JPH1193603A - Steam turbine power plant and steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise temperature of a specified steam temperature by using ferrite group heat resistant steel by setting a ratio of the total of a bearing-to-bearing distance of a high-pressure and a middle-pressure turbines connected to each other in tandem and a bearing-to-bearing distance of two low-pressure turbines in relation to the length of the final stage moving blade of a low-pressure turbine at a specified value. SOLUTION: A high-pressure turbine is provided with a high-pressure axle 23, in which a high-pressure moving blade is planted, and a middle-pressure turbine is provided with a static blade is opposition to a middle-pressure moving blade 17. A bearing- to-bearing distance of the high-pressure turbine is set at about 5.3 m, and a ratio of this bearing-to-bearing distance to the length of the final stage moving blade of the low-pressure turbine is set at 4.8. A bearing-to-bearing distance of the middle- pressure turbine is set at about 5.5 m, and a ratio of this bearing-to-bearing distance to the length of the final stage moving blade of the middle-pressure turbine is set at 5.0. Especially, ratio of the total of the bearing-to-bearing distance of the high- pressure turbine and the middle-pressure turbine connected to each other in tandem and the bearing-to-bearing distance of two low-pressure turbines connected to each other in tandem in relation to the length of the final stage moving blade of the low- pressure turbine is set at 26-30.

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 low-pressure steam turbine as a final stage rotor blade.
The present invention relates to a high-temperature steam turbine using% Cr steel.

[0002]

2. Description of the Related Art At present, 12Cr
-Mo-Ni-VN steel is used. In recent years, it has been desired to improve the thermal efficiency of gas turbines from the viewpoint of energy saving, and to reduce the size of equipment from the viewpoint of space saving.

[0003] To improve the thermal efficiency and make the equipment compact, it is effective means to increase the length of the steam turbine blades. Therefore, the blade length of the last stage of the low-pressure steam turbine tends to increase year by year. Along with this, the operating conditions of the blades of the steam turbine have become severe, 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 wing material, a tensile strength, which is a basic mechanical property, is required.

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

[0005] The tensile strength of the conventional 12Cr-Mo-Ni-
Ni-based alloys and Co-based alloys are generally known as structural materials higher than VN steel (martensitic steel), but they are inferior in hot workability, machinability and vibration damping properties.
It is not desirable as a wing material.

[0006] As a disk material for gas turbine,
-171856 and JP-A-4-120246 are known.

The conventional steam turbine has a maximum steam temperature of 566 ° C. and a steam pressure of 246 atg.

However, from the viewpoints of depletion of fossil fuels such as petroleum and coal, energy saving and prevention of environmental pollution, it is desired to increase the efficiency of thermal power plants. Raising the steam temperature of the steam turbine is the most effective means to increase the power generation efficiency. JP-A-7-233704 is known as a material for these high-efficiency ultrahigh-temperature steam turbines.

The present invention has been made in order to cope with the recent increase in length of low-pressure steam turbine blades.
JP-A-56-120 and JP-A-4-120246 do not disclose any moving blade material for a steam turbine.

[0010] In addition, the above-mentioned publication in JP-A-7-233704 discloses a rotor material, a casing material, and the like.
As described above, 12% is used as the final stage rotor blade in a high-to-medium pressure integrated steam turbine and a low-pressure steam turbine at higher temperatures.
There is no description regarding Cr-based martensitic steel.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a steam turbine having a high heat efficiency by enabling a high temperature of 600 to 660 ° C. by a heat-resistant ferritic steel, and a steam turbine power plant using the same. It is in.

[0012] Furthermore, the object of the present invention is to provide a temperature of 600 to 660 ° C.
It is an object of the present invention to provide a steam turbine whose basic structure is substantially the same at each operating temperature and a steam turbine power plant using the same.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a steam turbine power plant having a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine separately provided. And a total ratio of the distance between the bearings in which the intermediate pressure turbine is connected in tandem and the distance between the bearings of the two low pressure turbines connected in tandem is 26 to 30.

The present invention relates to a high-pressure turbine for a steam turbine power plant having a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately. The ratio of the distance is 3.5 to 6.0.

The present invention relates to a medium-pressure turbine for a steam turbine power plant having a high-pressure turbine, a medium-pressure turbine, and a low-pressure turbine separately, wherein the medium-pressure turbine has a blade length of a last-stage blade of the low-pressure turbine. The ratio of the distance between bearings is 4.0 to 6.0.

The present invention relates to a steam turbine power plant having a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately, wherein the two low-pressure turbines are connected in tandem with respect to the blade length of the last stage rotor blade of the low-pressure turbine. The ratio of the total distance between bearings of the turbine is 15.5 to 17.5.

According to the present invention, in a steam turbine power plant, a distance between bearings in which the high-pressure turbine and the medium-pressure turbine are connected in tandem with respect to a rated output (MW) of the power plant, and two low-pressure turbines connected in tandem The ratio of the total distance between bearings (mm) is 28.0 to 32.
It is characterized by being 0.

According to the present invention, in the above-described high-pressure turbine for a steam turbine power plant, a distance (mm) between bearings of the high-pressure turbine with respect to a rated output (MW) of the power plant is provided.
Is 3.5 to 6.5.

According to the present invention, in the above-mentioned medium-pressure turbine for a steam turbine power plant, a distance (mm) between bearings of the medium-pressure turbine with respect to a rated output (MW) of the power plant is provided.
Is 4.0 to 7.0.

According to the present invention, in the above-described low-pressure turbine for a steam turbine power plant, the ratio of the bearing distance (mm) of the two low-pressure turbines connected in tandem to the rated output (MW) of the power plant is 16. 0 to 19.0.

The present invention relates to a steam turbine power plant comprising a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated. The ratio of the sum of the distance between the bearings of the high and medium pressure integrated turbine and the distance between the bearings of the two low pressure turbines coupled in tandem is 24 to 28.

The present invention relates to a high-to-medium pressure integrated turbine for a steam turbine power plant comprising two low-pressure turbines coupled to the tandem as described above, wherein the high-to-medium pressure with respect to the blade length of the last stage blade of the low-pressure turbine is provided. The ratio of the distance between bearings of the integral turbine is 5.5 to 7.0.

The present invention provides a low-pressure turbine for a steam turbine power plant comprising two low-pressure turbines connected to the tandem as described above, wherein the low-pressure turbine is connected to the tandem with respect to the blade length of the last stage rotor blade. The ratio of the distance between the bearings of the low-pressure turbine is 15.0 to 17.5.

The present invention relates to a steam turbine power plant including a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated. The ratio of the total distance between the bearings of the high and medium pressure integrated turbine and the distance between the bearings of one low pressure turbine is 11.5 to 15.5.

The present invention provides the high-to-medium pressure integrated turbine for a steam turbine power plant as described above, wherein the ratio of the distance between the bearings of the high-to-medium pressure integrated turbine to the blade length of the last stage moving blade of the low-pressure turbine is 4.5. ６6.0.

According to the present invention, there is provided the low pressure turbine for a steam turbine power plant, wherein the ratio of the distance between the bearings of the one low pressure turbine to the blade length of the last stage rotor blade of the low pressure turbine is 4.5 to 4.5. 6.5.

The present invention relates to a steam turbine power plant including a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, wherein the high-to-medium pressure integrated power with respect to a rated output (MW) of the power plant is provided. The ratio of the total distance (mm) between the bearing distance of the turbine and the bearing distance of the two low-pressure turbines coupled in tandem is 35.0 to 35.0.
39.5.

The present invention relates to a high-to-medium pressure integrated turbine for a steam turbine power plant comprising two low-pressure turbines coupled to the above-mentioned tandem, wherein the high-to-medium pressure integrated turbine with respect to a rated output (MW) of the power plant is provided. Bearing distance
(mm) is 8.0 to 11.0.

The present invention relates to the aforementioned low-pressure turbine for a steam turbine power plant, wherein the total distance (mm) of the distance between the bearings of the two low-pressure turbines connected in tandem to the rated output (MW) of the power plant. Is 21.0
２５25.5.

The present invention relates to a steam turbine power plant provided with a high / medium pressure integrated turbine and a low pressure turbine in which a high pressure turbine and a medium pressure turbine are integrated, and wherein the high / medium pressure integrated power with respect to a rated output (MW) of the power plant is provided. The ratio of the total distance between the bearings of the turbine and the distance between the bearings of one of the low-pressure turbines is 22.0 to 26.5.

According to the present invention, there is provided the above-mentioned high-medium pressure integrated turbine for a steam turbine power plant, wherein a ratio of a bearing distance (mm) of the high-medium pressure integrated turbine to a rated output (MW) of the power plant is 8.0. １１11.0.

The present invention relates to the above-described low-pressure turbine for a steam turbine power plant, wherein a ratio of a bearing distance (mm) of the one low-pressure turbine to a rated output (MW) of the power plant is 8.5 to 8.5. 11.5.

The above requirements can be applied to the following inventions.

According to the present invention, a high-pressure turbine and 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. In the steam turbine power plant in which two low pressure turbines are connected to each other, the high pressure turbine and the medium pressure turbine or the high and
93-660 ° C (preferably 610-620 ° C, 620
630 ° C, 630 ° C to 640 ° C), the low pressure turbine has a steam inlet temperature to the first stage rotor blade of 350 to 4 ° C.
For the range of 00 ° C., the rotor shaft or the rotor shaft, the rotor blades, the stationary blades, and the inner casing all exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine or the high-to-medium pressure turbine contain 8 to 13% by weight of Cr. Or the first stage, two stages, or up to three stages of the rotor blades are made of a Ni-based alloy, and the blade length of the final stage rotor blade of the low-pressure turbine (the blade length ( Inch) x number of revolutions (rpm)] is 120,
000 or more (preferably 12,500 or more, more preferably 12,9
Martensitic steel of 00-15,000 or wing length of 4
Preferably, one inch or more is made of a Ti-based alloy.

The present invention has a rotor shaft, a moving blade implanted on the rotor shaft, a stationary blade for guiding the flow of steam to the moving blade, and an inner casing for holding the stationary blade. The temperature at which steam enters the first stage of the bucket is 59
3 to 660 ° C and a pressure of 250 kgf / cm ² or more (preferably 246 to 316 kgf / cm ² ) or 170 to 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., 625 ° C., 640 ° C., 650 ° C., 660 ° C.).
° C.) 10 ⁵ h creep rupture strength at a temperature corresponding to the 10 kgf / mm ² or more (preferably Cr8.5~13 wt% is 17 kgf / mm ² or higher) (preferably 10.5 to 1
(1.5% by weight) and a high-strength martensitic steel having a fully-tempered martensite structure, or, among these, the first stage, the second stage or the third stage of the blade is made of a Ni-based alloy, and the inner casing Has a 10 ⁵ hour creep rupture strength of 10 kgf at a temperature corresponding to each of the above steam temperatures.
Steam from a high-pressure steam turbine, a medium-pressure steam turbine or a high-pressure turbine made of a martensitic cast steel containing 8 to 9.5% by weight of Cr having a Cr / mm ² or more (preferably 10.5 kgf / mm ² or more). However, it is preferable to use a high / intermediate pressure integrated steam turbine which is heated to a temperature equal to or higher than the high pressure side inlet temperature and sent to the medium pressure side turbine.

In the high-pressure turbine and the intermediate-pressure turbine or the high- and intermediate-pressure integrated steam turbine, the first stage of the rotor shaft or at least one of the moving blade and the stationary blade is C
0.05 to 0.20%, Si 0.6% or less, preferably 0.15% or less, Mn 1.5% or less, preferably 0.05
~ 1.5%, Cr 8.5 ~ 13%, preferably 9.5 ~ 1
3%, Ni 0.05 to 1.0%, V 0.05 to 0.5%, preferably 0.05 to 0.35%, at least one of Nb and Ta 0.01 to 0.20%, N 0.2% 01 to 0.1%, preferably 0.01 to 0.06%, Mo 1.5% or less, preferably 0.05 to 1.5%, W 0.1 to 4.0%, preferably 1.0 to 1.0% 4.0%, Co 10% or less, preferably 2 to 10
%, B 0.03% or less, preferably 0.0005 to 0.0
High-strength martensitic steel containing 3% and having 78% or more Fe is preferred, preferably corresponding to a steam temperature of 593-660 ° C., or C 0.1-0.25%, Si
0.6% or less, Mn 1.5% or less, Cr 8.5 to 13%, N
i 0.05 to 1.0%, V 0.05 to 0.5%, W 0.10
0.65%, at least one of Nb and Ta
0.20%, Al 0.1% or less, Mo 1.5% or less, N 0.2%
A high-strength martensitic steel with 025 to 0.1% and 80% or more Fe is preferred, preferably corresponding to 600 to less than 620 ° C. The inner casing is C06-0.16%, Si0.5% or less, Mn1% by weight.
Hereinafter, Ni 0.2 to 1.0%, Cr 8 to 12%, and V 0.2.
0.5 to 0.35%, at least one of Nb and Ta is 0.0
1 to 0.15%, N 0.01 to 0.8%, Mo 1% or less,
W1-4%, B0.0005-0.003%, 85
It is preferably made of a high-strength martensitic steel having at least Fe.

In the high-pressure steam turbine according to the present invention,
The rotor blade has at least 9 stages, preferably at least 10 stages, 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 6500
mm) and the minimum diameter (D) at the portion where the vane is provided
Is 660 mm or more (preferably 680 to 740 mm), and the (L / D) is 6.8 to 9.9 (preferably 7.9).
To 8.7) of a high-strength martensitic steel containing 9 to 13% by weight of Cr.

In the medium-pressure steam turbine according to the present invention,
The rotor blade has a double flow structure in which each of the rotor blades has six or more stages symmetrically, and a first stage is implanted at the center of the rotor shaft. The rotor shaft has a bearing center distance (L) of 5000 mm or more (preferably 5100 mm or more). 6500 mm) and the minimum diameter (D) at the portion where the stator vanes are provided is 630 mm or more (preferably 650-710 mm), and the (L / D) is 7.0-9.2 (preferably 7 .8 to 8.3)
It is preferably made of a high-strength martensitic steel containing up to 13% by weight.

In a low-pressure steam turbine having a high-medium pressure turbine having a high-pressure turbine and a medium-pressure turbine separately, or having a high-medium pressure turbine in which the turbines are integrated, the rotor blades have six or more stages symmetrically to each other, and The rotor shaft has a bearing center distance (L) of 6500 mm or more (preferably 6600 to 71).
00 mm) and a minimum diameter (D) at a portion where the stationary blade is provided is 750 mm or more (preferably 760 to 900 mm).
And wherein the (L / D) is 7.8 to 10.2 (preferably 8.0 to 8.6) and contains 3.25 to 4.25% by weight of Ni-Cr-Mo-V. Made of alloy steel, the final stage rotor blade has a value of [wing length (inch) x rotation speed (rpm)] of 120,0
High strength martensitic steel with a wing length of 4 or more
Preferably, one inch or more is made of a Ti-based alloy.

Further, the present invention relates to a high-pressure turbine and 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. In a steam turbine power plant in which two low-pressure turbines are connected, the high-pressure turbine and the medium-pressure turbine or the high-medium-pressure turbine have a steam inlet temperature to the first-stage bucket of 593.
660 ° C., the low-pressure turbine has a steam inlet temperature to the first-stage blade of 350 to 400 ° C., and the metal temperature of the first-stage moving blade implanted portion of the rotor shaft of the high-pressure turbine and the metal temperature of the first-stage blade is higher than that of the high-pressure turbine. 40 ° C. or more from the steam inlet temperature to the first stage blade (preferably 20 to
Lower the temperature by 35 ° C) so that the temperature of the first stage rotor blades on the rotor shaft of the intermediate pressure turbine and the metal temperature of the first stage rotor blades are at least 75 ° C higher than the steam inlet temperature to the first stage rotor blades of the intermediate pressure turbine. (Preferably 50-
The rotor shafts of the high-pressure turbine and the intermediate-pressure turbine and at least the first-stage moving blades are made of martensitic steel containing 9.5 to 13% by weight of Cr, or the moving blades of these are used. First stage or 2
Stages or up to three stages are made of a Ni-based alloy, and the last stage blade of the low-pressure turbine is [blade length (inch) × rotation speed (rpm)].
Of a high-strength martensitic steel having a value of 120,000 or more or a Ti-based alloy having a wing length of 41 inches or more is preferable.

