KR19990082616A - Steam Turbine Power Plant and Steam Turbine - Google Patents

Abstract

It is an object of the present invention to provide a super-ultra-critical pressure steam turbine power plant that enables the high temperature of the steam temperature of 600 to 660 ° C. according to the use of ferritic steel and is convenient with high thermal efficiency.

The present invention is made of ferrite-based forged steel and cast steel, such as the rotor shaft exposed to the high temperature portion, the low-pressure turbine final stage blades are made of martensitic steel, the main steam temperature and reheat steam temperature of 600 to 660 ℃ easy ultra-ultra Critical pressure steam turbine is in power plant.

Tensile creep rupture strength of 11 kgf / mm2 or more at 100 kg of tensile strength of the final blade at 120 kgf / mm2 It consists of ferritic cast steel of kgf / mm 2 or more.

Description

Steam Turbine Power Plant and Steam Turbine

Currently, 12 Cr-Mo-Ni-V-N steels are used for rotor blades for steam turbines. In recent years, from the viewpoint of energy saving, the gas turbine's thermal efficiency has been improved, and from the viewpoint of space efficiency, there has been a demand for miniaturization of equipment.

Steam turbine blades are an effective means for improving thermal efficiency and miniaturizing equipment. As a result, the blade length of the low-pressure steam turbine final stage tends to rise every year. This leads to stricter steam turbine operating conditions, and to 12-Cr-Mo-Ni-V-N steels up to now, the strength is insufficient and a higher strength material is required. As strength of the blade material, tensile strength, which is the basis of mechanical properties, is required.

In addition, high strength and high toughness are required from the viewpoint of securing safety against fracture.

Although Ni base alloys and Co base alloys are generally known as structural materials having higher tensile strengths than conventional 12 Cr-Mo-Ni-V-N steels (martensitic steels), they have poor hot workability, machinability and vibration damping characteristics. As a raw material, it is not preferable.

As a disk material for a gas turbine, Japanese Patent Laid-Open No. 63-171856 and Japanese Patent Laid-Open No. Hei 4-120246 are known.

In addition, the conventional steam turbine had a steam temperature of up to 566 ° C and a steam pressure of 246 atg.

However, from the viewpoint of depletion of fossil fuels such as petroleum and coal, energy saving and environmental pollution prevention, there is a demand for high efficiency of a thermal power plant. In order to increase the power generation efficiency, increasing the steam temperature of the steam turbine is the most effective means. Japanese Patent Laid-Open No. 7-233704 is known as a material for these highly efficient ultra high temperature steam turbines.

The present invention has been made to cope with the blade expansion of a low pressure steam turbine in recent years, and Japanese Patent Laid-Open No. 63-171856 and Japanese Patent Laid-Open No. Hei 4-120246 disclose no rotor blade material for a steam turbine. .

Moreover, although the rotor member, the casing member, etc. are disclosed by the publication mentioned in Unexamined-Japanese-Patent No. 7-233704, the last stage rotor blade in the high medium pressure integrated steam turbine and low pressure steam turbine accompanying high temperature as mentioned above. There is no description of 12% Cr-based martensitic steel.

It is an object of the present invention to provide a steam turbine power plant using a steam turbine and a steam turbine which enables a high temperature of steam temperature 600 to 660 ° C. by ferritic heat resistant steel and has high thermal efficiency.

It is also an object of the present invention to provide a steam turbine power plant using steam turbines and steam turbines having substantially the same basic structure at each operating temperature of 600 to 660 ° C.

The present invention relates to a novel steam turbine, and more particularly to a high temperature steam turbine utilizing 12% Cr based steel as the final stage rotor of a low pressure steam turbine.

1 is a diagram showing the relationship between tensile strength and Ni-Mo (%).

2 is a diagram showing the relationship between impact value and Ni-Mo (%).

3 is a diagram showing the relationship between tensile strength and quenching temperature.

4 is a diagram showing the relationship between tensile strength and considered temperature.

5 is a diagram showing the relationship between the layer spacing value and the quenching temperature.

Fig. 6 is a diagram showing the relationship between impact value and considered temperature.

Fig. 7 is a diagram showing the relationship between impact value and tensile strength.

8 is a sectional view of a high pressure and medium pressure steam turbine according to the present invention;

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

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

11 is a sectional view of a high medium pressure steam turbine according to the present invention.

12 is a sectional view of a rotor shaft for a high medium pressure steam turbine according to the present invention.

Fig. 13 is a sectional view of a low pressure steam turbine according to the present invention.

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

15 is a perspective view of a distal end of a turbine rotor blade of the present invention.

According to the present invention, a high pressure turbine, a medium pressure turbine, a low pressure turbine and a low pressure turbine, or a high pressure turbine and a low pressure turbine, a medium pressure turbine and a low pressure turbine are connected, or a high and medium pressure integrated steam turbine and one or two low pressure turbines connected in tandem. In a steam turbine power plant, the high pressure turbine and the medium pressure turbine or the high pressure turbine have a steam inlet temperature of 600 to 660 ° C. (preferably 600 to 620 ° C., 620 to 630 ° C., 630 to 640 ° C.). For the range, the low pressure turbine may comprise a rotor shaft or rotor shaft, rotor blade exposed to the steam inlet temperature of the high pressure turbine and the medium or high pressure turbine, for a range of 350 to 400 ° C. for the ultrashort rotor. , The vane and the inner casing are composed of high strength martensitic steel containing 8 to 13% by weight of Cr, and the final stage of the low pressure turbine A steam turbine power plant comprising a martensitic steel having a rotor blade value (inch length x rotational speed) of 125,000 or more.

The present invention has a rotor shaft, a rotor blade inserted into the rotor shaft, a vane for guiding water vapor inflow into the rotor blade, and an inner casing holding the vane, which flows into the first stage of the rotor blade of the steam. A steam turbine having a temperature of 600 to 660 ° C. and a pressure of at least 250 kgf / cm 2 (preferably 246 to 316 kgf / cm 2) or 170 to 200 kgf / cm 2, wherein the rotor shaft or the rotor shaft and the rotor and stator blades are at least the shortest 10 ⁵ hours creep rupture strength at a temperature corresponding to each steam temperature (preferably 610 ° C, 625 ° C, 640 ° C, 650 ° C, 660 ° C) is 10 kgf / mm2 or more (preferably 17 kgf / mm2 or more) ) Is made of high strength martensitic steel with a fully considered martensitic structure containing 9.5 to 13% by weight (preferably 10.5 to 11.5% by weight) of Cr, wherein the inner casing is 10 ⁵ hours creep rupture strength of 10 kgf / ㎟ or more (preferably, 10.5 kgf / ㎟ or more), characterized in that comprising a martensite cast steel containing the Cr 8 to 9.5% by weight of the steam turbine at a temperature corresponding to Fig. Or a high and medium pressure integrated steam turbine which heats the steam from the high pressure side turbine, heats at least equal to the high pressure side inlet temperature, and sends it to the medium pressure side turbine.

In a high pressure turbine and a medium pressure turbine or a high-pressure integrated steam turbine, at least the first stage of the rotor shaft or the rotor and the stator blades has a weight ratio of C 0.05 to 0.20%, Si 0.15% or less, Mn 0.05 to 1.5%, Cr 9.5 to 13% , Ni 0.05-1.0%, V 0.05-0.35%, Nb 0.01-0.20%, N 0.01-0.06%, Mo 0.05-0.5%, W 1.0-4.0%, Co 2-10%, B 0.0005-0.03% It is made of a high strength martensitic steel having a Fe of 78% or more, preferably corresponding to the vapor temperature of 620 to 640 ℃, or C 0.1 to 0.25%, Si 0.6% or less, Mn 1.5% or less, Cr 8.5 to 13%, Ni 0.05-1.0%, V 0.05-0.5%, W 0.10-0.65%, Al 0.1% or less, made of high strength martensitic steel with 80% or more of Fe, corresponding to less than 600-620 ° C It is preferable. The inner casing is 0.06 to 0.16%, Si 0.5% or less, Mn 1% or less, Ni 0.2% to 1.0%, Cr 8 to 12%, V 0.05 to 0.35%, Nb 0.01 to 0.15%, N 0.01 to 0.8 by weight It is preferably made of a high strength martensitic steel containing%, Mo 1% or less, W 1-4%, B 0.0005-0.003%, and having 85% or more of 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, and the first stage is double flow, and the rotor shaft has a bearing distance L of 5000 mm or more (preferably 5100). To 6500 mm) and the minimum diameter D at the part where the vane is installed 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) It is preferable that it consists of high strength martensitic steel containing 9 to 13 weight% of phosphorus Cr.

In the medium-pressure steam turbine according to the present invention, the rotor blade has a six-stage or more in the symmetrical direction, each of which is a double flow structure provided by inserting the first stage into the center of the rotor shaft, the rotor shaft is 5000 mm between the bearing center (L) The above-mentioned (preferably 5100-6500 mm) and the minimum diameter (D) in the part in which the said vane was installed are 630 mm or more (preferably 650-710 mm), and said (L / D) is 7.0-9.2 (preferably It is preferably made of a high strength martensitic steel containing Cr 9 to 13% by weight of 7.8 to 8.3).

In a low pressure steam turbine having a high pressure turbine and a medium pressure turbine separately, the rotor blade has six or more stages each in symmetrical symmetry, and has a double flow structure in which a first stage is inserted in the center of the rotor shaft, and the rotor shaft has a distance between bearing centers (L). Is 6500 mm or more (preferably 6600-7100 mm) and the minimum diameter (D) in the part in which the said vane is provided is 750 mm or more (preferably 760-900 mm), and said (L / D) is 7.8- Ni-Cr-Mo-V low-alloy steel containing 3.25-4.25% by weight of Ni, preferably 10.2 (preferably 8.0-8.6), and the final stage rotor is [blade length (inch) x rotational speed (rpm)]. A low pressure steam turbine comprising a high strength martensitic steel having a value of 125,000 or more.

In addition, the present invention is connected to a high pressure turbine, 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, or a high or medium pressure turbine and one or two low pressure turbines connected in tandem. In the steam turbine power plant, the high pressure turbine and the medium pressure turbine or high medium pressure turbine has a steam inlet temperature of 600 to 660 ° C to the ultrashort rotor, the low pressure turbine has a steam inlet temperature of 350 to 400 ° C to the ultrashort rotor, To ensure that the rotor blade installation portion and the rotor blade metal temperature of the rotor shaft of the high pressure turbine are not lower than 40 ° C. (preferably 20 to 35 ° C. below the steam temperature) of the steam inlet temperature to the rotor blade of the high pressure turbine. And the metal temperature of the ultra-stage rotor insertion portion and the ultra-stage rotor of the rotor shaft of the medium pressure turbine is However, it should not be lower than 75 ° C. or more (preferably 50 to 70 ° C. below the steam temperature) to the steam inlet temperature to the rotor blade, and the rotor shaft and at least the ultra-short rotor of the high pressure turbine and the medium pressure turbine will be Cr 9.5 to 13% by weight. Steam turbine power plant, characterized in that it consists of martensitic steel containing a high-strength martensitic steel whose final stage rotor of the low-pressure turbine is at least 125,000 [inches length (inch) x rotational speed (rpm)]. Is in.

In addition, the present invention is a coal fired boiler, a steam turbine driven by water vapor obtained by the boiler, and one or two or more, preferably two or more power generation outputs of 1000 MW or more driven by the steam turbine. In the coal-fired thermal power plant having a generator having a high pressure turbine, medium pressure turbine and low pressure turbine and low pressure turbine or high pressure turbine and low pressure turbine, medium pressure turbine and low pressure turbine, or high pressure turbine and Two low pressure turbines are connected in a single or tandem manner, and the high pressure turbine and the medium pressure turbine or the high pressure turbine have a steam inlet temperature of 600 to 660 ° C. for the ultrashort rotor, and the low pressure turbine has a steam inlet temperature for the ultrashort rotor. 350 to 400 ° C., which is 3 ° C. above the steam inlet temperature of the high-speed turbine to the ultrashort rotor of the high pressure turbine by the superheater of the boiler. Water vapor heated to a high temperature (preferably from 3 to 10 ° C., more preferably from 3 to 7 ° C.) is introduced into the first stage rotor of the high pressure turbine, and the water vapor exiting the high pressure turbine is heated by the reheater of the boiler. It is heated to a temperature higher than the steam inlet temperature of the medium pressure turbine to the rotor blade of the medium pressure turbine by 2 ° C. or more (preferably 2 to 10 ° C., more preferably 2 to 5 ° C.), and flows into the first stage rotor of the medium pressure turbine. Water vapor from the turbine is preferably brought to a temperature higher than 3 ° C. (preferably 3 to 10 ° C., more preferably 3 to 6 ° C.) above the steam inlet temperature of the low pressure turbine to the ultrashort rotor of the low pressure turbine by means of a coal mill of the boiler. Heated to flow into the first stage rotor of the low pressure turbine, and the final stage rotor of the low pressure turbine has a value of [wing length (inch) x rotational speed (rpm)] of 12; The coal-fired thermal power plant is characterized by consisting of high strength martensitic steel of 5,000 or more.

Further, in the above-mentioned low pressure steam turbine having a high pressure turbine and a medium pressure turbine according to the present invention, or having a high medium pressure integrated turbine, the steam inlet temperature to the ultrashort rotor blade is 350 to 400 ° C (preferably 360 to 380 ° C). Wherein the rotor shaft has a weight ratio of C 0.2 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%, Mo 0.07 to 0.20%, V 0.07 to 0.2% and It is preferable that it consists of low alloy steel which is 92.5% or more of Fe.

In the above-described high pressure steam turbine, the rotor blade has 7 or more stages (preferably 9 to 12 stages) and the blade length is 25 to 180 mm in length from the upstream side to the downstream side of the steam stream, The insertion part diameter of the rotor blade is larger than the diameter of the part corresponding to the stator blade, and the width in the axial direction of the insertion part is larger than the upstream side by three steps or more (preferably 4 to 7 steps). It is preferable that the ratio with respect to the blade length is 0.2 to 1.6 (preferably 0.30 to 1.30, more preferably 0.65 to 0.95) so as to be small along the downstream side from the upstream side.

