JP2005133699A - Turbine rotor, its manufacturing method, and steam turbine plant using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine rotor for increasing creep rupture strength in the turbine first stage, increasing tensile strength and yield strength of the turbine last stage, and realizing high output of a turbine medium-pressure section, its manufacturing method, and a steam turbine plant using it. <P>SOLUTION: The turbine rotor has one of the turbine medium-pressure section and a high-medium-pressure integral type turbine section in a rotor structure 11a. The rotor structure 11a is configured so that the last stage 15a of the turbine medium-pressure section has a tensile strength higher than that of the first stage of the turbine medium-pressure section. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a turbine rotor and a method for manufacturing the same, and more particularly, a turbine rotor blade assembly that implants a long blade blade in a turbine intermediate pressure portion among a turbine high pressure portion, a turbine intermediate pressure portion, and a turbine low pressure portion. The present invention relates to a turbine rotor that further enhances the strength assurance of the insert portion, a manufacturing method thereof, and a steam turbine plant using the turbine rotor.

  In general, it is known that the steam turbine has higher steam temperature, pressure, and flow rate, and the higher the steam turbine, the higher the output and the higher the plant thermal efficiency.

  For this reason, steam turbines require a so-called three-casing type of a turbine high pressure section, a turbine intermediate pressure section, and a turbine low pressure section, or a turbine high pressure section, in a turbine, for higher output (large capacity) and higher plant thermal efficiency. The operation was carried out with a so-called four-casing type of the pressure section and the two turbine low-pressure sections.

  FIG. 11 shows a four-casing type steam turbine as an example. The turbine high-pressure part 1, the turbine intermediate pressure part 2, the first turbine low-pressure part 3, and the second turbine low-pressure part in order from one end to the other end. 4 is provided, and each turbine height, middle, and low pressure portions 1, 2, 3, and 4 are axially coupled to each other by a turbine rotor 5 divided into a plurality of portions.

  The four-casing type steam turbine includes a turbine rotor blade 6 planted along the circumferential direction of the turbine rotor 5 and a turbine nozzle (not shown) called a stationary blade disposed on the upstream side and fixed to the casing. The turbine stages are arranged in multiple stages in the axial direction, and the heat energy of the driving steam passing through each turbine stage is converted into rotational energy to extract power.

  By the way, the 4-casing or 3-casing steam turbine shown in FIG. 11 has a long axis span that exceeds 100 meters in total length.

  For this reason, in consideration of the fact that if the shaft span becomes long, it becomes difficult to secure the installation area, and in recent steam turbines, the turbine high-pressure section, turbine intermediate-pressure section, and turbine low-pressure section among the turbine high-pressure section and turbine intermediate-pressure section Development of the so-called high-medium pressure integrated type that accommodates the part in a single casing, or the so-called double-flow (counterflow) medium-pressure type of the turbine intermediate pressure part that supplies steam to the central part and splits it left and right As a result, the shaft span has already been shortened.

  FIGS. 12 and 13 are both examples in which the shaft span is shortened, in which FIG. 12 shows a double-flow medium pressure turbine rotor, and FIG. 13 shows a turbine high pressure portion 7 and a turbine intermediate pressure portion 8. 1 and 2 show a high-medium pressure integrated type turbine rotor, in which both solid line portions indicate intermediate shape rotor structures 9a and 9b during heat treatment, and broken line portions indicate final shape rotor structures cut by machining. The bodies 10a and 10b are shown.

  In addition, since the steam condition (temperature, pressure, etc.) does not change so much between the inlet and the outlet, the double-flow intermediate-pressure type intermediate shape rotor structure 9a shown in FIG. 12 is quenched under the same heat treatment conditions during the heat treatment. I was tempering.

  However, since the intermediate pressure rotor structure 9b of the high and medium pressure integrated type shown in FIG. 13 has different steam conditions between the turbine high pressure part 7 and the turbine intermediate pressure part 8, the turbine structure 9b is provided with The heat treatment temperature of the high pressure part 7 and the turbine intermediate pressure part 8 was changed.

For example, Japanese Patent Application Laid-Open No. 53-128522 (see Patent Document 1) discloses a case in which a plurality of turbine parts that handle driving steam having different pressures are accommodated in one casing and the plurality of turbine parts are integrated. JP-A-3-130502 (see Patent Document 2), JP-A-2002-349206 (see Patent Document 3), and the like have disclosed many techniques.
JP-A-53-128522 JP-A-3-130502 JP 2002-349206 A

  By the way, in recent steam turbines, further enhancement of higher output has been reviewed, and one of them is high output of the turbine intermediate pressure part, whether it is a high-medium pressure integrated type or a double flow type. .

  Realization of high output of the turbine intermediate pressure part depends on the lengthening of the turbine blades applied to the final stage of the turbine (lengthening) and the strength assurance of the turbine rotor material in the final stage of the turbine. The development of longer blades for turbine blades has reached a certain level, so it depends solely on the development of turbine rotor materials.

  Conventionally, the turbine intermediate pressure section has a steam temperature of about 400 ° C. at the turbine low pressure section communicating with the turbine intermediate pressure section. Therefore, a bainite steel or martensitic steel turbine rotor material that can cope with the steam temperature of 400 ° C. has been selected. It was.