Further, the present invention provides a coal-fired boiler, a steam turbine driven by steam obtained by the boiler, and a single unit or two driven by the steam turbine.
In a coal-fired thermal power plant comprising at least two, preferably two generators having a power output of at least 1000 MW, said steam turbine is a high-pressure turbine and a medium-pressure turbine and 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-medium-pressure turbine is connected to one or two tandem low-pressure turbines, and the high-pressure turbine and the medium-pressure turbine or the high-medium-pressure turbine The inlet temperature is 593 to 660 ° C. and the low pressure turbine has a steam inlet temperature to the first stage rotor blade of 350 to 400 ° C., and the superheater of the boiler is 3 ° C. or more higher than the steam inlet temperature to the first stage rotor blade of the high pressure turbine. (Preferably 3-10 ° C,
More preferably, the steam heated to a high temperature flows into the first stage rotor of the high-pressure turbine, and the steam exiting the high-pressure turbine is sent to the first stage rotor of the intermediate-pressure turbine by the reheater of the boiler. Is heated to a temperature 2 ° C. or higher (preferably 2 to 10 ° C., and more preferably 2 to 5 ° C.) higher than the steam inlet temperature of the steam turbine, flows into the first stage moving blades of the intermediate-pressure turbine, and exits from the intermediate-pressure turbine. Is preferably 3 ° C. or more (preferably 3 to 10 ° C.) from the steam inlet temperature to the first stage rotor blade of the low pressure turbine by the boiler's economizer.
° C, more preferably 3 to 6 ° C) and heated to a high temperature to flow into the first stage blade of the low-pressure turbine, and the last stage blade of the low-pressure turbine is [blade length (inch) x rotation speed
(rpm)] is preferably 120,000 or more, or a high strength martensitic steel or a Ti-based alloy having a wing length of 41 inches or more.

Further, in the above-mentioned low-pressure steam turbine having the high-pressure turbine and the intermediate-pressure turbine according to the present invention, or having the high-intermediate-pressure integrated turbine, the steam inlet temperature to the first-stage moving blade is 350 to 400 ° C. (preferably). Is 360-3
80 ° C.) and the rotor shaft is C0.
2 to 0.3%, Si 0.05% or less, Mn 0.1% or less,
Ni 3.25 to 4.25%, Cr 1.25 to 2.25%, M
o 0.07 to 0.20%, V 0.07 to 0.2% and Fe9
It is preferably made of a low alloy steel having a content of 2.5% or more.

In the above-described high-pressure steam turbine, the moving blade has 7 stages or more (preferably 9 to 12 stages), and the blade portion has a length of 25 to 180 mm from the upstream side to the downstream side of the steam flow. 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 three or more steps (preferably 4 to 7 steps) on the downstream side compared with the upstream side. The ratio to the wing length is 0.2 to 1.6 (preferably 0.30 to 1.6).
(1.30, more preferably 0.65 to 0.95), and preferably decreases from the upstream side to the downstream side.

Further, in the above high-pressure steam turbine,
According to 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.
180mm, the ratio of the wing length of each adjacent stage is 2.3
Hereinafter, it is preferable that the ratio is gradually increased on the downstream side, and the length of the wing portion is larger on the downstream side than on the upstream side.

Further, in the above high-pressure steam turbine,
According to 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.
The rotor shaft has a width in the axial direction of a portion corresponding to the stationary blade portion of the rotor shaft, the downstream side being smaller than the upstream side by two or more stages (preferably 2 to 4 stages) in a stepwise manner. It is preferable that the ratio gradually decreases toward the downstream side when the ratio to the side wing 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) in a symmetrical manner, and the blade length is 60 to 300 mm from the upstream side to the downstream side of the steam flow. The diameter of the implanted portion of the rotor blade of the rotor shaft is larger than the diameter of a portion corresponding to the stationary blade, and the axial width of the implanted portion is two or more steps (preferably 2 steps) at the downstream side as compared to the upstream side. ~ 6 stages), and the ratio to the wing length is 0.1%.
It is preferably from 35 to 0.80 (preferably from 0.5 to 0.7) and decreases from the upstream side to the downstream side.

Further, the present invention provides the above-mentioned medium-pressure steam turbine, wherein 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.
And the length of the adjacent wings 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) and gradually decreases on the downstream side. Preferably it is larger.

Further, according to the present invention, in the above-mentioned medium-pressure steam turbine, the moving blade has a double-flow structure having six or more stages symmetrically in a left-right direction, and the blade length is 60 from the upstream side to the downstream side of the steam flow.
And the axial width of the portion of the rotor shaft corresponding to the stationary blade portion is gradually reduced by two or more stages (preferably 3 to 6 stages) on the downstream side as compared with the upstream side. The ratio of the moving blade to the downstream wing length is 0.
It is preferable that the ratio gradually decreases in the range of 80 to 2.50 (preferably 1.0 to 2.0) toward the downstream side.

According to the present invention, in a low-pressure steam turbine in a power plant in which the above-mentioned high-pressure turbine and medium-pressure turbine are separately provided, each of the moving blades has six or more stages (preferably eight to ten stages) symmetrically. The double flow structure and the wing length are from 80 to 1300 from upstream to downstream of the steam flow.
mm, the diameter of the implanted portion of the rotor blade of the rotor shaft is larger than the diameter of a portion corresponding to the stationary blade, and the axial width of the implanted portion is preferably three or more steps in the downstream side as compared with the upstream side ( (More preferably 4 to 7 steps), and the ratio to the wing length is 0.2.
It is preferably from 0.7 to 0.7 (preferably from 0.3 to 0.55), decreasing from the upstream side to the downstream side.

Further, the present invention relates to a low-pressure steam turbine having the above-mentioned high-pressure turbine and medium-pressure turbine separately or integrally having a high-medium pressure turbine. And the wing length is 80 to 1300 mm from the upstream side to the downstream side of the steam flow, and the wing length of each adjacent stage is larger at the downstream side than at the upstream side, and the ratio is 1.2. It is preferable that the ratio is gradually increased on the downstream side in the range of ~ 1.8 (preferably 1.4 ~ 1.6).

Further, the present invention provides the low-pressure steam turbine according to the above-mentioned low pressure steam turbine, wherein the rotor blades have a double flow structure having six or more stages, preferably eight or more stages, in a bilaterally symmetrical manner, and the blade length is from upstream to downstream of the steam flow. 80 to 1300 mm, and the axial width of the portion corresponding to the stationary blade portion of the rotor shaft is preferably larger in three stages or more (more preferably 4 to 7 stages) on the downstream side than on the upstream side. The ratio of the moving blade to the length of the adjacent downstream blade portion is 0.2 to 1.4 (preferably 0.25 to 1.25, particularly 0.2.
It is preferable that the ratio gradually decreases in the range from 5 to 0.9) toward the downstream side.

In the above-described high-pressure steam turbine, the rotor blade has at least seven stages, preferably at least nine stages, and the rotor shaft has a portion corresponding to the stationary blade having a diameter corresponding to the blade implant portion. Smaller than the diameter, the axial width of the diameter corresponding to the stationary blade is gradually increased in two or more stages (preferably two to four stages) on the upstream side of the steam flow as compared with the downstream side, The width between the last stage of the rotor blade and the front thereof is 0.75 to 0.95 times (preferably 0.8 to 0.9) the width between the second and third stages of the rotor blade. More preferably 0.82 to 0.88), and the axial width of the rotor shaft implant portion at the downstream side of the steam flow is three or more stages (preferably 4 to 0.8). 7
And the axial width of the last stage of the rotor blade is 1 to 2 with respect to the axial width of the second stage.
It is preferably a factor of (preferably 1.4 to 1.7 times).

In the above-described medium-pressure steam turbine, the rotor blade has six or more stages, and the rotor shaft has a portion corresponding to the stationary blade having a diameter smaller than that of the portion corresponding to the rotor blade implantation portion. The axial width of the diameter corresponding to the stationary blade is preferably increased stepwise at two or more stages (more preferably 3 to 6 stages) on the upstream side of the steam flow as compared with the downstream side. The width between the last stage and the front of the blade is 0.5 to 0.5 of the width between the first stage and the second stage of the bucket.
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 implanted portion is preferably two stages on the downstream side of the steam flow as compared with the upstream side. As described above (preferably in 3 to 6 stages), the axial width of the last stage of the rotor blade is 0.8 to 2 times (preferably 1 to 2) the axial width of the first stage. .2 to 1.5
Times).

In the low-pressure steam turbine described above, the moving blade has a double flow structure having eight or more stages symmetrically, and the rotor shaft has a portion corresponding to the stationary blade and having a diameter corresponding to the moving blade implanted portion. And the axial width of the diameter corresponding to the stator vanes is preferably larger at three or more stages (more preferably at four to seven stages) on the upstream side of the steam flow than on the downstream side. The width between the last stage of the moving blade and the front of the last stage is equal to the width of the first stage of the moving blade.
1.5 to 3.0 times the width between the steps (preferably 2.0 to 3.0 times)
2.7 times), and the width of the rotor shaft in the axial direction of the moving blade portion implantation portion is preferably three or more stages (more preferably four to seven stages) on the downstream side of the steam flow as compared with the upstream side. The axial width of the last stage of the rotor blade is 5 to 8 times (preferably 6.2 to 7.0 times) the axial width of the first stage. preferable.

The structure 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 of 593 to 660 ° C., preferably 610 to 660 ° C. Things.

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

In the high / intermediate pressure integrated steam turbine according to the present invention, the high pressure side moving blade has 7 stages or more, preferably 8 stages or more, and the medium pressure side moving blade has 5 or more stages, preferably 6 or more stages. The distance (L) between the bearing centers is 6000 mm or more (preferably 6100 to 7000 mm), and the minimum diameter (D) at the portion where the stationary blade is provided is 660 mm or more (preferably 620 to 760 mm). D) is 8.0
Cr9 which is １１11.3 (preferably 9.0 to 10.0)
It is preferred to be composed of a high strength martensitic steel containing up to 13% by weight.

According to the present invention, a low-pressure steam turbine for a power plant having a high-medium pressure integrated turbine preferably has the following requirements. The rotor blade has left and right symmetrical stages each having 5 or more stages, preferably 6 stages or more. The rotor blade has a double flow structure in which the first stage is implanted at the center of the rotor shaft, and the rotor shaft has a bearing center distance (L). 6500 mm or more (preferably 6 mm
600 to 7500 mm) and a minimum diameter (D) at a portion where the stator vanes are provided is 750 mm or more (preferably 760 to 7500 mm).
900 mm) and (L / D) is 7.2 to 10.0.
(Preferably 8.0 to 9.0) Ni 3.0 to 4.5
%, Preferably 3.25 to 4.25% by weight of N
The final stage rotor blade is made of i-Cr-Mo-V low alloy steel, and the final stage rotor blade has a [wing length (inch) x rotation speed (rpm)] value of 120,000 or more or a high-strength martensitic steel or a blade length of 41. Those made of a Ti-based alloy of inches or more are preferable.

The rotor shaft for a low-pressure steam turbine has a diameter (D) of the stationary blade portion of 750 to 1300 mm, a center-to-center distance (L) of 5.0 to 9.5 times that of the above-mentioned D, and a weight of C0. 0.2-0.3%, Si 0.05% or less, Mn 0.1
% Or less, Ni 3.0 to 4.5%, Cr 1.25 to 2.25
%, Mo 0.07 to 0.20%, V 0.07 to 0.2%, and Fe92.5% or more are preferable.

The rotor blade has a double flow structure having at least five stages, preferably at least six stages in a bilaterally symmetrical manner, and the blade portion length is within a range of 80 to 1300 mm from the upstream side to the downstream side of the steam flow. The diameter of the implanted portion of the rotor blade is larger than the diameter of the portion corresponding to the stationary blade, the width of the root portion in the axial direction of the implanted portion is larger than the width of the blade implanted portion in a divergent manner, and from the downstream side to the upstream side. It gradually decreases, and the ratio to the wing length is 0.1.
25-0.80 is preferred.

The moving blade has a double-flow structure having at least 5 stages, preferably at least 6 stages, in a symmetrical manner, and the blade length is within a range of 80 to 1300 mm from the upstream side to the downstream side of the steam flow. The length of the wing is larger on the downstream side than on the upstream side, and the ratio is 1.2 to 1.7.
It is preferable that the length of the wing portion is gradually increased on the downstream side within the range described above.

The blade has a double-flow structure having five or more stages, preferably six or more stages in a symmetrical manner, and the blade length increases from upstream to downstream of the steam flow.
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. A larger one is preferred.

The high and medium pressure integrated steam turbine of the present invention preferably has the following configuration.

The moving blade on the high pressure side has at least seven stages and a blade length of 40 to 200 mm from the upstream side to the downstream side of the steam flow. The diameter of the root portion in the axial direction of the implanted portion is larger than the diameter of the corresponding portion, and the width of the root portion in the axial direction is stepwise larger on the upstream side than on the downstream side, and the ratio to the wing length is 0.20 to 1.
60, preferably from 0.25 to 1.30, increasing from the upstream side to the downstream side, the blades on the medium pressure side have five or more stages symmetrically in the left-right direction, and the blade length is on the upstream side of the steam flow. From 100 to 350 mm on the downstream side, the impeller diameter of the rotor blade of the rotor shaft is larger than the diameter of the portion corresponding to the stationary blade, and the axial width of the root portion of the implant is the same as that of the rotor except for the last stage. The downstream side is larger than the upstream side, and the ratio to the wing length is 0.35 to 0.8.
0, and preferably from 0.40 to 0.75, decreasing from the upstream side to the downstream side.

The moving blade has at least seven stages and a blade length of 25 to 200 mm from the upstream side to the downstream side of the steam flow, and the ratio of the blade length of each adjacent stage is 1.05 to 1.35. The blade length is gradually increased on the downstream side as compared with the upstream side, and the blades in the intermediate pressure section have five or more stages, and the blade length is 100 to 100 downstream from the upstream side of the steam flow. ~ 350mm
The length of the adjacent wings is larger on the downstream side than on the upstream side, and the ratio thereof is 1.10 to 1.30 and gradually increases on the downstream side.

The rotor blade on the high pressure side has at least six stages, preferably at least seven stages, and the rotor shaft has a portion corresponding to the stationary blade having a diameter smaller than that of the portion corresponding to the blade implant. The axial width of the root portion of the implanted portion of the blade is largest at the first stage, and is gradually increased in two or more stages, preferably three or more stages from the upstream side to the downstream side of the steam flow, The rotor blade has five or more stages, and the rotor shaft has a portion corresponding to the stationary blade having a diameter smaller than that of the portion corresponding to the rotor blade implanted portion, and an axial direction of a root portion of the rotor blade implanted portion. The upstream side of the steam flow preferably differs stepwise in four or more stages as compared with the downstream side, and the first stage of the blade is larger than the second stage, the last stage is larger than the other stages, and the first stage and the second stage are different. The stage is widening.

The final-stage steam turbine blade for a low-pressure steam turbine according to the present invention has a weight ratio of C 0.08 to 0.18%,
Si 0.25% or less, Mn 0.90% or less, Cr 8.0-
13.0%, Ni 2-3% or less, Mo 1.5-3.0%,
V 0.05 to 0.35%, the total amount of one or two of Nb and Ta is 0.02 to 0.20%, and N 0.02 to 0.1.
It is preferred to be made of martensitic steel containing 0%.

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

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

The long wing material has a tensile strength of 120 kgf / mm ² or more, preferably 128.5 kgf / mm ² or more.

Further, in order to obtain a homogeneous and high-strength low-pressure steam turbine blade material, after refining and forging,
After heating and holding at 1000 ° C. to 1100 ° C., preferably for 0.5 to 3 hours, quenching is performed by rapidly cooling to room temperature.
2 or more temperings: primary tempering at 1 to 6 hours after heating and cooling to room temperature, preferably 1 to 6 hours, and secondary tempering at 1 to 6 hours at 560 to 590 ° C. Heat treatment is performed.

The length of the last stage blade portion of the low pressure turbine according to the present invention is 864 mm (3 mm) for a 3600 rpm steam turbine.
4 ") or more, preferably 914 mm (36") or more, more preferably 965 mm (38 ") or a final stage blade length of 1041 mm (4") for a 3000 rpm low pressure steam turbine.
1 ") or more, preferably 1092 mm (43") or more, more preferably 1168 mm (46 ") or more, and the value of [wing length (inch) x number of rotations (rpm)] is 12
2,400 or more, preferably 125,000 or more, more preferably 1
2,900 to 15,000.

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

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

(1) Components of long blade material for low-pressure steam turbine In the present invention, C0.
25% or less, Mn 0.90% or less, Cr 8.0 to 13.0%,
Ni 2-3%, Mo 1.5-3.0%, V 0.05-0.35
%, The total amount of one or two of Nb and Ta is 0.02 to
It is preferable to consist of a martensitic steel containing 0.20% and 0.02 to 0.10% of N.

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

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

The tensile strength of the long wing material is 120 kgf / mm ² or more, preferably 128.5 kgf / mm ² or more.