In the above-described high pressure steam turbine, the present invention has a rotor blade having seven or more stages (preferably nine or more stages) and a blade length of 25 to 180 mm downstream from an upstream side of the steam stream, and adjacent to each other. It is preferable that the ratio of the blade length of the stage is 2.3 or less, and the ratio is gradually larger on the downstream side, and the blade length is larger on the downstream side than on the upstream side.

In the above-described high pressure steam turbine, the present invention is characterized in that the rotor blade has 7 or more stages (preferably 9 or more stages) and the blade length is 25 to 180 mm downstream from the upstream side of the steam stream, and the rotor shaft The width in the axial direction of the portion corresponding to the stator blades of the downstream side is smaller by two or more steps (preferably two to four steps) than the upstream side, and the ratio of the rotor blades to the downstream blade length is 4.5. It is preferable that the said ratio becomes small gradually as it becomes the said downstream side in the following ranges.

In the above-mentioned medium-pressure steam turbine, the rotor blade has a double flow structure having a six-stage or more (preferably 6 to 9 stages) in the symmetrical direction and the blade length is 60 to 300 mm downstream from the upstream side of the steam stream, The insertion mounting portion diameter of the rotor blade of the rotor shaft is larger than the diameter of the portion corresponding to the stator blade, and the width of the insertion mounting portion in the axial direction is two or more steps (preferably 2 to 6 steps) compared with the upstream side of the upstream side. ), And the ratio with respect to the blade length is preferably 0.35 to 0.80 (preferably 0.5 to 0.7), which is small along the downstream side from the upstream side.

In addition, in the above-described medium-pressure steam turbine, the rotor blade has a double flow structure and the blade length having at least six stages in symmetrical direction and the blade length is 60 to 300 mm downstream from the upstream side of the steam stream, adjacent blade length It is preferable that the downstream side is larger than the upstream side, and the ratio is 1.3 or less (preferably 1.1 to 1.2), and gradually increases on the downstream side.

In the above-described medium pressure steam turbine, the rotor blade has a double flow structure having six or more stages in symmetrical symmetry and a blade length of 60 to 300 mm from the upstream side of the steam stream to the downstream side of the rotor shaft. The axial width of the portion corresponding to the stator is smaller in stages in two or more stages (preferably three to six stages) compared to the upstream side, and the ratio of the rotor blades to the downstream blade length of the rotor is 0.80 to It is preferable that the said ratio becomes small gradually as it becomes the said downstream side in the range of 2.50 (preferably 1.0-2.0).

The present invention relates to a low pressure steam turbine in a power plant in which the above-described high pressure turbine and the medium pressure turbine are separately installed, and the rotor blade has a double flow structure and blade length having six or more stages (preferably 8 to 10 stages) in symmetry. 80 to 1300 mm from the upstream side to the downstream side of the water vapor stream, wherein the insertion mounting portion diameter of the rotor blade of the rotor shaft is larger than the diameter of the portion corresponding to the stator blade, and the width in the axial direction of the insertion mounting portion is The downstream side of the upstream side is preferably increased in steps of three or more stages (more preferably, 4 to 7 stages), and the ratio of the blade length is 0.2 to 0.7 (preferably 0.3 to 0.55). It is preferable that it becomes small along the downstream side from.

In addition, the present invention is a low-pressure steam turbine in the case of separately having the above-described high-pressure turbine and medium-pressure turbine, wherein the rotor blade has a double flow structure having six or more stages each in symmetry, and the blade length is downstream from the upstream side of the steam stream. Along the length of the blades of each neighboring stage, the downstream side is larger than the upstream side, and the ratio is gradually in the range of 1.2 to 1.8 (preferably 1.4 to 1.6). It is preferable that the ratio is large.

In the low-pressure steam turbine described above, the rotor blade has a reciprocating symmetrical structure and blade length having six or more stages, preferably eight or more stages, each of which has a blade length of 80 to 80 along the downstream side from the upstream side of the steam stream. 1300 mm, the width in the axial direction of the portion corresponding to the stator portion of the rotor shaft is increased in stages, preferably at least three stages (more preferably four to seven stages) compared to the upstream side, It is preferable that the said ratio becomes small step by step as the ratio with respect to the neighboring downstream wing part length of the said rotor blade becomes the said downstream side in the range of 0.2-1.4 (preferably 0.25-1.25 especially 0.5-0.9).

In the above-described high pressure steam turbine, the rotor blade has seven or more stages, preferably nine or more stages, the rotor shaft has a diameter smaller than the diameter of the portion corresponding to the rotor blade insert portion, The axial width of the diameter corresponding to the vane is increased stepwise in two or more steps (preferably two to four steps) compared with the downstream side of the water vapor stream, and between the final end and the front end of the rotor blade. Is a width of 0.75 to 0.95 times (preferably 0.82 to 0.88 times more than 0.8 to 0.9 times) between the second and third stages of the rotor blade, and the rotor shaft of the rotor shaft The width of the water vapor stream is increased stepwise by three or more steps (preferably 4 to 7 steps) compared with the upstream side, and the width in the axial direction of the final stage of the rotor blade is equal to 2 It is from 1 to 2 times the width direction of the second axis (preferably 1.4 to 1.7 times) is preferable.

In the above-mentioned medium-pressure steam turbine, the rotor blade has six or more stages, the rotor shaft diameter of the portion corresponding to the vane is smaller than the diameter of the portion corresponding to the rotor insertion portion, the diameter corresponding to the vane The width in the axial direction of the upstream side of the water vapor stream is preferably increased stepwise by two or more stages (more preferably, three to six stages), compared to the downstream side, and the width between the last end of the rotor blade and the front end thereof. Is 0.5 to 0.9 times the width (preferably 0.65 to 0.75 times) between the first and second stages of the rotor blade, and the width of the rotor shaft portion of the rotor portion insertion portion of the rotor shaft in the upstream side of the steam stream It is preferably increased stepwise in two or more steps (preferably 3 to 6 steps), and the width in the axial direction of the final end of the rotor blade is equal to the width in the axial direction of the first stage. It is to 0.8 to 2 times (preferably 1.2 to 1.5) is preferred.

In the above-described low pressure steam turbine, the rotor blade has a double-flow structure of at least eight stages in symmetrical symmetry, the rotor shaft has a diameter smaller than the diameter of the portion corresponding to the rotor blade insert portion, The width in the axial direction of the diameter corresponding to the stator is preferably increased stepwise in three or more stages (more preferably in four to seven stages) compared to the downstream side of the steam stream, and the final stage of the rotor blade. The width between the stage and the front end thereof is 1.5 to 3.0 times the width between the first and second stages of the rotor (preferably 2.0 to 2.7 times), and the width of the rotor shaft portion of the rotor shaft in the rotor shaft is axially. The downstream side of the stream is preferably enlarged stepwise in three or more stages (preferably between four and seven stages) as compared to the upstream side, and the width in the axial direction of the final stage of the rotor blade is It is preferable that it is 5 to 8 times (preferably 6.2 to 7.0 times) with respect to the width | variety of the axial direction of the said first stage.

The structures of the above-mentioned high pressure, medium pressure or high medium pressure integrated turbine and low pressure turbine can be the same structure with respect to any one temperature of each use steam temperature of 610-660 degreeC.

In the rotor member of the present invention, it is preferable to adjust the Cr equivalent calculated by the following formula to 4 to 8 in order to obtain high high temperature strength, low temperature toughness and high fatigue strength as the fully martensitic structure.

In the high-medium-pressure integrated steam turbine of the present invention, the rotor of the high pressure side has at least 7 stages, preferably at least 8 stages, and at least 5 stages of the intermediate pressure rotor blades, preferably at least 6 stages, and the rotor shaft has a distance between bearing centers (L). ) Is 6000 mm or more (preferably 6100 to 7000 mm) and the minimum diameter (D) in the part where the vane is installed is 660 mm or more (preferably 620 to 760 mm), and the (L / D) is 8.0 It is characterized by consisting of a high strength martensitic steel containing from 9 to 13% by weight of Cr, which is from 11.3 (preferably 9.0 to 10.0).

The low pressure steam turbine for the high medium pressure integrated turbine of the present invention has the following requirements. In the low pressure steam turbine, the rotor blades are bilaterally symmetrical, each having five or more stages, preferably six or more stages, and having a first stage inserted in the center of the rotor shaft, the rotor shaft having a distance between bearing centers (L). Is 6500 mm or more (preferably 6600-7500 mm) and the minimum diameter D in the part in which the said vane is provided is 750 mm or more (preferably 760-900 mm), and said (L / D) is 7.2- Ni-Cr-Mo-V low-alloy steel containing 3.25-4.25% by weight of Ni, preferably 10.0 (preferably 8.0-9.0), and the final stage rotor has a blade length (inches x revolutions rpm). It consists of high strength martensitic steel with a value of 125,000 or more.

The rotor shaft has a diameter (D) of the vane portion of 750 to 1300 mm, the distance between the center of the bearing (L) is 5.0 to 9.5 times that of the D, the weight ratio of C 0.2 to 0.3%, Si 0.05% or less, Mn 0.1 or less , Low alloy steel with 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 Fe 92.5% or more.

The rotor blades have a lateral symmetry and a double flow structure having five or more stages, preferably six or more stages, in the range of 80 to 1300 mm from the upstream side to the downstream side of the steam stream, and the rotor section of the rotor shaft. The diameter of the insertion portion is larger than the diameter of the portion corresponding to the stator blade, the width of the vicinity of the axial direction of the insertion portion is a trumpet shape, larger than the width of the blade portion insertion portion, and gradually decreases along the upstream side from the downstream side. , The ratio of the blade length is 0.25 to 0.80.

The rotor blades have a lateral symmetry and a double flow structure and a blade length each having five or more stages, preferably six or more stages, are in the range of 80 to 1300 mm from the upstream side to the downstream side of the steam stream, and the blade portions of adjacent stages. The length of the downstream side is larger than that of the upstream side, and the ratio is in the range of 1.2 to 1.7, and the blade length is gradually increased on the downstream side.

The rotor blade has a lateral symmetry and a double flow structure and a blade length each having five or more stages, preferably six or more stages, are increased from the upstream side to the downstream side of the steam stream, and are in the range of 80 to 1300 mm, and the rotor shaft The width | variety of the axial direction of the blade insertion part vicinity part of a rotor blade is large compared with an upstream side by the said downstream side in at least 3 steps, and is a trumpet shape and becomes larger than the width | variety of the said blade insertion part.

The high medium pressure integrated steam turbine in this invention has the following structures.

The rotor blade on the high pressure side has at least 7 stages and the blade length is 40 to 200 mm downstream from the upstream side of the steam stream, and the diameter of the insertion portion of the rotor blade of the rotor shaft is larger than the diameter of the portion corresponding to the stator blade. The upstream side is larger stepwise than the downstream side, and the width of the insertion-mounting portion in the axial direction is larger than the downstream side, and the ratio to the blade length is 0.20 to 1.60, preferably 0.25 to 1.30, along the downstream side from the upstream side. The rotor blade on the medium pressure side has at least five stages in lateral symmetry, and has a blade length of 100 to 350 mm downstream from the upstream side of the steam stream, and the diameter of the rotor shaft of the rotor shaft in the rotor shaft It is larger than the diameter of the corresponding part, and the width in the axial direction of the vicinity of the insertion portion is on the upstream side except for the final end. The ratio with respect to the said blade length becomes large compared with it, and becomes 0.35-0.80, Preferably it is 0.40-0.75, and becomes small along the downstream from the said upstream side.

The rotor blade has more than seven stages and the blade length is 25 to 200 mm downstream from the upstream side of the steam stream, the ratio of the blade length of each adjacent stage is 1.05 to 1.35, the blade length is the downstream side It is gradually larger than the upstream side, the rotor portion of the middle pressure portion has five or more stages, and the blade length is 100 to 350 mm downstream from the upstream side of the water vapor stream, and the adjacent blade length has the downstream side compared with the upstream side. It becomes large and the ratio becomes 1.10-1.30 gradually and becomes large on the said downstream side.

The rotor blade on the high pressure side has six or more stages, preferably seven or more stages, and the rotor shaft has a diameter smaller than that of the portion corresponding to the rotor blade inserting portion, and the rotor shaft has a diameter of the portion corresponding to the rotor blade inserting portion. The width in the axial direction of the vicinity of the portion is the largest in the first stage, and gradually increases in two or more stages, preferably three or more stages, from the upstream side to the downstream side of the steam stream, and the rotor blade on the medium pressure side has five or more stages. The rotor shaft has a diameter of a portion corresponding to the stator blade smaller than a diameter of a portion corresponding to the rotor insertion portion, and an axial width in the vicinity of the insertion portion of the rotor blade is located at an upstream side of the steam stream. In comparison, it is preferably different in stages by four or more stages, and the first stage of the rotor blade is larger than the second stage, and the final stage is larger than the other stage, and the first stage and the second stage are trumpets. It is.

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 to 13.0%, Ni 2 to 3% or less, Mo 1.5 to 3.0%, V 0.05 to 0.35%, Nb and Ta One or two types of total amounts are made of the martensitic steel which contains 0.02 to 0.20% and 0.02 to 0.10%, The steam turbine long blade characterized by the above-mentioned.

The steam turbine blades must have high tensile strength and high cycle fatigue strength to withstand the high centrifugal and vibrational stresses of high speed rotation. Therefore, the metal structure of the blade material should be a completely soothing martensite structure, since the presence of harmful δ ferrite significantly lowers the fatigue strength.

The steel of this invention needs to be adjusted so that Cr equivalent calculated by the above formula may be 10 or less, and substantially does not contain a δ ferrite phase.

The tensile strength of the blade member is 120 kgf / mm 2 or more, preferably 128.5 kgf / mm 2 or more.

Further, in order to obtain a homogeneously high strength steam turbine blade member, as a temper heat treatment, after dissolution and forging, quenching is performed at 1000 ° C. to 1100 ° C., preferably at 0.5 to 3 hours, and then quenched to room temperature, and then 550 ° C. 2 times of first consideration to cool to room temperature after heat holding at 1 to 6 hours preferably at 1 to 6 hours and 2 times of second cooling at room temperature after heat holding at 1 to 6 hours preferably at 560 to 590 ° C. The above mentioned heat treatment is performed.