  However, when the turbine intermediate pressure section is increased in output, a long blade blade is applied to the final stage of the turbine. However, the introduction of this long blade is sufficient for the centrifugal force generated during operation. There is a need for further strength assurance of resisting tensile strength and yield strength.

  This strengthening of tensile strength and proof stress is largely due to the heat treatment of the turbine rotor material. However, if the temperature setting of the heat treatment is mistaken, various inconveniences and inconveniences occur.

  For example, bainite steel or martensitic steel, which is a turbine rotor material in the turbine intermediate pressure section, is exposed to a driving steam temperature of 450 ° C or higher when the tempering temperature is lowered. The strength was remarkably lowered, and the creep rupture strength particularly in a low stress region was lowered.

  The turbine rotor of the high and medium pressure integrated type has a driving steam temperature of about 400 ° C. as described above, whereas the driving steam of the turbine first stage of each turbine in the turbine intermediate pressure section and the turbine high pressure section is as described above. The temperature is 550 ° C. or higher.

  For this reason, even if one turbine rotor is used, it is necessary to enhance the creep rupture strength rather than the above-described enhancement of tensile strength and proof stress in the first turbine stage of each of the turbine intermediate pressure portion 8 and the turbine high pressure portion 7. It had been.

  However, when the tempering temperature is lowered because the high-medium pressure integrated type turbine rotor places much emphasis on the tensile strength and proof stress in the final stage of the turbine described above, the turbine intermediate pressure part 8 and the turbine high pressure part 7 respectively. There has been a problem that the stress ratio in the first stage of the turbine (centrifugal force / creep rupture strength based on the rotation of the long blade turbine blade in the last stage of the turbine) exceeds the allowable value of the material strength.

  Therefore, the turbine rotor applied to the high-medium pressure integrated type or the double-flow turbine intermediate pressure section has a contradictory function that requires the reinforcement of the creep rupture strength on the one hand and the tensile strength and the proof strength on the other hand. It was required to meet at the same time.

  The present invention has been made based on such circumstances, and in a steam turbine having a short shaft span, the creep rupture strength of the first stage of the turbine is strengthened, and the tensile strength and proof stress of the last stage of the turbine are enhanced. It is an object of the present invention to provide a turbine rotor, a manufacturing method thereof, and a steam turbine plant using the turbine rotor that realize high output of a turbine intermediate pressure section.

  In order to achieve the above-mentioned object, the present inventors have completed the present invention based on experiences obtained through repeated trial and error research.

  The double-flow medium-pressure turbine rotor shown in FIG. 12 and the high-medium-pressure integral type turbine rotor shown in FIG. 13 have a high centrifugal stress when a long blade turbine blade is used in the final stage of the turbine. Therefore, tensile strength against high centrifugal stress is required.

  However, in the remaining turbine stages other than the final stage of the turbine, the blade length of the turbine blade is shorter than that of the final stage of the turbine, so that high tensile strength is not required.

  For this reason, in the final stage of the turbine, where high tensile strength is required, only the turbine itself is individually heat-treated, and the final stage of the turbine is tempered at a relatively lower temperature than the remaining turbine stages. I found it.

  Moreover, in the remaining turbine stages except the final stage of the turbine, it was found that tempering was performed at a relatively high temperature to achieve uniform aging characteristics and suppress a decrease in creep rupture strength in a low stress region.

  That is, in order to achieve the above-described object, the turbine rotor according to the present invention includes, as described in claim 1, any one of a turbine intermediate pressure portion and a high intermediate pressure integrated type turbine portion in the rotor structure. In the turbine rotor provided with the above, the rotor structure is configured such that the final stage of the turbine intermediate pressure part has higher tensile strength than the first stage of the turbine intermediate pressure part.

  Moreover, in order to achieve the above-described object, the turbine rotor according to the present invention includes, as described in claim 2, the rotor structure in mass%, Cr: 0.9 to 3.0, M0: 0. 0.7 to 1.8, V: 0.1 to 0.4, and C: 0.15 to 0.35 CrMoV steel.

  In order to achieve the above-mentioned object, the turbine rotor according to the present invention has a rotor structure in mass%, Cr: 0.9 to 3.0, M0: 0, as described in claim 3. 0.2 to 0.9, W: 0.5 to 2.5, V: 0.1 to 0.4, and C: 0.15 to 0.35.

  CrMоV steel and CrMоWV steel are turbine rotor materials applied to relatively high-temperature steam at 400 ° C. to 566 ° C. The reasons for limiting the components of each element will be described below.

  C (carbon) is an element that stabilizes the austenite phase at the time of quenching, and forms carbides with V, which will be described later, to increase the tensile strength and creep rupture strength. In order to exert this effect, 0.15% Add more. On the other hand, when the addition amount of C exceeds 0.35%, the carbide becomes excessive, and the tensile strength and ductility are lowered. Therefore, it is desirable that the amount of C added be in the range of 0.15 to 0.35%.

  Cr (chromium) is an element that increases the hardenability and imparts strength to the material. In order to exhibit this effect, 0.9% or more is added. On the other hand, if the added amount of Cr exceeds 3.0%, coarse carbides are formed, ductility is lowered, and journal characteristics are further lowered. Therefore, it is desirable that the amount of Cr added be in the range of 0.9 to 3.0%.

