JP2010236404A - Turbine rotor for steam turbine and steam turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine rotor for a steam turbine which has high strength at a high temperature operation and allows uniform rotation of a rotor blade outer peripheral part. <P>SOLUTION: A turbine rotor having a structure in which a rotor blade ring formed by integrating a plurality of rotor blades is welded to be integrated with an outer peripheral part of a rotor disk at the root part. An outer diameter of the rotor disk, an inner diameter of a rotor blade ring or a width of a welding metal part are changed between a steam inlet side and steam outlet side. In concrete, the outer diameter on the steam inlet side of the rotor disk is made smaller than the outer diameter on the steam outlet side. The inner diameter on the steam inlet side of the rotor blade ring is made larger than the inner diameter on the steam outlet side. The width on the steam inlet side of the welding metal part is made larger than that on the steam outlet side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a turbine rotor for a steam turbine.

As energy conservation and environmental conservation (reduction of CO ₂ ) increase, interest in increasing capacity and improving thermal efficiency is increasing in steam turbine power plants. In these cases, the thermal efficiency is improved by increasing the temperature and pressure of the steam, and further higher temperatures are expected in the future.

  The first stage blades of a high-pressure turbine are the elements that are first exposed to high-temperature and high-pressure steam among the rotating body elements, and ensuring the strength reliability is the greatest key to increasing the temperature. When the main steam temperature exceeds 600 ° C., the high-temperature strength of the material, particularly the creep strength, sharply decreases, and securing the strength is the biggest issue.

  In the prior art, as a joining structure for attaching the turbine blade to the rotor disk, the groove formed in the root portion of the turbine blade and the outer peripheral portion of the disk integrally provided in the rotor disk are fitted into the groove. A fastening method is used. Since this groove receives the centrifugal force of the turbine rotor blade, high stress acts on the groove. For this reason, the groove has been devised in various shapes so as to withstand high stress (Patent Documents 1 and 2).

  Further, in order to further improve the strength, Patent Document 3 discloses that a turbine blade obtained by cutting a blade shape from a series of material materials and a rotor disk are fastened by welding. According to the structure using the welded portion, it is possible to withstand a higher stress than in the case of fastening with a groove shape.

JP 2000-161007 A JP 2007-92695 A JP 2003-269106 A

  In the turbine rotor structure described in Patent Document 3, steam hits the moving blade from the moving blade inlet side and escapes to the outlet side. Therefore, the inlet side temperature of the rotor blade is higher than that on the outlet side, so that the thermal deformation of the rotor disk becomes uneven. As a result, the outer periphery of the moving blades may rotate unevenly during operation, or the gap between the moving blades and stationary blades during operation may deviate from the design specifications, which may reduce plant efficiency. Therefore, in order to further improve the efficiency, it is necessary to rotate the outer periphery of the moving blades uniformly during operation.

  Accordingly, an object of the present invention is to provide a turbine rotor that has high strength under high temperature conditions and can achieve uniform rotation even under high temperature conditions.

  The present invention relates to a rotor shaft, a rotor blade ring for at least one stage in which a plurality of rotor blades are integrally formed, a rotor disk that is integrated with the rotor shaft and fixes the rotor blade ring to the rotor shaft, and And a rotor for a steam turbine in which a base portion of the rotor blade ring and an outer peripheral portion of the rotor disk are welded together via a weld metal portion.

  In particular, a rotor ring in which a plurality of rotor blades are integrally formed is welded and integrated with the outer periphery of the rotor disk at the root, and the outer diameter of the rotor disk and the inner diameter of the rotor ring Or at least one of the widths of the weld metal portion is changed between the steam inlet side and the steam outlet side. The outer diameter of the rotor disk is made smaller on the steam inlet side than on the steam outlet side. The inner diameter of the rotor ring is larger on the steam inlet side than on the outlet side. The width of the weld metal is larger on the steam inlet side than on the steam outlet side. Furthermore, the width of the weld metal part is preferably 9 to 30 mm on the steam inlet side and 4 to 12 mm on the steam outlet side.

  The rotor ring may be integrally formed in an annular shape or may be a ring formed by welding several members. Although all the rotor blades of the turbine rotor may be replaced with rotor blade rings, at least one stage is replaced with a rotor blade ring. In particular, the first stage blade on the high temperature steam inlet side is preferably a blade ring.