The present invention provides a 3600 rpm steam turbine and a low pressure turbine end blade length of at least 914 mm (36 inches), preferably at least 965 mm (38 inches), of at least 1092 mm (43 inches). Preferably, it is set as the 3000 rpm steam turbine set to 1168 mm (46 inches) or more, and the value of [blade length (inch) x rotation speed (rpm)] is 125,000 or more, Preferably it is 138,000 or more.

In addition, in the casing member made of the heat-resistant cast steel of the present invention, the alloy composition is adjusted to have 95% or more of martensite (δ ferrite 5% or less) structure to obtain high high temperature roughness, low temperature toughness and high fatigue strength. It is preferable to adjust the Cr equivalent calculated by content of as weight% to 4-10.

Cr equivalent = Cr + 6Si + 4Mo + 1.5W + 11V + 5Nb-40C-30N

-30B-2Mn-4Ni-2Co + 2.5Ta

In the 12 Cr heat-resistant steel of the present invention, in particular, when used in steam of 621 ° C or higher, it is preferable to set it to 625 ° C, 10 ⁵ h creep rupture strength of 10 kgf / mm 2 or more, and room temperature shock absorption energy of 1 kgf-m or more.

(1) The reason for limiting the component range of the 12% Cr steel used for the final stage blade of the low pressure steam turbine according to the present invention will be described.

C needs at least 0.08% to obtain high tensile strength. Too much C deteriorates toughness, so it must be 0.20% or less. In particular, 0.10 to 0.18% is preferable. More preferably, it is 0.12 to 0.16%.

Si is a deoxidizer and Mn is a desulfuric acid deoxidizer and is added at the time of dissolution of the steel, and even a small amount is effective. Si is a δ ferrite generating element, and the addition of a large amount should be 0.25% or less, since it causes harmful δ ferrite generation which reduces fatigue and toughness. In addition, according to the carbon vacuum deoxidation method, the electroslag dissolving method, etc., Si addition is unnecessary and Si addition is good. In particular, 0.10% or less and 0.05% or less are more preferable.

Since a large amount of Mn lowers toughness, it should be 0.9% or less.

In particular, since Mn is effective as a deoxidizer, from the viewpoint of toughness improvement, 0.4% or less, more preferably 0.2% or less is preferable.

Cr increases corrosion resistance and tensile strength, but addition of 13% or more causes δ ferrite structure formation. If less than 8%, the corrosion resistance and tensile strength were insufficient, so Cr was determined to be 8 to 13%. 10.5 to 12.5% is particularly preferable in terms of strength, and more preferably 11 to 12%.

Mo has the effect of raising the tensile strength by solid solution strengthening and precipitation strengthening action. Mo is insufficient to improve the tensile strength, and when 3% or more becomes δ ferrite generation, it is limited to 1.5 to 3.0%. In particular, 1.8 to 2.7%, more preferably 2.0 to 2.5% are preferred. W and Co also have the same effect as Mo.

V and Nb precipitate carbides to increase tensile strength and increase toughness. In V 0.05% and Nb 0.02% or less, the effect is inadequate, and in V 0.35% and Nb 0.2% or more, it becomes a cause of δ ferrite production. In particular, V is 0.15 to 0.30%, more preferably 0.25 to 0.30%, and Nb is preferably 0.04 to 0.15%, more preferably 0.06 to 0.12%. Instead of Nb, all of Ta can be added as well, and complex addition is possible.

Ni increases the low temperature toughness and has an effect of preventing the generation of δ ferrite. This effect is insufficient below Ni 2%, and the effect is saturated with additions above 3%. In particular, 2.3 to 2.9% is preferable. More preferably, it is 2.4 to 2.8%.

N is effective in improving the tensile strength and preventing the formation of δ ferrite, but the effect is insufficient at less than 0.02%, and when it exceeds 0.1%, the toughness is lowered. In particular, excellent characteristics can be obtained in the range of 0.04 to 0.08, more preferably 0.06 to 0.08%.

Reduction of Si, P, and S has the effect of improving low-temperature toughness without damaging the tensile strength, and it is preferable to reduce it as much as possible. In view of improving low temperature toughness, Si is 0.1% or less, P 0.015% or less, and S 0.015% or less are preferable. In particular, Si 0.05% or less, P 0.010% or less, S 0.010% or less are preferable. Reduction of Sb, Sn, and As also has the effect of increasing low-temperature toughness, and it is preferable to reduce it as much as possible, but it is limited to Sb 0.0015% or less, Sn 0.01% or less, and As 0.02% or less from the viewpoint of developing steelmaking technology level. In particular, Sb 0.001%, Sn 0.005% and As 0.01% or less are preferable.

In addition, in this invention, it is preferable to make Mn / Ni ratio into 0.11 or less.

The heat treatment of the material of the invention is first heated uniformly to a temperature sufficient to transform into complete austenite, at least 1000 ° C., at most 1100 ° C., then quenched (preferably oil-cooled), and then heated to a temperature of 550-570 ° C. It is preferable to carry out 2nd consideration after carrying out support and cooling (primary consideration), and carrying out heat holding at the temperature of 560-680 degreeC, and to make it a completely soothing martensite structure.

(2) The reason for limiting the composition of the ferritic heat-resistant steel constituting the high pressure, medium or high pressure integrated rotor, blade, nozzle, internal casing fastening bolt, and medium pressure section ultra-short diaphragm of the 620 to 640 ° C. steam turbine according to the present invention. Explain.

C is an element that is indispensable to secure hardenability, precipitate carbide in the heat treatment process, and increase the high temperature strength, and C is required to obtain high tensile strength over 0.05%, but when it exceeds 0.20%, In this case, the metal structure becomes unstable and lowers the creep rupture strength for a long time, so it is limited to 0.05 to 0.20%. Preferably it is 0.08 to 0.13%, and especially 0.09 to 0.12% is preferable.

Mn is added for the deoxidizer and the like, and its effect is achieved by the addition of a small amount, and a large amount exceeding 1.5% is not preferable because it lowers the creep rupture strength. Especially 0.03-0.20% or 0.3-0.7% is preferable, and, for many, 0.35-0.65% is more preferable. Higher Mn yields higher strength. In addition, the higher the Mn amount, the better the workability.

Although Si is also added as a deoxidizer, Si deoxidation is unnecessary according to steelmaking techniques such as vacuum C deoxidation. By lowering Si, it is effective to prevent harmful δ ferrite structure generation and to reduce the toughness due to grain boundary segregation. Therefore, when adding, it is necessary to suppress it to 0.15% or less, Preferably it is 0.07% or less, Especially less than 0.04% is preferable.

Ni is an element which is very effective in increasing toughness and preventing the formation of δ ferrite, but its effect is not sufficient at less than 0.05%, and addition above 1.0% is not preferable because it lowers the creep rupture strength. Especially 0.3-0.7%, More preferably, 0.4-0.65% are preferable.

Cr is an indispensable element for increasing high temperature strength and high temperature oxidation resistance, and is required at least 9%, but exceeds 13% is limited to 9 to 12% because it generates harmful δ ferrite structure and lowers high temperature strength and toughness. Especially 10 to 12%, More preferably, 10.8 to 11.8% are preferable.

Mo addition is performed for high temperature strength improvement. However, in the case of containing more than 1% of W, such as the steel of the present invention, Mo addition of 0.5% or more is limited to 0.5% or less because it lowers toughness and fatigue strength. 0.05 to 0.45% is particularly preferable, and 0.1 to 0.2% is more preferable.

W suppresses the coarsening of carbides at high temperatures and strengthens the matrix so as to significantly increase the high temperature long time strength of 620 ° C or higher. It is preferable to set it as 1 to 1.5% at 620 degreeC, 1.6 to 2.0% at 630 degreeC, 2.1 to 2.5% at 640 degreeC, 2.6 to 3.0% at 650 degreeC, and 3.1 to 3.5% at 660 degreeC. When W exceeds 3.5%, δ ferrite is generated and the toughness is lowered, so it is limited to 1 to 3.5%. Especially, 2.4 to 3.0% is preferable, More preferably, 2.5 to 2.7% is preferable.

V has the effect of increasing the creep rupture strength by precipitating the carbonitride of V, but the effect is insufficient at less than 0.05%. If V exceeds 0.3%, δ ferrite is produced to lower the fatigue strength. 0.10 to 0.25% is particularly preferable, and 0.15 to 0.23% is more preferable.

Nb is a very effective element for precipitating NbC carbides and increasing high temperature strength, but when added in excessively large amounts, coarse eutectic NbC carbides are produced, especially in large ingots, and conversely, δ, which reduces strength or reduces fatigue strength. Since it causes precipitation of ferrite, it is necessary to suppress it to 0.20% or less. And at less than 0.01% of Nb, the effect is insufficient. In particular, 0.02 to 0.15% is more preferably 0.04 to 0.10%.

Co is an important element which distinguishes and distinguishes the present invention from the conventional invention. In the present invention, the addition of Co significantly improves the high temperature strength and also increases the toughness. This is considered to be due to interaction with W, and is a characteristic phenomenon in the alloy of the present invention containing 1% or more of W. In order to realize such an effect of Co, the lower limit of Co in the alloy of the present invention is 2.0%, but even if it is added excessively, a larger effect cannot be obtained, and since the ductility is lowered, the lower limit is 10%. Preferably 2 to 3% for 620 ° C, 3.5 to 4.5% for 630 ° C, 5 to 6% for 640 ° C, 6.5 to 7.5% for 650 ° C and 8 to 9% for 660 ° C. .

N is also an important element which distinguishes and distinguishes the present invention from the conventional invention. N is effective in improving the creep rupture strength and preventing the formation of the δ ferrite structure, but the effect is not sufficient at 0.01% or less, and when it exceeds 0.05%, the toughness is lowered and the creep rupture strength is also lowered. In particular, 0.01 to 0.03% is more preferably 0.015 to 0.025%.

B has the effect of increasing the high temperature strength by the grain boundary strength action and the action of solidifying in M ₂₃ C ₆ carbide and preventing coagulation coarsening of M ₂₃ C ₆ type carbide, and addition exceeding 0.001% is effective, but 0.03 When it exceeds%, since weldability and forgeability are inhibited, it is limited to 0.001 to 0.03%. Preferably it is 0.001-0.01%, or 0.01-0.02% is preferable.

The addition of Ta, Ti, and Zr has the effect of increasing the toughness, and sufficient effects can be obtained by adding alone or in combination with Ta 0.15% or less, Ti 0.1% or less and Zr 0.1% or less. When Ta is added 0.1% or more, the addition of Nb can be omitted.

At least the first stage of the rotor shaft and the rotor blade and stator in the present invention is C 0.09 to 0.20%, Si 0.15% or less, Mn 0.05 to 1.0%, Cr 9.5 to 12.5%, Ni 0.1 to the steam temperature of 620 to 630 ° C. Fully soothed martensite structure with 1.0%, V 0.05-0.30%, N 0.01-0.06%, Mo 0.05-0.50%, W 2-3.5%, Co 2-4.5%, B 0.001-0.030%, 77% Fe It is preferable that it is comprised by the steel which has. In addition, it is preferable to make the above-mentioned Co amount into 5 to 8% about the vapor temperature of 635-660 degreeC, and to be comprised by the steel which has a fully soothed martensite structure which has 78% or more of Fe. In particular, high strength can be obtained by reducing the amount of Mn to 0.03 to 0.2% and the amount of B to 0.001 to 0.01% with respect to both temperatures. In particular, it contains C 0.09 to 0.20%, Mn 0.1 to 0.7%, Ni 0.1 to 1.0%, V 0.10 to 0.30%, N 0.02 to 0.05%, Mo 0.05 to 0.5%, W 2 to 3.5%, and 630 DEG C or lower. Regarding Co 2 to 4%, B 0.001 to 0.01%, and 630 to 660 ° C, Co 5.5 to 9.0% and B 0.01 to 0.03% are preferred.

4-10.5, especially 6.5-9.5% are preferable with respect to a rotor shaft of Cr equivalent calculated | required by the formula mentioned later, and others are the same.

In the high and medium pressure rotor members of the steam turbine of the present invention, when the δ ferrite structure is mixed, the fatigue strength and toughness are lowered, so that the structure is preferably uniform and martensite structure. In order to obtain the martensitic structure, the Cr equivalent calculated in the above formula must be 10 or less by component adjustment. When Cr equivalent is made too low, creep rupture strength will fall, so it should be made 4 or more. In particular, Cr equivalent 5-8 is preferable.

The rotor of this invention melt | dissolves the alloy raw material made into a target composition in an electric furnace, degasses | carbon-vacuums, inject | pours into a metal mold, and forging-stretches, and produces an electrode rod. The electrode bar is re-dissolved in electroslag, forged and molded into a rotor shape. This forging stretching must be performed at a temperature of 1150 ° C. or lower to prevent forging cracking. In addition, after the annealing heat treatment of the forged steel, the steam turbine rotor can be used in steam of 620 ℃ or more by performing two times in the order of quenching treatment to heat and quench to 1000 to 1100 ℃, 550 to 650 ℃ and 670 to 770 ℃ It can manufacture.

In the present invention, the blade, the nozzle, the inner casing fastening bolt, and the intermediate pressure ultra-short diaphragm are melted by vacuum melting, cast into a mold under vacuum, and an ingot is produced. The ingot is hot forged to a predetermined shape at a temperature as described above, heated to 1050 to 1150 ° C., then water cooled or oil quenched, followed by a soaking treatment at 700 to 800 ° C., to form a blade having a desired shape by cutting. . Vacuum dissolution is carried out under 10 ⁻¹ to 10 ⁻⁴ mmHg. In particular, the heat-resistant steel in the present invention can be used for the whole stages of the blades and the nozzles of the high pressure section and the medium pressure section, but is particularly necessary for the first stage of both.

(3) The composition constituting the high pressure, medium pressure or high medium pressure integrated rotor shaft of the steam turbine of less than 600 to 620 ° C in the present invention is preferably the following.

C is an element that is required at least 0.05% to obtain a high tensile strength, but when the amount exceeds 0.25%, it is limited to 0.05 to 0.25% because the tissue becomes unstable and prolongs creep rupture strength after prolonged exposure to high temperature. . In particular, 0.1 to 0.2% is preferable.