  Mo (molybdenum) is an element that is necessary as a solid solution strengthening element, and further improves the hardenability of the steel and gives high tensile strength and high creep rupture strength. Add at least%. On the other hand, if the addition amount of Mo exceeds 1.8%, segregation during solidification of the steel ingot is promoted and a homogeneous rotor cannot be manufactured, and the ductility is significantly reduced. Therefore, it is desirable that the addition amount of Mo be in the range of 0.7 to 1.8%.

  Note that W, which will be described later, has substantially the same action, and when W is added, it is necessary to reduce the amount of Mo added. When W is added, if the amount of Mo is less than 0.2%, the effect as a solid solution strengthening element and an element that improves hardenability is insufficient, and if it exceeds 0.7%, the ductility is significantly reduced. Therefore, when adding W, it is desirable to make the addition amount of Mo into the range of 0.2-0.9%.

  V (vanadium) is an element that improves the hardenability of the steel and gives high tensile strength, and forms carbide with C to give high creep rupture strength. Add more. On the other hand, when the amount of V exceeds 0.4%, the ductility is significantly reduced. Therefore, it is desirable that the amount of V added be in the range of 0.1 to 0.4%.

  W (tungsten) is an element that provides high tensile strength and high creep rupture strength as a solid solution strengthening element, and is added when higher strength is required. If the content is less than 0.5%, these effects cannot be obtained. On the other hand, if the content exceeds 2.5%, the ductility is significantly lowered. Therefore, the amount of addition is preferably 0.5 to 2.5%.

  For the CrMoV steel and CrMoWV steel described above, elements such as B and Nb can be added as necessary in order to obtain further excellent characteristics.

  Moreover, in order to achieve the above-described object, the turbine rotor according to the present invention includes, as described in claim 4, the rotor structure in mass%, Cr: 8.5 to 13.0, M0: 0. .8 to 2.0, V: 0.1 to 0.4, and C: 0.05 to 0.25.

  In order to achieve the above object, the turbine rotor according to the present invention has a rotor structure in mass%, Cr: 8.5 to 13.0, M0: 0, as described in claim 5. .8, W: 1.0 to 5.0, V: 0.1 to 0.4, and C: 0.05 to 0.25.

  These martensitic steels are turbine rotor materials applied to high-temperature steam at 400 ° C. to 620 ° C. The reasons for limiting the components of each element will be described below.

  C is an element that combines with Cr, V, etc. to form carbides, contributes to precipitation strengthening and improves creep rupture strength, and is indispensable for improving hardenability and suppressing δ ferrite formation. Yes, in order to exert this effect, 0.05% or more is added. On the other hand, if the addition amount exceeds 0.25% or more, the coarsening of the carbide is promoted, the creep rupture strength over a long time is lowered, and the ductility is also lowered. Therefore, it is desirable that the C content be 0.05 to 0.25%.

Cr is an element that improves the oxidation resistance and corrosion resistance, and constitutes M ₂₃ C ₆ type precipitates that contribute to precipitation strengthening to improve creep rupture strength. In order to exert this effect, 8.5% Add more. On the other hand, if the addition amount exceeds 13%, δ ferrite harmful to ductility and creep rupture strength is likely to be generated. Therefore, it is desirable that the amount of Cr added is in the range of 8.5 to 13%.

  Mo (molybdenum) is an element that works as a solid solution strengthening element and a constituent element of carbide and improves the tensile strength and creep rupture strength. In order to exert this effect, 0.8% or more is added. On the other hand, if the amount of Mo exceeds 2%, the ductility is greatly reduced and harmful δ ferrite is easily generated. Therefore, it is desirable that the amount of Mo added is in the range of 0.8 to 2%.

  Note that W, which will be described later, has substantially the same action, and when W is added, it is necessary to reduce the amount of Mo added. When W is added, if the amount of Mo exceeds 0.8%, the ductility is greatly reduced and harmful δ ferrite is easily generated. Therefore, when adding W, it is desirable to make the addition amount of Mo less than 0.8%.

  V is an element that contributes to solid solution strengthening and the formation of fine V carbonitrides and improves the creep rupture strength. In order to exhibit this effect, V is added in an amount of 0.1% or more. On the other hand, when the amount of V exceeds 0.4%, the ductility is significantly reduced and harmful δ ferrite is easily generated. Therefore, it is desirable that the amount of V added be in the range of 0.1 to 0.4%.

  W contributes as a solid solution strengthening element and a carbide element, and further contributes to the formation of an intermetallic compound composed of Fe, Cr, and W. Therefore, W is added when a higher creep rupture strength is required. If the content is less than 1%, these effects cannot be obtained. On the other hand, if the content exceeds 5%, the ductility is significantly reduced and harmful δ ferrite is easily generated. Is desirable.

  For the above-described martensitic steel, elements such as N, B, Nb, and Co can be added as necessary in order to obtain further excellent characteristics.