Further, in order to obtain a homogeneous and high-strength steam turbine long blade material, 10 hours after melting and forging as a tempering heat treatment.
00 ° C to 1100 ° C (preferably 1000 to 1055
C.) for 0.5 to 3 hours, and then quenched by quenching to room temperature (especially oil quenching is preferred), followed by tempering at 550 to 620 ° C., especially 550 to 570 ° C.
C. for 1 to 6 hours, followed by primary tempering to cool to room temperature and 560 to 590.degree. C., preferably 1 to 6 hours.
It is preferable to perform two or more tempering heat treatments of a secondary tempering of cooling to room temperature after heating and holding for a time. The secondary tempering temperature is preferably higher than the primary tempering temperature.
Preferably, the temperature is increased by 0 to 30 ° C, more preferably by 15 to 20 ° C.

The present invention relates to a low pressure turbine last stage blade having a length of 3600 rpm for 60 cycle power generation and a 5600 rpm steam turbine.
For a 3000rpm steam turbine for zero cycle power generation,
As described above [wing length (inch) x number of rotations (rpm)]
Those having a value of 120,000 or more are preferred.

Further, in the blade material made of the heat-resistant steel of the present invention, in order to obtain high strength, low-temperature toughness and fatigue strength by adjusting the alloy composition so as to have a whole martensite structure, the following elements are contained. It is preferable to adjust the Cr equivalent, calculated as the amount by weight, to 4 to 10.

Cr equivalent = Cr + 6Si + 4Mo + 1.5
W + 11V + 5Nb-40C-30N-30B-2Mn
-4Ni-2Co + 2.5TaC is preferably not less than 0.08% in order to obtain a high tensile strength, and if too much C is used, the toughness is reduced. In particular, 0.10 to 0.18% is preferable. More preferably, it is 0.12 to 0.16%.

Si is a deoxidizing agent, and Mn is a desulfurizing / deoxidizing agent added during melting of steel, and is effective even in a small amount. Si is a δ-ferrite forming element, and if added in a large amount, causes harmful δ-ferrite formation which deteriorates fatigue and toughness, so is preferably not more than 0.25%. In addition,
According to the carbon vacuum deoxidation method, the electroslag melting method, or the like, there is no need to add Si, and it is preferable to add no Si. In particular, it is preferably 0.10% or less, more preferably 0.05% or less.

The addition of a small amount of Mn improves the toughness, but the addition of a large amount lowers the toughness.
In particular, since Mn is effective as a deoxidizing agent, it is preferably at most 0.4%, more preferably at most 0.2%, from the viewpoint of improving toughness.

Although Cr enhances the corrosion resistance and tensile strength,
% Or more causes formation of a δ ferrite structure.
If it is less than 8%, the corrosion resistance and tensile strength are insufficient, so that C
r is preferably 8 to 13%. Especially 10.5 from the point of strength
~ 12.5% is more preferable.

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

V and Nb precipitate carbides to increase tensile strength and also have an effect of improving toughness. V 0.05%, Nb
If the content is less than 0.02%, the effect is insufficient.
%, Nb 0.2% or less is preferable from the viewpoint of suppressing the formation of δ ferrite. In particular, V is 0.15 to 0.30%, more preferably 0.25 to
0.30%, Nb is 0.04 ~ 0.15%, more than 0.06 ~
0.12% is preferred. Ta can be added in exactly the same manner as in place of Nb, and can be added in combination.

Ni enhances low-temperature toughness and has an effect of preventing the formation of δ ferrite. This effect is insufficient when Ni is 2% or less, and the effect is saturated when added over 3%. In particular, it is preferably 2.3 to 2.9%. More preferably 2.4
~ 2.8%.

N is effective in improving tensile strength and preventing the formation of δ-ferrite, but if it is less than 0.02%, its effect is not sufficient, and if it exceeds 0.1%, toughness is reduced. In particular, excellent characteristics can be obtained in the range of 0.04 to 0.08%, and more preferably 0.06 to 0.08%. Reduction of Si, P and S
It 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. Si from the viewpoint of improving low-temperature toughness
0.1% or less, P 0.015% or less, S0.015% or less are preferable. In particular, Si 0.05% or less, P0.010
% Or less, and S0.010% or less. The reduction of Sb, Sn and As also has the effect of increasing the low-temperature toughness, and it is desirable to reduce it as much as possible. However, from the viewpoint of the current steelmaking technology level, Sb 0.0015% or less, Sn 0.01% or less, and As 0.02%. Limited to the following. In particular, Sb 0.001% or less, Sn 0.005% and As 0.01% or less are desirable.

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

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

It is preferable that an erosion prevention layer made of a Co-based alloy is provided on the leading edge etching portion of the last stage blade. As a specific wing length, 33.
5 ", 40", 46.5 ", 50" etc. can be used. Co-based alloy is Cr 25-30% by weight, W
It is preferable to provide a plate material having 1.5 to 7.0% and C having a value of 0.5 to 1.5% by welding.

(2) High- and medium-pressure or high- and medium-pressure integrated rotor shafts, moving blades, stationary blades, internal casing fastening bolts, and a middle pressure part first stage diaphragm of the 620 to 660 ° C. steam turbine of the present invention. The composition of the site-based heat-resistant steel will be described.

C is an element indispensable for securing quenchability, precipitating carbides during tempering heat treatment and increasing high-temperature strength, and 0.05% for obtaining high tensile strength.
The above elements are necessary. If the content exceeds 0.20%, the metal structure becomes unstable when exposed to a high temperature for a long time, and the creep rupture strength is reduced for a long time.
Is preferred. It is desirably 0.08 to 0.13%, and particularly preferably 0.09 to 0.12%.

Mn is added for a deoxidizing agent and the like, and its effect can be achieved by adding a small amount, and adding a large amount exceeding 1.5% is not preferable because it reduces the creep rupture strength. Especially 0.03 to 0.20% or 0.3 to 0.7%
Is preferable, and 0.35 to 0.65% is more preferable for the larger one. Higher strength is obtained at 620 ° C. or higher when Mn is smaller. In addition, the higher the Mn content, the better the workability of less than 620 ° C. is selected.

Although Si is also added as a deoxidizing agent, according to steelmaking techniques such as vacuum C deoxidizing method, Si deoxidizing is unnecessary. By lowering Si, there is an effect of preventing formation of a harmful δ ferrite structure and preventing a decrease in toughness due to segregation at crystal grain boundaries. Therefore, when adding, 0.1.
It must be suppressed to 15% or less, preferably 0.07%
Or less, and particularly preferably less than 0.04%.

Ni is a very effective element for increasing the toughness and preventing the formation of δ ferrite.
If it is less than 5%, the effect is not sufficient, and if it exceeds 1.0%, the creep rupture strength is lowered, so that it is not preferable. In particular, it is preferably from 0.3 to 0.7%, more preferably from 0.4 to 0.65%.

Cr is an element indispensable for enhancing high-temperature strength and high-temperature oxidation resistance, and requires at least 9%.
If it exceeds, a harmful δ ferrite structure is formed and the high-temperature strength and toughness are reduced, so that the content is preferably 8 to 13%. Particularly, it is preferably 10 to 12%, more preferably 10.8 to 11.8%.

The addition of Mo is performed to improve the high-temperature strength. However, when containing W exceeding 1% as in the steel of the present invention, Mo addition of 1.5% or more lowers toughness and fatigue strength, so that 1.5% or less is preferable. Especially 0.05
-1.0%, more preferably 0.1-0.5%.

W suppresses coarsening and coarsening of carbides at a high temperature and strengthens the solid solution of the matrix, so that it has an effect of remarkably increasing the high-temperature long-time strength of 620 ° C. or more. 620
1 to 1.5% at ℃, 1.6 to 2.0% at 630 ° C, 6
2.1-2.5% at 40 ° C, 2.6-3.0 at 650 ° C
% At 660 ° C. is preferably 3.1 to 3.5%.
On the other hand, if W exceeds 3.5%, δ ferrite is formed and the toughness is lowered, so the content is limited to 1 to 3.5%. In particular, 2.4-3.0% is preferable, and 2.5-2.7% is more preferable.

V has the effect of increasing the creep rupture strength by precipitating carbonitrides of V, but if it is less than 0.05%, the effect is insufficient, and if it exceeds 0.35%, δ ferrite is formed and the fatigue strength is increased. Lower. In particular, 0.10 to 0.25% is preferable, and 0.15 to 0.23% is more preferable.

Nb and Ta are elements that are very effective in precipitating NbC and TaC carbides and increasing the high-temperature strength. However, if they are added in a large amount, especially in large ingots, coarse eutectic NbC or TaC carbides are used. , Which causes precipitation of δ-ferrite, which lowers the strength and lowers the fatigue strength, and is therefore preferably not more than 0.20%. If the content of Nb or Ta is less than 0.01%, the effect is insufficient. In particular, 0.02 to 0.15%, preferably 0.04 to 0.10%, alone or in combination.

Co is an important element that distinguishes the present invention from the prior art. In the present invention, the high temperature strength is remarkably improved by the addition of Co, and the toughness is also increased. This is thought to be due to the interaction with W,
Is a characteristic phenomenon in the alloy of the present invention containing 1% or more. In order to realize such an effect of Co, the content of Co in the alloy of the present invention is preferably 2.0% or more. However, not only an excessive addition does not provide a larger effect, but also a decrease in ductility. 10% or less is preferable. Preferably 6
No addition below 10 ° C, 2 for 610-620 ° C
~ 3%, exceeding 620 ° C and 3.5-4.5 for 630 ° C.
5%, more than 630 ° C, 5-6% for 640 ° C, 6%
6.5-7.5%, 65 ° C over 40 ° C
When the temperature exceeds 0 ° C. and 660 ° C., 8 to 10% is desirable.

N is also an important element that distinguishes the present invention from the prior art. N is effective in improving the creep rupture strength and preventing the formation of the δ ferrite structure, but is effective at 0.0.
If the content is less than 1% or more than 0.1%, the effect is not sufficient, and if it exceeds 0.06%, the toughness is reduced and the creep rupture strength is also reduced. Therefore, the content is preferably 0.06% or less. In particular, 0.01 to 0.03% is more preferably 0.0%.
15-0.025% is preferred.

[0105] 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 0.0005% Is effective, but if it exceeds 0.03%, the weldability and forgeability are impaired, so 0.0005 to 0.03% is preferable.
Desirably 0.001 to 0.01%, or 0.01 to 0.02
% Is preferred.

The addition of Ti and Zr has the effect of increasing toughness, and a sufficient effect can be obtained by adding Ti 0.1% or less and Zr 0.1% or less singly or in combination.

In the present invention, at least the first stage of the rotor shaft and the moving blade and the stationary blade has a C of 0.09 to 0.20% and a Si of 0.15% or less for a steam temperature of 610 to 630 ° C.
Mn 0.05-1.0%, Cr 9.5-12.5%, Ni
0.1 to 1.0%, V 0.05 to 0.30%, N 0.01 to
0.06%, Nb and Ta alone or in combination of 0.01 to
0.20%, Mo 0.05-1.0%, W 2.0-3.5%,
Co 2.0-4.5%, B 0.001-0.030%, 77
It is preferable to use a steel having a fully tempered martensite structure having Fe of at least%. Also, 63
For a steam temperature of 5 to 660 ° C., the aforementioned Co amount is 5 to
It is preferably 9%, and is preferably constituted by steel having a fully tempered martensite structure having 78% or more of Fe. In particular, the Mn content is set to 0.03 to 0.2 with respect to both temperatures.
% And B content as small as 0.001 to 0.01% provide high strength. In particular, C 0.09 to 0.20
%, Mn 0.1-0.7%, Ni 0.1-1.0%, V0.1.
10 to 0.30%, Nb and Ta alone or in combination of 0.0
1 to 0.20%, N 0.02 to 0.05%, Mo 0.05 to 5%
0.5%, W2-3.5%, Co 3.5-4.5% for 620-630 ° C, 0.001-0.01% for B, and Co5.5 for 630-660 ° C. ~ 9.0%, B
The content is preferably 0.01 to 0.03%.

The blade of the present invention can be used preferably in two or three stages. The stationary blade does not require much strength, but can be used in up to two stages. Although the martensitic steel is used up to the third stage of the rotor blade of the present invention, a Ni-based alloy described later can be similarly used instead.

In the high-pressure and medium-pressure rotor materials of the steam turbine of the present invention, when the δ ferrite structure is mixed, the fatigue strength and the toughness are reduced, so that the structure is preferably a uniform tempered martensite structure. In order to obtain a tempered martensite structure, the Cr equivalent calculated by the above formula is preferably 4 to 10.5, and more preferably 10 or less, by adjusting the components. Cr
If the equivalent weight is too low, the creep rupture strength decreases, so that 4 or more is preferable. In particular, the Cr equivalent is 5 to 5.
6.5 to 8 are preferred from 9.5.

In the rotor of the present invention, an alloy material having a target composition is melted in an electric furnace, carbon is deoxidized in a vacuum, cast into a mold, and forged to produce an electrode rod. This electrode rod is redissolved in electroslag, and forged into a rotor shape and molded. This forging must be performed at a temperature of 1150 ° C. or less in order to prevent forging cracks. Further, the forged steel can be used in steam at 620 ° C. or higher by performing a quenching process of heating to 1000 ° C. to 1100 ° C. and quenching twice in the order of 550 ° C. to 650 ° C. and 670 ° C. to 770 ° C. after annealing heat treatment. A steam turbine rotor can be manufactured.

The blades, nozzles, inner casing fastening bolts, and first-stage diaphragm of the intermediate pressure section according to the present invention are melted by vacuum melting and cast in a mold under vacuum to produce an ingot. The ingot is hot forged into a predetermined shape at the same temperature as described above, heated at 1050 to 1150 ° C, water-cooled or oil-quenched, then tempered at 700 to 800 ° C, and cut into a blade having a desired shape. 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 blades and nozzles in the high-pressure section and the medium-pressure section, but is particularly necessary in the first step of both.

(3) In the present invention, the composition constituting the high pressure and medium pressure or high / medium pressure integrated rotor shaft of the steam turbine at 600 to less than 620 ° C. (preferably less than 610 to 620 ° C.) is preferably as follows.

C is 0.05% for obtaining high tensile strength.
These elements are necessary, but if the amount exceeds 0.25%, the structure becomes unstable when exposed to a high temperature for a long time, and the creep rupture strength is lowered for a long time.
It is limited to 0.25%. In particular, 0.1 to 0.2% is preferable.

Nb and Ta are very effective elements for increasing the high-temperature strength. However, if they are added in a large amount, especially in a large steel ingot, a large precipitation of Nb or Ta carbide occurs,
In addition, the C concentration in the matrix is lowered, and the strength is lowered, and the δ ferrite, which lowers the fatigue strength, is disadvantageously precipitated. Further, if the content of Nb and Ta is less than 0.02%, the effect is insufficient. In particular, 0.07 to 0.12 alone or in combination.
% Is preferred.

N is effective for improving the creep rupture strength and preventing the formation of δ ferrite. However, if it is less than 0.025%, the effect is not sufficient, and if it exceeds 0.1%, the toughness is remarkably reduced. In particular, 0.04 to 0.07% is preferable.

Although Cr improves the high-temperature strength, if it exceeds 13%, it causes the formation of δ ferrite, and if it is less than 8%, the corrosion resistance to high-temperature and high-pressure steam becomes insufficient.
In particular, 10 to 11.5% is preferable.

V has the effect of increasing the creep rupture strength, but if it is less than 0.02%, the effect is insufficient, and 0.5% is insufficient.
If it exceeds, ferrite is formed and the fatigue strength is reduced. In particular, 0.1 to 0.3% is preferable.

Mo improves creep strength by solid solution strengthening and precipitation hardening, but when it exceeds 2%, δ ferrite is formed, and toughness and creep rupture strength are reduced.
In particular, preferably 0.1 to 1.5%, more preferably 0.75 to 1.5%.
% Is preferred.

Ni is a very effective element for increasing toughness at 0.05% or more and preventing the formation of δ ferrite, but when it exceeds 1.5%, the addition lowers the creep rupture strength. Is not preferred. In particular, 0.4
~ 1% is preferred.

Mn is added as a deoxidizing agent.
The effect is achieved with a small addition, and a large addition exceeding 1.5% lowers the creep rupture strength. In particular, 0.5
~ 1% is preferred.

Although Si is also added as a deoxidizing agent, according to a steelmaking technique such as vacuum C deoxidizing method, Si deoxidizing is unnecessary. Also, lowering the Si content is effective in preventing the precipitation of δ ferrite and improving the toughness.
% Or less is preferable. When added, in particular, 0.25
% Is preferred.

[0122] A small amount of W significantly increases high-temperature strength. 0.
If it is less than 1%, the effect is small, and if it exceeds 0.65%, the strength rapidly decreases. W is preferably 0.1 to 0.65%. On the other hand, if W exceeds 0.65%, the toughness is remarkably reduced. Therefore, it is preferable that W is less than 0.5% for a member requiring toughness. In particular, 0.2 to 0.45% is preferable.

