%, the toughness is lowered. Particularly, excellent characteristics are obtained in the range of 0.04 to 0.08, and more preferably 0.06 to 0.08%.

The reduction of Si, P and S has the effect of increasing the low temperature toughness without impairing the tensile strength, and it is desirable to reduce it as much as possible. From the viewpoint of improving low temperature toughness, Si 0.1% or less,
P is preferably 0.015% or less and S is 0.015% or less. Especially, Si 0.05% or less, P 0.010% or less, S
0.010% or less is desirable. The reduction of Sb, Sn and As also has the effect of enhancing the low temperature toughness, and it is desirable to reduce it as much as possible, but from the viewpoint of the current steelmaking technology level, Sb0.
0015% or less, Sn 0.01% or less, and As 0.02%
Limited to the following. In particular, Sb 0.001%, Sn 0.00
5% and As 0.01% or less are desirable.

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

The material of the present invention is heat-treated by uniformly heating it to a temperature sufficient to transform it into complete austenite, a minimum temperature of 1000 ° C. and a maximum temperature of 1100 ° C., followed by rapid cooling (preferably oil cooling).
Next, it is preferable to maintain and cool the temperature to 550 to 570 ° C (primary tempering), and then to heat and maintain the temperature to 560 to 680 ° C to perform the secondary tempering to obtain a fully tempered martensite structure.

(3) In the steam turbine rotor shaft of 12 wt% Cr-based martensitic steel according to the present invention, it is preferable to form a build-up welding layer having high bearing characteristics on the surface of the base material forming the journal portion of the steel. Preferably, 3 to 10 layers of the overlay welding layer are formed by using the welding material consisting of, and the Cr amount of the welding material from the first layer to any of the 2nd to 4th layers is gradually decreased and The fourth and subsequent layers are welded using a welding material made of steel having the same Cr content, and the Cr content of the welding material used for the welding of the first layer is less than the Cr content of the base metal by about 2 to 6% by weight. However, the Cr content of the fourth and subsequent welding layers is 0.5 to 3% by weight (preferably 1 to 3% by weight).
2.5% by weight).

In the present invention, overlay welding is preferable in terms of the highest safety for improving the bearing characteristics of the journal portion. Further, it is possible to adopt a structure in which a sleeve made of a low alloy steel having a Cr content of 1 to 3% is shrink-fitted or fitted.

In order to increase the number of weld layers and gradually reduce the amount of Cr, three or more layers are preferable, and even if 10 or more layers are welded, no further effect can be obtained. As an example, the final finish is about 18
mm thickness is required. In order to form such a thickness, it is preferable to use at least five build-up welding layers even if the final finishing allowance by cutting is removed. It is preferable that the third and subsequent layers mainly have a tempered martensite structure and carbides are precipitated. In particular, as the composition of the fourth and subsequent welding layers, by weight, C
0.01-0.1%, Si 0.3-1%, Mn 0.3-1.5
%, Cr 0.5-3%, Mo 0.1-1.5% and the balance Fe.

(4) High-pressure turbine of the present invention, internal casing of high-pressure turbine and high-intermediate-pressure turbine Control valve box, combined reheat valve box, main steam reed pipe, main steam inlet pipe, reheat inlet pipe, high pressure turbine The reasons for limiting the composition of the ferritic heat-resistant steel that constitutes the nozzle box, the first-stage diaphragm of the medium-pressure turbine, the high-pressure turbine main steam inlet flange, the elbow, and the main steam stop valve will be explained.

In the ferritic heat-resistant cast steel casing material, especially by adjusting the Ni / W ratio to 0.25 to 0.75, an ultra-supercritical turbine high pressure and intermediate pressure inner casing of 621 ° C. and 250 kgf / cm ² or more is obtained. And the main steam stop valve and control valve casing, 625 ℃,
A heat-resistant cast steel casing material having a 10 ⁵ h creep rupture strength of 9 kgf / mm ² or more and a room temperature impact absorption energy of 1 kgf-m or more can be obtained.

In the ferritic heat-resistant cast steel casing material of the present invention, in order to obtain high high temperature strength, low temperature toughness and high fatigue strength, the Cr equivalent calculated by the above-mentioned formula is 4 to.
It is preferable to adjust the components to 10.

In the 12Cr heat-resistant steel of the present invention, 62
Since it is used in steam at 1 ℃ or higher, 625 ℃, 10 ⁵
h Creep rupture strength must be 9 kgf / mm ² or more, and room temperature impact absorption energy must be 1 kgf-m or more. Furthermore,
To secure higher reliability, 625 ℃, 10 ⁵
h It is preferable that the creep rupture strength is 10 kgf / mm ² or more and the room temperature impact absorption energy is 2 kgf-m or more.

C is 0.06% in order to obtain high tensile strength.
The above elements are necessary, but if the content exceeds 0.16%, the metal structure becomes unstable when exposed to high temperature for a long time, and the long-term creep rupture strength decreases, so 0.06 to 0.1
Limited to 6%. In particular, 0.09 to 0.14% is preferable.

N has the effect of improving the creep rupture strength and preventing the formation of the δ ferrite structure, but if it is less than 0.01%, the effect is not sufficient, and if it exceeds 0.1%, there is no remarkable effect. On the contrary, it reduces toughness and also creep rupture strength. In particular, 0.02 to 0.06% is preferable.

Mn is added as a deoxidizer,
The effect is achieved with a small amount of addition, and a large amount of addition exceeding 1% lowers the creep rupture strength, especially in the range of 0.4 to 0.7.
% Is preferred.

Although Si is also added as a deoxidizing agent, Si deoxidizing is not required according to the steelmaking technology such as vacuum C deoxidizing method. Further, by lowering Si, there is an effect of preventing harmful δ ferrite structure generation. Therefore, when adding it, it is necessary to suppress it to 0.5% or less, especially 0.5%.
1 to 0.4% is preferable.

V has the effect of increasing the creep rupture strength, but if it is less than 0.05%, the effect is insufficient and 0.35%.
If it exceeds, δ ferrite is formed to reduce the fatigue strength. Particularly, 0.15 to 0.25% is preferable.

Nb is a very effective element for increasing the high temperature strength. However, if added in a too large amount, coarse eutectic Nb carbides are generated especially in a large steel ingot, which rather lowers the strength or increases the fatigue strength. It causes the precipitation of δ-ferrite, which lowers the temperature, so it must be kept to 0.15% or less.
If the Nb content is less than 0.01%, the effect is insufficient. Especially in the case of large steel ingots, 0.02 to 0.1% is more than 0.04.
~ 0.08 is preferred. Ni is a very effective element for enhancing the toughness and preventing the formation of δ ferrite, but if it is less than 0.2%, its effect is not sufficient, and if it exceeds 1.0%, the creep rupture strength is increased. Is lowered, which is not preferable. Particularly, 0.4 to 0.8% is preferable.

Cr has the effect of improving high strength and high temperature oxidation. If it exceeds 12%, it causes harmful formation of δ ferrite structure, and if it is less than 8%, the oxidation resistance to high temperature and high pressure steam becomes insufficient. Further, addition of Cr has an effect of increasing creep rupture strength, but excessive addition causes harmful δ ferrite structure generation and toughness reduction. Especially 8.
0-10%, more preferably 8.5-9.5%.

W has the effect of significantly increasing the high temperature long-term strength. When W is less than 1%, the effect is insufficient as a heat-resistant steel used at 620 to 660 ° C. Further, if W exceeds 4%, the toughness becomes low. 1.0-1.5 at 620 ° C
%, 1.6-2.0% at 630 ° C, 2.1 at 640 ° C
~ 2.5%, 2.6-3.0% for 650 ° C, 66
It is preferably 3.1 to 3.5% at 0 ° C.

W and Ni are correlated with each other, and Ni /
By setting the W ratio to 0.25 to 0.75, one having high strength and toughness can be obtained.

Mo is added to improve the high temperature strength. However, in the case where the cast steel of the present invention contains more than 1% W, the addition of 1.5% or more of Mo lowers the toughness and fatigue strength, so 1.5% or less is preferable, and especially 0.4- 0.
8%, more preferably 0.55 to 0.70%.

The addition of Ta, Ti and Zr has the effect of increasing the toughness, and a sufficient effect can be obtained by adding Ta of 0.15% or less, Ti of 0.1% or less and Zr of 0.1% or less alone or in combination. If Ta is added in an amount of 0.1% or more, N
The addition of b can be omitted.

In the heat-resistant cast steel casing material of the present invention, if the δ ferrite structure is mixed, the fatigue strength and toughness are lowered, so the structure is preferably a tempered martensite structure. In order to obtain a tempered martensite structure, the Cr equivalent calculated by the above formula must be adjusted to 10 or less by adjusting the composition. If the Cr equivalent is too low, the creep rupture strength will decrease, so it must be 4 or more. Particularly, Cr equivalent of 6 to 9 is preferable.

Addition of B markedly increases the creep rupture strength at high temperature (620 ° C. or higher). If the B content exceeds 0.003%, the weldability deteriorates, so the upper limit is limited to 0.003%. In particular, the upper limit of the B content of the large casing is 0.0.
028%, more preferably 0.0005 to 0.0025%, particularly 0.001 to 0.002%.