Moreover, in order to achieve the above-described object, the method for manufacturing a turbine rotor according to the present invention includes either one of a turbine intermediate pressure part and a high intermediate pressure integrated type turbine part as described in claim 6. when manufacturing the rotor structure comprising, after quenching to the rotor structure, the temperature at which the tempering turbine intermediate pressure final stage, and the a ₃ transformation point temperature or lower, and the turbine intermediate pressure final stage The method is characterized in that the temperature is lower than the tempering temperature performed for the first stage of the remaining turbine intermediate pressure part other than the above.

  Here, the remaining turbine intermediate pressure section other than the turbine intermediate pressure section final paragraph refers to the turbine stage immediately before the turbine intermediate pressure section final paragraph to the turbine first stage.

  When the turbine structure according to the present embodiment selects any one of the above-described CrMoV steel and CrMoWV steel, the tempering temperature of the turbine intermediate pressure section final stage is set to 630 ° C. or higher, and the turbine intermediate pressure section final stage other than The tempering temperature of the remaining turbine intermediate pressure section is desirably 660 ° C to 720 ° C.

  This is because when the tempering temperature in the final stage of the intermediate pressure section of the turbine is less than 630 ° C., the tensile strength and proof stress increase, but the ductility decreases.

  Further, when the tempering temperature of the remaining turbine intermediate pressure section other than the final stage of the turbine intermediate pressure section is less than 660 ° C., the tensile strength and proof stress increase, but on the other hand, the creep rupture strength decreases, and the tempering temperature further decreases. When the temperature exceeds 720 ° C., the tempering action becomes excessive, and the tensile strength, proof stress and creep rupture strength are reduced.

  Further, when the rotor structure according to the present embodiment is composed of any one of the above-described CrMoV steel and CrMoVW steel, the temperature when quenching the turbine intermediate pressure section final stage is 940 ° C to It is desirable to set it as 1060 degreeC. If the quenching temperature is less than 940 ° C, austenitization during quenching is incomplete, and the required tensile strength, proof stress and creep rupture strength cannot be obtained, and if the quenching temperature exceeds 1060 ° C, This is because the crystal grains become coarse and the ductility is lowered, and the notch sensitivity is increased to impair reliability.

  Further, when the rotor structure according to the present embodiment is composed of the martensitic steel described above, the tempering temperature of the turbine intermediate pressure part final paragraph is set to 570 ° C. or more, and the remaining parts other than the turbine intermediate pressure part final paragraph are set. It is desirable that the tempering temperature of the turbine intermediate pressure stage is 630 to 720 ° C.

  This is because, when the tempering temperature in the final stage of the intermediate pressure section of the turbine is less than 570 ° C., the tensile strength and the proof stress increase, but the ductility decreases. In addition, when the tempering temperature of the remaining turbine intermediate pressure section other than the final stage of the turbine intermediate pressure section is less than 630 ° C., the tensile strength and proof stress increase, but on the other hand, the creep rupture strength decreases, and the tempering temperature further decreases. This is because if the temperature exceeds 720 ° C., the tempering action becomes excessive, and the tensile strength, proof stress and creep rupture strength are reduced.

  Further, when the rotor structure according to the present embodiment is composed of the martensitic steel described above, the temperature at which the rotor structure is quenched is preferably 1000 ° C. to 1150 ° C. If the quenching temperature is less than 1000 ° C, austenitization at the time of quenching is incomplete, and the required tensile strength, proof stress and creep rupture strength cannot be obtained, and if the quenching temperature exceeds 1150 ° C, heating is in progress. This is because the crystal grains become coarse and the ductility is lowered, and the notch sensitivity is increased to impair strength assurance.

  Moreover, in order to achieve the above-described object, the method for manufacturing a turbine rotor according to the present invention includes any one of a turbine intermediate pressure portion and a high / medium pressure integrated type turbine portion as described in claim 11. When the rotor structure is provided, after quenching the rotor structure, the rotor intermediate pressure section is provided between the turbine intermediate pressure section final paragraph and the remaining turbine intermediate pressure section other than the turbine intermediate pressure section final paragraph. This is a method in which a heat shielding plate is inserted into a groove section to partition, and the turbine intermediate pressure section final stage and the remaining turbine intermediate pressure section other than the turbine intermediate pressure section final stage are heat-treated at different tempering temperatures.

  The properties of the rotor structure produced by the turbine rotor manufacturing method according to the present invention, such as tensile strength, proof stress, ductility, and creep rupture strength, should be evaluated by the tensile test and creep rupture test described below. Can do.

  The tensile test is a material test for the purpose of obtaining the tensile strength, proof stress, elongation, drawing, etc. of the test material. Tensile strength and yield strength indicate the tensile strength of the test material, and elongation and drawing indicate the ductility of the test material. The larger the respective values, the better the characteristics.

The creep rupture test is a material test for the purpose of determining the creep rupture strength of the specimen. The creep rupture strength is a characteristic corresponding to the creep rupture time, and the longer the creep rupture time, the higher the creep rupture strength accordingly. Furthermore, the creep rupture test results of a plurality of test strips (test temperature, test stress and fracture time) by organizing in Larson Miller parameter, the creep rupture strength (10 ⁵ h strength at break, etc.) at various temperatures Can be sought.