Nb is a very effective element for increasing the high temperature strength, but when added in excessive amounts, coarse precipitation of Nb carbides occurs, especially in large ingots, and also lowers the C concentration of the matrix, but rather decreases the strength or fatigue strength. It is necessary to suppress it to 0.15% or less because it has a defect of precipitating? Ferrite to be reduced. In addition, the effect is insufficient at Nb of less than 0.02%. In particular, 0.07 to 0.12% is preferable.

N is effective in improving the creep rupture strength and preventing the formation of δ ferrite, but the effect is not sufficient at less than 0.025%, and when the content exceeds 0.1%, the toughness is significantly lowered. In particular, 0.04 to 0.07% is preferable.

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

V has an effect of increasing the creep rupture strength, but less than 0.02%, the effect is insufficient. If V exceeds 0.5%, δ ferrite is generated to lower the fatigue strength. In particular, 0.1 to 0.3% is preferable.

Mo improves creep strength by solid solution strengthening and precipitation hardening action, but when the content is less than 0.5%, the effect is small. When Mo exceeds 2%, Mo produces ferrite and reduces toughness and creep rupture strength. In particular, 0.75 to 1.5% is preferable.

Ni is a very effective element for increasing the toughness and preventing the formation of δ ferrite, but when it exceeds 1.5%, the addition lowers the creep rupture strength, which is not preferable. Especially 0.4-1% is preferable.

Mn is added as a deoxidizer, and the effect is achieved with a small amount of addition, and a large amount of more than 1.5% lowers the creep rupture strength. In particular, 0.5 to 1% is preferable.

Although Si is also added as a deoxidizer, Si deoxidation is unnecessary according to steelmaking techniques such as vacuum C deoxidation. In addition, since it is effective in preventing δ ferrite precipitation and improving toughness by lowering Si, it is necessary to suppress it to 0.6% or less. 0.25% is particularly preferred when added.

W significantly increases the high temperature strength. If it is less than 0.1%, the effect is small, and if it exceeds 0.65%, the strength is sharply lowered. W should be 0.1 to 0.65% or less. On the other hand, if W exceeds 0.5%, the toughness is remarkably lowered, so it is preferable to set it to less than 0.5% in the member requiring toughness. In particular, 0.2 to 0.45% is preferable.

Al is added as an effective deoxidizer to 0.02% or less. An amount of Al exceeding 0.02% lowers the high temperature strength.

(4) In the present invention, the steam turbine rotor shaft made of 12 wt% Cr-based martensitic steel preferably forms a high weld layer having bearing characteristics on the surface of the base material forming the journal, and is made of steel. Using the above, preferably the said 3rd thru | or 10th layer of the said welding welding layer is formed, and the Cr amount of the said welding member to one layer of 1st-2nd-4th layer is lowered one by one, and after 4th layer, Welding using a welding member made of steel having the same Cr amount, and making the Cr amount of the welding member used for the welding of the first layer about 2 to 6 wt% smaller than the Cr amount of the base material, and welding after the fourth layer. The amount of Cr in the layer is 0.5 to 3% by weight (preferably 1 to 2.5%).

In the present invention, the wet welding is preferable for improving the bearing characteristics of the journal portion, in terms of the highest safety. Moreover, it can also be set as the structure which heat-fits and fits the sleeve which consists of low-alloy steels with Cr amount 1-3%.

In order to increase the number of welding layers and gradually reduce the amount of Cr, three or more layers are preferable, and even if it welds ten or more layers, the further effect cannot be acquired. As an example a thickness of about 18 mm is required in the final finishing step. In order to form such a thickness, at least five layers of the build-up welding layer are preferable even if the final finishing value due to cutting is excluded. It is preferable that after the 3rd layer, it has a mainly martensite structure and carbide is precipitated. In particular, the composition of the weld layer after the fourth layer contains C by 0.01 to 0.1%, Si 0.3 to 1%, Mn 0.3 to 1.5%, Cr 0.5 to 3%, Mo 0.1 to 1.5% and the balance Fe desirable.

(5) Internal casing regulating valve valve housing, combination reheat valve valve housing, main steam lead pipe, main steam inlet pipe, reheat inlet pipe, high pressure turbine nozzle box, medium pressure turbine of high pressure turbine, medium pressure turbine and high medium pressure turbine of the present invention The reason for limitation of the ferritic heat resistant steel composition which comprises an ultra-short diaphragm, a high pressure turbine main steam inlet flange, an elbow, and a main steam stop valve is demonstrated.

In the ferritic heat-resistant cast steel casing member, in particular, the Ni / W ratio is adjusted to 0.25 to 0.75, which is required for ultra-high threshold pressure turbine high pressure and medium pressure internal casing and main steam stop valve and regulating valve casing at 621 ° C and 250 kgf / cm 2 or more. . A heat resistant cast steel casing member of 625 ° C, 10 ⁵ h creep rupture strength of 9 kgf / mm 2 or more, and room temperature shock absorption energy of 1 kgf-m or more can be obtained.

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

In the 12 Cr heat-resistant steel of the present invention, since it is used in steam of 621 ° C or higher, it must be 625 ° C, 10 ⁵ h creep rupture strength of 9 kgf / mm 2 or more, and room temperature shock absorption energy of 1 kgf-m or more. Moreover, in order to ensure higher reliability, it is preferable that it is 625 degreeC, 10 ⁵ h creep rupture strength 10 kgf / mm <2> or more, and room temperature shock absorption energy 2kgf-m or more.

C is an element necessary for at least 0.06% to obtain a high tensile strength, but when it exceeds 0.16%, the metal structure becomes unstable when exposed to high temperature for a long time and lowers the creep rupture strength for a long time, so it is limited to 0.06 to 0.16%. 0.90 to 0.14% is particularly preferable.

N is effective in improving creep rupture strength and preventing the formation of δ ferrite tissue, but the effect is not sufficient at less than 0.01%, and there is no remarkable effect at more than 0.1%. Also lowers. In particular, 0.02 to 0.06% is preferable.

Mn is added as a deoxidizer, and the effect is achieved by the addition of a small amount, and the addition of a large amount of more than 1% lowers the creep rupture strength, and particularly preferably 0.4 to 0.7%.

Although Si is also added as a deoxidizer, Si deoxidation is unnecessary according to steelmaking techniques such as vacuum C deoxidation. In addition, by lowering Si, it is possible to prevent harmful δ ferrite structure generation. Therefore, when added, it is necessary to suppress it to 0.5% or less, and 0.1 to 0.4% is especially preferable.

V has an effect of increasing creep rupture strength, but less than 0.05%, the effect is insufficient. If V exceeds 0.35%, δ ferrite is generated to lower the fatigue strength. In particular, 0.15 to 0.25% is preferable.

Nb is a very effective element to increase the high temperature strength, but when added in excessively large amounts, especially large ingots produce coarse eutectic Nb carbide, which in turn causes precipitation of δ ferrite, which lowers the strength or decreases the fatigue strength. It is necessary to suppress it to 0.15% or less. In addition, the effect is insufficient at Nb of less than 0.01%. Especially in the case of a large ingot, 0.02 to 0.1% is more preferable.

Ni is a very effective element for increasing toughness and preventing the formation of δ ferrite, but its effect is insufficient at less than 0.2%, and an addition exceeding 1.0% is not preferable because it lowers the creep rupture strength. 0.4 to 0.8% is particularly preferable.

Cr has the effect of improving high strength and high temperature oxidation. If it exceeds 12%, it causes harmful δ ferrite tissue formation, and if it is less than 8%, oxidation resistance to high temperature and high pressure steam is insufficient. In addition, Cr addition has an effect of increasing creep rupture strength, but excessive addition causes harmful δ ferrite structure generation and toughness degradation. In particular, it is 8.0 to 10%, more preferably 8.5 to 9.5%.

W has the effect of significantly increasing the high temperature long time strength. At W less than 1%, the effect is insufficient for the heat resistant steel used at 620 to 660 ° C. In addition, when W exceeds 4%, toughness becomes low. 1.0 to 1.5% at 620 ° C, 1.6 to 2.0% at 630 ° C, 2.1 to 2.5% at 640 ° C, 2.6 to 3.0% at 650 ° C and 3.1 to 3.5% at 660 ° C.

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

Mo addition is performed for high temperature strength improvement. However, in the case of containing more than 1% of W, such as the cast steel of the present invention, since 1.5% or more of Mo decreases toughness and fatigue strength, 1.5% or less is preferable, particularly 0.4 to 0.8%, more preferably 0.55. To 0.70% is preferred.

The addition of Ta, Ti, and Zr has the effect of increasing the toughness, and sufficient effects can be obtained by adding alone or in combination with Ta 0.15% or less, Ti 0.1% or less and Zr 0.1% or less. When Ta is added 0.1% or more, the addition of Nb can be omitted.

In the heat-resistant cast steel casing member of the present invention, when the δ ferrite structure is mixed, the fatigue strength and toughness are lowered, and therefore, the martensite structure is preferably uniform in structure. In order to obtain the martensitic structure, the Cr equivalent calculated in the above formula must be 10 or less by component adjustment. When Cr equivalent is made too low, creep rupture strength will fall, so it must be made 4 or more. In particular, Cr equivalent 6-9% is preferable.

The addition of B significantly increases the high temperature (above 620 ° C) 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 preferably 0.0028%, more preferably 0.0005 to 0.0025%, particularly preferably 0.001 to 0.002%.

The casing covers high pressure steam of 620 ° C. or higher, and thus high stress acts on the internal pressure. Therefore, 10 ⁵ h creep rupture strength of 10 kgf / mm 2 or more is required from the viewpoint of creep fracture prevention. In addition, since the thermal stress acts when the metal temperature is low at the start, a room temperature shock absorbing energy of 1 kgf-m or more is required from the viewpoint of preventing brittle fracture. On the higher temperature side, reinforcement is aimed at by containing 10% or less of Co. In particular, 1 to 2% for 620 ° C, 2.5 to 3.5% for 630 ° C, 4 to 5% for 640 ° C, 5.5 to 6.5% for 650 ° C, and 7 to 8% for 660 ° C. At 600-620 degreeC, you may add no addition.

In order to manufacture a casing with a small defect, since it becomes large about 50 tons of ingot weight, advanced manufacturing technology is required. The ferritic heat-resistant cast steel casing member of the present invention can produce a healthy one by dissolving an alloy raw material having a target composition in an electric furnace and after injection ladle refining, by injection molding into a sand mold. By performing sufficient refining and deoxidation before injection, casting defects, such as a shrinkage cavity, can be made small.

In addition, the annealing heat treatment of the cast steel at 1000 to 1150 ℃, and then subjected to two times in the order of annealing heat treatment to be quenched by heating to 1000 to 1100 ℃, 550 to 750 ℃ and 670 to 770 ℃ in the steam of 621 ℃ or more Usable steam turbine casings can be made. In the annealing and annealing temperature, carbonitride cannot be fully dissolved at 1000 degrees C or less, and when too high, it will cause coarse crystal grains. Then, the two-time soak can completely decompose the retained austenite and have a uniform sour martensite structure. By producing by the above production method, it is possible to obtain 625 ° C of 10 kgf / mm 2 or more, 10 ⁵ h creep rupture strength and 1 kgf-m of room temperature shock absorbing energy, and to use a steam turbine casing that can be used in steam of 620 ° C or higher. have.

When O exceeds 0.015%, since high temperature strength and toughness fall, 0.015% or less is preferable, and 0.010% or less is especially preferable.

It is preferable that the casing in this invention is made into Cr equivalent mentioned above, and (delta ferrite amount is 5% or less), More preferably, it is 0%.

It is preferable to manufacture the inner casing by forging steel in addition to manufacturing by cast steel.

(6) other

(A) Low pressure steam turbine rotor shafts by weight ratio of C 0.2 to 0.3%, Si 0.1% or less, Mn 0.2% or less, Ni 3.2 to 4.0%, Cr 1.25 to 2.25%, Mo 0.1 to 0.6%, V 0.05 to 0.25% Low-alloy steels having a fully known bainite structure with a metal are preferable, and are preferably produced by a manufacturing method such as the high pressure and medium pressure rotor shafts described above. Particularly, the amount of Si is less than 0.05%, Mn is 0.1% or less, and other impurities such as P, S, As, Sb, Sn, etc. are used so that the total amount of the raw materials used is less than 0.025% by using raw materials with the lowest possible amount. It is preferable to set it as the supercleaned manufacture to be used. P and S are preferably 0.010% or less, Sn, As 0.005% or less, and Sb 0.001% or less.

(B) Other than the final end of the blade for low pressure turbines and the nozzles are fully soothed martensitic steels with C 0.05 to 0.2%, Si 0.1 to 0.5%, Mn 0.2 to 1.0%, Cr 10 to 13%, Mo 0.04 to 0.2% This is preferred.

(C) Carbon cast steels having C 0.2 to 0.3%, Si 0.3 to 0.7%, and Mn 1% or less are preferred for both the inner and outer casings for the low pressure turbine.

(D) the main steam stop valve casing and the steam regulating valve casing are C 0.1 to 0.2%, Si 0.1 to 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%, Preferred martensitic steels containing V 0.1 to 0.3%, Nb 0.03 to 0.1%, N 0.03 to 0.08%, and B 0.0005 to 0.003% are preferred.

(E) Ti alloys other than 12% Cr steel are used as final stage rotors of low pressure turbines, in particular Ti alloys having 5 to 8% by weight of Al and V 3 to 6% by weight for lengths exceeding 40 inches. do. In particular, a high-strength material having an Al of 5.5 to 6.5%, V 3.5 to 4.5% at 43 inches, and an Al 4 to 7% V 4 to 7% and Sn 1 to 3% at 46 inches is preferable.