Since the casing covers high-pressure steam at 620 ° C. or higher, high stress due to the internal pressure acts. Therefore, from the viewpoint of preventing creep fracture, 10 ⁵ h creep rupture strength of 10 kgf / mm ² or more is required. Further, at the time of start-up, thermal stress acts when the metal temperature is low, and therefore room temperature impact absorption energy of 1 kgf-m or more is required from the viewpoint of preventing brittle fracture. On the higher temperature side, strengthening can be achieved by containing 10% or less of Co. In particular, 1-2% for 620, 2.5-3.5% for 630 ° C, 4-5% for 640 ° C, 6%
5.5 to 6.5% for 50 ° C and 7 to 8% for 660 ° C are preferred. It may be added at 600 to 620 ° C.

To produce a casing with few defects,
Since the weight of the ingot is as large as about 50 tons, advanced manufacturing technology is required. The ferritic heat-resistant cast steel casing material of the present invention can be made sound by melting an alloy raw material having a target composition in an electric furnace, refining it with a ladle, and then casting it into a sand mold. By performing sufficient refining and deoxidation before casting, it is possible to reduce casting defects such as shrinkage cavities.

In addition, the above cast steel is heated to 1000 to 1150 ° C.
A steam turbine that can be used in steam at 621 ° C or higher by performing normalizing heat treatment of heating to 1000 to 1100 ° C and quenching after annealing heat treatment, and tempering twice in the order of 550 to 750 ° C and 670 to 770 ° C. Casing can be manufactured.
If the annealing and normalizing temperature is 1000 ° C. or lower, carbonitride cannot be sufficiently dissolved, and if it is too high, it causes coarsening of crystal grains. Further, the double tempering can completely decompose the retained austenite and form a uniform tempered martensite structure. A steam turbine that can be used in steam at 620 ° C. or higher by producing 625 ° C. and 10 ⁵ h creep rupture strength of 10 kgf / mm ² or more and room temperature impact absorption energy of 1 kgf-m or more by manufacturing by the above method. Can be made into a casing.

When O exceeds 0.015%, the high temperature strength and toughness value are lowered, so 0.01% or less is preferable, and 0.010% or less is particularly preferable.

The casing in the present invention has the above-mentioned Cr equivalent, and the amount of δ ferrite is preferably 5% or less, more preferably 0%.

The inner casing is preferably made of forged steel, as well as cast steel.

(5) Others (a) The low-pressure steam turbine rotor shaft is C by weight.
0.2-0.3%, Si 0.1% or less, Mn 0.2% or less,
Ni 3.2-4.0%, Cr 1.25-2.25%, Mo0.
A low alloy steel having a fully tempered bainite structure having 1 to 0.6% and V0.05 to 0.25% is preferable, and is preferably manufactured by the same manufacturing method as the above-described high pressure and medium pressure rotor shaft. Especially, the amount of Si is less than 0.05%, Mn
In addition to 0.1% or less, it uses a raw material with impurities such as P, S, As, Sb, Sn, etc. as low as possible, and the total amount is 0.025% or less. It is preferable to carry out the production.
P and S are preferably 0.010% or less, Sn and As are 0.005% or less, and Sb is 0.001% or less.

(B) Except for the final stage of the blade for the low-pressure turbine and the nozzle, C0.05 to 0.2%, Si0.1 to 0.1.
5%, Mn 0.2-1.0%, Cr 10-13%, Mo 0.
Fully tempered martensitic steel with 04-0.2% is preferred.

(C) C0.2-0.3%, Si0.3-0.7%, M for both the inner and outer casings for the low-pressure turbine
Carbon cast steel with n1% or less is preferred.

(D) Main steam stop valve casing and steam control valve casing are C0.1-0.2%, Si0.1-0.4.
%, Mn 0.2 to 1.0%, Cr 8.5 to 10.5%, Mo
0.3-1.0%, W1.0-3.0%, V0.1-0.3
%, Nb 0.03 to 0.1%, Nb 0.03 to 0.08%,
A fully tempered martensitic steel containing B 0.0005 to 0.003% is preferred.

(E) 1 as the final stage rotor blade of the low pressure turbine
In addition to 2% Cr steel, Ti alloy is used, especially for lengths over 40 inches, Al 5-8 wt% and V 3-6.
A Ti alloy with% by weight is used. In particular, at 43 inches, Al 5.5-6.5%, V 3.5-4.5
For 46 inches, a high-strength material having 4 to 7% of Al, 4 to 7% of V, and 1 to 3% of Sn is preferable.

(F) C0.10-0.20 for the outer casing for the high-pressure turbine, the intermediate-pressure turbine, and the high-intermediate-pressure turbine.
%, Si 0.05-0.6%, Mn 0.1-1.0%, Ni
0.1-0.5%, Cr1-2.5%, Mo 0.5-1.5
%, V 0.1 to 0.35%, preferably Al 0.0
25% or less, B 0.0005 to 0.004% and Ti0.0
It is preferable to manufacture the cast steel containing at least one of 5 to 0.2% and having a fully tempered bainite structure.
In particular, C 0.10 to 0.18%, Si 0.20 to 0.60%,
Mn 0.20-0.50%, Ni 0.1-0.5%, Cr
1.0 to 1.5%, Mo 0.9 to 1.2%, V 0.2 to 0.3
%, 0.001 to 0.005% of Al, 0.045 to 0.10 of Ti
% And B 0.0005-0.0020%. More preferably, the Ti / Al ratio is from 0.5 to 10.

(G) C0.03 to 0.20% (preferably 0.03 to 20% by weight) as the first stage blade of high-pressure, medium-pressure and high-intermediate-pressure turbines (high-pressure side and medium-pressure side) at a steam temperature of 625 to 650 ° C. 0.15%), Cr12-20%, Mo9
-20% (preferably 12-20%), Co 12% or less (preferably 5-12%), Al 0.5-1.5%, Ti
1-3%, Fe 5% or less, Si 0.3% or less, Mn 0.2
%, B 0.003 to 0.015%, Ni-based alloy containing Mg 0.1% or less, rare earth element 0.5% or less, Zr 0.5% or less. 0% for
Including. After forging, a solution treatment is performed, and an aging treatment is performed at 700 to 870 ° C.

[0121]

BEST MODE FOR CARRYING OUT THE INVENTION

[Example 1] Table 1 shows 12% of long blade material for steam turbine.
It shows the chemical composition (% by weight) of Cr steel. Each sample was melted in a 150 kg vacuum arc, heated to ˜1150 ° C., and forged to obtain a test material. Sample No. 1 is 100
After heating at 0 ° C. for 1 h, it was cooled to room temperature by oil quenching, then heated at 570 ° C. and kept for 2 h, and then air-cooled to room temperature. N
Regarding o.2, after heating at 1050 ° C. for 1 hour, it was cooled to room temperature by oil quenching, then heated to 570 ° C. and kept for 2 hours, and then air-cooled to room temperature. Samples No. 3 to No. 6 were heated at 1050 ° C. for 1 h, cooled to room temperature by oil quenching, then heated to 560 ° C., held for 2 h, air-cooled to room temperature (primary tempering), and further heated to 580 ° C. After holding for 2 hours, the furnace was cooled to room temperature (secondary tempering).

In Table 1, Nos. 3, 4 and 5 are materials of the present invention, No. 6 is a comparative material, and Nos. 1 and 2 are currently used long blade materials.

Table 2 shows the room temperature mechanical properties of these samples. The material of the present invention (No. 3 to 5) has a tensile strength (120 kgf / mm ² or more or 1 or more) required as a long blade material for a steam turbine.
28.5 kgf / mm ² or more) and low temperature toughness (20 ° C. V notch Charpy impact value of 2.5 kgf-m / cm ² or more) were sufficiently satisfied.

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

[0125]

[Table 1]

[0126]

[Table 2]

The relationship between the (Ni-Mo) content and the tensile strength is
In this embodiment, both Ni and Mo contents are increased in both strength and toughness at low temperatures by containing Ni and Mo in the same amount, and the strength tends to decrease as the difference between the two contents increases. . When the Ni content is less than 0.6% by the Mo content, the strength sharply decreases, and conversely, when the Ni content increases by more than 1.0%, the strength sharply decreases. Therefore, it is preferable to set the amount of (Ni-Mo) to -0.6 to 1.0%.

As for the relationship between the (Ni-Mo) amount and the impact value, the impact value decreases when the (Ni-Mo) amount is around -0.5%, but shows a high value before and after that.

The effect of heat treatment conditions (quenching temperature and secondary tempering temperature) on the tensile strength and impact value at room temperature of Sample No. 3 was examined. Quenching temperature is 975 to 1125
C., the primary tempering temperature is 550 to 560.degree. C., and the secondary tempering temperature is 560 to 590.degree. The material of the present invention has the characteristics required as a long blade material (tensile strength ≧ 128.5 kgf / mm ² , 2
0 ° C V notch Charpy impact value ≧ 4 kgfm-cm ² )
It was confirmed to be satisfied. Tensile strength is 128.5 kgf / mm ² at a quenching temperature of 975 ° C and is 1 at 1125 ° C.
It was 37 kgf / mm ² . Also, the tempering temperature is 550 ° C.
143kgf / mm ^{2 and} 118kgf / m at 610 ℃
It dropped to m ² .