  The turbine rotor according to the present invention, the manufacturing method thereof, and the steam turbine plant using the turbine rotor have high tensile strength and proof strength even when a long blade blade is implanted in the final stage of the turbine intermediate pressure section of the rotor structure. In addition, it is possible to provide a high creep rupture strength to the first stage of the intermediate pressure section of the turbine or the first stage of the high pressure section of the turbine that is exposed to high-temperature driving steam.

  Therefore, even with a steam turbine having a short shaft span, high output and high plant thermal efficiency can be realized, and stable operation can be performed for a long time.

  In addition, by using such a turbine rotor, higher-temperature steam can be circulated to the turbine intermediate pressure portion than in the past, so the efficiency of the steam turbine plant as a whole is improved and the output is highly reliable. It becomes possible with sex.

  Embodiments of a turbine rotor, a manufacturing method thereof, and a steam turbine plant using the turbine rotor according to the present invention will be described below with reference to the drawings.

  For the turbine rotor according to the present embodiment, one of CrMоV steel, CrMоWV steel, and martensitic steel produced based on the above-described component elements is selected. The selected steel is melted and cast into a steel ingot, and then forged to form a drum-shaped rotor structure.

  FIG. 1 and FIG. 2 are conceptual diagrams showing a rotor structure 11a applied to a double-flow turbine intermediate pressure portion in the turbine rotor according to the present embodiment.

  3 and 4 are conceptual diagrams showing a rotor structure 11b applied to the high-medium pressure integrated type among the turbine rotors according to the present embodiment.

  1 to 4, the solid line portion is the intermediate shape rotor structure 12a at the time of heat treatment, and the broken line portion is the final shape rotor structure 13a cut by machining.

  Further, the remaining portion of the broken line portion removed by machining cutting is a turbine disk 14a in which a turbine rotor blade (not shown) is implanted. Furthermore, in the rotor structure 11a shown in FIGS. 1 and 2 and applied to the intermediate pressure portion of the double-flow turbine, turbine disks 14a are sequentially formed from the central portion toward both the left and right ends, and the turbine disk 14a is subjected to turbine motion. The last stage where the blades (not shown) are implanted and the turbine blades are implanted is the turbine final stage 15a.

  The rotor structure 11b shown in FIG. 3 and FIG. 4 and applied to the high-medium pressure integrated type is also divided into a turbine high-pressure part 16 and a turbine intermediate-pressure part 17, but the turbine is configured in the axial direction. Turbine blades are implanted in the disk 14b, and the final stage where the turbine blades are implanted is the turbine final stage 15b.

  In the turbine rotor formed in such a shape, each of the rotor structure 11a applied to the double-flow turbine intermediate pressure portion shown in FIG. 1 and the rotor structure 11b applied to the high-medium pressure integrated type shown in FIG. Quenching is performed after the groove 18 is cut by machining between the turbine final stages 15a and 15b and the turbine stage L-1 immediately before.

  After quenching, the rotor structures 11a and 11b are partitioned by inserting a heat shielding plate 19 into the groove 18 as shown in FIGS. 2 and 4, and the turbine disks 14a and 15b of the turbine final stages 15a and 15b are separated. 14b and the part from the turbine stage L-1 immediately before that to the turbine first stage are tempered at different temperatures.

At that time, heat treatment temperature, rotor structures 11a to be applied to each of the double-flow turbine intermediate pressure and high-intermediate pressure integrated type, 11b or less of A ₃ transformation temperature of the material, and the turbine final stage 15a, the remaining non-15b It is set lower than the tempering temperature of the turbine stage.

  The rotor structure 11a applied to the double-flow turbine intermediate pressure portion and the rotor structure 11b applied to the high-medium pressure integrated type are both planted in the turbine stage L-1 immediately before the turbine final stage 15a, 15b. When the turbine rotor blade is a long blade, the groove 18 may be provided between the turbine stage L-1 immediately before the turbine final stage 15a, 15b and the turbine stage L-2 two before.

  Next, each sample was produced under the heat treatment temperature conditions from Example 1 to Example 4, and various characteristics were evaluated.

  For Examples 1 and 2, the sample No. shown in FIG. 1, no. 2 was used. Sample No. 1 is mass%, 0.9-3.0% Cr, 0.7-1.8% Mo, 0.1-0.4% V, 0.15-0.35% C CrMoV steel containing Fe as a main component. 2 is mass%, 0.9-3.0% Cr, 0.2-0.9% Mo, 0.5-2.5% W, 0.1-0.4% V , CrMoVW steel mainly composed of Fe containing 0.15 to 0.35% of C.

[Example 1] (FIGS. 5 and 6)
In this example, the CrMoV steel and the CrMoVW steel were examined for tensile properties and creep rupture strength by changing the tempering temperature.

  Sample No. shown in FIG. 1, no. 200 kg of 2 was prepared, melted in a vacuum high-frequency induction electric furnace, and cast. After casting, press forging was performed and forged into a round bar with a diameter of 100 mm. 1, no. 2 was produced. Thereafter, the sample material was quenched at a temperature of 970 ° C., and the sample material was tempered at a temperature range of 600 ° C. to 740 ° C. as shown in FIG.