(F) External casings for high pressure turbines, medium and high pressure turbines include C 0.10 to 0.20%, Si 0.05 to 0.6%, Mn 0.1 to 1.0%, Ni 0.1 to 0.5%, Cr 1 to 2.5%, Mo 0.5 to 1.5 %, Containing from 0.1 to 0.35% of V, preferably made of cast steel containing at least one of 0.025% or less of Al, 0.0005 to 0.004% of B and 0.05 to 0.2% of Ti, and having a fully soaked bainite structure It is preferable. In particular, C 0.10 to 0.18%, Si 0.20 to 0.60%, Mn 0.20 to 0.50%, Ni 0.1 to 0.5%, Cr 1.0 to 1.5%, Mo 0.9 to 1.2%, V 0.2 to 0.3%, Al 0.001 to 0.005%, Cast steels comprising 0.045 to 0.10% Ti and 0.0005 to 0.0020% B are preferred. More preferably, the Ti / Al ratio is 0.5 to 10.

(G) Ultrashort blades of high pressure, medium pressure, and high pressure turbines (high pressure side and medium pressure side) at steam temperatures of 625 to 650 ° C. with a weight ratio of C 0.03 to 0.20% (preferably 0.03 to 0.15%), Cr 12 to 20%, Mo 9-20% (preferably 12-20%), Co 12% or less (preferably 5-12%), Al 0.5-1.5%, Ti 1-3%, Fe 5% or less, Si Ni base alloys containing one or more of 0.3% or less, Mn 0.2% or less, B 0.003 to 0.015%, Mg 0.1% or less, rare earth elements 0.5% or less, and Zr 0.5% or less are used. The following also includes 0%. After forging, the solution is subjected to solution treatment and aged at 700 to 870 ° C.

<Example 1>

Table 1 shows the chemical composition (% by weight) of 12% Cr steels for the steam turbine benefit material. Each sample was melt | dissolved by 150 kg vacuum arc, and heated and forged at 1150 degreeC, respectively, and it was set as the experimental material. Sample No. 1 was cooled to room temperature by oil quenching after 1h heating to 1000 degreeC, and it heated at 570 degreeC, and then cooled to room temperature after 2 h holding | maintenance. No. 2 was cooled to room temperature by oil quenching after 1 h of heating to 1050 ° C, and then heated to 570 ° C to cool to room temperature after 2h holding. Sample No. 3 to No. 6 is heated to 1050 ℃ 1h, then cooled to room temperature by oil quenching, then heated to 560 ℃ to hold for 2h, then cooled to room temperature (primary consideration), and heated to 580 ℃ to be cooled to room temperature after 2h holding (Second opinion).

In Table 1, No. 3, 4, and 5 are materials of the present invention, No. 6 is a comparative material and No. 1 and 2 are the present field materials.

Table 2 shows the mechanical properties of these samples at room temperature. The materials of the present invention (Nos. 3 to 5) are characterized by tensile strength (120 kgf / mm 2 or more or 128.5 kgf / mm 2 or more) and low temperature toughness (20 ° C. V notch Charpy impact value 2.5 kgf-m /) required as a steam turbine benefit material. Cm 2 or more) was confirmed to be sufficiently satisfied.

In contrast, the No. 1 and 6 are low values for tensile strength and impact value for use as a steam turbine benefit. Comparative Material Sample No. 2 has low tensile strength and toughness. No. 5 has a slightly lower impact value of 3.8 kgf-m / cm 2, and slightly less than 4 kgf-m / cm 2 or more for 43 inches or more.

1 is a diagram showing the relationship between the (Ni-Mo) amount and the tensile strength. In the present embodiment, the content and content of Ni and Mo are added to increase the strength and toughness at low temperature at the same time, and the strength tends to decrease as the difference between the two contents increases. When the amount of Ni becomes 0.6% or more smaller than the amount of Mo, the strength decreases rapidly. On the contrary, the strength decreases rapidly as the amount of Ni increases by 1.0% or more. Therefore, the (Ni-Mo) amount of -0.6 to 1.0% shows high strength.

Fig. 2 is a diagram showing the relationship between the (Ni-Mo) amount and the impact value. As shown in the figure, the (Ni-Mo) amount shows a high value at around -0.5% while the impact value decreases.

4 to 6 show Sample No. 3 is a diagram showing the influence of heat treatment conditions (annealing temperature and secondary consideration temperature) on tensile strength and impact value of 3. FIG. After the quenching temperature is performed at 975 to 1125 ° C and the first source of 550 to 560 ° C, the second source temperature is 560 to 590 ° C. As shown in the figure, it was confirmed that the characteristics (tension strength ≧ 128.5 kgf / mm 2, 20 ° C. V notch Charpy impact value ≧ 4 kgf −m / cm 2) required as the blade material were satisfied. 3 and 5 are 575 ° C, and the quenching temperature of Figs. 4 and 6 is 1050 ° C.

Fig. 7 is a diagram showing the relationship between tensile strength and impact value. As described above, the 12% Cr steel in the present embodiment preferably has a tensile strength of 120 kgf / mm 2 or more and an impact value of 4 kgf −m / cm 2 or more, but the impact value y is [-0.45 × (tension strength) It is especially preferable to set it as the value calculated | required by +61.5].

As for 12% Cr steel which concerns on this invention, C + Nb amount is 0.18 to 0.35% especially, (Nb / C) ratio is 0.45 to 1.00, and (Nb / N) ratio is preferable 0.8-3.0.

<Example 2>

A steam temperature of 600 ° C to 649 ° C pulverized coal direct combustion boilers and steam turbines are required to improve thermal efficiency by improving steam conditions in response to the fuel cost surge after oil shock. An example of such a steam condition boiler is shown in Table 3.

Along with the increased capacity, pulverized coal-fired furnaces are enlarged, and the furnace width is 31m, furnace depth 16m, furnace depth 34m and furnace depth 18m at 1050 MW.

Table 4 gives the main specifications for a steam temperature of 625 ° C and a 1050 MW steam turbine. In this example, the final wing length of the cross-compound type 4-class exhaust and low pressure turbine is 43 inches, A is 3000 r / min with two HP-IP and LP, and B is HP-LP and IP-LP, respectively. Similarly, it has the rotation speed of 3000 r / min, and is comprised by the main material shown to a table in a high temperature part. The steam temperature of the high pressure part HP is a pressure of 625 degreeC and 250 kgf / cm <2>, and the steam temperature of the medium pressure part IP is heated by a reheater to 625 degreeC, and is operated by the pressure of 45-65 kgf / cm <2>. The low pressure (LP) vapor temperature enters 400 ° C. and is transferred to the condenser in a vacuum of 100 ° C. or less and 722 mm Hg.

FIG. 8 is a sectional configuration diagram of the high pressure and medium pressure steam turbine in the turbine configuration A of Table 4. FIG. The high pressure steam turbine is provided with a high pressure axle (high pressure rotor shaft) 23 in which a high pressure rotor 16 is inserted into a high pressure inner compartment 18 and an outer high pressure outer compartment 19. The above-mentioned high temperature and high pressure steam can be obtained by the above-described boiler, and from the flange, elbow 25, which constitutes the main steam inlet through the main steam pipe, from the nozzle box 38 through the main steam inlet 29 through the main steam inlet Induced by rotor blade. The first stage is double-flow and 8 stages are installed on one side. Corresponding to these rotor blades, static vanes are respectively provided. The rotor has a saddle-shaped dovetail type, double tinn and ultrashort blade length of about 35 mm. The length between the axles is about 5.8 m and the diameter of the smallest part in the portion corresponding to the stator is about 710 mm and the ratio of length to diameter is about 8.2.

The rotor blades of the first and final stages of the rotor shaft are almost equal in width, and gradually decrease along the downstream side in the fifth stage of the second, third, fifth, sixth, and seventh to eighth stages, and the second stage is installed. The negative axial width is 0.71 times the opposite end.

As for the part corresponding to the stator blade of a rotor shaft, the rotor shaft diameter becomes small with respect to the rotor blade insertion part. The width in the axial direction of the part is gradually reduced to the width between the final stage rotor and the immediately preceding rotor in relation to the width between the 2nd stage rotor and the 3rd stage rotor, and the latter width is 0.86 times smaller than the former width. ought. It is made small in 2 steps from 2nd stage to 6th stage, and 6th stage to 9th stage.

In the present embodiment, the materials shown in Table 5 described later are all composed of 12% Cr-based steel that does not contain W, Co, and B except for using the ultra short blades and the nozzles. The blade length of the rotor blade in this embodiment is longer at each stage as the first stage becomes 35 to 50 mm and the second stage to the final stage, and in particular, the length from the second stage to the final stage is 65 to 180 by the output of the steam turbine. It is mm, and the number of stages is 9-12, and the length of each blade | wing part becomes longer in the ratio of 1.10-1.15 of the length which adjoins downstream compared with an upstream side, and the ratio is gradually increasing in the downstream side.

The medium pressure steam turbine rotates the generator together with the high pressure steam turbine by the steam heated by the reheater to the steam discharged from the high pressure steam turbine again, and is rotated by the rotation speed of 3000 times / min. The medium pressure turbine has a medium pressure internal compartment 21 and an external compartment 22 similarly to a high pressure turbine, and a stator is provided against the medium pressure rotor blade 17. The rotor blade 17 is divided into six stages in six stages, and is installed at right and left symmetrically with respect to the longitudinal direction of the medium pressure axle (medium pressure rotor shaft). The distance between the centers of the bearings is about 5.8 m, the ultra short blade length is about 100 mm and the final blade length is about 230 mm. The first and second stage dovetails are reverse cut. The diameter of the rotor shaft corresponding to the stator in front of the final rotor is about 630 mm and the ratio of the distance between bearings to that diameter is about 9.2 times.

The rotor shaft of the medium pressure steam turbine according to the present embodiment has a axial width of the rotor insert installation portion gradually increasing in three stages from the first stage to the fourth stage, the fifth stage and the final stage, and the width at the final stage is about 1.4 times larger than the initial stage. have.

The rotor shaft of the present steam turbine has a smaller diameter corresponding to the stator blade portion, and the width thereof becomes smaller in four stages depending on the first stage rotor, two to three stages, and the final stage rotor blade. The width in the axial direction is about 0.7 times smaller.

In this embodiment, a 12% Cr-based steel is used which does not contain W, Co, and B, which are used for ultrashort blades and nozzles in the materials shown in Table 5 described later. In the present embodiment, the length of the rotor blade portion is increased at each stage as it is from the first stage to the final stage, and the length from the first stage to the final stage is 60 to 300 mm by the output of the steam turbine. As for the length of a blade | wing part, the length which adjoins the length downstream of the upstream side is 1.1-1.2.

The insertion portion of the rotor blade is larger in diameter than the portion corresponding to the stator blade, and the width of the blade portion is larger as the blade length of the rotor blade is larger. The ratio of the width to the rotor blade length is 0.35 to 0.8 from the first stage to the final stage, and gradually decreases from the first stage to the final stage.

9 is a sectional view of a low pressure turbine. Two low-pressure turbines are connected in tandem and have almost the same structure. Each of the rotor blades 41 has eight stages to the left and right, becomes substantially symmetrical to the left and right, and the stator blades 42 are provided corresponding to the rotor blades. The blade length of the last stage was 43 inches, and No. A 12% Cr steel of 7 is used, and has a double tinnon, saddle-shaped dovetail as shown in FIG. 10, and the nozzle box 44 is a double flow type. The rotor shaft 43 has a forged steel having a fully polished bainite structure of a super clean material composed of Ni 3.75%, Cr 1.75%, Mo 0.4%, V 0.15%, C 0.25%, Si 0.05%, Mn 0.10%, and the remaining Fe. Is used. As for the rotor blade and the stator blade other than the final stage, 12% Cr steel containing 0.1% of Mo is used. Cast steel of C 0.25% is used for the inner and outer casing members. The center-to-center distance in the bearing 43 in this embodiment is 7500 mm, the diameter of the rotor shaft corresponding to the stator blade portion is about 1280 mm, and the diameter in the rotor blade insert portion is 2275 mm. The distance between the bearing centers for this rotor shaft diameter is about 5.9.

10 is a perspective view of a 1092 mm (43 inch) long blade. 51 is a blade portion where high-speed steam abuts, 52 is a blade insertion portion to the rotor shaft, 53 is a hole for inserting a pin for supporting the centrifugal force of the blade, 54 is an erosion shield to prevent erosion by water droplets in the steam (Co The stellite plate of base alloy is joined by welding), and 57 is a cover. In this embodiment, it is formed by cutting after all integral forging. In addition, the cover 57 may be formed integrally mechanically.

The 43-inch long blade was melted by an electroslag remelting method and subjected to forging heat and treatment. Forging was performed in the temperature range of 850-1150 degreeC, and heat processing was performed on the conditions shown in Example 1. No. of Table 1 7 shows the chemical composition (weight%) of this palm member. The metal structure of this funeral was a fully considered martensite structure.

No. of Table 1 7 shows room temperature tension and 20 degreeC V notch Charpy impact value. It was confirmed that the mechanical properties of the 43-inch long blade had required characteristics, a tensile strength of 128.5 kgf / mm 2 or more, and a 20 ° C. V notch Charpy impact value of 4 kgf −m / cm 2 or more, and were sufficiently satisfied.

In the low pressure turbine of the present embodiment, the width in the axial direction of the rotor insertion installation portion is gradually increased in four stages of first to third stage, four stages, five stages, six to seven stages, and eight stages, and the width of the final stage is larger than that of the first stage. It is about 6.8 times bigger.

And the diameter of the part corresponding to a stator blade part becomes small, the width | variety of the axial direction of the part becomes gradually larger in three steps of 5th stage, 6th stage, and 7th stage from the first stage rotor blade side, and the width | variety of the final stage side is the first stage and the second stage About 2.5 times larger.

In the present embodiment, the rotor blade has six stages, and the blade length is longer at each stage as it becomes the final stage of about 3 inches to 43 inches of the first stage, and the length of the final stage is 80 from the first stage by the output of the steam turbine. It is 1100 mm, and the length of the blade | wing of each stage in 8 steps | paragraphs or 9 steps | paragraphs becomes longer by the ratio of 1.2 to 1.8 times the length which adjoins downstream compared with an upstream side.

The insertion portion of the rotor blade is larger in diameter than the portion corresponding to the stator blade, and the width of the blade is larger as the blade length of the blade is larger. The ratio of the width to the rotor blade length is 0.15 to 0.91 from the first stage to the final stage, and gradually decreases from the first stage to the final stage.