  Further, it is desirable that the rotor disk is subjected to buttering using a material for the rotor blade ring, or the rotor blade material is subjected to buttering using the material of the rotor disk.

  Further, the rotor blade ring and the rotor disk can be welded not only through the weld metal part but also through the intermediate ring.

  In turbine rotors that replace multiple stages of rotor blades with rotor blade rings, the rotor disk diameter on the steam inlet side (front stage) is used on the steam outlet side (rear stage) to weld the rotor blade rings to multiple rotor disks. It is made smaller than the innermost diameter of the rotor blade ring. As a result, the annular rotor blade ring can be passed from the front stage side of the low shaft and welded to the rotor disk on the rear stage side.

  In a double-flow steam turbine, the steam inlet is located on the inner side in the axial direction of the rotor. Therefore, in order to weld the blade ring to the rotor disk, a plurality of parts divided on the high-pressure side than the rotor disk that welds the blade ring are used. The rotor shaft which consists of these members is used. Alternatively, the rotor blade ring is composed of a plurality of members (at least two members). Both can be integrated by welding. At least one location is welded in the circumferential direction on the rotor shaft, and at least two locations are welded in the radial direction on the rotor blade ring.

  The material of the rotor ring is a high chromium steel material, and the material of the rotor shaft and rotor disk is a low alloy steel material. Alternatively, the rotor ring material is a Ni-based superalloy material, and the rotor shaft or rotor disk material is a combination of high chromium steel materials.

  According to the above configuration, it is possible to provide a turbine rotor that maintains a gap between a moving blade and a stationary blade, has high strength under high temperature conditions, and can achieve uniform rotation even under high temperature conditions. Improve plant efficiency.

Sectional drawing of the welding rotor for high pressure turbines which concerns on Example 1 of this invention. The schematic diagram of the turbine rotor welding apparatus for welding a turbine rotor. The flowchart which shows the turbine rotor welding process which concerns on Example 1 of this invention. The schematic diagram of the welding part vicinity. The cross-sectional schematic diagram of the rotor disk to which the moving blade ring was welded. The schematic diagram which shows the turbine rotor welding process which concerns on Example 4 of this invention. The schematic diagram which shows the buttering process which concerns on Example 4 of this invention. The schematic diagram which shows the turbine rotor welding process which concerns on Example 5 of this invention. The schematic diagram which shows the turbine rotor welding process which concerns on Example 6 of this invention. The schematic diagram which shows the turbine rotor welding process which concerns on Example 7 of this invention. The schematic diagram of the welding part vicinity which concerns on Example 8 of this invention. The schematic diagram which shows the turbine rotor welding process which concerns on Example 9 of this invention. Sectional drawing of the welding rotor for high pressure turbines which concerns on Example 10 of this invention. Sectional drawing of the welding rotor for high pressure turbines which concerns on Example 11 of this invention.

  As described above, the present invention has a structure in which a moving blade ring in which a plurality of moving blades are integrally formed is welded and integrated with the outer peripheral portion of the rotor disk at the root portion. A turbine rotor in which at least one stage of the integrally formed blade ring is used and the root portion of the blade ring and the outer periphery of the rotor disk are welded together via a weld metal. It is characterized in that at least one of the width and the inner diameter of the rotor blade is asymmetric between the steam inlet side and the outlet side. Specifically, the outer diameter on the steam inlet side of the rotor disk is smaller than the outer diameter on the steam outlet side, the inner diameter on the steam inlet side of the rotor blade ring is larger than the inner diameter on the steam outlet side, and the steam inlet of the weld metal part The width on the side is larger than the width on the steam outlet side.

  Hereinafter, the form for implementing the turbine rotor of this invention is demonstrated in detail by a specific Example.

  A first embodiment will be described with reference to FIGS.

  FIG. 1 is a sectional view of a turbine rotor for high-pressure steam according to the present invention. The turbine rotor includes a rotor shaft, a rotor disk provided in an annular shape on the rotor shaft, and a moving blade fixed to the rotor disk. Steam flows in from the high temperature side of the turbine rotor and flows out from the low temperature side. In the present embodiment, the first stage rotor blade of the turbine rotor that first hits the steam is composed of a rotor blade ring fixed to the rotor disk.

  As shown in FIG. 1, the rotor ring is fastened to the rotor disk by welding. As a welding method, a tungsten / inert gas (TIG) welding method, a submerged arc (SAW) welding method, a covering arc welding method, a metal / inert gas (MIG) welding method, or a combination thereof may be employed. it can.