Subjected each sample obtained in this manner in the tensile test and the creep rupture test at a temperature 400 ° C., the tensile strength, 0.02% yield strength, elongation, diaphragm, 10 ⁵ hours rupture strength at FATT, 560 ° C. Asked. The result is shown in FIG.

  As shown in FIG. 1, no. As a result of the tensile test of 2, when the tempering temperature is lowered, the tensile strength and the proof stress are increased.

  However, when tempering is performed at a temperature lower than 630 ° C., the ductility (elongation and drawing) is greatly reduced, and the reliability of the material is impaired.

  Therefore, the tempering temperature in the final stage of the turbine where the tensile strength is important is preferably 630 ° C. or higher, which provides excellent tensile strength, yield strength, and ductility.

  Next, the test material No. 1, no. As a result of the creep rupture test of No. 2, the creep rupture strength decreases at a tempering temperature lower than 660 ° C., and the creep rupture strength also decreases at a tempering temperature higher than 720 ° C.

  Accordingly, the tempering temperature of the remaining turbine stages, particularly the turbine first stage, excluding the turbine final stage where the creep rupture strength is important, is preferably 660 ° C. to 720 ° C. at which excellent creep rupture strength is obtained.

  Thus, according to the present example, in mass%, 0.9 to 3.0% Cr, 0.7 to 1.8% Mo, 0.1 to 0.4% V,. CrMoV steel based on Fe containing 15 to 0.35% C, and 0.9 to 3.0% Cr, 0.2 to 0.9% Mo, 0.5% by mass A rotor structure using a CrMoVW steel mainly composed of Fe containing ~ 2.5% W, 0.1-0.4% V, 0.15-0.35% C By tempering the final stage at 630 ° C. or higher and tempering the remaining turbine stages excluding the turbine final stage at 660 to 720 ° C., each turbine final stage of the double-flow turbine intermediate pressure part and the high intermediate pressure integrated type Can provide suitable tensile strength for connecting the long blades and is exposed to high temperature driving steam. The bottle first paragraph, it was found that given a suitable creep rupture strength.

[Example 2] (FIGS. 5 and 7)
In this example, the CrMoV steel and the CrMoVW steel were examined for tensile strength and creep rupture strength by changing the quenching temperature.

  Sample No. shown in FIG. 1, no. 200 kg of 2 was prepared, melted in a vacuum high-frequency induction electric furnace, and cast. After casting, press forging was performed and forged into a round bar with a diameter of 100 mm. 1, no. 2 was produced. Thereafter, as shown in FIG. 7, the test material was quenched at a temperature range of 910 ° C. to 1080 ° C., and the test material was further tempered at a temperature of 680 ° C.

Subjected each sample obtained in this manner in the tensile test and the creep rupture test at a temperature 400 ° C., the tensile strength, 0.02% yield strength, elongation, diaphragm, 10 ⁵ hours rupture strength at FATT, 560 ° C. Asked. The result is shown in FIG.

  As shown in FIG. 1, no. As a result of the tensile test and the creep rupture test of No. 2, the tensile strength, yield strength and creep rupture strength are significantly reduced at a quenching temperature lower than 940 ° C., and the tensile test ductility (elongation at a quenching temperature higher than 1060 ° C. , Aperture) is greatly reduced and the reliability of the material is impaired.

  Accordingly, the quenching temperature of the rotor structure is preferably 940 ° C. to 1060 ° C. at which excellent tensile strength, yield strength, ductility, and creep rupture strength are obtained.

  Therefore, according to this example, in mass%, 0.9 to 3.0% Cr, 0.7 to 1.8% Mo, 0.1 to 0.4% V, 0.15 to CrMoV steel based on Fe containing 0.35% C, and in mass%, 0.9-3.0% Cr, 0.2-0.9% Mo, 0.5-2 The temperature is 940 for a rotor structure using CrMoVW steel mainly composed of Fe containing 0.5% W, 0.1-0.4% V, 0.15-0.35% C. By performing quenching at 10 ° C. to 1060 ° C., a suitable tensile strength can be given to the final stage of each turbine of the double flow turbine intermediate pressure unit and the high intermediate pressure integrated type, and it is exposed to high-temperature driving steam. It was found that the first stage of the turbine can be given a suitable creep rupture strength.

  For Examples 3 and 4, sample no. 3, no. 4 was used. Sample No. 3 is Fe by mass%, containing 8.5-13% Cr, 0.8-2% Mo, 0.1-0.4% V, 0.05-0.25% C. Is the martensitic steel mainly composed of 4 is mass%, 8.5-13% Cr, less than 0.8% Mo, 1-5% W, 0.1-0.4% V, 0.05-0.25% It is a martensitic steel mainly containing Fe containing C.

[Example 3] (FIGS. 8 and 9)
In this example, the tensile properties and creep rupture strength of the martensitic steel were investigated by changing the tempering temperature.

  Sample No. 2 shown in FIG. 3, no. 200 kg of 4 was prepared, melted in a vacuum high frequency induction electric furnace, and cast. After casting, press forging was performed and forged into a round bar with a diameter of 100 mm. 3, no. 4 was produced. Thereafter, the sample material was quenched at a temperature of 1050 ° C., and the sample material was tempered at a temperature range of 540 ° C. to 750 ° C. as shown in FIG.