In addition, the width of the rotor shaft of the portion corresponding to each vane increases stepwise at each stage from the first stage and the second stage to the final stage and immediately preceding stage. The ratio with respect to the blade length of the rotor blade of the width becomes 0.25-1.25 as it becomes downstream from an upstream side.

The same configuration can be applied to a 1000 MW class large-scale power generation plant having a steam inlet temperature of 610 ° C. to the high pressure steam turbine and a medium pressure steam turbine other than the present embodiment, and a steam inlet temperature of 385 ° C. to the two low pressure steam turbines.

The high temperature high pressure steam turbine plant in this embodiment is mainly a coal-only combustion boiler, a high pressure turbine, a medium pressure turbine, two low pressure turbines, a condenser, a plurality of pumps, a low pressure water heater system, a deaerator, a boost pump, a water feed pump, a high pressure water supply It consists of a heater and the like. That is, the ultra-high pressure steam generated in the boiler enters the high pressure turbine to generate power, and is then reheated in the boiler to enter the medium pressure turbine to generate power. The medium pressure turbine exhaust steam enters the low pressure turbine to generate power, and then condenses in the condenser. This condensate is transferred from a plurality of pumps to a low pressure feed water heater system, a degasser. The degassed water from this deaerator is transferred to the high pressure water heater from the boost pump and the feed pump, is raised, and then returned to the pump.

Here, the water supply in the boiler is steam of high temperature and high pressure through a coal mill, an evaporator, and a superheater. On the other hand, the boiler combustion gas which heated the steam exits a coal mill, and enters an air heater, and heats air. Here, the feed pump drive turbine which operates with the bleed steam from a medium pressure turbine is used for driving a feed pump.

In the high temperature high pressure steam turbine plant configured as described above, since the temperature of the water supply from the high pressure water heater system is much higher than the temperature of the water supply in the conventional thermal power plant, the temperature of the combustion gas from the coal firer in the boiler is inevitably also increased in the conventional boiler. Much higher than that. For this reason, the heat recovery from this boiler exhaust gas is measured, and a gas temperature is not reduced.

In addition, instead of the present embodiment, the same high-pressure turbine, medium-pressure turbine and one or two low-pressure turbines can be similarly configured as a tandem compound type power plant in which tandem type is connected and power is generated by rotating one generator. As in the present embodiment, in the output 1050 MW class generator, a higher strength one is used as the generator shaft. In particular, a fully considered bainite structure containing C 0.15 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%, Mo 0.25 to 0.60%, V 0.05 to 0.20% It is preferable to have a tensile strength of 93 kgf / mm 2 or more, in particular 100 kgf / mm 2 or more, and 50% FATT of 0 ° C. or less, especially −20 ° C. or less, and the magnetization force at 21.2 KG is 985 AT / cm. It is preferable to make it into the following and to make the total amount of P, S, Sn, Sb, and As into 0.025% or less and Ni / Cr ratio to 2.0 or less as an impurity.

The high pressure turbine shaft has a structure in which nine blades are inserted and installed around the ultra-stage blade insertion installation unit on the multi-stage side. In the medium pressure turbine shaft, the blade insert installation part is provided in a symmetrical manner with six stages each of which the multi-stage blades are right and left, and is almost centered. Although the rotor shaft for low pressure turbine is not shown, the center hole is also provided in the rotor shaft of any turbine of a high pressure, medium pressure, and low pressure turbine, and the defect is prevented by ultrasonic inspection, visual inspection, and fluorescence damage through this center hole. The presence is checked. Moreover, since it can carry out by an ultrasonic test from an outer surface, it is not necessary to have a center hole.

Table 5 shows the chemical composition (weight%) used for the main parts of the high pressure turbine, the medium pressure turbine, and the low pressure turbine of a present Example. In this embodiment, the high-temperature portion and the high-temperature portion were assumed to have a thermal expansion coefficient of about 12 × 10 ⁻⁶ / ° C. having a ferrite-based crystal structure, so there was no problem due to the difference in the thermal expansion coefficient.

The rotor shaft of the high pressure turbine and the medium pressure turbine melts 30 tons of the heat-resistant cast steel shown in Table 5 in an electric furnace, degassing carbon in carbon, injects and forges the mold into a mold mold, and fabricates an electrode rod from the upper portion of the cast steel to the lower portion. The electroslag was melt | dissolved so that it might melt | dissolve, and forging-stretched and shape | molded to rotor shape (diameter 1050mm, length 3700mm). This forging stretching was performed at a temperature of 1150 ° C. or lower to prevent forging cracking. After the annealing heat treatment, the forged steel was heated to 1050 ° C, subjected to water spray cooling quenching treatment, twice at 570 ° C and 690 ° C, and obtained by cutting into the shapes shown in FIGS. 5 and 6. In the present Example, the upper side of the electroslag ingot was made into the ultra short blade | wing side, and the lower side was made into the final edge side.

Similarly, the blades and nozzles of the high pressure part and the medium pressure part melted the heat-resistant steels shown in Table 5 in a vacuum arc melting furnace, and were forged and molded into blade and nozzle material shapes (width 150 mm, height 50 mm, length 1000 mm). This forging stretching was performed at a temperature of 1150 ° C. or lower to prevent forging cracking. Moreover, this forged steel is heated to 1050 degreeC, the oil quenching process is performed at 690 degreeC, and is then cut into predetermined shape.

The inner casing of the high pressure section and the medium pressure section, the main steam stop valve casing, and the steam regulating valve casing melted the heat-resistant cast steel shown in Table 5 in an electric furnace, and after injection ladle refining, was injected into a sand mold. By performing sufficient refining and deoxidation before injection, it was possible to be free from casting defects such as shrinkage cavities. The weldability evaluation using this casing member was performed based on JISZ3158. The preheating, interpass, and postheating start temperatures were 200 ° C and the postheating treatment was 400 ° C x 30 minutes. Weld cracks could not be confirmed in the member of this invention, and weldability was favorable.

Table 6 shows the mechanical properties and heat treatment conditions obtained by cutting and irradiating the main members of the high temperature steam turbine made of the ferritic steel described above.

As a result of examining the center of the rotor shaft, it was confirmed that the characteristics (625 ° C., 10 ⁵ h strength ≥ 10 kgf / mm 2, 20 ° C. impact absorption energy ≥ 1.5 kgf-m) required for the high pressure and medium pressure turbine rotor were sufficiently satisfied. . This demonstrated that the steam turbine rotor which can be used in steam of 620 degreeC or more can be manufactured.

As a result of investigating the characteristics of the blade, it was confirmed that the characteristics (625 ° C., 10 ⁵ h strength ≥ 15 kgf / mm 2) required for the ultrashort blades of the high pressure and medium pressure turbine were sufficiently satisfied. This demonstrated that the steam turbine blade which can be used in steam of 620 degreeC or more can be manufactured.

As a result of calculating the casing's characteristics, it is sufficient to meet the characteristics required for high and medium pressure turbine casings (625 ° C, 10 ⁵ h strength ≥ 10 kgf / mm2, 20 ° C impact absorption energy ≥ 1 kgf-m) and welding. It was confirmed that it was possible. This demonstrated that the steam turbine casing which can be used in steam of 620 degreeC or more can be manufactured.

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

A covered arc welding rod (4.0 φ in diameter) was used as the welding rod for testing. Although the welding was carried out using the electrode, the chemical composition (wt%) of the weld metal is shown in Table 7. The composition of this weld metal is substantially the same as the composition of a welding member.

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

As shown in Table 8 on the surface of the test base material for the above-described welding, eight-layer welding was performed by combining the electrode used for each layer. The thickness of each layer was 3-4 mm, the total thickness was about 28 mm, and the surface was ground about 5 mm.

Welding construction conditions are preheating, pass-through, stress relief annealing (SR) start temperature of 250-350 degreeC, and SR processing conditions are 630 degreeC x 36 hours hold | maintain.

In order to confirm the performance of a welded part, the board member was similarly grown and welded (welded in a bulging state) and subjected to a 160 ° side bending test, but no crack was found in the welded part.

Moreover, although the bearing sliding test by the rotation in this invention was done, all had no bad influence to a bearing, and were excellent also in oxidation resistance.

Instead of the present embodiment, in the tandem type power plant in which the high pressure steam turbine, the medium pressure steam turbine and one or two low pressure steam turbines are combined in tandem, and the turbine configuration (B) of Table 4 and the turbine configuration (B) of Table 4 The high pressure turbine, the medium pressure turbine, and the low pressure turbine can be configured similarly.

<Example 3>

Table 9 lists the main specifications for a 600 MW steam turbine with a steam temperature of 600 ° C. This embodiment has a final wing length of 43 inches in a tandem compound double-flow, low-pressure turbine, and has a rotation speed of 3000 r / min for one HP / IP integrated unit and one LP (C) or two (D). In the high temperature part, it is comprised by the main material shown in the table | surface. The steam temperature of the high pressure part HP is 600 degreeC and the pressure of 250 kgf / cm <2>, The steam temperature of the medium pressure part IP is heated to 600 degreeC by a reheater, and is operated by the pressure of 45-65 kgf / cm <2>. The low pressure (LP) vapor temperature enters 400 ° C. and is transferred to the condenser in a vacuum of 100 ° C. or less and 722 mm Hg.

Fig. 11 is a sectional configuration diagram of the high pressure medium pressure integrated steam turbine, and Fig. 12 is a sectional view of the rotor shaft. The high pressure side steam turbine is provided with a high medium pressure axle (high pressure rotor shaft) 33 in which a high pressure side rotor 16 is inserted into an inner compartment 18 and an outer outer compartment 19 thereof. The above-mentioned high temperature and high pressure steam can be obtained by the above-described boiler, and the first stage rotor blade from the nozzle box 38 through the main steam inlet 28 from the elbow 25, the flange constituting the main steam inlet through the main steam pipe. Is induced. The rotor blades are provided in eight stages on the high pressure side on the left side of the figure and six stages on the medium pressure side (about 1/2 of the right side in the figure). Corresponding to these rotor blades, static vanes are respectively provided. The rotor blade has a saddle type or clogs type dovetail type, double tinon, about 40 mm in the high pressure side short blade length, and 100 mm in the medium pressure side ultra short blade length. The length between the bearings 43 is about 6.7 m and the diameter of the smallest part in the portion corresponding to the stator is about 740 mm and the ratio of the length to the diameter is about 9.0.

The width of the first and final stages of the rotor shaft of the high-pressure side rotor shaft is the widest at the first stage, the second to seventh stage is smaller than that, and 0.40 to 0.56 times the first stage, and the final stage is the same as both the first and second stages. It is between the stage sizes and is 0.46 to 0.62 times the size of the first stage.

In the high pressure side, a blade and a nozzle are comprised by 12% Cr type steel shown in Table 5 mentioned later. The blade length of the rotor blade in this embodiment is longer at each stage as the first stage becomes 35 to 50 mm and the second stage is the final stage, and in particular, the length from the second stage to the final stage is 50 by the output of the steam turbine. It is in the range of to 150 mm, the number of stages is in the range of 7 to 12 stages, and the length of the blade portion of each stage is longer in the range of 1.05 to 1.35 times the length of the downstream side adjacent to the upstream side, The ratio is gradually increasing on the downstream side.

The medium pressure side steam turbine rotates the generator together with the high pressure steam turbine by the steam heated by the reheater to the steam discharged from the high pressure side steam turbine again to 600 ℃, it is rotated by the rotation speed of 3000 RPM. The medium pressure side turbine has an internal compartment 21 and an external compartment 22 similarly to the high pressure side turbine, and the vane is provided against the rotor blade 17. The rotor blade 17 has six stages. Ultrashort blade length is about 130 mm and final blade length is about 260 mm. The dovetail is reverse cut. The diameter of the rotor shaft corresponding to the vane is about 740 mm.

The rotor shaft of the medium-pressure steam turbine has the largest axial width in the vicinity of the rotor roots, the second stage is smaller, the third to fifth stages are smaller than the second stage, and the final stages are the same in the third and fifth stages and the second stage. Size between, 0.48 to 0.64 times of the first stage. The first stage is 1.1 to 1.5 times of the second stage.

On the medium pressure side, a 12% Cr-based steel shown in Table 5 below describing the blades and the nozzles is used. In the present embodiment, the length of the rotor blade portion becomes longer at each stage as it becomes from the first stage to the final stage, and the length from the first stage to the final stage is 90 to 350 mm and the number of stages is 6 to 9 stages by the output of the steam turbine. It is in a range, and the length of the blade | wing part of each stage is long in the ratio of 1.10-1.25 in the length which a downstream side adjoins with respect to an upstream side.

The blade insert portion is larger in diameter than the portion corresponding to the stator blade, and its width is related to the blade length and position of the blade blade. The ratio of the rotor blade length to the width is the largest at the first stage, 1.35 to 1.80 times, the second stage is 0.88 to 1.18 times, and the third to sixth stage becomes the final stage, and is 0.40 to 0.65 times.

13 is a sectional view of a low pressure turbine and FIG. 14 is a sectional view of the rotor shaft thereof. The low-pressure turbine is a tandem type coupled to high medium pressure in one unit. The rotor blade 41 has six stages in the left and right, and becomes substantially symmetrical in left and right, and the stator blade 42 is provided correspondingly to the rotor blade. The blade length of the final stage is 43 inches, and 12% Cr steel or Ti base alloy shown in Table 1 is used. An aging hardening process is performed and Ti base alloy contains A16% and V4% by weight ratio. The rotor shaft 43 has a forged steel having a fully polished bainite structure of a super clean material composed of Ni 3.75%, Cr 1.75%, Mo 0.4%, V 0.15%, C 0.25%, Si 0.05%, Mn 0.10%, and the remaining Fe. Is used. 12% Cr steels containing 0.1% Mo are used for the rotor blades and stator blades other than the final stage and its front end. Cast steel of C 0.25% is used for the inner and outer casing members. The distance between the centers in the bearing 43 in this embodiment is 7000 mm, the diameter of the rotor shaft corresponding to a stator blade is about 800 mm, and the diameter in the rotor blade insertion part is the same at each end. The distance between the bearing centers relative to the rotor shaft diameter corresponding to the stator is about 8.8.