Al is an element effective as a deoxidizing agent.
It is preferably at most 2%. Al content exceeding 0.02% lowers the high temperature strength.

The high-pressure, medium-pressure or high-medium-pressure integrated steam turbine rotor shaft according to the present invention is a 12% Cr-based alloy steel having better weldability in the journal portion and the low-temperature region than the body portion, and the body portion has a higher strength than the journal portion. It is preferable to integrally form a 12% Cr-based alloy steel having a high hardness. In particular, in the rotor shaft for an ultra supercritical pressure turbine, the journal portion and the low-temperature portion have no B added or 0.003% in the above-described composition.
The following are preferable, and in particular, C 0.05 to 0.20% by weight ratio
, Preferably 0.06 to 0.14%, Si 0.6% or less,
Preferably 0.5% or less, Mn 2% or less, Cr 8-13
%, Ni 0.2 to 2.0%, preferably 0.2 to 1.0%
%, V 0.05 to 0.35%, Nb and Ta alone or in combination 0.01 to 0.20%, N 0.005 to 0.05%,
Mo 1.5% or less, W 0.1 to 4.0%, preferably 1.
0 to 3.0%, no B added or 0.003% or less and Co1
A martensitic steel containing 0% or less, preferably 5% or less is preferable, and a body portion has a weight ratio of C 0.05 to 0.20%, preferably 0.06 to 0.14%, and Si 0.6% or less, preferably. Is 0.15% or less, Mn 1.5% or less, preferably
0.03 to 1.5%, Cr 8 to 13%, Ni 0.05 to 1.
0%, V 0.05 to 0.35%, Nb and Ta alone or in combination 0.01 to 0.20%, N 0.005 to 0.1%, preferably 0.005 to 0.06%, Mo0 .05 to 1.5
%, W 0.1 to 4.0%, preferably 1.0 to 3.5%, B
A martensitic steel containing 0.0005-0.03% and 10% or less of Co, preferably 2-10% is preferable, and is preferably made of a 12% Cr-based alloy steel having higher high-temperature strength than the journal portion.

The rotor shaft for an ultra-supercritical pressure turbine according to the present invention is characterized in that the journal has higher weldability than the body.
Two or more consumable electrodes of alloy steel whose body is higher in hot strength than the journal part are separately prepared, and the consumable electrode corresponding to the former journal part is first electroslag-melted to obtain a desired length. As soon as the latter, the consumable electrode corresponding to the body portion is electroslag-melted and joined, and then the consumable electrode corresponding to the former journal portion is electroslag-melted, added again and joined together.

Further, in the rotor shaft for an ultra-supercritical turbine according to the present invention, the journal portion and the low-temperature region are made of alloy steel (upper and lower ends) having good weldability, and the body (center) is made of an alloy having high high-temperature strength. Prepare an integrated consumable electrode made of steel,
The consumable electrode can also be manufactured by electroslag melting.

(4) The steam turbine rotor shaft made of 12% by weight Cr-based martensite steel in the present invention has a build-up weld layer of a Cr-Mo low alloy steel having high bearing characteristics on the surface of the base material forming the journal portion. It is preferable to form, preferably 3 to 10 layers of the overlay welding layer is formed using a welding material, and the Cr content of the welding material from the first layer to any of the second to fourth layers is reduced. While decreasing sequentially,
The fourth and subsequent layers are welded using a welding material made of steel having the same amount of Cr, and the welding material Cr used for the first layer is welded.
The amount is about 2 to 6% by weight less than the amount of Cr in the base material,
The Cr content of the fourth and subsequent welding layers is set to 0.5 to 3% by weight (preferably 1 to 2.5% by weight).

In the present invention, build-up welding is preferred for improving the bearing characteristics of the journal portion because it is the safest. Further, a sleeve made of a low alloy steel having a Cr content of 1 to 3% may be formed by shrink fitting or fitting.

In order to increase the number of weld layers and gradually reduce the Cr content, three or more layers are preferable, and even more than ten layers cannot be obtained. As an example, about 18 in the final finish
mm thickness is required. In order to form such a thickness, at least five build-up weld layers are preferable even if the final finishing allowance by cutting is excluded. The third and subsequent layers preferably have a tempered martensite structure mainly and have carbides precipitated. In particular, the weight of the composition of the fourth and subsequent welding layers is C
0.01-0.1%, Si 0.3-1%, Mn 0.3-1.5
%, 0.5 to 3% of Cr, and 0.1 to 1.5% of Mo.

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

In the case of a heat-resistant ferritic cast steel casing material, particularly, by adjusting the Ni / W ratio to 0.25 to 0.75, the super-supercritical turbine high-pressure and medium-pressure internal casing of 621 ° C. and 250 kgf / cm ² or more are used. 625 ° C, required for main steam stop valve and control valve casing
A heat-resistant cast steel casing material having a 10 ⁵ h creep rupture strength of 9 kgf / mm ² or more and a shock absorption energy at room temperature of 1 kgf-m or more can be obtained.

In the heat-resistant ferritic 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 set to 4 to 4.
It is preferable to adjust the components to 10.

In the 12Cr heat resistant steel of the present invention, 62
625 ° C, 10 ⁵
h The creep rupture strength must be 9 kgf / mm ² or more, and the impact absorption energy at room temperature must be 1 kgf-m or more. Furthermore,
To ensure higher reliability, 625 ° C., 10 ⁵
h The creep rupture strength is preferably 10 kgf / mm ² or more, and the impact absorption energy at room temperature is 2 kgf-m or more.

C is 0.06% to obtain high tensile strength.
The above elements are necessary. However, if the content exceeds 0.16%, the metal structure becomes unstable when exposed to a high temperature for a long time, and the creep rupture strength is reduced for a long time.
%. In particular, 0.09 to 0.14% is preferable.

N is effective in improving the creep rupture strength and preventing the formation of a δ ferrite structure. However, if it is less than 0.01%, the effect is not sufficient, and if it exceeds 0.1%, there is no remarkable effect. Conversely, it reduces toughness and creep rupture strength. In particular, 0.02 to 0.06% is preferable.

Mn is added as a deoxidizing agent.
The effect can be achieved with a small amount of addition, and a large amount exceeding 1% lowers the creep rupture strength, especially from 0.4 to 0.7.
% Is preferred.

Although Si is also added as a deoxidizing agent, according to steelmaking techniques such as vacuum C deoxidizing method, Si deoxidizing is not required. Also, lowering Si has an effect of preventing formation of a harmful δ ferrite structure. Therefore, when it is added, it must be suppressed to 0.5% or less, especially 0.5%.
1-0.4% is preferred.

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, ferrite is formed and the fatigue strength is reduced. In particular, 0.15 to 0.25% is preferable.

Nb is a very effective element for increasing the high-temperature strength. However, if it is added in an excessively large amount, coarse eutectic Nb carbides are generated, especially in large ingots. Must be suppressed to 0.15% or less because it causes δ ferrite to precipitate.
Further, if Nb is less than 0.01%, the effect is insufficient. Especially in the case of large steel ingots, 0.02 to 0.1% is more preferable.
~ 0.08 is preferred. Ni is a very effective element for increasing the toughness and preventing the formation of δ ferrite, but the effect is insufficient when the content is less than 0.2%, and the creep rupture strength is increased when the content exceeds 1.0%. Is not preferred. Particularly, it is preferably from 0.4 to 0.8%.

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

W has the effect of significantly increasing the high-temperature long-time strength. If W is less than 1%, the effect is insufficient for heat-resistant steel used at 620 to 660 ° C. If W exceeds 4%, the toughness decreases. 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
At 0 ° C, 3.1 to 3.5% is preferred.

W and Ni have a correlation with each other, and Ni /
By setting the W ratio to 0.25 to 0.75, high strength and toughness can be obtained.

The addition of Mo is performed to improve the high-temperature strength. However, when the content of W exceeds 1% as in the cast steel of the present invention, the addition of Mo of 1.5% or more lowers the toughness and the fatigue strength. 0.
8%, more preferably 0.55 to 0.70%.

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

In the heat-resistant cast steel casing material of the present invention, when the δ ferrite structure is mixed, the fatigue strength and the toughness are reduced. Therefore, the structure is preferably a uniform tempered martensite structure. In order to obtain a tempered martensite structure, the Cr equivalent calculated by the above equation must be reduced to 10 or less by adjusting the components. If the Cr equivalent is too low, the creep rupture strength decreases, so it must be 4 or more. Particularly, a Cr equivalent of 6 to 9 is preferable.

The addition of B significantly increases the high temperature (620 ° C. or higher) creep rupture strength. 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 0.0028%, preferably 0.0005 to 0.0025%, more preferably 0.001 to 0.002%.

Since the casing covers high-pressure steam of 620 ° C. or higher, high stress due to internal pressure acts. Therefore, from the viewpoint of preventing creep rupture, a creep rupture strength of 10 ⁵ h of 10 kgf / mm ² or more is required. In addition, at the time of startup, thermal stress acts when the metal temperature is low, so that 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 ° C, 2.5-3.5% for 630 ° C, 4-5% for 640 ° C,
It is preferably 5.5-6.5% for 650 ° C and 7-8% for 660 ° C. At 600 to 620 ° C, it may not be added.

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

Further, the above cast steel is heated at 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 performing tempering twice in the order of 550 to 750 ° C and 670 to 770 ° C. Casing can be manufactured. If the annealing and normalizing temperatures are lower than 1000 ° C., the carbonitrides cannot be sufficiently dissolved, and if they are too high, the crystal grains become coarse. In addition, the twice-tempering completely decomposes the retained austenite and can provide a uniform tempered martensite structure. A steam turbine that can be used in steam at 620 ° C. or more can be obtained by producing 625 ° C., 10 ⁵ h creep rupture strength of 10 kgf / mm ² or more and impact absorption energy at room temperature of 1 kgf-m or more by manufacturing by the above method. Can be made into a casing.

If O exceeds 0.015%, the high-temperature strength and toughness decrease, so that it is preferably 0.015% or less, particularly preferably 0.010% or less.

In the present invention, the casing has the above-mentioned Cr equivalent, and the δ ferrite content is preferably 5% or less, more preferably 0%.

It is preferable that the inner casing is made of forged steel except that it is made of cast steel.

(6) The low-pressure steam turbine rotor shaft is C-0.2-0.3%, Si-0.1% or less, Mn-0.1 by weight.
2% or less, Ni 3.2 to 4.0%, Cr 1.25 to 2.2
A low-alloy steel having a total tempered bainite structure of 5%, Mo 0.1 to 0.6%, and V 0.05 to 0.25% is preferable, and is manufactured by the same manufacturing method as the above-described high-pressure and medium-pressure rotor shafts. Is preferred. In particular, the Si content is 0.05
%, Mn 0.1% or less, P, S, As, Sb, S
It is preferable to use a raw material in which impurities such as n are reduced as much as possible and to use a super-clean production using a raw material having a small amount of impurities so as to have a total amount of 0.025% or less. P and S each 0.010% or less, Sn and As 0.00
It is preferably 5% or less and Sb 0.001% or less.

(7) The nozzles other than the last stage of the low pressure turbine blade and the nozzles are C 0.05-0.2%, Si 0.1-0.1%.
5%, Mn 0.2-1.0%, Cr 10-13%, Mo 0.2%
Preference is given to a fully tempered martensitic steel having a content of between 0.4 and 0.2%.

(8) Both the inner and outer casings for the low-pressure turbine have C of 0.2 to 0.3%, Si of 0.3 to 0.7%, M
Carbon cast steel with n1% or less is preferred.

(9) The main steam stop valve casing and the steam control valve casing are C 0.1-0.2%, Si 0.1-0.4.
%, Mn 0.2 to 1.0%, Cr 8.5 to 10.5%, Mo
0.3 to 1.0%, W 1.0 to 3.0%, V 0.1 to 0.3
%, Nb 0.03 to 0.1%, N 0.03 to 0.08%, B
A fully tempered martensitic steel containing 0.0005 to 0.003% is preferred.

(10) As the last stage rotor blade of the low pressure turbine, 1
In addition to 2% Cr steel, a Ti alloy is used. Particularly, for a length exceeding 40 inches, Al 5 to 8% by weight and V 3 to 6
A Ti alloy with% by weight is used. In particular, at 43 inches, Al 5.5-6.5% and V 3.5-4.5%, and at 46 inches Al 4-7%, V 4-7% and Sn.
A high strength material having 1-3% is preferred.

(11) The high pressure turbine, the medium pressure turbine, and the outer casing for the high / medium pressure turbine have C0.10 to 0.20.
%, Si 0.05-0.6%, Mn 0.1-1.0%, Ni
0.1 to 0.5%, Cr 1 to 2.5%, Mo 0.5 to 1.5
%, V0.1-0.35%, preferably Al0.0
25% or less, B 0.0005 to 0.004%, and Ti
Preferably, it is manufactured from cast steel containing at least one of 0.5 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%, C
r 1.0 to 1.5%, Mo 0.9 to 1.2%, V 0.2 to 0.2.
3%, 0.001 to 0.005% Al, 0.045 to Ti
Cast steels containing 0.10% and B 0.0005 to 0.0020% are preferred. More preferably, the Ti / Al ratio is 0.5.
10 to 10.

(12) First-stage blades of high-pressure, medium-pressure, high-medium-pressure turbines (high-pressure side and medium-pressure side) at a steam temperature of 625 to 650 ° C., preferably up to two or three stages on the high-pressure side of the high-pressure turbine and high-medium-pressure turbine On the medium pressure side of the intermediate pressure turbine and the high intermediate pressure turbine, up to the second stage are replaced with the above-mentioned martensitic steel by weight, and are C 0.03 to 0.20% (preferably 0.03 to 0.15%), Cr 12 to 20%, Mo9 ~ 2
0% (preferably 12 to 20%), Co 12% or less (preferably 5 to 12%), Al 0.5 to 1.5%, Ti1 to
3%, Fe 5% or less, Si 0.3% or less, Mn 0.2% or less, B 0.003 to 0.015%, Mg 0.1% or less, rare earth element 0.5% or less, Zr 0.5% or less A Ni-based alloy containing at least one kind can be used. The following includes 0%. After forging, it is subjected to a solution treatment and an aging treatment.

The reasons for the component ranges of the Ni-based precipitation strengthened alloy are as follows.

When C is added in an amount of 0.03% or more, C forms a solid solution or precipitates carbide during use at a high temperature to increase the proof stress and creep strength at a high temperature. Precipitation of carbides is remarkable, lowering the high-temperature tensile drawing ratio. More preferably, the content is 0.03 to 0.15%.

Cr forms a solid solution in the alloy and has a proof stress at high temperatures.
In order to increase the creep strength and further enhance the high-temperature oxidation resistance and the sulfidation corrosion resistance of the alloy, it is preferable to contain the alloy in an amount of 12% or more. However, if it exceeds 20%, a sigma phase is precipitated, and the draw ratio in a high-temperature tensile test is reduced. A more preferred range is 12 to 20%.

Mo, when added in excess of 9%, forms a solid solution with the alloy to significantly increase proof stress at high temperatures and further significantly increase creep rupture strength. However, if it exceeds 20%, on the contrary, the yield strength at high temperatures is sharply reduced, and further, cold workability and sigma phase are precipitated, and the draw ratio at high temperature tensile is reduced. A more preferred range is 12 to 20%.

[0164] Co is added to the alloy in an amount of not more than 12% to form a solid solution in the alloy, thereby significantly increasing the creep rupture strength at room temperature and high temperature.
However, when it exceeds 12%, the high-temperature ductility rapidly decreases and a sigma phase is precipitated, thereby reducing the draw ratio in high-temperature tensile. More preferably, it is 5 to 12%.

When Al is added in an amount of 0.5 to 1.5%, it forms a solid solution in the alloy, and further precipitates a gamma-prime phase during long-time use at a high temperature to increase the proof stress and creep rupture strength at high temperature tensile strength. . However, if it exceeds 1.5%, the draw ratio in high-temperature tension is reduced. A more preferred range is 0.5 to 1.2%.

When 1% to 3% of Ti is added, it forms a solid solution in the alloy and precipitates a gamma-prime phase during long-time use at a high temperature to increase the proof stress and creep rupture strength at high temperature tensile strength. However, if the content of Ti exceeds 3%, the draw ratio in high-temperature tension is reduced.

Since Fe lowers the creep rupture strength, its content should be avoided as much as possible. Even when it is contained as an impurity, it is preferably at most 5%.

Si and Mn are used as a deoxidizing agent or for improving hot workability, respectively, in an amount of 0.3% or less and 0.2% or less,
In any case, no addition is most preferable.

B is an element that segregates at an austenite crystal grain boundary in a very small amount and improves the creep rupture strength and high-temperature ductility. The effect can be obtained at 0.003% or more.
If it exceeds 5%, the hot plastic workability is lowered and the high-temperature ductility is lowered. Therefore, 0.003 to 0.015% is preferable.