Impact value is 9.7 kgf at 975 ° C. quenching temperature
-M / cm ² but 3 kgf-m / cm ^{2 at} 1125 ° C
And fell. 3.7kgfm when tempering temperature is 550 ℃
/ Cm ² , but at 610 ° C., it was as high as 6.3 kgfm-cm ² .

FIG. 1 is a diagram showing the relationship between tensile strength and impact value. As described above, the 12% Cr steel in this example has a tensile strength of 120 kgf / mm ² or more and an impact value of 4 kgf-m /.
Those having a cm ² or more are preferable, but those having an impact value (y) of not less than the value obtained by [−0.45 × (tensile strength) +61.5] are particularly preferable.

The 12% Cr steel according to the present invention is especially C + N.
b amount is 0.18 to 0.35%, (Nb / C) ratio is 0.4
5 to 1.00 and (Nb / N) ratio of 0.8 to 3.0 are preferable.

In order to improve the thermal efficiency by improving the steam conditions, the steam temperature 60
0 ° C-649 ° C pulverized coal direct combustion boiler and steam turbine are required. Table 3 shows an example of a boiler under such steam conditions.

[0134]

[Table 3]

With the increase in capacity, the pulverized coal combustion furnace became larger and the 1050 MW class had a furnace width of 31 m and a furnace depth of 16
m, 1400 MW class, furnace width 34 m, furnace depth 18 m
Becomes

Table 4 shows the main specifications of a 1050 MW steam turbine with a steam temperature of 625 ° C. In this embodiment, the last stage blade length in a cross-compound type four-flow exhaust, low-pressure turbine is 43 inches, and A is 3 for two HP-IP and LP units.
HP-LP and IP-LP each have a rotation speed of 3000 r / min and B are composed of the main materials shown in the table in the high temperature part. High pressure section (H
The steam temperature of P) is 625 ° C. and a pressure of 250 kgf / cm ² , and the steam temperature of the medium pressure part (IP) is heated to 625 ° C. by a reheater and operated at a pressure of 45 to 65 kgf / cm ^2. . The low pressure section (LP) enters at a steam temperature of 400 ° C,
It is sent to the condenser under a vacuum of 722 mmHg below 00 ° C.

[0137]

[Table 4]

FIG. 2 is a sectional view of the high-pressure and intermediate-pressure steam turbines of the turbine configuration A shown in Table 4. The high-pressure steam turbine is provided with a high-pressure axle (high-pressure rotor shaft) 23 in which a high-pressure rotor blade 16 is planted in a high-pressure inner casing 18 and a high-pressure outer casing 19 outside thereof. The above-mentioned high-temperature and high-pressure steam is obtained by the above-mentioned boiler, passes through the main steam pipe, passes through the main steam inlet 28 from the flange and elbow 25 constituting the main steam inlet, and is guided from the nozzle box 38 to the first-stage double-flow moving blades. Get burned. The first stage is a double flow, and eight stages are provided on one side. A stationary blade is provided corresponding to each of these moving blades. The blade is a saddle-type dovetil type, double tinon, and the first stage blade length is about 35 mm. The length between the axles is about 5.8 m, the diameter of the smallest part corresponding to the stationary blade part is about 710 mm, and the ratio of the length to the diameter is about 8.2.

The widths of the rotor blades at the first stage and the last stage of the rotor shaft are almost equal, and the stages are stepwise according to the downstream side in the fifth stage of the second stage, the third to fifth stages, the sixth stage, and the seventh to eighth stage. It is smaller, and the axial width of the implant in the second stage is 0.71 times as large as that in the final stage.

In the portion of the rotor shaft corresponding to the stationary blade, the diameter of the rotor shaft is smaller than that of the moving blade embedded portion. The axial width of that portion is gradually reduced from the width between the second-stage rotor blade and the third-stage rotor blade to the width between the final-stage rotor blade and the rotor blade in front of it. The width of the latter is 0.86 times smaller than the width of the former. Second stage ~
The size is reduced in two steps, up to the sixth step and from the sixth step to the ninth step.

In this example, the materials shown in Table 5 to be described later were all made of 12% Cr type steel containing no W, Co and B except that the first stage blade and nozzle were used. The blade length of the rotor blade in this embodiment is 35 to 50 mm in the first stage and becomes longer in each stage from the second stage to the last stage. Particularly, the length from the second stage to the last stage depends on the output of the steam turbine. Is 65-180mm,
The number of stages is 9 to 12, and the length of the wing portion of each stage is 1.10 to 1.15, which is the length of the downstream side adjacent to the upstream side, and the ratio is Is gradually increasing.

The medium-pressure steam turbine rotates the generator discharged together with the high-pressure steam turbine by the steam discharged from the high-pressure steam turbine to the temperature of 625 ° C. by the reheater again. Is rotated. The medium-pressure turbine has a medium-pressure inner casing 21 and an outer casing 22 like the high-pressure turbine. The moving blade 17 has two flows in six stages,
It is provided on the left and right almost symmetrically with respect to the longitudinal direction of the medium pressure axle (medium pressure rotor shaft). Bearing center distance is about 5.8m
The first stage blade length is about 100 mm, and the last stage blade length is about 230
mm. The first and second stage dovetails are inverted chestnut type.
The diameter of the rotor shaft corresponding to the stationary blade before the final stage rotor blade is about 630 mm, and the ratio of the bearing distance to the diameter is about 9.2 times.

In the rotor shaft of the medium-pressure steam turbine of the present embodiment, the axial width of the blade-implanted portion is gradually increased in three stages from the first stage to the fourth stage, the fifth stage, and the final stage.
The width at the final stage is about 1.4 times larger than that at the first stage.

Further, in the rotor shaft of the steam turbine, the diameter of the portion corresponding to the stationary blade portion is small, and the width thereof is stepwise in four stages according to the first-stage rotor blade, the second-third stage and the final-stage rotor blade side. The width of the latter in the axial direction is about 0.75 times smaller than that of the former.

In this example, the materials shown in Table 5 described later are used for the first stage blade and nozzle, and 12% Cr type steel containing no W, Co and B is used. The length of the blade portion of the moving blade in this embodiment becomes longer at each stage from the first stage to the last stage, and the length from the first stage to the last stage is 60 to 300 mm depending on the output of the steam turbine, and is 6 to
In the 9 stages, the length of the blades in each stage is such that the downstream side is adjacent to the upstream side at a ratio of 1.1 to 1.2.

The diameter of the implanting portion of the moving blade is larger than that of the portion corresponding to the stationary blade, and the width thereof becomes larger as the blade length of the moving blade increases. The ratio of the width to the blade length of the rotor blade is 0.1 in the first stage to the last stage.
It is 35 to 0.8, and gradually decreases from the first stage to the last stage.

FIG. 3 is a sectional view of the low pressure turbine. The low-pressure turbine is connected in two tandems and has almost the same structure. Each of the moving blades 41 has eight stages on the left and right, and is substantially symmetrical to the left and right, and a stationary blade 42 is provided corresponding to the moving blades. The blade length of the last stage is 43 inches.
No. 7 12% Cr steel is used, and it has the double tinon and saddle type dovetail shown in FIG. 4, and the nozzle box 44 is a double flow type. The rotor shaft 43 is Ni 3.75%, Cr
1.75%, Mo 0.4%, V 0.15%, C 0.25%
Forged steel having a fully tempered bainite structure of a super clean material consisting of Ni, Si 0.05%, Mn 0.10%, and residual Fe is used. A 12% Cr steel containing 0.1% Mo is used for both the moving blades and the stationary blades other than the last stage.
For the inner and outer casing materials, C0.25% cast steel is used. The center-to-center distance of the bearing 43 in this embodiment is 750.
0mm, the rotor shaft diameter corresponding to the stator vane is about 12
The diameter at the blade implantation part is 2275 mm. The distance between the bearing centers for this rotor shaft diameter is about 5.
9.

4 is a perspective view of a 1092 mm (43 ″) long wing. 51 is a wing portion against which high-speed steam impinges, 52 is a blade implantation portion on a rotor shaft, and 53 is a pin for supporting centrifugal force of the blade. Is a hole for inserting an erosion shield, 54 is an erosion shield for preventing erosion due to water droplets in steam (welding a stellite plate of a Co-based alloy), and 57 is a cover. The cover 57 is formed by processing.
Can be formed mechanically integrally.

The 43 "long blade was manufactured by electroslag remelting method and subjected to forging heat / treatment. Forging was performed within a temperature range of 850 to 1150 ° C, and heat treatment was performed under the above-mentioned conditions. No. 7 in Table 1 shows the chemical composition (% by weight) of the long blade material.The metal structure of the long blade material was a fully tempered martensite structure.

Table 1 No. 7 shows room temperature tensile and 20 ° C. V notch Charpy impact values. The mechanical properties of this 43 ″ long blade are the required properties, tensile strength of 128.5 kgf / mm ² or more, 20 ° C. V-notch Charpy impact value of 4 kgf-m / cm ²
It was confirmed that the above was satisfied, and that it was sufficiently satisfied.