The low-pressure turbine has the smallest first stage in the axial width of the rotor blade vicinity, the second and third stages are equivalent, the fourth and fifth stages are equally gradually along the downstream side, and gradually increase in four stages. Compared to 6.2 to 7.0 times larger. The 2nd and 3rd stages are 1.15 to 1.40 times of the first stage, the 4th and 5th stages are 2.2 to 2.6 times of the 2nd and 3rd stages, and the last stage is 2.8 to 3.2 times of the 4th and 5th stages. The width of the vicinity is shown by the point connecting the extension of the trumpet with the diameter of the rotor shaft.

The blade length of the rotor blade in this embodiment becomes longer at each stage as it becomes the final stage of 4 inches to 43 inches of the first stage, and the length of the first stage to the final stage is within the range of 100 to 1270 mm by the output of the steam turbine. The maximum length of the blade at each stage is longer in the range of 1.2 to 1.9 times the length adjacent to the upstream side on the downstream side.

The portion near the root of the rotor blade has a large trumpet-shaped diameter compared to the portion corresponding to the stator blade, and the width of the rotor blade becomes larger as the blade length of the rotor blade increases. The ratio of the blade length of the rotor blade of the width is 0.30 to 1.5 from the first edge to the front edge of the final stage, and the ratio decreases gradually from the first edge to the front edge of the final stage, and the ratio of the rear stage is 0.15 to more than just the front edge thereof. It gradually becomes small in the range of 0.40. The final stage is in the ratio of 0.50 to 0.65.

The final stage rotor blade in this Example is the same as that of Example 2. As shown in FIG. Fig. 15 is a sectional view and a perspective view showing a state in which the erosion shield (stellite alloy) 54 is bonded by electron beam welding or TIG welding 56 in this embodiment. As shown in the figure, the shield 54 is welded at two places on the front and back sides.

In addition to the present embodiment, the same configuration can be used for a 1000 MW class large-scale power generation plant having a steam inlet temperature of 610 ° C. or higher, a steam inlet temperature of about 400 ° C. to a low pressure steam turbine, and an outlet temperature of about 60 ° C. have.

The high temperature high pressure steam turbine power generation plant in the present embodiment mainly includes a boiler, a high pressure turbine, a low pressure turbine, a condenser, a plurality of pumps, a low pressure water heater system, a deaerator, a boost pump, a water feed pump, a high pressure water heater system, and the like. . That is, the ultra high temperature high pressure steam generated in the boiler enters the high pressure side turbine to generate power, and is then reheated in the boiler to enter the medium pressure side turbine to generate power. This high-pressure turbine exhaust steam enters the low-pressure turbine, generates power, and condenses in the condenser. This condensate is transferred from a plurality of pumps to a low pressure feed water heater system, a degasser. The degassed water from this deaerator is transferred to a high pressure feed water heater from a boost pump and a feed pump, heated up, and then returned to the boiler.

In the boiler, the feed water is steam of high temperature and high pressure through a coal mill, an evaporator, and a superheater. On the other hand, the boiler combustion gas which heated the steam exits a coal mill, and enters an air heater, and heats air. Here, the feed pump drive turbine which operates with the bleed steam from a medium pressure turbine is used for driving a feed pump.

In the high temperature and high pressure steam turbine plant configured as described above, since the water supply temperature from the high pressure water heater system is much higher than the water supply temperature of the conventional thermal power plant, the temperature of the combustion gas from the coal firer in the boiler is inevitably compared with that of the conventional boiler. Much higher. For this reason, the heat recovery from this boiler exhaust gas is measured, and a gas temperature is not reduced.

In this embodiment, a high-medium voltage turbine and one low-pressure turbine are constructed as a tandem compound double flow type power generation plant that generates power by connecting a single generator to a generator in tandem. As another example, the turbine (D) of Table 9 is used, and two low-pressure turbines are connected in tandem and can be configured in the same manner as in the present embodiment in the output of 1050 MW class power generation. As the generator shaft, a higher strength one is used. In particular, a fully considered bainite structure containing C 0.15 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%, Mo 0.25 to 0.60%, V 0.05 to 0.20% It is preferable to have a tensile strength of 93 kgf / mm 2 or more, in particular 100 kgf / mm 2 or more, and 50% FATT of 0 ° C. or less, especially −20 ° C. or less, and the magnetization force at 21.2 KG is 985 AT / cm. It is preferable to make it into the following and to make the total amount of P, S, Sn, Sb, and As into an impurity 0.00.0% or less, and Ni / Cr ratio to 2.0 or less.

Table 5 mentioned above shows the chemical composition (weight%) used for the principal part of the high medium pressure turbine and the low pressure turbine of a present Example. In the present embodiment, the No. Since the martensitic steel of 9 was used as the thing of Table 5, it was set as the thermal expansion coefficient of 12x10 <^-6> / degreeC which has all the ferrite type crystal structure, and there was no problem by the difference of a thermal expansion coefficient at all.

The rotor shaft of the high-pressure part is listed in No. 10 in Table 10. 30 tons of the heat-resistant cast steel described in 1 is melted in an electric furnace, carbon vacuum deoxidation, injected into a mold mold, forged and stretched to produce an electrode rod, and the electrode slag is redissolved so as to dissolve from the upper portion of the cast steel to the lower portion. (1450 mm in diameter and 5000 mm in length) were forged and molded. This forging stretching was performed at a temperature of 1150 ° C. or lower to prevent forging cracking. After the annealing heat treatment, the forged steel was heated to 1050 ° C, subjected to water spray quench hardening treatment, 570 ° C and 690 ° C twice, and obtained by cutting in the shape shown in FIG. Materials and manufacturing conditions of the other parts are the same as in Example 2. Moreover, the welding welding to the bearing journal part 45 was similarly performed.

<Example 4>

The alloy of the composition shown in Table 10 is cast into a 10 kg ingot by vacuum melting and forged to a 30 mm angle. In the case of a large steam turbine rotor shaft, the center of the shaft is simulated and held at 1050 ° C for 5 hours, and then the cooling rate at the center is quenched at 100 ° C / h, the primary consideration is 570 ° C for 20 hours, and 690 ° C for 20 hours. In the second consideration and the blade, quenching at 1100 ° C. for 1 hour and 750 ° C. for 1 hour were performed, and a creep rupture test was performed at 625 ° C. and 30 kgf / mm 2. The results are summarized in Table 7.

No. of Table 10 1 to No. The alloy of this invention of 6 is preferable to apply to the vapor conditions of 620 degreeC or more, and it turns out that creep rupture life is long.

As the amount of Co increases, creep rupture time is improved. However, a large increase in Co tends to cause heat embrittlement when heated to 600 to 660 ° C., thus increasing both toughening and toughness to 2 to about 620 to 630 ° C. About 5% and 630-660 degreeC, 5.5 to 8% is preferable. B exhibits excellent strength at 0.03% or less. At 620 to 630 ° C., the amount of B is 0.001 to 0.01%, the amount of Co is 2 to 4%, and on the higher temperature side of 630 to 660 ° C., the amount of B is 0.01 to 0.03% and the amount of Co is increased to 5 to 7.5%. Can be obtained.

As for N, the less one strengthened at the temperature over 600 degreeC in the Example, and it turned out that intensity | strength is higher than the one with much N amount. As for N amount, 0.01 to 0.04% is preferable. Since N is hardly contained in vacuum melting, it is added according to a master alloy.

As shown in Table 10, the rotor member is the No. It corresponds to the alloy of 2, and high strength can be obtained. No. As is apparent from the fact that the Mn amount of 8 is as low as 0.09% as compared with the same Co amount, it is preferable that the Mn amount be 0.03 to 0.20% in order to further strengthen.

Similarly, Table 11 shows the chemical composition (% by weight) of the rotor shaft material suitable for the 600 ° C class. The heat treatment was cooled to 1100 ° C. × 2 h → 100 ° C./h, and then cooled to 565 ° C. × 15 h → 20 ° C./h, and cooled to 665 ° C. × 45 h → 20 ° C./h. All the heat processing was performed, rotating about the rotating shaft.

Table 12 shows the mechanical properties of the rotor shaft material. Impact value is V notch Charpy value, FATT is 50% wavefront transition temperature.

In terms of creep rupture strength, 600 ° C and 10 ⁵ h creep rupture strength of the member of the present invention is 11 kgf / mm 2, and exhibits high values of strength (10 kgf / mm 2) or more and toughness of 1 kgf −m or more that are required as a high efficiency turbine member. have.

No. 2 is more than 0.015% of Al, but the strength slightly decreases to a creep rupture strength of 11 kgf / mm 2 or less for 10 ⁵ hours. It was also confirmed that when W increased by about 1.0%, δ ferrite precipitated, the strength and toughness were low at the same time, and the object of the invention was not achieved.

W can obtain high strength from 0.1 to 0.65%.

The influence of W on FATT is that W has a low FATT in the range of 0.1 to 0.65% and has high toughness, but the toughness decreases even below and above. In particular, FATT as low as 0.2 to 0.5% can be obtained.

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

Example 5

Table 13 shows the chemical compositions (% by weight) of the inner casing members for high, medium and high pressure turbines of the present invention. The sample melt | dissolved 200 kg using the high frequency induction melting furnace assuming the thickness part of a large casing, and injected | poured and produced the ingot in the sand mold of maximum thickness 200mm, width 380mm, and height 440mm. After annealing treatment at 1050 ° C × 8h furnace cooling, assuming the thickness of the large steam turbine casing, the sample should be roughened (1050 ° C × 8h → air cooling), or so (710 ° × 7h → air cooling, 710 ° C × 7h → air cooling twice). The heat treatment of was performed.

Weldability evaluation was performed according to JIS Z3158. The preheating, interpass, and postheating start temperatures were 150 ° C, and the postheating treatment was 400 ° C x 30 minutes.

Table 14 shows tensile properties at room temperature, V notch Charpy impact absorption energy at 20 ° C, 650 ° C, 10 ⁵ h creep rupture strength, and weld crack test results.

The creep rupture strength and impact absorption energy of the present invention with the addition of appropriate amounts of B, Mo and W are required for high temperature and high pressure turbine casings (625 ° C, 10 ⁵ h strength ≥ 8 kgf / mm2, 20 ° C impact absorption energy ≥ 1 kgf-m) are fully satisfied. In particular, the high value of 9 kgf / mm <2> or more is shown. In addition, weld cracks cannot be confirmed in the member of the present invention, and weldability is good. As a result of examining the relationship between the amount of B and the weld crack, when the amount of B exceeded 0.0035%, a weld crack occurred. No. One was a bit cracky. In view of the influence of Mo on the mechanical properties, the Mo content of 1.18% was high in creep rupture strength, but the impact value was low and the required toughness could not be satisfied. On the other hand, Mo 0.11% had high toughness but low creep rupture strength and could not satisfy the required strength.

As a result of investigating the influence of W on the mechanical properties, the creep rupture strength is remarkably increased when the amount of W is 1.1% or more. On the contrary, when the amount of W is 2% or more, the room temperature shock absorbing energy is low. In particular, by adjusting the Ni / W ratio to 0.25 to 0.75, it is required for the high pressure and medium pressure internal casing and the main steam stop valve and the regulating valve casing of the high temperature and high pressure turbine of temperature 621 ° C and pressure 250 kgf / cm 2 or more. A heat resistant cast steel casing member of 625 ° C, 10 ⁵ h creep rupture strength of 9 kgf / mm 2 or more and room temperature shock absorbing energy of 1 kgf-m or more can be obtained. In particular, by adjusting the W amount of 1.2 to 2% and the Ni / W ratio to 0.25 to 0.75, an excellent heat-resistant cast steel casing member of 625 ° C, 10 ⁵ h creep rupture strength of 10 kgf / mm 2 or more, and room temperature shock absorbing energy of 2 kgf-m or more You can get it.

The amount of W is reinforced remarkably by setting it to 1.0% or more, and especially the value of 8.0 kgf / mm <2> or more can be obtained at 1.5% or more. No. of the present invention 7 satisfy | filled the intensity | strength of sufficient requirements below 640 degreeC.

The alloy raw material which makes the heat-resistant cast steel of this invention the target composition was melt | dissolved in an electric furnace for 1 ton, and after ladle refinement, it injected | poured into the sand mold and obtained the internal casing of the high-medium pressure part of Example 3. After this casing was subjected to 1.050 ° C. × 8 h furnace cold annealing heat treatment, two times of 1050 ° C. × 8 h crash-air cooling and annealing heat treatment and 730 ° C. × 8 h furnace cooling were performed. This test fabrication casing, which has a fully considered martensitic structure, was cut and examined to find the characteristics required for a 250 atm, 625 ° C. high temperature and high pressure turbine casing (625 ° C., 10 ⁵ h strength ≥ 9 kgf / mm 2, 20 ° C. impact absorption energy ≥ 1 It was confirmed that kgf-m) was sufficiently satisfied and weldable.

<Example 6>

In this embodiment, the steam temperature of the high pressure steam turbine, the medium pressure steam turbine, or the high medium pressure steam turbine is set to 649 ° C. instead of 625 ° C., and the structure and size can be obtained with the same design as in Example 2 or 3. Changed to Example 2 herein is the rotor shaft, ultra-low rotor and ultra-low stator and inner casing of a high pressure, medium or high pressure integrated steam turbine directly in contact with this temperature. Except for the inner casing, as these materials, the amount of B in the materials shown in Table 7 above was increased from 0.01 to 0.03%, and the amount of Co was increased to 5 to 7%, and as the inner casing member, the amount of W in Example 2 was increased to 2-3. By increasing the percentage and adding Co by 3%, the required strength is satisfied, and there is an advantage that a conventional design can be used. That is, in this embodiment, since the structural material exposed to high temperature is comprised by all the ferritic steels, the conventional design idea can be used as it is. Moreover, since the steam inlet temperature of the rotor blades and stator blades of a 2nd stage | paragraph becomes about 610 degreeC, it is preferable to use the material used for the first stage of Example 1 for these.

The steam temperature of the low pressure steam turbine is about 405 ° C., which is slightly higher than about 380 ° C. of Example 2 or 3, but the rotor shaft itself uses the super clean material as the material of Example 2 is sufficiently high in strength. do.