  Since the blade ring requires high temperature strength, high chromium steel represented by 12Cr steel is used. On the other hand, since the rotor disk does not require high-temperature strength as much as the rotor blade, low-alloy steel typified by cheaper Cr—Mo—V steel is used. For the weld metal part for welding them, a high chromium steel material is used when the exposed temperature is close to the rotor ring, and a low alloy high material is used when the temperature is close to the rotor disk. Table 1 exemplifies the chemical composition (% by weight) of the base material and the welding wire constituting the rotor of the turbine rotor. The balance is Fe and inevitable impurities.

  As an example of the turbine rotor manufacturing apparatus, FIG. 2 shows a schematic diagram of a welding apparatus for manufacturing the turbine rotor of FIG. 1 by a tungsten / inert gas (TIG) welding method. The turbine rotor welding apparatus 8 includes a torch 10 to which an electrode 9 is attached, a welding wire 11 that forms a welding portion 6, an arm 12 that supports and fixes the torch 10 and the welding wire 11, and a welding power source that supplies a predetermined value of current to the electrode 9. 13. Gas cylinder 14 for supplying an inert gas injected from the periphery of electrode 9 to suppress oxidation of weld 6, turbine rotor rotating device 15 for rotating turbine rotor 1 while supporting it, and welding wire 11 6 includes a welding wire feeding device 16 that feeds the welding wire. A power transmission line 17 from the welding power source 13 is attached to the electrode 9, and current is supplied from the welding power source 13. A gas hose 18 is attached to the torch 10 in order to receive an inert gas from the gas cylinder 14. An electric wire 19 is attached to the turbine rotor 1 in order to generate an electric arc between the electrode 9 and the turbine rotor 1. A rotation signal line 20 is attached to the turbine rotor rotating device 15, and the rotational speed and direction of the turbine rotor rotating device 15 are controlled by receiving a control signal from the welding power source 13. The welding wire feeding device 16 is configured to receive the control signal from the feeding signal line 21 and to control the feeding speed of the welding wire 22. Although FIG. 2 illustrates an example in which the rotor is vertically arranged and welded downward, the rotor may be horizontally arranged and welded sideways.

  FIG. 3 shows an example of a process flow for welding the rotor blade 35 to the rotor disk 36 in the turbine rotor according to the present invention. First, at step 101, the rotor blade ring 35 is incorporated into the rotor disk 36. Thereafter, when an instruction to start the welding process is given at step 102, the rotor is preheated at step 103 in order to relieve thermal stress during welding. In step 104, welding is performed by the turbine rotor welding apparatus shown in FIG. In step 105, stress-relief annealing is performed in order to make uniform the heat that has entered the welded part 6 in the main welding. In step 106, a weld defect inspection of the weld 6 is performed. If a defect is detected in step 107 and the defect size is not acceptable in mechanical strength in step 108, the weld 6 is cut in step 109, and the rotor end face is grooved in step 110. If no defect is detected in step 107 or if it is confirmed in step 108 that the defect size is acceptable, the process proceeds to step 111 and the joining process is terminated.

  FIG. 4 shows a cross section in the vicinity of the weld before and after welding. The rotor ring has a shape in which the inner diameter on the high temperature side (steam inflow direction) is larger than the inner diameter on the low temperature side (steam outflow side). The rotor disk has a shape in which the outer diameter on the high temperature side is the same as or smaller than the outer diameter on the low temperature side. As a result, a groove opened on the high temperature side is formed in the mating portion. The moving blade ring 35 and the rotor disk 35 are in contact with each other at a butted portion processed into an inlay (key shape), and are supported so that the moving blade ring 35 fits in a predetermined position. At this time, gravity is applied to the moving blade ring 35, so the abutting portion is located on the front side with respect to the direction in which the moving blade ring is assembled. After the blade ring 35 is properly assembled in the rotor disk 36, the weld metal is melted into the welding groove 30 between the blade ring 35 and the rotor disk 36. By doing in this way, it becomes possible to adjust the thermal deformation in the high temperature side and the low temperature side.

  FIG. 5 is a schematic cross-sectional view of the rotor disk 36 to which the blade ring 35 is welded. (A) is this invention, (b) shows a prior art example. In the rotor, a temperature difference occurs between the steam inlet side and the steam outlet side. Formula (1) shows a simple formula indicating the amount of thermal deformation.