In the low-pressure turbine of the present embodiment, the axial width of the blade-implanted portion is from the first stage to the third stage, the fourth stage, the fifth stage, the sixth stage to the seventh stage and the eighth stage.
The width gradually increases in the four stages, and the width of the final stage is about 6.8 times larger than the width of the first stage.

Further, the diameter of the portion corresponding to the stationary blade portion is small, and the axial width of that portion is gradually increased in the three stages of the fifth, sixth and seventh stages from the first stage moving blade side. The width of the last stage is about 2.
It is 5 times bigger.

The moving blades in this embodiment have six stages, and the length of the blades increases at each stage from the initial stage of about 3 "to the final stage of 43". The length of the stage is 80 to 1100 mm, 8 stages or 9 stages, and the blade length of each stage becomes 1.2 to 1.8 times as long as the downstream side is adjacent to the upstream side. There is.

The diameter of the implanting portion of the moving blade is larger than that of the portion corresponding to the stationary blade, and the width of the implanting portion increases as the blade length of the moving blade increases. The ratio of the width to the blade length of the rotor blade is 0.1 in the first stage to the last stage.
It is 15 to 0.91 and gradually decreases from the first stage to the last stage.

Further, the width of the rotor shaft in the portion corresponding to each vane is gradually increased in each stage from the first stage and the second stage to the final stage and the front thereof. The ratio of the width to the blade length of the moving blade is 0.25 to 1.25 and becomes smaller from the upstream side to the downstream side.

In addition to this embodiment, the steam inlet temperature to the high-pressure steam turbine and the medium-pressure steam turbine is 610 ° C., and the steam inlet temperature to the two low-pressure steam turbines is 385 ° C.
A similar configuration can be applied to a large-scale large-capacity power plant.

The high-temperature high-pressure steam turbine plant in this embodiment is mainly a coal-fired boiler, high-pressure turbine, medium-pressure turbine, two low-pressure turbines, condenser, condensate pump, low-pressure feed water heater system, deaerator, booster pump. , Water supply pump,
It is composed of a high-pressure feed water heater system. That is, the ultra-high-temperature and high-pressure steam generated in the boiler enters the high-pressure turbine to generate power, is reheated again in the boiler, and enters the medium-pressure turbine to generate power. This medium-pressure turbine exhaust steam enters the low-pressure turbine and generates power,
Condensate in the condenser. This condensate is sent to the low pressure feed water heater system and deaerator by a condensate pump. The feed water deaerated by the deaerator is sent to the high-pressure feed water heater by the booster pump and the feed water pump, heated, and then returned to the boiler.

In the boiler, the feed water passes through the economizer, the evaporator and the superheater to become high temperature and high pressure steam. On the other hand, the boiler combustion gas that heated the steam, after leaving the economizer,
Enter the air heater to heat the air. Here, a water supply pump driving turbine that operates with the extracted steam from the intermediate pressure turbine is used to drive the water supply pump.

In the high-temperature and high-pressure steam turbine plant configured as described above, the temperature of the feed water leaving the high-pressure feed water heater system 63 is inevitably higher than the feed water temperature in the conventional thermal power plant. The temperature of the combustion gas leaving the economizer inside the boiler is also much higher than that of the conventional boiler. For this reason, heat is recovered from the boiler exhaust gas so as not to lower the gas temperature.

Incidentally, instead of the present embodiment, the same high-pressure turbine,
The medium pressure turbine and one or two low pressure turbines may be connected in a tandem, and a tandem compound power generation plant that rotates one generator to generate electricity may be similarly configured. As in the present embodiment, in a generator having an output of 1050 MW class, a higher strength generator shaft is used. In particular, C 0.15 to 0.30%,
Si 0.1-0.3%, Mn 0.5% or less, Ni 3.25-
4.5%, Cr 2.05-3.0%, Mo 0.25-0.6
0% has a fully tempered bainite structure containing V0.05～0.20% at room temperature tensile strength of 93kgf / mm ² or more, particularly 100 kgf / mm ² or more, 50% FATT is 0 ℃ or less,
Especially, it is preferable that the temperature is -20 ° C or lower, and 21.2KG
Magnetizing force at 985 AT / cm or less, and the total amount of P, S, Sn, Sb and As as impurities is 0.02.
It is preferable that the Ni / Cr ratio is 5% or less and the Ni / Cr ratio is 2.0 or less.

The high-pressure turbine shaft has a structure in which nine stages of blades are planted around the first-stage blade planting portion on the multistage side. The intermediate-pressure turbine shaft has multi-stage blades having left and right six-stage blade-implanted portions that are substantially symmetrical, with the center being the boundary. Although the low-pressure turbine rotor shaft is not shown, a center hole is provided in each of the high-pressure, medium-pressure, and low-pressure turbine rotor shafts, and whether there is a defect through ultrasonic inspection, visual inspection, or fluorescent flaw detection through the center hole. Is inspected. Further, it can be performed by ultrasonic inspection from the outer surface, and the central hole may be omitted.

Table 5 shows the chemical composition (% by weight) used for the main parts of the high pressure turbine, the intermediate pressure turbine and the low pressure turbine of this embodiment. In the present embodiment, the high temperature part and the high temperature part of the medium pressure part were all made to have a thermal expansion coefficient of about 12 × 10 ⁻⁶ / ° C. having a ferrite-based crystal structure, so that there is no problem due to the difference in thermal expansion coefficient. There wasn't.

For rotor shafts of high-pressure turbines and medium-pressure turbines, 30 tons of heat-resistant cast steel shown in Table 5 was melted in an electric furnace, carbon vacuum deoxidized, cast in a metal mold and forged to prepare electrode rods. Then, as this electrode rod, electroslag was remelted so as to be melted from the upper part to the lower part of cast steel, and forged into a rotor shape (diameter 1050 mm, length 3700 mm) and molded. This forging is 1150 to prevent forging cracking.
It was performed at a temperature of ℃ or less. Also, after annealing this forged steel,
It was obtained by heating to 1050 ° C., quenching with water spray cooling, tempering twice at 570 ° C. and 690 ° C., and cutting into the shape shown in FIGS. 5 and 6. In the present embodiment, the upper side of the electroslag steel ingot is the first-stage blade side and the lower side is the final-stage side.

For the blades and nozzles of the high pressure portion and the medium pressure portion, the heat resistant steels listed in Table 5 were melted in a vacuum arc melting furnace to obtain blade and nozzle material shapes (width 150 mm, height 50 mm, length 1000 mm). Forged and molded. This forging was performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. Further, this forged steel is heated to 1050 ° C., oil-quenched, tempered at 690 ° C., and then cut into a predetermined shape.

Table 5 shows the inner casing of the high pressure part and the intermediate pressure part, the main steam stop valve casing and the steam control valve casing.
The heat-resistant cast steel described in 1 above was melted in an electric furnace, and after ladle refining, cast into a sand mold to produce. By performing sufficient refining and deoxidation before casting, it was possible to obtain a product having no casting defects such as shrinkage cavities. Weldability evaluation using this casing material is J
It carried out according to IS Z3158. The preheating, inter-pass and post-heating start temperatures were 200 ° C., and the post-heat treatment was 400 ° C. × 30 minutes. No weld crack was observed in the material of the present invention, and the weldability was good.

[0166]

[Table 5]

Table 6 shows the mechanical properties and heat treatment conditions of the above-mentioned ferritic steel high temperature steam turbine main members which were cut and investigated.

As a result of investigating the center portion of this rotor shaft, the characteristics required for the high-pressure and medium-pressure turbine rotor (62
It was confirmed that 5 ° C., 10 ⁵ h strength ≧ 10 kgf / mm ² , 20 ° C. shock absorption energy ≧ 1.5 kgf-m) were sufficiently satisfied. This proves that a steam turbine rotor that can be used in steam at 620 ° C. or higher can be manufactured. In addition, as a result of investigating the characteristics of this blade, the characteristics required for the first stage blade of a high-pressure and medium-pressure turbine (625 ° C, 10
It was confirmed that ⁵ h strength ≧ 15 kgf / mm ² ) was sufficiently satisfied. This demonstrates that a steam turbine blade that can be used in steam at 620 ° C. or higher can be manufactured.

Further, as a result of investigating the characteristics of this casing, the characteristics (625 ° C., 10 ⁵ h strength ≧ 10 kgf / mm ² , 20 ° C. shock absorption energy ≧ 1 kgf-m) required for high-pressure and medium-pressure turbine casings are sufficiently satisfied. It was confirmed that it was satisfactory and that welding was possible. By this, 620 ℃
It was demonstrated that a steam turbine casing usable in the above steam can be manufactured.

[0170]

[Table 6]

In this example, Cr-Mo low alloy steel was overlay welded to the journal portion of the rotor shaft to improve the bearing characteristics. The overlay welding is as follows.

A coated arc welding rod (diameter 4.0φ) was used as a test welding rod. Table 7 shows the chemical composition (% by weight) of the deposited metal that was welded using the welding rod. The composition of the deposited metal is almost the same as the composition of the welding material.

The welding conditions are welding current 170 A and voltage 24.
V, speed is 26 cm / min.