In addition, the tandem type which is directly connected to the cross compound type in the present embodiment can also be implemented at a rotational speed of 3600 rpm.

According to the present invention, since martensitic heat resistance and cast steel having high creep rupture strength and room temperature toughness can be obtained at 600 to 660 ° C., the main member for the ultra-supercritical pressure turbine at each temperature can be made of all ferritic heat-resistant steel, The basic design of the steam turbine so far can be used as it is, resulting in a reliable thermal power plant.

Conventionally, at such a temperature, it cannot be made into an austenitic alloy, and therefore, a healthy large rotor could not be manufactured from the viewpoint of manufacturability, but according to the ferritic heat-resistant forged steel of the present invention, a healthy large rotor can be manufactured.

In addition, the high temperature steam turbine made of all ferritic steels of the present invention does not use an austenitic alloy having a large coefficient of thermal expansion, so that the turbine can be started quickly and hardly damaged by thermal fatigue.

Claims (18)

In a steam turbine power plant equipped with a high pressure turbine, a medium pressure turbine and a low pressure turbine or a high medium pressure turbine and a low pressure turbine, the high pressure turbine and the medium pressure turbine or the high pressure turbine have a steam inlet temperature of 600 to 660 ° C. in the ultrashort rotor; Low pressure turbines have a Cr 8-13 wt.% Cr 8-13 wt% rotor shaft, rotor, stator and internal casing at which the steam inlet temperature to the ultrashort rotor is exposed to the steam inlet temperatures of the high and medium or high pressure turbines. A steam turbine power plant comprising a high strength martensitic steel containing and having a value of [wing length (inch) x rotational speed (rpm)] of the final stage rotor of the low pressure turbine. And a rotor shaft, a rotor blade installed on the rotor shaft, a vane for guiding the inflow of water vapor into the rotor blade, and an inner casing for holding the vane, wherein the temperature flowing into the first stage of the rotor blade of the steam is 600 to A high-pressure steam turbine which heats steam from the high-pressure side turbine at 660 ° C., heats equal to or higher than the high-pressure side inlet temperature, and sends it to the medium-pressure side turbine, wherein the rotor shaft or the rotor shaft and the rotor and at least the first stage of the stator vane are the rotor blades. of made up of 10 ⁵ hours creep rupture high strength intensity has a complete tempering martensite structure containing 10 kgf / ㎟ than Cr 9 to 13% by weight of the martensitic steel in a temperature corresponding to the inlet steam temperature of the first stage, the 10 ⁵ hours creep rupture strength at the inner casing corresponding to the respective steam temperatures temperature 10 kgf / And intermediate pressure integrated steam turbine, characterized in that at least made of a martensite cast steel containing Cr 8 to 12% by weight. A medium-pressure integrated steam turbine having a rotor shaft, a rotor blade installed on the rotor shaft, a vane for guiding the inflow of water vapor into the rotor blade, and an inner casing holding the vane, wherein the rotor shaft, the rotor blade, and the vane are provided. At least the first stage of C by weight ratio, C 0.05 to 0.20%, Si 0.15% or less, Mn 0.03 to 1.5%, Cr 9.5 to 13%, Ni 0.05 to 1.0%, V 0.05 to 0.35%, Nb 0.01 to 0.20%, N 0.01 To 0.06%, Mo 0.05 to 0.5%, W 1.0 to 3.5%, Co 2 to 10%, B 0.0005 to 0.03%, made of high strength martensitic steel with 78% or more of Fe, the inner casing is weight ratio 0.06 to 0.16%, Si 0.5% or less, Mn 1% or less, Ni 0.2% to 1.0%, Cr 8-12%, V 0.05 to 0.35%, Nb 0.01 to 0.15%, N 0.01 to 0.1%, Mo 1.5% Or less, containing W 1 to 4%, B 0.0005 to 0.003%, and having 85% or more of Fe And which comprises a strength martensite steel intermediate pressure integrated steam turbine. A high and medium pressure integrated steam turbine having a rotor shaft, a rotor planted on the rotor shaft, a vane for guiding the inflow of water vapor into the rotor, and an inner casing for retaining the vane, wherein the rotor has seven stages of high pressure. The rotor shaft has five or more stages, and the rotor shaft has a distance (L) between bearing centers of at least 6000 mm and a minimum diameter (D) at a portion where the vane is installed, at least 660 mm. A high-pressure martensitic steam turbine comprising a high strength martensitic steel containing from 9 to 13% by weight of Cr having an amount of 8.0 to 11.3. A high-pressure integrated steam turbine having a rotor shaft, a rotor blade installed on the rotor shaft, a vane for guiding inflow of water vapor into the rotor blade, and an inner casing holding the vane, wherein the rotor shaft, the rotor blade, and the vane are provided. At least the first stage of C by weight ratio, C 0.1 to 0.25%, Si 0.6% or less, Mn 1.5% or less, Cr 8.5 to 13%, Ni 0.05 to 1.0%, V 0.05 to 0.5%, Nb 0.02 to 0.20%, N 0.01 to A high-mid-pressure integrated steam turbine having 0.1%, Mo 0.5-2.5%, W 0.10-0.65% and Al 0.1% or less, and made of high strength martensitic steel having 80% or more of Fe. In a low pressure steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding inflow of water vapor into the rotor, and an inner casing for retaining the vane, the rotors are symmetrically arranged in five stages. In the rotor shaft, the rotor shaft has a dual flow structure provided by inserting the first stage into the center of the rotor shaft, wherein the rotor shaft has a distance L between bearing centers of 6500 mm or more and a minimum diameter D of 750 mm or more at the portion where the vane is installed. The (L / D) is made of Ni-Cr-Mo-V low alloy steel containing 1 to 2.5% by weight of Cr and 7.2 to 10.0% by weight of Ni and 3.0 to 4.5% by weight of Ni. Rotational speed (rpm)] is a low pressure steam turbine comprising a high strength martensitic steel having a value of 125,000 or more. In a steam turbine power plant having a high pressure turbine and a medium pressure turbine connected to each other and having two tandem low or medium pressure turbines and a low pressure turbine, the high pressure turbine, the medium pressure turbine, or the high pressure turbine may be used as an ultrashort rotor. The steam inlet temperature of the low pressure turbine is 600 to 660 ° C., and the low pressure turbine has a steam inlet temperature of 350 to 400 ° C., and the final stage rotor of the low pressure turbine is [the blade length (inch) × rotational speed (rpm)]. A steam turbine power plant comprising a high strength martensitic steel having a value of 125,000 or more, wherein the high-speed rotors of the high pressure turbine and the medium pressure turbine are made of high strength martensitic steel or Ni base alloy containing 9.5 to 13 wt% Cr. In a coal-fired thermal power plant having a coal-fired boiler, a steam turbine driven by water vapor obtained by the boiler, and a generator having a power generation output of 1000 MW or more in one or two driven by the steam turbine. The steam turbine has a medium pressure turbine connected to a high pressure turbine and a high pressure turbine, two low pressure turbines, or a high pressure turbine and a low pressure turbine, and the high pressure turbine and the medium pressure turbine or the high pressure turbine are steam inlets to the ultra-short rotor. The temperature is 600 to 660 ° C. and the low pressure turbine has a water vapor inlet temperature of 380 to 400 ° C. and is heated to a temperature higher than 3 ° C. above the steam inlet temperature of the high pressure turbine to the ultra short blade of the high pressure turbine. One steam is introduced into the first rotor blade of the high pressure turbine, and the steam from the high pressure turbine is discharged to the boiler. The reheater is heated to a temperature higher than the steam inlet temperature of the medium pressure turbine to the rotor blade by 2 ° C or more and is introduced into the rotor blade of the medium pressure turbine, and the steam from the medium pressure turbine is transferred to the low pressure turbine by the coal mill of the boiler. At a temperature above 3 ° C. above the steam inlet temperature to the ultra-stage rotor, and introduced into the ultra-stage rotor of the low-pressure turbine, while the final stage rotor of the low-pressure steam turbine was (blade length (inch) x rotational speed (rpm)). A coal fired thermal power plant characterized in that the value is made of high strength martensitic steel having a value of 125,000 or more. In a low pressure steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding the inflow of water vapor into the rotor and an inner casing for retaining the vane, the steam inlet temperature to the ultrashort rotor is 350 to 450 ° C, the rotor shaft has a diameter (D) of the vane portion of 750 to 1000 mm, a distance between bearing centers (L) of 7.2 to 10.0 times that of the D, C 0.2 to 0.3% by weight, Si Low pressure steam turbine, characterized in that made of low alloy steel of 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 Fe 92.5% or more. A high-mid-pressure integrated steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding inflow of water vapor into the rotor, and an inner casing for retaining the vane, wherein the rotor on the high pressure side is 7 The above stage and the blade length are 30 to 150 mm from the upstream side of the steam stream to the downstream side, and the diameter of the insertion portion of the rotor blade of the rotor shaft is larger than the diameter of the portion corresponding to the stator blade, and the shaft of the insertion portion is The width of the vicinity of the direction portion is larger stepwise than the downstream side of the upstream side, and the ratio of the blade length is 0.20 to 1.60, which increases along the downstream side from the upstream side, and the rotor blade on the medium pressure side is five or more stages symmetrically. And the blade length is 100 to 350 mm from the upstream side to the downstream side of the steam stream, and the top of the rotor shaft The insertion blade diameter of the rotor blade is larger than the diameter of the portion corresponding to the stator blade, and the width in the axial direction of the vicinity of the blade insertion portion is smaller than the upstream side except for the final end. A high medium pressure integrated steam turbine, wherein the ratio is 0.35 to 0.80, which is smaller from the upstream side to the downstream side. A high pressure steam turbine having a rotor shaft, a rotor mounted to the rotor shaft, a vane for guiding inflow of water vapor into the rotor and an inner casing for retaining the vane, wherein the rotor is at least 7 stages and blade length. Is 25 to 200 mm from the upstream side to the downstream side of the steam stream, and the ratio of the blade lengths of the adjacent stages is 1.05 to 1.35, wherein the blade length gradually increases as compared with the upstream side. The rotor blade has five or more stages, and the blade length is 100 to 300 mm from the upstream side to the downstream side of the steam stream, and the adjacent blade length is larger than the upstream side, and the ratio is 1.05 to 1.35. It is enlarged in the said downstream side, The high medium pressure integrated steam turbine characterized by the above-mentioned. In a low pressure steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding inflow of water vapor into the rotor, and an inner casing for retaining the vane, the rotors are symmetrically arranged in five stages. The above-described double flow structure and the blade length are in the range of 80 to 1300 mm from the upstream side to the downstream side of the steam stream, the rotor insertion portion diameter of the rotor shaft is larger than the diameter of the portion corresponding to the stator blade, The width of the vicinity of the insertion direction of the insertion portion is in the shape of a trumpet, which is larger than the width of the blade insertion portion, and gradually increases from the downstream side to the upstream side, and the ratio of the length of the blade portion from the first edge to the first edge of the tip end. Low pressure steam turbine, characterized in that gradually increasing from 0.20 to 1.60. In a low pressure steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding inflow of water vapor into the rotor, and an inner casing for retaining the vane, the rotors are symmetrically arranged in five stages. The ideal upstream structure and the blade length are in the range of 80 to 1300 mm from the upstream side to the downstream side of the steam stream, and the blade length of each adjacent stage is larger than the upstream side of the downstream side, and the ratio is Low pressure steam turbine, characterized in that the blade length is gradually increased on the downstream side in the range of 1.2 to 1.7. In a low pressure steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding inflow of water vapor into the rotor, and an inner casing for retaining the vane, the rotors are symmetrically arranged in five stages. The above-described double flow structure and the blade length increase from the upstream side to the downstream side of the steam stream, and are in the range of 80 to 1300 mm, and the width in the axial direction of the rotor blade shaft vicinity of the rotor shaft is at least three steps. A low pressure steam turbine, characterized in that the downstream side is larger than the upstream side and is larger than the width of the blade insert installation portion in a trumpet shape. In the high-pressure pressure integrated steam turbine having a rotor shaft, a rotor fitted to the rotor shaft, a vane for guiding the inflow of water vapor into the rotor and an inner casing for retaining the vane, wherein the rotor on the high pressure side is 6 In the rotor shaft, the rotor shaft has a diameter smaller than the diameter of the portion corresponding to the rotor blade inserting portion, and the width of the rotor shaft in the axial direction of the vicinity of the insertion portion of the rotor blade is largest. Step by step from the upstream side to the downstream side of the steam flow is increased in three or more stages, the rotor blade on the medium pressure side has five or more stages, the rotor shaft diameter of the portion corresponding to the stator blades corresponding to the rotor insertion portion It is smaller than the diameter of the portion, and the width in the axial direction near the insertion portion of the rotor blade is downstream from the upstream side of the steam stream. Compared to vary in a stepwise manner to step 4, the first stage of the rotor, two-stage and high, characterized in that the final stage is larger than the other stage intermediate pressure integrated steam turbine. By weight ratio of C 0.08 to 0.18%, Si 0.25% or less, Mn 0.90% or less, Cr 8.0 to 13.0%, Ni 2 to 3% or less, Mo 1.5 to 3.0%, V 0.05 to 0.35%, Nb and Ta or A steam turbine comprising two kinds of martensitic steels containing a total amount of 0.02 to 0.20% and N 0.02 to 1.10%. The martensitic steel has a tensile strength of 120 kgf / mm 2 or more and a blade length of 36 inches or more, and has a value of [blade length (inch) x rotational speed (rpm)] of 125,000 or more. Steam turbine blades. By weight ratio of C 0.08 to 0.18%, Si 0.25% or less, Mn 0.90% or less, Cr 8.0 to 13.0%, Ni 2 to 3% or less, Mo 1.5 to 3.0%, V 0.05 to 0.35%, Nb and Ta or It is composed of martensitic steel containing two total amounts of 0.02 to 0.20% and 0.02 to 1.10%, and after dissolution and forging, subjected to quenching treatment after quenching after heating and holding at 1000 to 1100 ° C, followed by 550 ° C. A method of producing a steam turbine blade, characterized by performing a first heat treatment for cooling after heating holding to 570 ° C. and a second heat treatment for cooling after heating holding at 560 ° C. to 590 ° C.