Subjected each sample obtained in this manner in the tensile test and the creep rupture test at a temperature 400 ° C., the tensile strength, 0.02% yield strength, elongation, diaphragm, FATT, 10 ⁵ hours rupture strength at a temperature 600 ° C. Asked. The result is shown in FIG.

  As shown in FIG. 3, no. As a result of the tensile test of No. 4, when the tempering temperature is lowered, the tensile strength and the proof stress are increased.

  However, when tempering is performed at a temperature lower than 570 ° C., the ductility (elongation and drawing) is greatly reduced, and the reliability of the material is impaired.

  Accordingly, the tempering temperature in the final stage of the turbine where the tensile strength is important is preferably 570 ° C. or higher, which provides excellent tensile strength, yield strength, and ductility.

  Next, the test material No. 3, no. As a result of the creep rupture test of No. 4, the creep rupture strength decreases at a tempering temperature lower than 630 ° C, and the creep rupture strength also decreases at a tempering temperature higher than 720 ° C.

  Accordingly, the tempering temperature of the remaining turbine stages except the turbine final stage where the creep rupture strength is important is preferably 630 ° C. to 720 ° C. at which excellent creep rupture strength is obtained.

  Thus, according to this example, by mass, 8.5-13% Cr, 0.8-2% Mo, 0.1-0.4% V, 0.05-0. Martensitic steel containing 25% C as a main component, and in mass%, 8.5 to 13% Cr, less than 0.8% Mo, 1 to 5% W, 0.1 Tempering the final turbine stage at 570 ° C. or higher for a rotor structure using martensitic steel containing Fe of 0.4% V and 0.05 to 0.25% C as a main component. The remaining turbine stage excluding the turbine final stage is tempered at 630 ° C. to 720 ° C., so that a suitable tensile strength is given to each turbine final stage of the double flow turbine intermediate pressure unit and the high intermediate pressure integrated type. Suitable for the first stage of a turbine that can be heated and exposed to hot driving steam It was found that given the creep rupture strength.

[Example 4] (FIGS. 8 and 10)
In this example, the tensile strength and creep rupture strength of the martensitic steel were investigated by changing the quenching temperature.

  Sample No. 2 shown in FIG. 3, no. 200 kg of 4 was prepared, melted in a vacuum high frequency induction electric furnace, and cast. After casting, press forging was performed and forged into a round bar with a diameter of 100 mm. 3, no. 4 was produced. Thereafter, the test material was quenched in the temperature range of 990 ° C. to 1180 ° C. as shown in FIG. 10, and the test material was further tempered at a temperature of 650 ° C.

Subjected each sample obtained in this manner in the tensile test and the creep rupture test at a temperature 400 ° C., the tensile strength, 0.02% yield strength, elongation, diaphragm, FATT, 10 ⁵ hours rupture strength at a temperature 600 ° C. Asked. The result is shown in FIG.

  As shown in FIG. 3, no. As a result of the tensile test and creep rupture test of No. 4, the tensile strength, proof stress, and creep rupture strength are greatly reduced at a quenching temperature below 1020 ° C. , Aperture) is greatly reduced and the reliability of the material is impaired.

  Therefore, the quenching temperature of the rotor structure is desirably 1020 to 1150 ° C. at which excellent tensile strength, proof stress, ductility, and creep rupture strength are obtained.

Thus, according to the present Example, by mass%, 8.5-13% Cr, 0.8-2% Mo, 0.1-0.4% V, 0.05-0. Martensitic steel containing 25% C and containing Fe as a main component, and by mass, 8.5 to 13% Cr, less than 0.8% Mo, 1 to 5% W, 0.1 Quenching is performed at a temperature of 1020 ° C. to 1150 ° C. for a rotor structure using martensitic steel containing Fe of 0.4% V and 0.05 to 0.25% C as a main component. By doing so, a suitable tensile strength can be given to the turbine final stage of the double flow turbine intermediate pressure part and the high / medium pressure integrated type, and it is suitable for the turbine first stage exposed to high temperature driving steam. It was found that a good creep rupture strength was obtained.

The conceptual diagram which shows the rotor structure applied to a double flow turbine intermediate pressure part among the turbine rotors which concern on this invention. The conceptual diagram which shows the heat treatment preparation stage of the rotor structure applied to a double flow turbine intermediate pressure part among the turbine rotors which concern on this invention. The conceptual diagram which shows the rotor structure applied to the turbine part of a high intermediate pressure integrated type among the turbine rotors which concern on this invention. The conceptual diagram which shows the heat treatment preparation stage of the rotor structure applied to the turbine part of a high intermediate pressure integrated type among the turbine rotors which concern on this invention. The chart which shows the chemical composition of CrMоV steel applied to the rotor structure of the turbine rotor which concerns on this invention, and CrMоWV steel. The chart which shows the strength test result when changing the tempering temperature of CrMоV steel and CrMоWV steel shown in FIG. The chart which shows the strength test result when changing the quenching temperature of CrMоV steel and CrMоWV steel shown in FIG. The chart which shows the chemical composition of the martensitic steel applied to the rotor structure of the turbine rotor of this invention. The table | surface which shows the strength test result when changing the tempering temperature of martensitic steel in FIG. The chart which shows the strength test result when changing the quenching temperature of martensitic steel in FIG. The upper half notch perspective view which shows the conventional steam turbine. The conceptual diagram which shows the rotor structure applied to a double flow turbine intermediate pressure part among the conventional turbine rotors. The conceptual diagram which shows the rotor structure applied to the turbine part of a high intermediate pressure integrated type among the conventional turbine rotors.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine high pressure part 2 Turbine intermediate pressure part 3 1st turbine low pressure part 4 2nd turbine low pressure part 5 Turbine rotor 6 Turbine blade 7 Turbine high pressure part 8 Turbine intermediate pressure part 9a, 9b Intermediate shape rotor structure 10a, 10b Final shape Rotor structure 11a, 11b Rotor structure 12a, 12b Intermediate shape rotor structure 13a, 13b Final shape rotor structure 14a, 14b Turbine disk 15a, 15b Turbine final stage 16 Turbine high pressure part 17 Turbine intermediate pressure part 18 Groove part 19 Heat shield Board