[0174]

[Table 7]

Overlay welding was carried out on the surface of the above-mentioned base metal, as shown in Table 8, by combining the welding rods used for each layer and welding eight layers. The thickness of each layer was 3-4 mm, the total thickness was about 28 mm, and the surface was ground about 5 mm.

The welding conditions are preheating, between passes, the stress relief annealing (SR) start temperature is 250 to 350 ° C., and the SR treatment condition is 630 ° C. × holding for 36 hours.

[0177]

[Table 8]

In order to confirm the performance of the welded portion, overlay welding was similarly performed on the plate material and a side bending test at 160 ° was conducted, but no crack was observed in the welded portion.

Further, a bearing sliding test by rotation according to the present invention was carried out.
It was also excellent in oxidation resistance.

In place of the present embodiment, a high pressure steam turbine, an intermediate pressure steam turbine and one or two low pressure steam turbines are connected in tandem, and a tandem type power plant having 3600 rotations and a turbine configuration B in Table 4 are also used. The high-pressure turbine, the intermediate-pressure turbine, and the low-pressure turbine of this embodiment can be similarly combined and configured.

Example 2 Table 9 shows steam temperatures of 600 ° C. and 6
The main specifications of the 00MW steam turbine. In this embodiment,
Tandem compound double flow type, last stage blade length in low pressure turbine is 43 inches, HP / IP integrated type and 3000r / mi with 1 LP (C) or 2 LPs (D)
It has a rotation speed of n and is composed of the main materials shown in the table at high temperatures. Steam temperature of high pressure part (HP) is 60
0 ° C, 250 kgf / cm ² pressure, intermediate pressure part (IP)
The steam temperature of the product was heated to 600 ° C by a reheater,
It is operated at a pressure of ~ 65 kgf / cm ² . Low pressure part (LP)
Steam temperature is 400 ℃, below 100 ℃, 722mm
It is sent to a condenser with Hg vacuum.

[0182]

[Table 9]

FIG. 7 is a sectional view of a high-pressure and intermediate-pressure integrated steam turbine, and FIG. 8 is a sectional view of its rotor shaft.
The high-pressure side steam turbine is provided with a high-to-medium pressure axle (high-pressure rotor shaft) 23 in which the high-pressure side moving blades 16 are implanted in the inner casing 18 and the outer casing 19 outside thereof. The high-temperature and high-pressure steam is obtained by the boiler, passes through the main steam pipe, passes through the main steam inlet 28 through the flange and elbow 25 constituting the main steam inlet, and is guided from the nozzle box 38 to the first stage rotor blades. . The rotor blades are provided in eight stages on the high pressure side on the left side in the figure and six stages on the medium pressure side (about half of the right side in the figure). A stationary blade is provided corresponding to each of these moving blades. The blades are saddle type, getter type, dovetail type, double tinon, high pressure side first stage blade length is about 40 mm, and medium pressure side first stage blade length is 100 mm. Bearing 4
The length between the three is about 6.7 m and the diameter of the smallest part corresponding to the stationary blade portion is about 740 mm, and the ratio of the length to the diameter is about 9.0.

The width of the root portion of the high-pressure side rotor shaft in which the rotor blades are embedded in the first stage and the final stage is widest in the first stage, smaller in the second stage to the seventh stage, and 0.40 to 0.56 times the initial stage. Is the same size, and the final stage is between the size of the first stage and the size of the second stage to the seventh stage, which is 0.46 to 0.62 times the size of the first stage.

On the high pressure side, the blades and nozzles were made of 12% Cr-based steel shown in Table 5 described later. The blade length of the rotor blade in this embodiment is 3 in the first stage.
5 to 50 mm, the length of each stage increases from the second stage to the final stage, and the length from the second stage to the final stage is within the range of 50 to 150 mm, especially depending on the output of the steam turbine.
The number of stages is in the range of 7 to 12, and the length of the blade portion of each stage is 1.05 to 1.3 in terms of the length in which the downstream side is adjacent to the upstream side.
The length is increased within the range of 5 times, and the ratio is gradually increased on the downstream side.

The intermediate pressure side steam turbine rotates the generator discharged together with the high pressure steam turbine by the steam discharged from the high pressure side steam turbine to 600 ° C. by the reheater, and is rotated at a rotation speed of 3000 RPM. It The intermediate-pressure turbine has an inner casing 21 and an outer casing 22 similarly to the high-pressure turbine, and stationary vanes are provided to oppose the moving blades 17. The bucket 17 has six stages. The length of the first stage blade is about 130 mm and the length of the last stage blade is about 260 mm. Dovetail is a reverse chestnut type. The diameter of the rotor shaft corresponding to the vane is about 740 mm.

In the rotor shaft of the intermediate-pressure steam turbine, the axial width of the root part with the blades embedded is the largest in the first stage, smaller in the second stage, smaller in the third to fifth stages than the second stage, and the same in all cases. The width of the final stage is the size between the third and fifth stages and the second stage, which is 0.48 to 0.64 times the first stage. The first stage is 1.1 to 1.5 times the second stage.

On the medium pressure side, the blade and nozzle are made of 12% Cr type steel shown in Table 5 described later. The length of the blade portion of the rotor blade in this embodiment is longer in each stage from the first stage to the last stage, and the length from the first stage to the last stage is 90 to 350 mm and the number of stages is 6 to 6 depending on the output of the steam turbine. It is within the range of 9 stages, and the length of the blades of each stage is such that the downstream side is adjacent to the upstream side at a rate of 1.10 to 1.25. The diameter of the implanted portion of the rotor blade is larger than that of the portion corresponding to the stationary blade, and its width is related to the blade portion length and position of the rotor blade. The ratio of the width to the blade length of the moving blade is the highest in the first stage, 1.35 to 1.80.
The second stage is 0.88 to 1.18 times, and the third to sixth stages are smaller toward the final stage, and are 0.40 to 0.65 times. FIG. 9 is a sectional view of the low-pressure turbine, and FIG. 10 is a sectional view of the rotor shaft thereof. One low pressure turbine is tandemly coupled to high and medium pressure. The moving blades 41 have six stages on the left and right, are substantially symmetrical to each other, and the stationary blades 42 are provided corresponding to the moving blades. The blade length of the final stage is 43 inches, and 12% Cr steel or Ti base alloy shown in Table 1 is used. The Ti-based alloy is age-hardened and is
6% and V4% are included. The rotor shaft 43 is composed of Ni 3.75%, Cr 1.75%, Mo 0.4%, V0.1.
5%, C 0.25%, Si 0.05%, Mn 0.10%,
Forged steel having a fully tempered bainite structure of a super clean material composed of residual Fe is used. 12% Cr steel containing 0.1% of Mo is used for the moving blades and the stationary blades other than the final stage and the preceding stage. C for inner and outer casing materials
0.25% cast steel is used. In the present embodiment, the bearing 43 has a center-to-center distance of 7,000 mm, the diameter of the rotor shaft corresponding to the stationary blade portion is about 800 mm, and the diameter at the moving blade embedded portion is the same at each stage. The distance between the bearing centers for the rotor shaft diameter corresponding to the vanes is about 8.8.

In the low-pressure turbine, the axial width of the root portion with the blades embedded therein is the smallest in the first stage, and in the downstream side, the second and third stages are equivalent, the fourth and fifth stages are equivalent, and gradually increase in four stages. The width of the final stage is 6.2 to 7.0 times larger than the width of the first stage. The second and third stages are 1.15 to 1.40 times the first stage,
4,5 stage is 2.2-2.6 times of 2-3 stage, last stage is 4,5
It is 2.8 to 3.2 times the number of steps. The width of the root portion is indicated by a point connecting the extension line of the diverging end and the diameter of the rotor shaft.

The blade length of the rotor blade in this embodiment becomes longer in each stage from the initial stage of 4 ″ to the final stage of 43 ″, and the length from the initial stage to the final stage is 100 to 100 depending on the output of the steam turbine. Within the range of 1270 mm, with a maximum of 8 steps,
The blade length of each stage is 1.2 to 1.9 times as long as the downstream side is adjacent to the upstream side.

The root portion of the root of the moving blade has a larger diameter and is wider than the portion corresponding to the stationary blade, and the width thereof is larger as the blade length of the moving blade is larger. The ratio of the width to the blade length of the rotor blade is 0.30 to 1.5 from the first stage to the last stage, and the ratio gradually decreases from the first stage to the last stage before the last stage. Is 0.15 higher than the previous one
It gradually decreases within the range of -0.40. The final stage has a ratio of 0.50 to 0.65.

The final stage rotor blade in this embodiment is the same as that in the first embodiment. FIG. 11 shows that the erosion shield (stellite alloy) 54 in this embodiment is welded by electron beam welding or T-beam welding.
It is a cross section and a perspective view showing the state where it joined by IG welding 56. As shown in the figure, the shield 54 has two front and rear sides.
Welded in places.

In addition to this embodiment, the steam inlet temperature of the high and medium pressure steam turbine is 610 ° C. or higher, the steam inlet temperature of the low pressure steam turbine is about 400 ° C., and the outlet temperature is about 60 ° C. 1000
The same configuration can be applied to the MW class large capacity power plant.