Mg and rare earth elements segregate at the austenite grain boundaries of the alloy and increase the creep rupture strength. Further, Zr is a strong carbide-forming element, and increases the creep rupture strength by synergistic action together with the formation of other carbides such as Ti when added in a small amount. However, if these elements are added excessively, the ductility at high temperatures is reduced, such as reducing the bonding strength of the grain boundaries and forming coarse carbides, so that Mg is less than 0.1%, rare earth element is less than 0.5% and Zr is less than 0.5%. 5% or less, especially Mg 0.005 to 0.05
%, Rare earth element 0.005 to 0.1% and Zr 0.01 to
It is preferred to add 0.2%.

The alloy according to the present invention is subjected to an aging treatment after the solution treatment.

The solution treatment is carried out at 1050 to 1200 ° C. for 3 hours.
It is preferable to perform water cooling or air cooling after holding for 0 minutes to 10 hours, or to perform water cooling by pouring the alloy into water at a predetermined temperature or, in the case of a plate, spraying water on the alloy surface at a predetermined temperature. .

The aging treatment is performed after the solution treatment described above.
It is preferable to carry out by heating and holding at 870 ° C. for 4 to 24 hours.

The alloy according to the present invention is preferably dissolved in a non-oxidizing atmosphere. Since the raw material used for the alloy according to the present invention uses a pure metal, it is heated up to just before melting down in a vacuum, and then the non-oxidizing gas is sealed and dissolved to improve the yield of the alloy element and improve the composition. It is preferable from the viewpoint of eliminating the variation of.

Further, the material thus melted can be obtained by vacuum arc remelting or electroslag remelting.

The Ni-based precipitation strengthened alloy of the present invention has a tensile strength at room temperature of 90 kg / mm ² or more, preferably 100 kg / mm ^2.
mm ² or more, the tensile strength at 732 ° C. is preferably 80 kg / mm ² or more, and the elongation is preferably 10% or more.

[0177]

BEST MODE FOR CARRYING OUT THE INVENTION

[Example 1] In response to a rise in fuel after an oil shock, a steam temperature of 60 to improve thermal efficiency by improving steam conditions was used.
0 ° C to 649 ° C pulverized coal direct combustion boiler and steam turbine are required. Table 1 shows an example of a boiler under such steam conditions.

[0178]

[Table 1]

With the increase in capacity, the furnace for pulverized coal combustion became larger, and the furnace width was 31 m and the furnace depth was 16 at 1050 MW class.
m, 1400MW class, furnace width 34m, furnace depth 18m
Becomes

Table 2 shows the main specifications of the steam turbine at 625 ° C. and 1050 MW. In this embodiment, the blade length of the last stage rotor blade in the cross-compound type four-flow exhaust low-pressure turbine is 43 inches, and A is HP-IP and L
3000 r / min with P2 units, B is HP-LP and IP-
Each of the LPs has the same rotation speed of 3000 r / min, and is constituted by the main materials shown in the table in the high temperature part.
The steam temperature of the high pressure section (HP) is 625 ° C, 250kgf / cm
² , and the steam temperature of the medium pressure part (IP) is 625 ° C.
And operated at a pressure of 45 to 65 kgf / cm ² . The low-pressure part (LP) has a steam temperature of 400 ° C
And sent to a condenser at a temperature of 100 ° C. or less and a vacuum of 722 mmHg.

In this embodiment, the distance between the bearings of the high-pressure turbine and the intermediate-pressure turbine connected in tandem and the distance between the bearings of the two low-pressure turbines connected in tandem with respect to the blade length of the last stage rotor blade of the low-pressure turbine are described. Total is about 3
It is 1.5m, the ratio is 28.8, and it is compact.

In addition, the distance between the bearings in which the high-pressure turbine and the intermediate-pressure turbine are connected in tandem with respect to the rated output (MW) of the steam turbine power plant in this embodiment, and the distance between the bearings of the two low-pressure turbines connected in tandem. The ratio of the total distance (mm) of the distances is 30.

[0183]

[Table 2]

FIG. 1 is a cross-sectional view of the high-pressure and medium-pressure steam turbines in turbine configuration A in Table 2. The high-pressure steam turbine is provided with a high-pressure axle (high-pressure rotor shaft) 23 in which high-pressure moving blades 16 are implanted in a high-pressure inner casing 18 and a high-pressure outer casing 19 outside thereof. The aforementioned high-temperature and high-pressure steam is obtained by the aforementioned 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 double-flow blade. I will The first stage has a double flow, and eight stages are provided on one side.
A stationary blade is provided for each of these moving blades. The moving blade is a saddle type dove-til type, double tinon, first stage blade length about 35
mm. The distance between the axles is about 5.8m and the diameter of the smallest part corresponding to the stationary blade part is about 710mm,
The ratio of length to diameter is about 8.2.

The width of the rotor blade implanted portions at the first stage and the last stage of the rotor shaft are almost equal, and the width of the rotor shaft is stepwise in five stages of the second stage, the third to fifth stages, the sixth stage, and the seventh to eighth stages. The axial width of the second stage implant is 0.71 times as large as that of the last 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 rotor blade implantation portion. The axial width of that part is gradually reduced to the width between the final stage rotor blade and the rotor blade in front of it between the second stage rotor blade and the third stage rotor blade. The width of the latter is 0.86 times smaller than the width of the former. 2nd stage ~
The size is reduced in two stages, up to the sixth stage and the sixth to ninth stages.

In this embodiment, the materials shown in Table 3 to be described later are used for the first stage blade and the first stage nozzle, and the other blades and nozzles do not contain W, Co and B.
% Cr-based steel. 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. The length is 65 to 180 mm, the number of stages is 9 to 12, and the length of the wing of each stage is 1.
The length is increased at a rate of 10 to 1.15, and the rate is gradually increased on the downstream side.

The high-pressure turbine in this embodiment has a distance between bearings of about 5.3 m, and the ratio of the distance between the bearings to the blade length of the last stage rotor blade of the low-pressure turbine is 4.8. The ratio of the distance (mm) between bearings of the high-pressure turbine to the rated output (MW) of the power plant is 5.0.

The medium-pressure steam turbine rotates the generator discharged from the high-pressure steam turbine together with the high-pressure steam turbine by the steam heated by the reheater to 625 ° C. at a speed of 3000 rpm. Rotated. The medium pressure turbine has a medium pressure inner second casing 21 and a medium pressure outer casing 22 similarly to the high pressure turbine.
7 is provided with a stationary vane. The moving blades 17 have two flows in six stages, and are provided on the left and right substantially symmetrically with respect to the longitudinal direction of the medium pressure axle (medium pressure rotor shaft). The distance between the bearing centers is about 5.8 m, the length of the first stage blade is about 100 mm, and the length of the last stage blade 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 last stage rotor blade is about 630 mm, and the ratio of the distance between bearings to the diameter is about 9.2 times.

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

The rotor shaft of the present steam turbine has a smaller diameter at a portion corresponding to the stationary blade portion, and the width thereof is stepwise in four stages according to the first stage blade, the second to third stages and the last stage blade side. The width of the latter in the axial direction with respect to the former is reduced to about 0.75 times.

In this embodiment, a 12% Cr steel containing no W, Co and B is used except that the materials shown in Table 5 described later are used for the first stage blade and the nozzle. The length of the blade portion of the moving blade in this embodiment is longer at each stage as it goes 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.
In the nine stages, the length of the wing portion of each stage is longer at a ratio of 1.1 to 1.2 as the length on the downstream side is adjacent to the upstream side.

The implanted portion of the moving blade has a diameter larger than that of the portion corresponding to the stationary blade, and the implant width 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 0.1 in the first stage to the last stage.
35 to 0.8, and gradually decreases from the first stage to the last stage.

The intermediate pressure turbine in this embodiment has a distance between bearings of about 5.5 m, and the ratio of the distance between the bearings of the intermediate pressure turbine to the blade length of the last stage rotor blade of the low pressure turbine is as follows.
The ratio of the distance between bearings (mm) to the rated output (MW) of the power plant is 5.2.

FIG. 2 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 sides and is substantially symmetrical on the left and right sides, and stationary blades 42 are provided corresponding to the moving blades. The blade length of the last stage is 43 inches.
No. 7 12% Cr steel is used, has a double tinon and saddle type dovetail shown in FIG.
Is a double-flow type. The rotor shaft 44 is made of Ni 3.75.
%, Cr 1.75%, Mo 0.4%, V 0.15%, C 0.
A forged steel having a fully tempered bainite structure of a super clean material consisting of 25%, 0.05% of Si, 0.10% of Mn, and the remaining 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. The inner and outer casing members are made of C25% cast steel. The center-to-center distance of the bearing 43 in this embodiment is 7500 mm, the diameter of the rotor shaft corresponding to the stationary blade portion is about 1280 mm, and the diameter of the rotor blade implantation portion is 2275 mm. The distance between the bearing centers for this rotor shaft diameter is about 5.9.

FIG. 3 is a perspective view of a 1092 mm (43 ″) long wing. Reference numeral 51 denotes a wing portion against which high-speed steam strikes, 52 denotes a wing implantation portion on a rotor shaft, and 53 denotes a wing portion. A hole for inserting a pin for supporting a centrifugal force, an erosion shield 54 for preventing erosion due to water droplets in steam (a Co-based alloy containing 1.0% of C, 28.0% of Cr, and 4.0% of W by weight) In this embodiment, the continuous cover 57 is formed by a cutting process after forging of the whole, and the continuous cover 57 is mechanically integrated. Can also be formed.

The 43 ″ long blade was prepared by melting and electroforging and performing forging heat and processing by electroslag remelting. Forging was performed within a temperature range of 850 to 1150 ° C., and heat treatment was performed under the conditions described below. No. 7 in Table 7 shows the chemical composition (% by weight) of this long blade material, and the metal structure of this long blade material was a fully tempered martensite structure.

No. 7 in Table 7 shows room temperature tensile and 20 ° C. V notch Charpy impact values. The mechanical properties of this 43 ″ long wing are required characteristics, tensile strength of 128.5 kgf / mm ² or more, 20 ° C. V notch Charpy impact value 4 kgfm / cm ²
Having the above, it was confirmed that they were sufficiently satisfied.

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

The diameter of the portion corresponding to the stationary blade portion is reduced, and the axial width of the portion is gradually increased in the three stages of the fifth, sixth, and seventh stages from the first stage blade side. The width of the last stage is about 2.
It is five times larger.

In this embodiment, there are six stages of moving blades, and the length of the blade portion is longer in each stage as it goes from the initial stage of about 3 ″ to the last stage of 43 ″, and depends on the output of the steam turbine. The length of the step is 80 ~ 1100mm, 8 steps or 9 steps, and the wing length of each step is 1.2 to 1.8 times as long as the downstream side is adjacent to the upstream side. I have.

The implanted portion of the moving blade has a diameter larger than that of the portion corresponding to the stationary blade, and the implant width 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 0.1 in the first stage to the last stage.
15 to 0.91, and gradually decreases from the first stage to the last stage.

Further, the width of the rotor shaft corresponding to each stator vane is gradually increased in each stage from the first stage and the second stage to the last stage and immediately before. The ratio of the width to the blade length of the rotor blade is 0.25 to 1.25, and decreases from upstream to downstream.

In this embodiment, two low pressure turbines are connected in tandem, and the total distance between the bearings is about 18.3 m.
And the ratio of the total distance between the bearings of the two low-pressure turbines connected in tandem to the blade length of the last stage rotor blade of the low-pressure turbine is 16.7, and the rated output of the power plant is 1050 (MW). Tandem bound to 2
The ratio of the sum of the distances (mm) between the bearings of the low-pressure turbine at both ends of the table is 17.4. In addition to the present embodiment, the steam inlet temperatures to the high-pressure steam turbine and the medium-pressure steam turbine are 610 ° C., and the steam inlet temperatures to the two low-pressure steam turbines are 385 ° C.10
The same configuration can be applied to a 00MW class large-capacity power plant.

The high-temperature high-pressure steam turbine plant in this embodiment is mainly composed of a coal-fired boiler, a high-pressure turbine, a medium-pressure turbine, two low-pressure turbines, a condenser, a condensate pump, a low-pressure feedwater heater system, a deaerator, and a booster pump. , Feed water 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,
Condenses in the condenser. This condensate is sent to the low pressure feed water heater system and deaerator by the condensate pump. The feedwater degassed by this deaerator is sent to a high-pressure feedwater heater by a booster pump and a feedwater pump to be heated, and then returned to the boiler.

Here, in the boiler, the water supply passes through a economizer, an evaporator, and a superheater to become high-temperature and high-pressure steam. On the other hand, the boiler combustion gas that heated the steam exited the economizer,
Enter the air heater to heat the air. Here, the feedwater pump is driven by a feedwater pump drive turbine that operates with the extracted steam from the medium pressure turbine.

In the high-temperature and high-pressure steam turbine plant configured as described above, the temperature of the feedwater leaving the high-pressure feedwater heater system is much higher than the feedwater temperature in the conventional thermal power plant. The temperature of the combustion gas exiting the economizer will also be much higher than in conventional boilers. Therefore, heat is recovered from the boiler exhaust gas so as not to lower the gas temperature.

Incidentally, the same high-pressure turbine as in this embodiment,
A medium-pressure turbine and one or two low-pressure turbines may be connected in tandem, and a single generator may be rotated to generate power, and a tandem compound-type power plant 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 to 3.0%, Mo 0.25 to 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,
Particularly, it is preferable that the temperature be -20 ° C 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 be 5% or less and the Ni / Cr ratio be 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 multi-stage side. The medium-pressure turbine shaft has a multi-stage blade provided on the left and right with approximately six stages of symmetrical blade installation portions, and substantially centered on the center. Although the rotor shaft for the low-pressure turbine is not shown, a center hole is provided in any of the rotor shafts of the high-pressure, medium-pressure, and low-pressure turbines, and through this center hole, the presence or absence of a defect is determined by ultrasonic inspection, visual inspection, and fluorescence inspection. Is inspected. Further, the inspection can be performed by ultrasonic inspection from the outer surface, and the center hole may not be provided.

Table 3 shows the chemical compositions (% by weight) used for the main parts of the high-pressure turbine, medium-pressure turbine and low-pressure turbine of this embodiment. In this embodiment, since the high-temperature portion of the high-pressure portion and the intermediate-pressure portion are all made to have a thermal expansion coefficient of about 12 × 10 ⁻⁶ / ° C. having a ferrite crystal structure, there is no problem due to the difference in the thermal expansion coefficient. Did not.

The rotor shafts of the high-pressure turbine and the intermediate-pressure turbine were prepared by melting 30 tons of the heat-resistant cast steel shown in Table 3 in an electric furnace, deoxidizing carbon in a vacuum, casting it in a mold, forging and drawing to produce an electrode rod. Then, the electroslag was melted again as the electrode rod so as to melt from the upper part to the lower part of the cast steel, and forged into a rotor shape (diameter 1050 mm, length 3700 mm) and formed. This forging is carried out at 1150 to prevent forging cracks.
Performed at a temperature of less than or equal to ° C After annealing this forged steel,
Heating to 1050 ° C., water spray cooling quenching, and tempering twice at 570 ° C. and 690 ° C.
This was obtained by cutting into the shape shown in FIG. In the present embodiment, the upper side of the electroslag steel ingot is the first stage blade side, and the lower side is the last stage side. Each rotor shaft has a center hole, and as shown in the third embodiment, the center hole can be eliminated by reducing impurities.

The high-pressure part and the medium-pressure part of the blade and the nozzle were melted in a vacuum arc melting furnace of the heat-resistant steel also shown in Table 3 to form a blade and a nozzle material shape (width 150 mm, height 50 mm, length 1000 mm). Forged and molded. The forging was performed at a temperature of 1150 ° C. or less in order to prevent forging cracks. The forged steel was heated to 1050 ° C., subjected to oil quenching, tempered at 690 ° C., and then cut into a predetermined shape.

The inner casing, the main steam stop valve casing and the steam control valve casing of the high pressure section and the medium pressure section are shown in Table 3.
Was melted in an electric furnace, and after ladle refining, it was cast into a sand mold to produce. By performing sufficient refining and deoxidation before casting, a casting free of casting defects such as shrinkage cavities was obtained. Weldability evaluation using this casing material
The measurement was performed according to IS Z3158. The pre-heating, inter-pass and post-heating onset temperatures were 200 ° C, and the post-heat treatment was 400 ° C x 30 minutes. No weld crack was observed in the material of the present invention, and the weldability was good.

[0214]

[Table 3]

[0215] Table 4 shows the mechanical properties and heat treatment conditions of the main members of the high temperature steam turbine made of ferritic steel described above.