ΔL = α · L · (T−T ₀ ) (1)

  ΔL is the amount of thermal deformation, α is the coefficient of thermal expansion, L is the length of the member, and T is the temperature.

  Expression (1) shows that ΔL increases as α, L, and ΔT increase. Based on this relational expression, the amount of thermal deformation of the rotor is as shown in Expression (2) and Expression (3).

ΔL ⁱ = ΔL ⁱ _R + ΔL ⁱ _D + ΔL ⁱ _{B
^{= (Α R L i R +}} α D L i D + α B L i B) (T i -rt) ... Equation (2)
ΔL ^o = ΔL ^o _R + ΔL ^o _D + ΔL ^o _{B
^{= (Α R L o R +}} α D L o D + α B L o B) (T o -rt) ... Equation (3)

The subscript R indicates the rotor disk 36, D indicates the weld metal 37, and B indicates the rotor blade ring 35. rt is room temperature. That is, L _R is the outer diameter of the rotor disk, L _D is the width of the weld metal, and L _B is the width of the rotor blade ring (outer diameter-inner diameter).

In order to equalize the amount of thermal deformation of the steam inlet side and the outlet side during operation ([Delta] L ⁱ = [Delta] L ^o) should be equal to Equation (2) Equation (3). The temperatures (T ^i, T ^o ) on the steam inlet side and the steam outlet side are operating conditions, and α is a physical property value of the material and cannot be easily changed. For this reason, in the present invention, first, the shape factor L is adjusted. If the equations (2) and (3) are arranged, the relationship of the equation (4) is established.

^{(T i -rt) / (T} o -rt)
_{^{= (Α R L o R +}} α D L o D + α B L o B) / (α R L i R + α D L i D + α B L i B) ... Equation (4)

  Furthermore, since the steam temperature is higher on the inlet side than on the outlet side, equation (5) is established.

(T ⁱ −rt) / (T ^o −rt)> 1 (5)

  From Expression (4) and Expression (5), Expression (6) is established.

^{_{(Α R L o R + α}} D L o D + α B L o B)> (α R L i R + α D L i D + α B L i B) ... (6)

Of the three members (the rotor blade ring 35, the rotor disk 36, and the weld metal 37), the outer diameter (L ⁱ _R , L ^o _R ) of the rotor disk 36 is the largest. Therefore, setting the outer diameter of the rotor disk 36 to L ^o _R > L ⁱ _R is most effective in satisfying Equation (6), that is, equalizing the thermal deformation. As in the conventional example shown in FIG. 5B, if L ⁱ _R ≈L ^o _R , it is difficult to equalize the thermal deformation. Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained, so that the efficiency of the plant can be improved.

  A second embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the target length and the other is the same, the description is omitted.

The rotor disk 36 to which the rotor ring 35 is welded starts operation from room temperature and operates at a predetermined high temperature. During this time, it is desirable that the outer diameter (L ⁱ , L ^o ) of the blade ring 35 be uniformly deformed. From this, Formula (7) and Formula (8) are materialized.

L ⁱ = L ⁱ _R + L ⁱ _D + L ⁱ _B, L ^o = L ^O _R + L ^O _D + L ^O _B (7)
L ⁱ _R + L ⁱ _D + L ⁱ _B = L ^O _R + L ^O _D + L ^O _B (8)

Accordingly, when L ⁱ _R <L ^o _R shown in the first embodiment is satisfied, the width of the weld metal is preferably L ⁱ _D > L ^o _D in order to satisfy Expression (8). This is effective in equalizing thermal deformation. Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained from the start of operation at room temperature to the steady operation, so that the efficiency of the plant can be improved.

  A third embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the target length and the other is the same, the description is omitted.

In Example 1, the rotor disk diameter L _R was specified, and in Example 2, the width L _{D of the} weld metal was specified. Similarly, when L ⁱ _R <L ^o _R shown in the first embodiment is satisfied, the inner diameter of the rotor ring 35 satisfies L ⁱ _B > L ^o _B in order to satisfy the expression (8). It is desirable. This is effective in equalizing thermal deformation. Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained from the start of operation at room temperature to the steady operation, so that the efficiency of the plant can be improved.