The high-temperature and high-pressure steam turbine power plant in this embodiment is mainly a boiler, a high-intermediate-pressure turbine, a low-pressure turbine, a condenser, a condensate pump, a low-pressure feed water heater system, a deaerator, a boost pump, a feed pump, a high-pressure feed water. It consists of a heater system. That is, the ultra-high temperature and high pressure steam generated in the boiler enters the high pressure side turbine to generate power, and is then reheated in the boiler to enter the intermediate pressure side turbine to generate power. The high-intermediate-pressure turbine exhaust steam enters the low-pressure turbine to generate power, and then is condensed in the condenser.
This condensate is sent to the low pressure feed water heater system and deaerator by a condensate pump. The feed water deaerated by the deaerator is sent to the high-pressure feed water heater by the booster pump and the feed water pump, heated, and then returned to the boiler.

Here, in the boiler, the feed water passes through the economizer, the evaporator and the superheater to become high temperature and high pressure steam. On the other hand, the boiler combustion gas that heated the steam, after leaving the economizer,
Enter the air heater to heat the air. Here, a water supply pump driving turbine that operates with the extracted steam from the intermediate pressure turbine is used to drive the water supply pump.

In the high-temperature and high-pressure steam turbine plant configured as described above, the temperature of the feed water exiting the high-pressure feed water heater system 63 is inevitably higher than the feed water temperature in the conventional thermal power plant, so that it is inevitable. The temperature of the combustion gas leaving the economizer inside the boiler is also much higher than that of the conventional boiler. For this reason, heat is recovered from the boiler exhaust gas so as not to lower the gas temperature.

In this embodiment, the high-intermediate pressure turbine and one low-pressure turbine are connected to a single tandem generator to constitute a tandem compound double-flow power plant. As another embodiment, the turbine configuration (D) in Table 9 is used, and two low-pressure turbines are connected in tandem, and power generation with an output of 1050 MW class can be configured in the same manner as this embodiment. Higher strength is used as the generator shaft. Especially C0.15
~ 0.30%, Si 0.1-0.3%, Mn 0.5% or less,
Ni3.25-4.5%, Cr2.05-3.0%, Mo
Has a fully tempered bainite structure containing 0.25 to 0.60% and V0.05 to 0.20%, and room temperature tensile strength 93 kgf
/ Mm ² or more, especially 100 kgf / mm ² or more, 50% FATT
Is preferably 0 ° C or lower, particularly preferably -20 ° C or lower,
It is preferable that the magnetizing force at 21.2 KG is 985 AT / cm or less, the total amount of P, S, Sn, Sb and As as impurities is 0.025% or less and the Ni / Cr ratio is 2.0 or less. .

Table 5 above shows the chemical composition (% by weight) used for the main parts of the high and medium pressure turbines and the low pressure turbine of this embodiment. In this example, a high temperature part in which the high pressure side and the medium pressure side were integrated was used, except that martensitic steel No. 9 of Example 3 described later was used, and all of the ferrite type crystal structures were used. Since the thermal expansion coefficient was set to 12 × 10 ⁻⁶ / ° C., there was no problem due to the difference in thermal expansion coefficient.

The rotor shaft of the high and medium pressure parts is N in Table 10.
Melt 30 tons of the heat-resistant cast steel described in o.1 in an electric furnace, deoxidize carbon in vacuum, cast it into a mold, forge and stretch to make an electrode rod, and melt it from the top to the bottom of the cast steel as this electrode rod Then, the electroslag was melted again and forged into a rotor shape (diameter 1450 mm, length 5000 mm) and molded. This forging was performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. After annealing the forged steel, 1050 ° C
To 570 ° C and 690 ° C
Was tempered twice and then cut into the shape shown in FIG. The materials and manufacturing conditions of the other parts are the same as in the second embodiment. Further, overlay welding to the bearing journal 45 was performed in the same manner.

Example 3 An alloy having the composition shown in Table 10 was cast into a 10 kg ingot by vacuum melting to give a thickness of 30 mm.
It is a forged corner. In the case of a large steam turbine rotor shaft, the central part is simulated to 1050 ° C x 5
After holding for a period of time, quenching at a cooling rate of 100 ° C / h in the center, primary tempering of 570 ° C x 20 hours and 690 ° C x 2
1100 ° C for 0 hour secondary tempering and blade
After quenching for 1 hour and tempering at 750 ° C. for 1 hour, creep rupture test and impact test were performed at 680 ° C. and 17.5 kgf / mm ² . The results are shown in Table 11.

The alloys of the present invention of No. 1 to No. 6 in Table 10 are
It is preferable to apply it to steam conditions of 620 ° C or higher, and it can be seen that the creep rupture life is long. Creep rupture time improves as the amount of Co increases, but a large amount of Co tends to cause heat embrittlement when heated at 600 to 660 ° C.
The preferred range is 2 to 5% for 630 to 630 ° C, and 5.5 to 8% for 630 to 660 ° C. B has an excellent strength at 0.03% or less. The amount of B is 0.0 at 620 to 630 ° C.
01-0.01% and Co content 2-4%, 630-66
On the higher temperature side of 0 ° C, the B content is set to 0.01 to 0.03%,
High strength can be obtained by increasing the Co content to 5 to 7.5%.

It was revealed that N was strengthened at a temperature higher than 600 ° C. in the examples of the present application, and the strength was higher than that at a higher N content. The amount of N is 0.01-0.
04% is preferable. Since N is hardly contained in the vacuum melting, it is added by the master alloy.

As shown in Table 10, the rotor material corresponds to the No. 2 alloy of this embodiment, and high strength is obtained. No.8
As is clear from the fact that those with a low Mn content of 0.09% show higher strength than the same Co content, the Mn content is set to 0.03 to 0.20% for further strengthening. Is preferred.

[0204]

[Table 10]

[0205]

[Table 11]

Example 4 In the rotor of the high pressure and medium pressure steam turbine of Example 1, 30 tons of heat-resistant cast steel relating to the body and bearing shown in Table 12 was melted in an electric furnace, and carbon vacuum deoxidation was performed. , Casting in a mold and forging to make an electrode rod,
Using this electrode rod, the bearing portion was first electroslag-melted, then the body portion was immediately electro-melted again, and then the bearing portion was electro-slag-remelted thereon, and the rotor shape (diameter 1050 mm, length 3700 mm) was forged. It was stretched and molded. This forging is 1150 ° C to prevent forging cracks.
The following temperatures were used. After annealing heat treatment of this forged steel, 1
It was obtained by heating to 050 ° C., water spray cooling quenching treatment, tempering twice at 570 ° C. and 690 ° C., and cutting into the shapes shown in FIGS. 5, 6 and 8. The body and the bearing are joined at a position shown by a dotted line. As shown in FIG. 5, in the rotor shaft for the high-pressure steam turbine, between the downstream final stage of the blade and the front thereof, the rotor shaft for the intermediate-pressure steam turbine shown in FIG. 6 and the rotor shaft for the high-intermediate-pressure integrated steam turbine shown in FIG. They are joined between the final stage on the downstream side and the front stage. In this embodiment, the upper side of the electroslag steel ingot is the first-stage blade side of the body and the lower side is the final-stage side.

For the blades and nozzles of the high pressure portion and the medium pressure portion, the heat resistant steels listed in Table 5 were melted in a vacuum arc melting furnace to obtain blade and nozzle material shapes (width 150 mm, height 50 mm, length 1000 mm). Forged and molded. This forging was performed at a temperature of 1150 ° C. or lower in order to prevent forging cracks. Further, this forged steel was heated to 1050 ° C., oil-quenched, tempered at 690 ° C., and then cut into a predetermined shape.

The high-pressure, medium-pressure and high-medium-pressure integrated type inner casings of the high-pressure part and the medium-pressure part, the main steam stop valve casing and the steam control valve casing were prepared by melting the heat-resistant cast steel shown in Table 5 in an electric furnace. After refining, the sand was cast into a sand mold. By performing sufficient refining and deoxidation before casting, it was possible to obtain a product having no casting defects such as shrinkage cavities. Weldability evaluation using this casing material was performed according to JIS Z3158. Preheat, interpass and postheat onset temperatures are 200
° C, and the post heat treatment was performed at 400 ° C for 30 minutes. No weld crack was observed in the material of the present invention, and the weldability was good.

[0209]

[Table 12]

[Embodiment 5] Table 12 shows the chemical composition (% by weight) of the inner casing materials for high pressure, medium pressure and high and medium pressure turbines of the first and second embodiments. Assuming a thick part of a large casing, 200 kg of a sample was melted using a high-frequency induction melting furnace and cast into a sand mold having a maximum thickness of 200 mm, a width of 380 mm, and a height of 440 mm to produce an ingot. Sample is 1050 ℃ ×
After annealing for 8h furnace cooling, normalizing (1050 ° C × 8h → air cooling), tempering (710 ° C × 7h → air cooling, 710 ° C × 7h → air cooling twice) assuming the thick part of the large steam turbine casing. Was heat treated.

The weldability was evaluated according to JIS Z3158. Preheat, interpass and postheat start temperature is 150 ℃
The post heat treatment was 400 ° C. × 30 minutes.