As a result of examining the center of the rotor shaft, it was found that the characteristics (62
5 ° C., 10 ⁵ h strength ≧ 10 kgf / mm ² , 20 ° C. shock absorption energy ≧ 1.5 kgf-m). This demonstrated that a steam turbine rotor usable in steam at 620 ° C. or higher can be manufactured. Also, as a result of investigating the characteristics of this blade, the characteristics (625 ° C., 10
It was confirmed that ⁵ h strength ≧ 15 kgf / mm ² ) was sufficiently satisfied. This demonstrated that a steam turbine blade usable in steam at 620 ° C. or higher can be manufactured.

Further, as a result of investigating the characteristics of this casing, it was found that the characteristics (625 ° C., 10 ⁵ h strength ≧ 10 kgf / mm ² , 20 ° C. shock absorption energy ≧ 1 kgfm) required for the high-pressure and intermediate-pressure turbine casings were sufficient. Satisfaction and weldability were confirmed. Thereby, 620 ° C
It was proved that a steam turbine casing usable in the above steam could be manufactured.

[0218]

[Table 4]

In the present embodiment, a Cr-Mo low alloy steel was build-up welded on the journal portion of the rotor shaft to improve the bearing characteristics. The overlay welding is as follows.

A coated arc welding rod (diameter: 4.0 φ) was used as a test welding rod. Table 5 shows the chemical composition (% by weight) of the deposited metal obtained by welding using the welding rod. The composition of the deposited metal is almost the same as the composition of the welding material.

The welding conditions were as follows: welding current 170 A, voltage 24
V, speed 26 cm / min.

[0222]

[Table 5]

As shown in Table 6, the overlay welding was carried out on the surface of the base metal to be tested by combining the welding rods used for each layer and 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 were preheating, inter-pass, stress relief annealing (SR) start temperature of 250 to 350 ° C., and SR processing conditions of 630 ° C. × 36 hours.

[0225]

[Table 6]

In order to confirm the performance of the welded portion, the plate material was similarly overlaid and subjected to a side bending test of 160 °, but no crack was found in the welded portion.

Further, a bearing sliding test by rotation in the present invention was performed.
It was also excellent in oxidation resistance.

Instead of this embodiment, a tandem type power plant having 3000 revolutions and a high pressure steam turbine, a medium pressure steam turbine and one or two low pressure steam turbines connected in tandem, and turbine configuration B in Table 2 The high-pressure turbine, the intermediate-pressure turbine and the low-pressure turbine of the present embodiment can be similarly combined and configured.

Table 7 shows the chemical composition (% by weight) of 12% Cr steel for the last stage blade material for a low-pressure steam turbine.
Samples No. 1 to No. 6 were each subjected to high-frequency vacuum melting of 150 kg, heated to 1150 ° C. and forged to obtain experimental materials. Sample No. 1 was heated at 1000 ° C. for 1 h, cooled to room temperature by oil quenching, then heated to 570 ° C., held for 2 h, and air-cooled to room temperature. No. 2 was heated at 1050 ° C. for 1 hour, cooled to room temperature by oil quenching, then heated to 570 ° C., kept for 2 hours, and then tempered by air cooling to room temperature. Sample No.
3-No. 7 was heated at 1050 ° C for 1 hour, cooled to room temperature by oil quenching, then heated to 560 ° C, kept for 2 hours, air-cooled to room temperature (primary tempering), further heated to 580 ° C, and kept for 2 hours. The furnace was cooled to room temperature (second tempering).

[0230]

[Table 7]

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

Table 8 shows the mechanical properties of these samples at room temperature. The materials of the present invention (Nos. 3, 4 and 7) have the tensile strength (120 kgf / mm ² or more or 128.5 kgf / mm ² or more) and low temperature toughness (20 ° C.) required as long blade materials for steam turbines.
(V-notch Charpy impact value of 4 kgf-m / cm ² or more) was confirmed to be sufficiently satisfied.

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

[0234]

[Table 8]

FIG. 4 is a diagram showing the relationship between the (Ni-Mo) amount and the tensile strength. In this example, the Ni and Mo contents are contained at the same content to increase both the strength and toughness at a low temperature, and the strength tends to decrease as the difference between the two increases. . When the amount of Ni is less than 0.6% or less than the amount of Mo, the strength is sharply reduced, and conversely, when the amount of Ni is more than 1.0%, the strength is sharply reduced. Therefore, the (Ni-Mo) content of -0.6 to 1.0% indicates high strength.

FIG. 5 is a diagram showing the relationship between the (Ni-Mo) amount and the impact value. As shown in the figure, the impact value of (Ni-Mo) decreases around -0.5%, but shows a high value before and after that.

FIGS. 6 to 9 are diagrams showing the effects of heat treatment conditions (quenching temperature and secondary tempering temperature) on the tensile strength and impact value of Sample No. 3. FIG. Quenching temperature is 975 ~ 112
After tempering at 550-560 ° C. for 1 h at 5 ° C., the secondary tempering temperature is 560-590 ° C. As shown in the figure, the characteristics required for long wing material (tensile strength ≧ 128.5 kgf /
mm ² , 20 ° C Notch Charpy impact value ≧ 4kgfm / c
m ² ) was confirmed to be satisfactory. 6 and 8
Is 575 ° C., and the quenching temperature in FIGS. 7 and 9 is 1050 ° C.

The 12% Cr steel according to the present invention is particularly suitable for C + N
The amount of b is 0.18 to 0.35% and the (Nb / C) ratio is 0.45.
1.00 and (Nb / N) ratio of 0.8 to 3.0 are preferred.

The above-described Ti alloy can be used in place of the 43-inch final stage rotor blade of this embodiment.

Example 2 Table 9 shows the chemical composition (% by weight) of 12% Cr-based steel used in place of the last long blade material for a low-pressure steam turbine of Example 1. Other configurations are exactly the same as those of the first embodiment. Each sample was subjected to vacuum arc melting and 11
It was forged at around 50 ° C.

Table 10 shows the heat treatment of each sample, its mechanical properties at room temperature, and its metal structure. All samples have a fully tempered martensite structure. The average crystal grain size of each sample is 5.5 to 6.0 in grain size number (GSNo.).

[0242]

[Table 9]

[0243]

[Table 10]

FIG. 10 shows the results obtained at 20 ° C.
It is a diagram which shows the relationship between a notch Charpy impact value and tensile strength. As shown in FIG.
It is a high value of not less than 2.5 kgf-m / cm ² , and the impact value (y) is preferably not less than the value obtained by subtracting 0.6 times the tensile strength (x) from 77.2. 80.4
It is more preferable that the value be equal to or more than the value similarly subtracted from, particularly, equal to or more than the value subtracted from 84.0.

FIG. 11 is a graph showing the relationship between 0.2% proof stress and tensile strength. The material according to the invention is in particular 0.2%
It is preferable that the proof stress (y) be equal to or more than a value obtained by adding a value obtained by multiplying the tensile strength (x) by 0.5 to 36.0.

FIG. 12 is a diagram showing the relationship between 0.2% proof stress and 0.02% proof stress. The material according to the present invention is particularly suitable for 0.1.
It is preferable that the 2% proof stress (y) be equal to or greater than a value obtained by adding a value obtained by adding 0.54 times the 0.02% proof stress (x) to 58.4.

Example 3 Table 11 shows that the steam temperature was 600 ° C.
This is the main specification of a 600 MW steam turbine. In this embodiment, a tandem compound double flow type, the last stage blade length in a low pressure turbine is 43 inches, and an HP (high pressure) / IP (medium pressure) integrated type and one LP (C) or two LPs (D) are 3000 r. / Min, and is composed of the main materials shown in the table in the high temperature part. High pressure section
The steam temperature of (HP) is 600 ° C. and a pressure of 250 kgf / cm ² , and the steam temperature of the medium pressure part (IP) is heated to 600 ° C. by a reheater and operated at a pressure of 45 to 65 kgf / cm ^2. You. The low pressure section (LP) enters at a steam temperature of 400 ° C,
It is sent to the condenser at a temperature of 100 ° C. or less and a vacuum of 722 mmHg.

In this embodiment, the steam turbine power plant equipped with the high-medium pressure integrated turbine and the low-pressure turbine in which the high-pressure turbine and the medium-pressure turbine are integrated has a distance between bearings of about 22.3 m. The ratio of the distance between the bearings of the high-to-medium pressure integrated turbine and the distance between the bearings of the two low-pressure turbines connected in tandem to the blade length of the stage rotor blades is 26.2, and the rated output (MW) of the power plant is The ratio of the total distance (mm) of the distance between the bearings of the high- and medium-pressure integrated turbine and the distance between the bearings of the two low-pressure turbines coupled in tandem is 37.1).

Further, in the steam turbine power plant having the high-medium pressure integrated turbine and the low-pressure turbine in which the high-pressure turbine and the medium-pressure turbine are integrated in this embodiment, the distance between the bearings is about 14.5 m, The ratio of the sum of the distance between the bearings of the high and medium pressure integrated turbine and the distance between the bearings of one low pressure turbine to the blade length of the step rotor blade is 1
3.3. In addition, the ratio of the total distance between the bearings of the high and medium pressure integrated turbine and the distance between the bearings of one low pressure turbine to the rated output (MW) of the power plant is 24.2.

[0250]

[Table 11]

FIG. 13 is a sectional view of a high-pressure / intermediate-pressure integrated steam turbine, and FIG. 14 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 having high-pressure moving blades 16 implanted in a high-pressure inner casing 18 and a high-pressure outer casing 19 outside thereof. The aforementioned high-temperature and high-pressure steam is obtained by the aforementioned boiler, passes through a main steam pipe, and forms a flange and an elbow 2 that constitute a main steam inlet.
5 through the main steam inlet 28 and from the nozzle box 38 to the first stage rotor blades. The steam enters from the center of the rotor shaft and flows toward the bearing. The rotor blade has eight stages on the high pressure side on the left side in the figure and six stages on the medium pressure side (about half the right side in the figure).
Steps are provided. A stationary blade is provided for each of these moving blades. The moving blade has a saddle type or a getter type, a dove-til type, a double tinon, a high pressure side first stage blade length of about 40 mm, and a medium pressure side first stage blade length of 100 mm. The length between the bearings 43 is about 6.7 m, and the diameter of the smallest part corresponding to the stationary blade part is about 74.
0 mm and the ratio of length to diameter is about 9.0.

The first stage and the last stage of the rotor blade implanted root portion of the high pressure side rotor shaft have the largest width at the first stage, the second stage to the seventh stage are smaller than that, and 0.40 to 0.56 times the first stage. Are the same size, the last stage is between the first stage and the size of the second to seventh stages, and 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 steel shown in Table 3 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. In particular, the length from the second stage to the final stage is in the range of 50 to 150 mm depending on the output of the steam turbine,
The number of stages is in the range of 7 to 12 stages, and the length of the wing portion of each stage is 1.05 to 1.3 as the length that the downstream side is adjacent to the upstream side.
The ratio is longer within the range of 5 times, and the ratio gradually increases on the downstream side.

The medium-pressure side steam turbine rotates the generator discharged from the high-pressure side steam turbine together with the high-pressure steam turbine by the steam heated to 600 ° C. again by the reheater, and is rotated at 3000 RPM. You. The intermediate pressure side turbine has an intermediate pressure inner second casing 21 and an intermediate pressure outer casing 22 similarly to the high pressure side turbine, and a stationary blade is provided to oppose the intermediate pressure moving blade 17. The medium-pressure bucket 17 has six stages. First stage wing length about 130mm, last stage wing length about 2
60 mm. Dovetil is an inverted chestnut type. The diameter of the rotor shaft corresponding to the stationary blade is about 740 mm.

In the rotor shaft of the medium-pressure steam turbine, the axial width of the root portion of the rotor blade implantation is the largest at the first stage, smaller at the second stage, smaller at the third to fifth stages less than the second stage, and the same. The width of the last stage is between the third to fifth stages and the second stage, and is 0.48 to 0.64 times that of the first stage. The first stage is the second stage 1.
It is 1 to 1.5 times.

On the medium pressure side, a blade and a nozzle are made of 12% Cr-based steel shown in Table 3 described later. The length of the blade portion of the moving blade in this embodiment is longer at each stage as it goes 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. There are nine stages, and the length of the wing of each stage is 1.10 to 1.25, which is longer than the length adjacent to the upstream side on the downstream side. The implanted portion of the moving blade has a larger diameter than that corresponding to the stationary blade, and its width is related to the blade length and position of the moving blade. The ratio of the width to the blade length of the rotor blade is the largest in the first stage, from 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. The high-to-medium pressure integrated turbine for a steam turbine power plant equipped with two low-pressure turbines connected in tandem in this embodiment has a bearing distance of about 5.7 m 2, and a length corresponding to the blade length of the last stage blade of the low-pressure turbine. The ratio of the distance between the bearings of the high and medium pressure integrated turbine is 6.7, and the ratio of the distance between the bearings (mm) of the high and medium pressure integrated turbine to the rated output (MW) of the power plant is 9.5.

Further, in the present embodiment, the high / medium pressure integrated steam turbine for a steam turbine power plant having one high pressure / medium pressure turbine and one low pressure turbine in which the high pressure turbine and the medium pressure turbine are integrated has a bearing distance of 14 hours. The ratio of the distance between bearings (mm) of the high- and medium-pressure integrated turbine to the rated output (MW) of the power plant is 9.5. The ratio of the distance between the bearings of the high-to-medium pressure integrated turbine to the blade length of the last stage rotor blade of the low-pressure turbine is 5.2.

FIG. 15 is a sectional view of the low-pressure turbine and FIG.
Is a sectional view of the rotor shaft. The low pressure turbine is tandemly coupled to high and medium pressure by one unit. The moving blades 41 have six stages on the left and right sides and are substantially symmetrical on the left and right, and stationary blades 42 are provided corresponding to the moving blades. The blade length of the last stage is 43
There is an inch, and 12% Cr steel or a Ti-based alloy shown in Table 1 is used. The Ti-based alloy is subjected to age hardening treatment and contains Al 6% and V 4% by weight. The rotor shaft 43 has Ni 3.75%, Cr 1.75%, Mo 0.4%,
V 0.15%, C 0.25%, Si 0.05%, Mn 0.1
Forged steel having a fully tempered bainite structure of a super-clean material consisting of 0% and residual Fe is used. Mo is 0.1% for the moving blades and stationary blades other than the last stage and the preceding stage.
The contained 12% Cr steel is used. 0.25% cast steel is used for the inner and outer casing materials. The center-to-center distance of the bearing 43 in this embodiment is 7000 mm, the diameter of the rotor shaft corresponding to the stationary blade portion is about 800 mm, and the diameter of the rotor blade implantation portion is the same for each stage. The distance between the bearing centers for the rotor shaft diameter corresponding to the vane section is about 8.8.

In the low-pressure turbine, the axial width of the root portion of the blade implant is the smallest at the first stage, and at the downstream side, the two and three stages are equal, the four and the fifth stages are equal, and the width gradually increases in four stages. The width of the last stage is 6.2 to 7.0 times larger than the width of the first stage. A few steps are 1.15 to 1.40 times the first step,
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 stage. The width of the root portion is indicated by a point connecting the extended line extending to the diameter of the rotor shaft.

In this embodiment, the blade length of the rotor blades increases in each stage from the first stage of 4 ″ to the last stage of 43 ″. Depending on the output of the steam turbine, the length of the first stage to the last stage is 100 to 100%. Within 1270mm, up to 8 steps,
The wing length of each stage is longer within a range of 1.2 to 1.9 times as long as the downstream side is adjacent to the upstream side.

The implant root portion of the moving blade has a large diameter and widens as compared with the portion corresponding to the stationary blade, and its width increases as the blade length of the moving blade increases. The ratio of the width to the blade length of the rotor blade is from 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 or higher than the previous one.
It gradually decreases within the range of 0.40. The last stage has a ratio of 0.50 to 0.65.

The last stage rotor blade in this embodiment is the same as that in the first embodiment. FIG. 17 shows that the erosion shield (stellite alloy) 54 in this embodiment is welded by electron beam welding or T-beam welding.
FIG. 3 is a cross-sectional view and a perspective view showing a state where the IG welding 56 is used for joining. As shown in the figure, the erosion shield 54 is welded at two places, a front side and a back side.

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

The high-temperature high-pressure steam turbine power plant in this embodiment is mainly composed of a boiler, high-medium-pressure turbine, low-pressure turbine, condenser, condensate pump, low-pressure feedwater heater system, deaerator, booster pump, feedwater pump, high-pressure feedwater. It is composed of a heater system. That is, the ultra-high-temperature and high-pressure steam generated in the boiler enters the high-pressure side turbine and generates power, and is then reheated in the boiler again to enter the medium-pressure side turbine and generate power. The high- and medium-pressure turbine exhaust steam enters the low-pressure turbine and generates power, and then condenses in the condenser.
This condensate is sent to the low pressure feed water heater system and deaerator by the condensate pump. The feedwater degassed by this deaerator is sent to a high-pressure feedwater heater by a booster pump and a feedwater pump to be heated, and then returned to the boiler.