Claims (12)

In the turbine rotor having either one of the turbine intermediate pressure portion and the high intermediate pressure integral type turbine portion in the rotor structure, the rotor structure is configured such that the turbine intermediate pressure portion final paragraph is more than the turbine intermediate pressure portion first paragraph. A turbine rotor characterized by having a high tensile strength. The rotor structure includes, in mass%, Cr: 0.9 to 3.0, Mо: 0.7 to 1.8, V: 0.1 to 0.4, C: 0.15 to 0.35. The turbine rotor according to claim 1, wherein the turbine rotor is CrMOV steel. The rotor structure is in mass%, Cr: 0.9 to 3.0, Mо: 0.2 to 0.9, W: 0.5 to 2.5, V: 0.1 to 0.4, C The turbine rotor according to claim 1, wherein the turbine rotor is CrMOWV steel containing 0.15 to 0.35. The rotor structure includes, in mass%, Cr: 8.5 to 13.0, Mо: 0.8 to 2.0, V: 0.1 to 0.4, and C: 0.05 to 0.25. The turbine rotor according to claim 1, wherein the turbine rotor is martensitic steel. The rotor structure is, by mass%, Cr: 8.5 to 13.0, Mo: less than 0.8, W: 1.0 to 5.0, V: 0.1 to 0.4, C: 0.00. The turbine rotor according to claim 1, wherein the turbine rotor is martensitic steel containing 05 to 0.25. When manufacturing a rotor structure including either one of the turbine intermediate pressure part and the high / intermediate pressure integrated type turbine part, the temperature at which the rotor intermediate body is quenched and then tempered in the final stage of the turbine intermediate pressure part the, or less a ₃ transformation temperature, and manufacturing method of the turbine rotor, characterized by a temperature lower than the tempering temperature to be performed for the remaining turbine intermediate pressure first paragraph other than said turbine intermediate pressure final stage . After manufacturing a rotor structure having either one of a turbine intermediate pressure part and a high / medium pressure integrated type turbine part, one of CrMоV steel and CrMоWV steel, after quenching the rotor structure The temperature at which the turbine intermediate pressure part final stage is tempered is 630 ° C. or higher, and the temperature at which the remaining turbine intermediate pressure part other than the turbine final stage is tempered is set to 660 ° C. to 720 ° C. A method for manufacturing a turbine rotor. Among the turbine intermediate pressure part and the high-medium pressure integrated type turbine part, when producing a rotor structure including either one of CrMоV steel and CrMоWV steel, a quenching temperature to be applied to the rotor structure, A method for manufacturing a turbine rotor, wherein the temperature is set to 940 ° C to 1060 ° C. When producing a rotor structure having either one of the turbine intermediate pressure part and the high-medium pressure integrated type turbine part from martensitic steel, after quenching the rotor structure, the turbine intermediate pressure part final paragraph The temperature for tempering is set to 570 ° C. or higher, and the temperature for tempering to the remaining first stage of the turbine intermediate pressure section other than the final stage of the turbine is set to 630 ° C. to 720 ° C. . When manufacturing a rotor structure having either one of the turbine intermediate pressure part and the high-medium pressure integrated type turbine part from martensitic steel, the quenching temperature for the rotor structure is set to 1000 ° C to 1150 ° C. A method for manufacturing a turbine rotor. When manufacturing a rotor structure including either one of the turbine intermediate pressure part and the high / medium pressure integrated type turbine part, after quenching the rotor structure, the turbine intermediate pressure part final stage and A heat shielding plate is inserted into a groove portion provided between the turbine intermediate pressure section other than the pressure section final stage and the remaining section other than the turbine intermediate pressure section final paragraph. A method for manufacturing a turbine rotor, comprising heat-treating a turbine intermediate pressure section at different tempering temperatures. In a steam turbine plant provided with a rotor high-pressure part and either a turbine high-pressure part and a turbine intermediate-pressure part or a turbine low-pressure part, or a turbine high-pressure part, a turbine intermediate-pressure part, and a turbine low-pressure part, the rotor structure is A steam turbine plant comprising the turbine rotor according to any one of claims 1 to 5.

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