[0212]

[Table 13]

Table 14 shows tensile properties at room temperature, V-notch Charpy impact absorption energy at 20 ° C, 650 ° C, 1
The results of the 0 ⁵ h creep rupture strength and weld crack test are shown.

The creep rupture strength and impact absorption energy of the material of the present invention to which appropriate amounts of B, Mo and W are added have the characteristics (625 ° C., 1
0 ⁵ h Strength ≧ 8 kgf / mm ² , 20 ℃ Impact absorption energy ≧
1 kgfm) is sufficiently satisfied. Particularly, it shows a high value of 9 kgf / mm ² or more. Further, the material of the present invention has no weld cracks and has good weldability. As a result of investigating the relationship between the B content and weld cracking, when the B content exceeded 0.0035%, weld cracking occurred. The No. 1 one had some concerns about cracking. Looking at the effect of Mo on the mechanical properties, those with a large Mo content of 1.18% had a high creep rupture strength but a low impact value and could not satisfy the required toughness. On the other hand, Mo 0.11% had a high toughness but a low creep rupture strength, and could not satisfy the required strength.

As a result of examining the influence of W on the mechanical properties, creep rupture strength is remarkably increased when the W content is 1.1% or more, but conversely, room temperature impact absorption energy is increased when the W content is 2% or more. Will be lower. Especially Ni / W ratio of 0.2
By adjusting to 5 to 0.75, the temperature is 621 ° C and the pressure is 250kgf / cm ² or more. ⁵ h creep rupture strength 9 kgf / mm ² or more, room temperature impact absorption energy 1 kgf-m
The above heat-resistant cast steel casing material is obtained. In particular, by adjusting the W amount of 1.2 to 2% and the Ni / W ratio to 0.25 to 0.75, the creep rupture strength of 625 ° C. and 10 ⁵ h of 1
0 kgf / mm ² or more, room temperature shock absorption energy 2 kgf-m
The above excellent heat-resistant cast steel casing material can be obtained.

[0216]

[Table 14]

When the amount of W is 1.0% or more, it is remarkably strengthened, and especially when it is 1.5% or more, it is 8.0 kg.
A value of f / mm ² or more is obtained. No. 7 of the present invention is 640
The strength was sufficiently satisfied at a temperature of ℃ or below.

An alloy raw material having the target composition of the heat-resistant cast steel of the present invention was melted in an electric furnace in an amount of 1 ton, and after ladle refining, it was cast into a sand mold to obtain the inner casing of the high and medium pressure part described in Example 2. This casing was annealed at 1050 ° C. for 8 hours and then heat-treated at 1050 ° C. for 8 hours by air blow, and heat-treated at 730 ° C.
× 8h furnace cooling was performed twice for tempering. As a result of cutting and investigating this prototype casing having a fully tempered martensite structure, the characteristics required for a 250 atm, 625 ° C high temperature and high pressure turbine casing (625 ° C, 10 ⁵ h strength ≧ 9 kgf / mm
² , it was confirmed that the impact absorption energy at 20 ° C ≥ 1 kgf-m) was sufficiently satisfied and that welding was possible.

[Embodiment 6] In this embodiment, the steam temperature of the high-pressure steam turbine and the intermediate-pressure steam turbine or the high-intermediate-pressure steam turbine is set to 649 ° C. instead of 625 ° C., and the structure and size are implemented. It is obtained with almost the same design as Example 1 or 2. Here, what is different from the first embodiment is the rotor shaft, the first-stage moving blades, the first-stage stationary blades, and the inner casing of the high-pressure, intermediate-pressure, or high-intermediate-pressure integrated steam turbine that are in direct contact with this temperature. As these materials excluding the inner casing, the amount of B among the materials shown in Table 7 above is 0.01
.About.0.03% and the amount of Co were increased to 5 to 7%, and as the inner casing material, the amount of W of Example 1 was increased to 2 to 3%,
By adding 3% of Co, the required strength is satisfied, and there is a great merit that the conventional design can be used. That is, in the present embodiment, the conventional design concept can be used as it is in that all the structural materials exposed to high temperatures are made of ferritic steel. Since the steam inlet temperature of the second stage moving blade and the stationary blade is about 610 ° C., it is preferable to use the material used in the first stage of Example 1 for these.

Further, the steam temperature of the low-pressure steam turbine is about 405 ° C., which is slightly higher than the temperature of about 380 ° C. of Example 1 or 2, but the rotor shaft itself has a sufficiently high strength because the material of Example 1 has sufficiently high strength. Similarly, super clean materials are used.

Further, in the tandem type in which all are directly connected to the cross compound type in this embodiment, 3600 rpm
It can also be carried out at a rotational speed of.

[0222]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain martensitic heat-resistant and cast steel having high creep rupture strength and room temperature toughness at 600 to 660 ° C. Therefore, all the main members for ultra-supercritical pressure turbines at each temperature are ferrite-based. It can be made of heat-resistant steel, and the basic design of steam turbines up to now can be used as it is, resulting in a highly reliable thermal power plant.

Conventionally, at such a temperature, an austenitic alloy was inevitably used, and therefore, a large-sized rotor which was sound could not be manufactured from the viewpoint of manufacturability. It is possible to manufacture large rotors.

Further, since the all-ferritic steel high temperature steam turbine of the present invention does not use an austenitic alloy having a large coefficient of thermal expansion, rapid start of the turbine is facilitated and thermal fatigue damage is less likely to occur. There are advantages.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between impact value and tensile strength.

FIG. 2 is a cross-sectional view of a high pressure and medium pressure steam turbine according to the present invention.

FIG. 3 is a sectional structural view of a low-pressure steam turbine according to the present invention.

FIG. 4 is a perspective view of a turbine rotor blade according to the present invention.

FIG. 5 is a sectional view of a rotor shaft for a high-pressure steam turbine.

FIG. 6 is a sectional view of a rotor shaft for a medium-pressure steam turbine.

FIG. 7 is a cross-sectional view of a high / middle pressure steam turbine according to the present invention.

FIG. 8 is a cross-sectional view of a rotor shaft for high and medium pressure steam turbines according to the present invention.

FIG. 9 is a cross-sectional view of a low pressure steam turbine according to the present invention.

FIG. 10 is a cross-sectional view of a low-pressure steam turbine rotor shaft according to the present invention.

FIG. 11 is a perspective view of a tip end portion of the turbine rotor blade of the present invention.

[Explanation of symbols]

1 ... 1st bearing, 2 ... 2nd bearing, 3 ... 3rd bearing, 4 ... 4th
Bearing, 5 ... Thrust bearing, 10 ... First shaft packing, 1
1 ... 2nd shaft packing, 12 ... 3rd shaft packing, 13 ... 4th shaft packing, 14 ... High pressure partition plate, 1
5 ... Medium pressure diaphragm, 16 ... High pressure blade, 17 ... Medium pressure blade, 18
... High-pressure inner compartment, 19 ... High-pressure outer compartment, 20 ... Medium-pressure inner first compartment, 21 ... Medium-pressure inner second compartment, 22 ... Medium-pressure outer compartment, 23 ... High-pressure axle, 24 ... Medium-pressure Axle, 25 ... Flange, Elbow, 26 ... Front bearing box, 27 ... Journal part,
28 ... Main steam inlet, 29 ... Reheat steam inlet, 30 ... High pressure steam exhaust port, 31 ... Cylinder connecting pipe, 38 ... Nozzle box (high pressure first stage), 39 ... Thrust bearing wear blocking device, 40 ...
Warm-up steam inlet, 43 ... Bearing, 51 ... Boiler, 52 ... High pressure turbine, 53 ... Medium pressure turbine, 54, 55 ... Low pressure turbine, 56 ... Condenser, 57 ... Condensate pump, 58 ... Low pressure feed water heater system , 59 ... Deaerator, 60 ... Booster pump, 61
... water supply pump, 63 ... high-pressure water supply heater system, 64 ... economizer, 65 ... evaporator, 66 ... superheater, 67 ... air heater,
68 ... Generator.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F01D 5/28 F01D 5/28

Claims (12)