Here, in the boiler, the water supply passes through a economizer, an evaporator, and a superheater to become high-temperature and high-pressure steam. On the other hand, the boiler combustion gas that heated the steam exited the economizer,
Enter the air heater to heat the air. Here, the feedwater pump is driven by a feedwater pump drive turbine that operates with the extracted steam from the medium pressure turbine.

In the high-temperature and high-pressure steam turbine plant configured as described above, the temperature of the feedwater exiting the high-pressure feedwater heater system is much higher than the temperature of the feedwater in the conventional thermal power plant. The temperature of the combustion gas exiting the economizer will also be much higher than in conventional boilers. Therefore, heat is recovered from the boiler exhaust gas so as not to lower the gas temperature.

In this embodiment, a high-medium pressure turbine and one low pressure turbine are connected to one generator tandem to constitute a tandem compound double flow type power plant. As another embodiment, a turbine configuration (D) shown in Table 11 is used, and two low-pressure turbines are connected in tandem, so that power generation with an output of 1050 MW class can be configured in the same manner as this embodiment. A higher strength shaft is used as the generator shaft. In particular, C0.1
5 to 0.30%, Si 0.1 to 0.3%, Mn 0.5% or less, Ni 3.25 to 4.5%, Cr 2.05 to 3.0%, M
o It has a fully tempered bainite structure containing 0.25 to 0.60% and V 0.05 to 0.20%, and has a tensile strength at room temperature of 93 kg.
f / mm ² or more, especially 100 kgf / mm ² or more, 50% FAT
It is preferable that T is 0 ° C. or less, particularly -20 ° C. or less, that the magnetizing force at 21.2 KG is 985 AT / cm or less, and that the total amount of P, S, Sn, Sb and As as impurities is 0.025. % Or less, and the Ni / Cr ratio is preferably 2.0 or less.

Table 3 above shows the chemical compositions (% by weight) used for the main parts of the high-medium pressure turbine and the low pressure turbine of this embodiment. In the present embodiment, the rotor shaft integrated with the high-pressure side and the medium-pressure side is the same as that shown in Table 3 except that a martensitic steel of No. 9 in Example 4 described later is used. Thermal expansion coefficient of 12 × 10 ^-6 /
° C, there was no problem due to the difference in the coefficient of thermal expansion.

For the steam temperature of 620 ° C. or higher for the rotor shaft of the high-medium pressure turbine, the materials shown in Table 12 of Example 1 or Example 4 described later can be used. In this example, No. 1 in Table 12 is suitable for 625 ° C., and 30 tons of heat-resistant cast steel is melted in an electric furnace, carbon is deoxidized in vacuum, cast into a mold, forged and stretched to produce an electrode rod, Electroslag was melted again as the electrode rod so as to melt from the upper part to the lower part of the cast steel, and the rotor shape (diameter 1450 mm, length 5000)
mm). The forging was performed at a temperature of 1150 ° C. or less in order to prevent forging cracks. Further, after the annealing heat treatment, the forged steel was heated to 1050 ° C., subjected to water spray cooling quenching, and tempered twice at 570 ° C. and 690 ° C.
This was obtained by cutting into the shape shown in FIG. The materials and manufacturing conditions of the other parts are the same as in the first embodiment. Further, a build-up welding layer of Cr-Mo low alloy steel on the bearing portion 27 was formed in the same manner as in Example 1.

The low pressure turbine for a steam turbine power plant having two low pressure turbines connected in tandem in this embodiment has a total bearing distance of 13.9 m, and the blade length of the last stage blade of the low pressure turbine. The ratio of the distance between the bearings of the two low-pressure turbines connected in tandem to
3 and the rated output (MW) of the power plant
, The ratio of the total distance (mm) between the bearings of the two low-pressure turbines coupled in tandem is 23.1.

In the present embodiment, the low-pressure turbine for a steam turbine power plant having a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated and one low-pressure turbine has a bearing distance of about 6 m. The ratio of the last stage blade of the turbine to the blade length is 5.5, and the distance between the bearings of one low-pressure turbine relative to the rated output (MW) of the power plant is the distance between the bearings of one low-pressure turbine.
(mm) ratio is 10.0.

Although the high / medium pressure integrated rotor shaft of this embodiment or the rotor shafts of any of embodiments 4 to 8 described later have a center hole, particularly, P0.01.
By setting the content to be 0% or less, S0.005% or less, As 0.005% or less, Sn 0.005% or less, and Sb0.003% or less, the center hole can be eliminated by high purification in any of the embodiments.

The long blade material of the second embodiment can be applied to the 43-inch final stage rotor blade of the present embodiment.

Example 4 Instead of the rotor shafts of Examples 1 and 3, an alloy having the composition shown in Table 12 was cast into an ingot of 10 kg by vacuum melting and forged into a 30 mm square. In the case of a large-sized steam turbine rotor shaft, after simulating the central part and holding at 1050 ° C. × 5 hours,
Quenching at a cooling rate of 100 ° C / h at the center, 570
Primary tempering at 20 ° C. × 20 hours, secondary tempering at 690 ° C. × 20 hours, and quenching at 1100 ° C. × 1 hour and tempering at 750 ° C. × 1 hour for the blade.
A creep rupture test was performed at 0 kgf / mm ² . The results are shown in Table 12.

The alloys of the present invention No. 1 to No. 6 in Table 12 are as follows:
It is preferable to apply to steam conditions of 620 ° C. or higher, and it is understood that the creep rupture life is long. Although the creep rupture time improves as the amount of Co increases, the increase in the 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 shows excellent strength when 0.03% or less. At 620 to 630 ° C, the amount of B is 0.0.
0.01 to 0.01% and the Co content is 2 to 4%, 630 to 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 has been clarified that N is strengthened when the temperature is higher than 600 ° C. in the examples of the present invention, and that the N is higher in strength than that having a large amount of N. The N content is 0.01 to 0.1.
04% is preferred. Since N is hardly contained in the vacuum melting, it is added by the master alloy.

As shown in Table 12, No. 8 of the rotor material has a higher Mn content, as is clear from the fact that a material having a low Mn content of 0.09% has a higher strength than the same Co content. For this purpose, the Mn content is preferably set to 0.03 to 0.20%.

[0278]

[Table 12]

Similarly, Table 13 shows the chemical composition (% by weight) of the material for the rotor shaft suitable for the 600 ° C. class. The heat treatment is performed after cooling at 1100 ° C. × 2 h → 100 ° C./h, and then 565 ° C.
℃ 15h → cooling at 20 ° C / h, 665 ° C 45h → 2
Cooled at 0 ° C / h. All the heat treatments were performed while rotating around a rotation axis.

Table 14 shows the mechanical properties of the rotor shaft material. Impact value is V notch Charpy value, FA
TT is the 50% fracture surface transition temperature.

[0281]

[Table 13]

[0282]

[Table 14]

The creep rupture strength of the material of the present invention was 60%.
0 ° C, 10 ⁵ h creep rupture strength is 11 kgf / mm ² ,
Strength required for high-efficiency turbine materials (10 kgf / mm ² )
The above and toughness also show high values of 1 kgfm or more.

[0284] In No. 2, the Al content was more than 0.015%, but the creep rupture strength for 10 ⁵ hours was 11 kgf / mm ^2.
Below, the strength is slightly reduced. When W was increased by about 1.0%, δ ferrite was precipitated, and both strength and toughness were low, and it was also confirmed that the object of the invention was not achieved.

A high strength is obtained when W is 0.1 to 0.65%.

The effect of W on FATT is 0.1 to 0.1%.
In the range of 0.65%, FATT is low and high toughness is obtained. Especially 0.2
A low FATT is obtained at ~ 0.5%.

The martensitic steel of this example has a remarkably high high-temperature creep rupture strength at around 600 ° C., and sufficiently satisfies the strength required for a rotor shaft for an ultra-high-temperature and high-pressure steam turbine. It is also suitable as a high-efficiency turbine blade at around 600 ° C.

Example 5 Table 15 shows the chemical composition (% by weight) of the internal casing material for high, medium and high pressure turbines of the present invention in Examples 1 and 3. Assuming the thick portion of the large casing, the sample was melted in a high-frequency induction melting furnace to melt 200 kg 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. The sample is
1050 ° C. × 8 h After furnace cooling annealing, normalizing (1050 ° C. × 8 h) assuming a thick part of a large steam turbine casing
→ air cooling, tempering (710 ° C × 7h → air cooling, 710 ° C ×
7h → air cooling twice).

The weldability was evaluated in accordance with JIS Z3158. Pre-heat, inter-pass and post-heat onset temperature is 150 ° C
The post heat treatment was performed at 400 ° C. for 30 minutes.

[0290]

[Table 15]

Table 16 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 tests are shown.

The creep rupture strength and the impact absorption energy of the material of the present invention to which appropriate amounts of B, Mo and W were added were determined in accordance with the characteristics (625 ° C., 1
0 ⁵ h strength ≧ 8 kgf / mm ² , shock absorption energy at 20 ° C. ≧
1 kgf-m). In particular, it shows a high value of 9 kgf / mm ² or more. In addition, no weld cracking was observed in the material of the present invention, and the weldability was good. As a result of examining the relationship between the B content and weld cracking, when the B content exceeded 0.0035%, weld cracks occurred. No. 1 was a little worried about cracking. Looking at the effect of Mo on the mechanical properties, those with a high Mo content of 1.18%, although having high creep rupture strength, had low impact values and could not satisfy the required toughness. On the other hand, the alloy with Mo 0.11% had high toughness but low creep rupture strength, and could not satisfy the required strength.

As a result of examining the effect of W on mechanical properties, creep rupture strength was remarkably increased when the W amount was 1.1% or more. Becomes lower. In particular, when the Ni / W ratio is 0.2
By adjusting the 5-0.75, temperature 621 ° C., are required to a pressure 250 kgf / cm ² or more high pressure and intermediate pressure internal casing of the high-temperature and high-pressure turbine and a main steam stop valve and governor valve casing, 625 ° C., 10 ⁵ h creep rupture strength 9 kgf / mm ² or more, shock absorption energy at room temperature 1 kgfm
The above heat-resistant cast steel casing material is obtained. In particular, by adjusting the W content to 1.2 to 2% and the Ni / W ratio to 0.25 to 0.75, the creep rupture strength at 625 ° C. and 10 ⁵ h is 10 kgf / mm ² or more, and the impact absorption energy at room temperature is ² kgf−
m or more excellent heat-resistant cast steel casing material can be obtained.

[0294]

[Table 16]

The content of W is remarkably strengthened by setting it to 1.0% or more, and especially 8.0 kg at 1.5% or more.
A value of f / mm ² or more is obtained. No. 7 of the present invention is 640
The required strength was sufficiently satisfied at a temperature of not more than ℃.

One ton of an alloy material having the target composition of the heat-resistant cast steel of the present invention was melted in an electric furnace, and after ladle refining, it was cast into a sand mold to obtain an internal casing of a high-to-medium pressure portion described in Example 3. This casing is subjected to an annealing heat treatment at 1050 ° C. × 8 h for furnace cooling, then a normal heat treatment at 1050 ° C. × 8 h for blast cooling, and 730 ° C.
Tempering was performed twice in a furnace for 8 hours. As a result of cutting investigation of this prototype casing having a fully tempered martensite structure, characteristics required for a high-pressure and high-pressure turbine casing at 250 atm, 625 ° C (625 ° C, 10 ⁵ h strength ≥ 9 kgf / mm)
^2. It was confirmed that 20 ° C impact absorption energy ≧ 1 kgf-m) was sufficiently satisfied and that welding was possible.

[Embodiment 6] In this embodiment, the steam temperature of the 625 ° C high-pressure steam turbine and the medium-pressure steam turbine of the first embodiment or the steam temperature of the 600 ° C and 625 ° C high-medium-pressure steam turbine of the third embodiment is replaced. The temperature was set at 649 ° C., and the structure and size were obtained with almost the same design as in Example 1 or 3. Here, what is different from the first or third embodiment is the rotor shaft, the first stage moving blade, the first stage stationary blade, and the inner casing of the high-pressure, medium-pressure or high-medium-pressure integrated steam turbine which is in direct contact with this temperature. Among these materials excluding the inner casing, the B content of the materials shown in Table 4 was 0.01 to
0.03% and the amount of Co are increased to 5 to 7%, and as the inner casing material, the W amount of Example 2 is increased to 2 to 3%.
By adding 3% of o, the required strength is satisfied,
There is a significant advantage that conventional designs can be used. That is,
In this 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 moving blade and the stationary blade of the second stage is about 610 ° C., it is preferable to use the material used in the first stage of the first embodiment.

Furthermore, the steam temperature of the low-pressure steam turbine is about 405 ° C., which is slightly higher than about 380 ° C. of the first or third embodiment. However, the rotor shaft itself has a sufficiently high strength because the material of the first embodiment has a sufficiently high strength. Also, a super clean material is used.

Further, in contrast to the cross-compound type in this embodiment, a tandem compound type can be used at a rotational speed of 3600 rpm.

Table 17 shows the chemical composition of the Ni-based precipitation-strengthened alloy used for each of the moving blades of up to three stages in a high-pressure turbine having a steam temperature of 640 ° C. or higher and in the first stage in a medium-pressure turbine. These alloys are hot-forged after manufacturing an ingot by vacuum arc remelting, and then heat-treated at 1070 to 1200 ° C. for 1 to 8 hours and then air-cooled according to the alloy composition to obtain an ingot.
It has been subjected to an aging treatment of heating at 0 to 870 ° C for 4 to 24 hours.

In the high-pressure turbine, the high-strength martensitic steel of the present invention was used in the fourth and fifth stages, and in the second and third stages of the medium-pressure turbine. Another example is steam temperature 610-6
The above-described Ni-based alloy can be used in the first stage of the high-pressure turbine and the intermediate-pressure turbine at 38 ° C., and the high-strength martensitic steel of the present invention can be used in the second and third stages of the high-pressure turbine and the second stage of the medium-pressure turbine. .

Embodiments 2, 4, and 5 can be applied to this embodiment.

[0303]

[Table 17]

Example 7 A rotor shaft for a high-pressure turbine and a medium-pressure turbine in the power plant according to Example 1 was manufactured by changing the amount of B for the body and the bearing. Other configurations are exactly the same as those of the first embodiment. 30 tons of heat-resistant cast steel according to the body and bearing described in Table 18 (% by weight) were melted in an electric furnace, carbon deoxidized, cast into a mold, and forged to produce an electrode rod. First, the bearing portion was electroslag-dissolved using an electrode rod, then the body portion was electro-dissolved immediately, and the bearing portion was further electro-slag-dissolved thereon. The rotor shape (diameter 1050 mm, length 3700 m)
m). This forging was performed at a temperature of 1150 ° C. or less in order to prevent forging cracks. In addition, after annealing heat treatment, the forged steel was heated to 1050 ° C., subjected to water spray cooling and quenching, and tempered twice at 570 ° C. and 690 ° C.
And obtained by cutting into the shape shown in FIG. The body and the bearing are joined at a position shown by a dotted line. As shown in FIG. 18, in the rotor shaft for the high-pressure steam turbine, between the downstream last stage of the blade and the front side thereof,
In the rotor shaft for a medium-pressure steam turbine shown in FIG. 19, the rotor shaft is joined between the last stage on the downstream side and the front side thereof. In the present embodiment, the upper side of the electroslag steel ingot is set to the first stage side of the body, and the lower side is set to the last stage side.

The high-pressure and medium-pressure blades and nozzles were prepared by melting the heat-resistant steel listed in Table 18 in a vacuum arc melting furnace to form a blade and nozzle material (width 150 mm, height 50 mm, length 1000 mm). Forged and molded. The forging was performed at a temperature of 1150 ° C. or less in order to prevent forging cracks. The forged steel is heated to 1050 ° C., subjected to oil quenching, tempered at 690 ° C., and then cut into a predetermined shape. The internal casing, the main steam stop valve casing, and the steam control valve casing of the high-pressure part and the medium-pressure part were prepared by melting the heat-resistant cast steel shown in Table 17 in an electric furnace, refining the ladle, and pouring it into a sand mold. By performing sufficient refining and deoxidation before casting, a casting free of casting defects such as shrinkage cavities was obtained. Weldability evaluation using this casing material was performed according to JIS Z3158. Preheating,
Inter-pass and post heat onset temperature is 200 ° C, post heat treatment is 40 ° C.
It was 0 ° C. × 30 minutes. No weld crack was observed in the material of the present invention, and the weldability was good.