[Claims] 1. A rotor journal portion and a low temperature region portion have a weight ratio of C0.06-0.14%, Si0.5% or less, Mn2% or less, Cr7-12%, Ni0.1-1.0%, V0. 0.05
0.3%, Nb 0.01 to 0.20%, N 0.005 to 0.
It is made of martensite steel containing 1%, Mo 3.5% or less, W 3.5% or less, B-free or 0.015% or less and Co 1-10%, and the rotor body has a weight ratio of C 0.06 to 0.0.
14%, Si 0.15% or less, Mn 1% or less, Cr8-
12%, Ni 0.1-1.0%, V 0.05-0.3%, N
b 0.01 to 0.20%, N 0.005 to 0.1%, Mo
More than 0.5% and 3.5% or less, W3.5% or less, B0.0
A rotor for a steam turbine, which is made of martensitic steel containing 05 to 0.03% and Co to 10%, and in which the body portion has an alloy composition having higher high-temperature strength or lower weldability than the journal portion. shaft. 2. A high pressure having a rotor shaft, a rotor blade planted on the rotor shaft, a stator vane for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the stator vane,
In a steam turbine of medium or high intermediate pressure, the rotor shaft has a weight of C0.05 to 0.20%, Si
0.15% or less, Mn 0.03 to 1.5%, Cr 9.5 to 1
3%, Ni 0.05-1.0%, V 0.05-0.35%,
Nb 0.01 to 0.20%, N 0.005 to 0.06%, M
o More than 0.5% and 3.5% or less, W3.5% or less, Co1-
10%, B 0.0005 to 0.03%, high-strength martensitic steel having 78% or more of Fe, and the bearing portion of the rotor shaft is made of martensitic steel having lower strength or higher weldability than the body. A steam turbine characterized by becoming. 3. A steam turbine power plant comprising a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine or a high-intermediate-pressure turbine and a low-pressure turbine, wherein the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate turbine have a steam inlet temperature to a first-stage rotor blade. 610 to 660 ° C., the low-pressure turbine has a steam inlet temperature to the first stage rotor blade of 380 to 475 ° C., and the rotor shaft exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine, or the rotor shaft and the rotor blade,
At least one of the vane and the inner casing is made of Cr8-
A high-strength martensitic steel containing 13% by weight and Ta 0.01-0.20% by weight, wherein the bearing portion of the rotor shaft is made of martensitic steel having a lower strength or higher welding than the body. And steam turbine power plant. 4. A rotor shaft, a rotor blade embedded in the rotor shaft, a stator blade for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the stator blade. The temperature flowing into the first stage of the moving blade is 600 to 660.
℃ and pressure is 250kg / cm ² or more or 150-200kg
/ Cm ² of a high-pressure, medium-pressure or high-medium pressure turbine, wherein the rotor shaft or the rotor shaft and at least the first stage of the moving blades and the stationary blades have a temperature of steam flowing into the first stage of the moving blades. 10 ⁵ h creep rupture strength at the corresponding temperature is 10 kgf / mm ² or more Cr9~
Made of high-strength martensitic steel having a fully tempered martensitic structure containing 13% by weight and Ta 0.01-0.20% by weight, the inner casing being 10 ⁵ hours creep rupture strength at a temperature corresponding to the steam temperature. Is 10 kg
A steam turbine characterized by comprising martensitic cast steel containing 8 to 13% by weight of Cr, which is f / mm ² or more, and a bearing portion of the rotor shaft comprising martensitic steel having lower strength or higher weldability than a body portion. . 5. A high pressure having a rotor shaft, a rotor blade embedded in the rotor shaft, a stator vane for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the stator vane.
In a steam turbine of medium or high intermediate pressure, the rotor shaft has a weight of C0.05 to 0.20%, Si
0.15% or less, Mn 0.03 to 1.5%, Cr 9.5 to 1
3%, Ni 0.05-1.0%, V 0.05-0.35%,
Ta 0.01 to 0.20% or Ta and Nb in the total amount of 0.01 to 0.20%, N 0.005 to 0.06%, Mo 3.
5% or less, W 1.0 to 3.5% or less, Co 1 to 10%, B
A high-strength martensitic steel containing 0.0005 to 0.03% and having Fe of 78% or more, wherein the bearing portion of the rotor shaft is made of martensitic steel having lower strength or higher weldability than the body portion. Characteristic steam turbine. 6. A steam turbine power plant comprising a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine, or a high-intermediate pressure turbine and a low-pressure turbine, wherein the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate turbine have a steam inlet temperature to a first-stage rotor blade. Is 600 to 660 ° C., the low-pressure turbine has a steam inlet temperature to the first-stage rotor blades of 380 to 475 ° C., and the rotor shaft is exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure turbine, or the rotor shaft. And at least one of the moving blades, the stationary blades, and the inner casing have a Cr content of 8 to 13% by weight and a Ta content of 0.01 to 0.2.
0% by weight of high-strength martensitic steel, and the final stage rotor blade of the low-pressure turbine [blade length
The value of (inch) × rotation speed (rpm)] is 125,000 or more. 7. A high pressure having a rotor shaft, a rotor blade embedded in the rotor shaft, a stator vane for guiding the inflow of water vapor into the rotor blade, and an internal casing for holding the stator vane,
An intermediate-pressure or high-intermediate-pressure integrated steam turbine, wherein the rotor shaft and at least the first stage of the moving blades and the stationary blades are by weight, C0.05 to 0.20%, Si 0.15% or less, M
n 0.03 to 1.5%, Cr 9.5 to 13%, Ni 0.05
~ 1.0%, V0.05-0.35%, Ta0.01-0.0.
20% or the total amount of Ta and Nb 0.01 to 0.20%, N
From a high-strength martensitic steel containing 0.01 to 0.06%, Mo 3.5% or less, W 3.5% or less, Co 1 to 10%, B 0.0005 to 0.03%, and Fe of 78% or more. The weight of the inner casing is 0.06 to 0.0.
16%, Si 0.5% or less, Mn 1% or less, Ni 0.2-
1.0%, Cr 8-12%, V 0.05-0.35%, N
b0.01-0.15%, N0.01-0.1%, Mo1.
A steam turbine comprising a high-strength martensitic steel containing 5% or less, W1 to 4%, B0.0005 to 0.003%, and Fe of 85% or more. 8. A high pressure having a rotor shaft, a rotor blade planted in the rotor shaft, a stator vane for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the stator vane,
An intermediate-pressure or high-intermediate-pressure integrated steam turbine, wherein the rotor shaft or the rotor shaft and at least the first stage of the moving blades and the stationary blades are C0.1-0.25%, S by weight.
i 0.15% or less, Mn 1.5% or less, Cr 8.5 to 13
%, Ni 0.05 to 1.0%, V 0.05 to 0.5%, Nb
0.02 to 0.20%, N 0.01 to 0.1%, Mo 0.5
%, 3.5% or less, W3.5% or less, Co1-10%
And B 0.001 to 0.030% and consisting of a high-strength martensitic steel having 80% or more Fe. 9. A steam turbine power plant comprising a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine or a high-intermediate-pressure turbine and a low-pressure turbine, wherein the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate turbine have a steam inlet temperature to a first-stage rotor blade. Is 600 to 660 ° C., the low-pressure turbine has a steam inlet temperature to the first-stage rotor blades of 380 to 475 ° C., and the rotor shaft is exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine or the high-intermediate-pressure turbine, or the rotor shaft. At least the first stage of the moving blades and the stationary blades and at least one of the inner casings are made of a high-strength martensitic steel containing Cr 8 to 13% and Mo in excess of 0.5% and less than 1%, and The value of [blade length (inch) x rotation speed (rpm)] of the final stage rotor blade is 1
Steam turbine power plant characterized by over 25,000. 10. A high-pressure, medium-pressure or a rotor shaft, a rotor blade embedded in the rotor shaft, a stator vane guiding the inflow of water vapor into the rotor blade, and an internal casing holding the stator vane. A high-intermediate-pressure integrated steam turbine, wherein the rotor shaft and at least the first stage of the moving blades and the stationary blades are by weight, C 0.05 to 0.20%, Si 0.15% or less, and Mn 0.03 to 1.5. %, Cr 9.5 to 13%, Ni
0.05-1.0%, V0.05-0.35%, Nb0.0
1 to 0.20%, N 0.01 to 0.1%, Mo 0.5% to less than 1%, W 3.5% or less, Co 1 to 10%, B 0.
It is made of high-strength martensitic steel containing 0005 to 0.03% and 78% or more of Fe, and the inner casing has a weight of C0.06 to 0.16%, Si of 0.5% or less, and M.
n1% or less, Ni 0.2-1.0%, Cr 8-12%, V
0.05 to 0.35%, Nb 0.01 to 0.15%, N 0.01
~ 0.1%, Mo1.5% or less, W1-4%, B0.00
A steam turbine characterized by comprising a high-strength martensitic steel containing Fe of 85% or more, including 05 to 0.003%. 11. The rotor journal portion and the low temperature region are made of Ta-containing martensitic steel having good weldability, and the rotor body is made of Ta-containing martensitic steel having a higher high temperature strength than the martensitic steel. Rotor shaft for steam turbine. 12. A rotor journal portion and a low temperature region portion have a weight ratio of C0.06 to 0.14%, Si of 0.5% or less, and Mn of 2%.
Below, Cr 7-12%, Ni 0.1-1.0%, V0.05
~ 0.3%, Ta 0.01-0.20% or Ta and Nb
In the total amount of 0.01 to 0.20%, N 0.005 to 0.1
%, Mo 1% or less, W 1.0 to 3.5%, no B added or 0.
Made of martensitic steel containing less than 30% Co and 1-10% Co, and the rotor body has a weight ratio of C0.06-0.14.
%, Si 0.1% or less, Mn 1% or less, Cr 8 to 12
%, Ni 0.1-1.0%, V 0.05-0.3%, Ta
0.01 to 0.20% or Ta and Nb in a total amount of 0.0
1 to 0.20%, N 0.005 to 0.035%, Mo 3.5%
Below, W3.5% or below, B0.005-0.03% and C
A rotor shaft for a steam turbine, which is made of martensitic steel containing 1 to 10% of o and has an alloy composition in which the body portion has higher high-temperature strength or lower weldability than the journal portion.