[0306]

[Table 18]

[0307] Table 19 shows the mechanical properties of the body of the rotor shaft described above. The heat treatment was carried out by water spray cooling after heating and holding at 1050 ° C. × 15 h, and then cooling at 570 ° C. × 20 h and heating at 690 ° C. × 20 h.

As a result of examining the center of the rotor shaft, it was found that the characteristics (62
5 ° C., 10 ⁵ h strength ≧ 13 kgf / mm ² , and 20 ° C. shock absorption energy ≧ 1.5 kgf-m). This demonstrated that a steam turbine rotor usable in steam at 620 ° C. or higher can be manufactured. Also, as a result of investigating the characteristics of this blade, the characteristics (625 ° C., 10
It was confirmed that ⁵ h strength ≧ 15 kgf / mm ² ) was sufficiently satisfied. This demonstrated that a steam turbine blade usable in steam at 620 ° C. or higher can be manufactured.

Further, as a result of investigating the characteristics of this casing, it was found that the characteristics (625 ° C., 10 ⁵ h strength ≧ 10 kgf / mm ² , 20 ° C. shock absorption energy ≧ 1 kgf-m) required for the high-pressure and intermediate-pressure turbine casings were sufficiently improved. Satisfaction and weldability were confirmed. Thereby, 620 ° C
It was proved that a steam turbine casing usable in the above steam could be manufactured.

[0310]

[Table 19]

In this embodiment, as in the case of Embodiment 1, Cr-Mo low alloy steel was build-up welded to the journal portion of the rotor shaft to improve the bearing characteristics.

[0312] In order to confirm the performance of the welded portion, the plate material was similarly overlaid and subjected to a side bending test of 160 °, but no crack was found in any of the welded portions. In each case, the sixth and subsequent layers have the compositions shown in the respective tables.

Further, a bearing sliding test by rotation in the present invention was performed.
It was also excellent in oxidation resistance.

In place of the present embodiment, a high-pressure steam turbine, a medium-pressure steam turbine and two low-pressure steam turbines may be connected in tandem to form a tandem-type power plant having 3000 revolutions.

Embodiments 2, 4 and 5 can be applied to this embodiment, and the same can be applied to the steam temperature of Embodiment 6.

[Embodiment 8] In this embodiment, the last stage blade length in a tandem compound double flow type, low pressure turbine similar to Embodiment 3 is 43 inches, and HP (high pressure) is used.
・ IP (medium pressure) integrated type and 3000r with one or two LPs
It has a rotation speed of pm and is made of the main material as in the third embodiment. The steam temperature of the high pressure section (HP) on the left is 60
0 ° C, pressure of 250 kg / cm ² , medium pressure part (I
The vapor temperature of P) is heated to 600 ° C. by a reheater,
It is operated at a pressure of 170-180 kg / cm ² . The low pressure part (LP) has a steam temperature of 450 ° C,
It is sent to the condenser at a vacuum of 722 mmHg.

FIG. 20 is a sectional view of the rotor shaft of the high-pressure / intermediate-pressure integrated steam turbine used in this embodiment.
As shown in the figure, the steam enters both the high-pressure part and the medium-pressure part from the center of the rotor shaft and has a configuration in which the steam flows to the bearing part side, and therefore the temperature is low on the bearing part side. The rotor shaft in this embodiment is manufactured by the electroslag remelting method by changing the alloy composition of the bearing portion and the body portion in the same manner as in the seventh embodiment, and in each case, the composition is changed before the final stage. is there. The structure of FIG.
It is exactly the same as 4. The composition of the body in this example was No. 5 in Table 12, and only the B content of the bearing was 0.003%.
And the other components are the same. The heat treatment after forging is the same as described above.

In this embodiment, as in the third embodiment, a cladding welding layer of Cr-Mo low alloy steel is formed on the bearing portion.

The embodiments 2, 4 and 5 can be applied to the present embodiment, and can be similarly applied to the steam temperature of the embodiment 6.

[0320]

According to the present invention, martensitic heat resistance and cast steel having high creep rupture strength and room temperature toughness at 600 to 660 ° C. can be obtained. The steam turbine can be made of heat-resistant steel, the basic design of the steam turbine can be used as it is, and a highly reliable thermal power plant can be obtained.

Conventionally, at such a temperature, an austenitic alloy had to be formed, so that a sound large-sized rotor could not be manufactured from the viewpoint of manufacturability. Large rotors can be manufactured.

Further, the high-temperature steam turbine made of all-ferritic steel of the present invention does not use an austenitic alloy having a large thermal expansion coefficient, so that the turbine can be quickly started and is hardly damaged by thermal fatigue. There are advantages.

[Brief description of the drawings]

FIG. 1 is a sectional view of a high-pressure, medium-pressure steam turbine according to the present invention.

FIG. 2 is a sectional structural view of the low-pressure steam turbine according to the present invention.

FIG. 3 is a perspective view of a turbine blade according to the present invention.

FIG. 4 is a diagram showing a relationship between tensile strength and Ni—Mo (%).

FIG. 5 is a diagram showing a relationship between an impact value and Ni-Mo (%).

FIG. 6 is a diagram showing a relationship between tensile strength and quenching temperature.

FIG. 7 is a diagram showing the relationship between tensile strength and tempering temperature.

FIG. 8 is a diagram showing a relationship between an impact value and a quenching temperature.

FIG. 9 is a diagram showing a relationship between an impact value and a tempering temperature.

FIG. 10 is a diagram showing a relationship between an impact value and a tensile strength.

FIG. 11 is a diagram showing the relationship between 0.2% proof stress and tensile strength.

FIG. 12 is a diagram showing the relationship between 0.2% proof stress and 0.02% proof stress.

FIG. 13 is a cross-sectional view of a high- and medium-pressure steam turbine according to the present invention.

FIG. 14 is a sectional view of a rotor shaft for a high- and medium-pressure steam turbine according to the present invention.

FIG. 15 is a sectional view of a low-pressure steam turbine according to the present invention.

FIG. 16 is a sectional view of a rotor shaft for a low-pressure steam turbine according to the present invention.

FIG. 17 is a perspective view of the tip of a turbine blade of the present invention.

FIG. 18 is a front view of a rotor shaft for a high-pressure turbine.

FIG. 19 is a front view of a rotor shaft for a medium-pressure turbine.

FIG. 20 is a sectional view of a rotor shaft for a high-medium pressure turbine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st bearing, 2 ... 2nd bearing, 3 ... 3rd bearing, 4 ... 4th
Bearing, 5: Thrust bearing, 10: First shaft packing, 1
DESCRIPTION OF SYMBOLS 1 ... 2nd shaft packing, 12 ... 3rd shaft packing, 13 ... 4th shaft packing, 14 ... High-pressure diaphragm, 1
5: Medium pressure diaphragm, 16: High pressure blade, 17: Medium pressure blade, 18
... High-pressure internal casing, 19 ... High-pressure external casing, 20 ... Medium-pressure internal first casing, 21 ... Medium-pressure internal second casing, 22 ... Medium-pressure external casing, 23 ... High-pressure axle, 24 ... Medium pressure Axle, 25 ... flange, elbow, 26 ... front bearing box, 27 ... bearing 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 shutoff device, 40: Warm-up steam inlet, 41: moving blade, 42: stationary blade, 43: bearing, 44: rotor shaft, 51: wing part, 52: wing implantation part, 53 ...
Hole, 54: erosion shield, 55: tie boss, 5
6 ... Weld, 57 ... Continuous cover.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Shiga 3-10-2 Bentencho, Hitachi City, Ibaraki Prefecture Within Hitachi Kyowa Engineering Co., Ltd.

Claims (23)

[Claims] In a steam turbine power plant having a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately, the high-pressure turbine and the medium-pressure turbine are tandemly connected to the blade length of the last stage moving blade of the low-pressure turbine. A steam turbine power plant wherein the ratio of the sum of the distance between the bearings and the distance between the bearings of the two low-pressure turbines coupled in tandem is 26 to 30. 2. A high-pressure turbine for a steam turbine power plant comprising a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately, wherein a distance between bearings of the high-pressure turbine with respect to a blade length of a last stage rotor blade of the low-pressure turbine. A high-pressure turbine for a steam turbine power plant, wherein the ratio is 3.5 to 6.0. 3. A medium pressure turbine for a steam turbine power plant comprising a high pressure turbine, a medium pressure turbine, and a low pressure turbine separately, wherein a distance between bearings of the medium pressure turbine with respect to a blade length of a last stage rotor blade of the low pressure turbine. An intermediate-pressure turbine for a steam turbine power plant, wherein a distance ratio is 4.0 to 6.0. 4. A steam turbine power plant comprising a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately, wherein two low-pressure turbines connected in tandem with respect to a blade length of a last stage rotor blade of the low-pressure turbine. A low-pressure turbine for a steam turbine power plant, wherein a ratio of a total distance between bearings is 15.5 to 17.5. 5. A steam turbine power plant having a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately provided between bearings in which the high-pressure turbine and the medium-pressure turbine are connected in tandem with respect to the rated output (MW) of the power plant. A steam turbine power plant wherein the ratio of the distance and the total distance (mm) of the bearing distances of the two low-pressure turbines coupled in tandem is 28.0 to 32.0. 6. A high-pressure turbine for a steam turbine power plant having a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately, wherein a rated output (MW) of the power plant is provided.
Wherein the ratio of the distance (mm) between bearings of the high-pressure turbine to 3.5 is 6.5 to 6.5. 7. A rated output (MW) of a power plant for a steam turbine power plant having a high pressure turbine, a medium pressure turbine and a low pressure turbine separately provided.
A ratio of a distance (mm) between bearings of the intermediate pressure turbine to the intermediate pressure turbine is 4.0 to 7.0. 8. A low-pressure turbine for a steam turbine power plant comprising a high-pressure turbine, a medium-pressure turbine and a low-pressure turbine separately, wherein a rated output (MW) of the power plant is provided.
A ratio of a distance (mm) between bearings of the two low-pressure turbines connected in tandem to the low-pressure turbine is 16.0 to 19.0. 9. A steam turbine power plant comprising a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, wherein the high-to-medium pressure with respect to the blade length of the last stage blade of the low-pressure turbine. A steam turbine power plant wherein the ratio of the distance between the bearings of the integral turbine and the distance between the bearings of the two low-pressure turbines coupled in tandem is 24-28. 10. A high-to-medium pressure integrated turbine for a steam turbine power plant, comprising: a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated; and two low-pressure turbines connected in tandem. A high-to-medium pressure integrated turbine for a steam turbine power plant, wherein a ratio of a distance between bearings of the high-to-medium pressure integrated turbine to a blade length of a last stage rotor blade is 5.5 to 7.0. 11. A low-pressure turbine for a steam turbine power plant comprising a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, and two low-pressure turbines connected in tandem, wherein the last stage of the low-pressure turbine is provided. A low pressure turbine for a steam turbine power plant, wherein a ratio of a distance between bearings of the two low pressure turbines connected in tandem to a blade length of a moving blade is 15.0 to 17.5. 12. A steam turbine power plant comprising a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, wherein the high-to-medium pressure with respect to the blade length of the last stage blade of the low-pressure turbine. A steam turbine power plant, wherein the ratio of the distance between the bearings of the integral turbine and the distance between the bearings of one of the low-pressure turbines is 11.5 to 15.5. 13. A high-to-medium pressure integrated turbine for a steam turbine power plant comprising a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, and a low-pressure turbine final stage rotor blade. The ratio of the distance between the bearings of the high-medium pressure integrated turbine to the blade length of
A high-to-medium pressure integrated turbine for a steam turbine power plant, which is 6.0. 14. A low-pressure turbine for a steam turbine power plant comprising a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, and one low-pressure turbine.
A low pressure turbine for a steam turbine power plant, wherein a ratio of a distance between bearings of the one low pressure turbine to a blade length of a last stage rotor blade of the low pressure turbine is 4.5 to 6.5. 15. A steam turbine power plant comprising a high / medium pressure integrated turbine and a low pressure turbine in which a high pressure turbine and a medium pressure turbine are integrated, wherein the high / medium pressure integrated turbine has a rated output (MW) of the power plant. A steam turbine power plant, wherein a ratio of a distance between bearings and a total distance (mm) of distances between bearings of the two low-pressure turbines coupled in tandem is 35.0 to 39.5. 16. A high-to-medium pressure integrated turbine for a steam turbine power plant, comprising a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, and two low-pressure turbines connected in tandem. A high-intermediate-pressure integrated turbine for a steam turbine power plant, wherein a ratio of a bearing distance (mm) of the high-intermediate-pressure integrated turbine to a rated output (MW) is 8.0 to 11.0. 17. A low-pressure turbine for a steam turbine power plant comprising a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, wherein the low-pressure turbine is coupled to a tandem with respect to a rated output (MW) of the power plant. The ratio of the total distance (mm) of the bearing distances of the two low-pressure turbines is 21.0 to 25.5. 18. A steam turbine power plant comprising a high-to-medium pressure integrated turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, wherein the high-medium-pressure integrated turbine has a rated output (MW) of the power plant. A steam turbine power plant, wherein a ratio of a total distance between bearings and a distance between bearings of one low-pressure turbine is 22.0 to 26.5. 19. A high-to-medium pressure integrated turbine for a steam turbine power plant comprising a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, and a low-pressure turbine, wherein a rated output (MW) of the power plant is provided. ) With respect to the distance between bearings (mm) of the high- and medium-pressure integrated turbine is 8.0.
A high-to-medium pressure integrated turbine for a steam turbine power plant, wherein 20. A low-pressure turbine for a steam turbine power plant, comprising a high-to-medium pressure integrated turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, and one low-pressure turbine.
The ratio of the bearing distance (mm) of the one low-pressure turbine to the rated power (MW) of the power plant is 8.5 to 11.
5. A low-pressure turbine for a steam turbine power plant, wherein 21. A steam turbine power plant comprising a high-pressure turbine and a low-pressure turbine in which a high-pressure turbine and a medium-pressure turbine are integrated, wherein the medium-pressure turbine has a steam inlet temperature to a first-stage moving blade of 610 to 660 ° C. The low-pressure turbine has a steam inlet temperature to the first-stage bucket of 380 to 475.
C., a high-strength martensitic steel in which at least the first stage of a rotor shaft and a stationary blade, and a casing contains 8 to 13% by weight of Cr, wherein the rotor blade is exposed to the steam inlet temperature of the high-pressure turbine and the intermediate-pressure turbine. A steam turbine power plant comprising a combination of steel and a Ni-based alloy. 22. A rotor shaft, a moving blade implanted on the rotor shaft, a stationary blade for guiding inflow of steam to the rotating blade, and an inner casing for holding the stationary blade, wherein: The temperature flowing into the first stage of the rotor blade is 610 to 66.
0 ° C and pressure 250kg / cm ² or more or 150-200k
g / cm ² , wherein the rotor shaft and at least the first stage of the stationary blade have a 10 ⁵ hour creep rupture strength of 15 kg / at a temperature corresponding to the steam temperature flowing into the first stage of the moving blade. The high-strength martensitic steel having a fully tempered martensite structure containing 9 to 13% by weight of Cr of not less than ² mm ² and the above-mentioned rotor blade are the same as the above martensite steel and a Ni-based alloy having a tensile strength at room temperature of not less than 90 kg / mm ^2. Wherein the inner casing is made of a martensitic cast steel containing 8 to 12% by weight of Cr having a 10 ⁵ hour creep rupture strength of 10 kg / mm ² or more at a temperature corresponding to the steam temperature. High and medium pressure steam turbine. 23. A high-to-medium pressure steam turbine having a rotor shaft, a moving blade implanted on the rotor shaft, a stationary blade for guiding the flow of steam to the rotating blade, and an inner casing holding the stationary blade. The weight of the rotor shaft and at least the first stage of the stator vane is C 0.05 to 0.20.
%, Si 0.15% or less, Mn 0.03 to 1.5%, Cr
9.5-13%, Ni 0.05-1.0%, V 0.05-
0.35%, Nb 0.01 to 0.20%, N 0.01 to 0.1%
06%, Mo 0.05-0.5%, W 1.0-3.5%, C
o2-10%, B 0.0005-0.03%, 78
% Of high strength martensitic steel having Fe in the range of 0.03 to 0.15 in weight with the martensitic steel.
%, Si 0.3% or less, Mn 0.2% or less, Cr12
~ 20%, No.9 ~ 20%, Al 0.5 ~ 1.5%, Ti
2 to 3%, B: 0.003 to 0.015%, and the inner casing is C06 to 0.16%, Si0.5% or less, Mn1 by weight.
% Or less, Ni 0.2 to 1.0%, Cr 8 to 12%, V 0.2
0.05 to 0.35%, Nb 0.01 to 0.15%, N0.0
1 to 0.1%, Mo 1.5% or less, W1 to 4%, B0.0
A high- and medium-pressure steam turbine comprising high-strength martensitic steel containing 005 to 0.003% and having 85% or more Fe.