  A fourth embodiment of the present invention will be described with reference to FIGS. Since the present embodiment is different from the first embodiment only in the presence or absence of buttering and the others are the same, the description is omitted. By battering, during butt welding, a metal layer is formed on the surface of each member to be butt welded by overlay welding or the like, thereby reducing the influence of welding on each member.

  In the case where the thermal deformation cannot be made equal only by the shape shown in the first embodiment, buttering 38 is applied to the end face of the rotor disk 36 with the same material as the moving blade. At that time, the coefficient of thermal expansion of the rotor disk 36 can be adjusted by performing a large amount of buttering on the surface on the steam inlet side.

FIG. 6 shows a schematic diagram of the vicinity of the weld according to the present embodiment. This coefficient of thermal expansion of the rotor disc 36 is larger than the rotor vane ring _{35 (α R> α B)} , is particularly effective. This means that the first term on the right side in Equation (6) shown in Example 1 is changed as in Equation (9).

α _R L ⁱ _R → α _R (L ⁱ _R -L _BU ) + α _B L _BU (9)

L _BU is the width of buttering. Since L _BU > 0, Expression (10) is satisfied, and therefore Expression (6) is easily satisfied.

α _R L ⁱ _R > α _R (L ⁱ _R− L _BU ) + α _B L _BU Equation (10)

  FIG. 7 shows an example of a process flow for performing buttering. First, when an instruction to start buttering is issued in step 201, in step 202, the workpiece is preheated in order to relieve thermal stress during welding. In step 203, buttering is performed by the turbine rotor welding apparatus shown in FIG. In step 204, stress relief annealing is performed in order to uniformize the heat that has entered the buttering. In step 205, a buttering weld defect inspection is performed. If a defect is detected in step 206 and the defect size is unacceptable in mechanical strength in step 207, the weld 6 is cut in step 208, and the groove is reworked in step 209. If no defect is detected in step 206 or if it is confirmed that the defect size is acceptable in step 207, the groove for main welding is processed in step 210, and then the process proceeds to step 211 to end the buttering. The main welding of the buttering is the same as that in FIG.

  Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained from the start of operation at room temperature to the steady operation, so that the efficiency of the plant can be improved.

  A fifth embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the presence or absence of buttering and the others are the same, the description is omitted.

When the thermal deformation cannot be made equal only by the shape of the rotor disk shown in the first embodiment, buttering 39 is applied to the end face of the rotor blade ring 35 with the same material as the rotor. In that case, the thermal expansion coefficient of the moving blade ring 35 can be adjusted by carrying out a large amount of buttering on the surface of the moving blade ring 35 on the steam outlet side. FIG. 8 shows a schematic diagram of the vicinity of the weld according to the present embodiment. This is particularly effective when the thermal expansion coefficient of the rotor disk 36 is larger than that of the rotor blade ring 35 (α _R > α _B ). This means that the third term on the left side in Equation (6) shown in Embodiment 1 changes as in Equation (11).

α _B ^Lo _B → α _R L _BU + α _B ( ^Lo _R −L _BU ) (11)

Since L _BU > 0, Expression (12) is satisfied, and therefore Expression (6) is easily satisfied.

α _B ^Lo _B <α _R L _BU + α _B ( ^Lo _R −L _BU ) (12)

  Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained from the start of operation at room temperature to the steady operation, so that the efficiency of the plant can be improved.

  A sixth embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the presence or absence of buttering and the others are the same, the description is omitted.

In the case where thermal deformation cannot be made equal only by the shape of the rotor disk shown in the first embodiment, buttering 38 is applied to the end face of the rotor disk 36 with the same material as the moving blade. At that time, the coefficient of thermal expansion of the rotor disk 36 can be adjusted by applying a large amount of buttering 38 to the surface of the rotor disk 36 on the steam outlet side. FIG. 9 shows a schematic diagram of the vicinity of the weld according to the present embodiment. This is particularly effective when the thermal expansion coefficient of the rotor disk 36 is smaller than that of the rotor blade ring 35 (α _R <α _B ). This means that the first term on the left side in equation (6) shown in the first embodiment is changed as in equation (13).

α _R ^Lo _R → α _R ( ^Lo _R −L _BU ) + α _B L _BU (Formula (13))

Since L _BU > 0, Expression (14) is satisfied, and therefore Expression (6) is easily satisfied.

α _R L ^O _R <α _R (L ^O _R -L _BU ) + α _B L _BU (Formula (14))

  Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained from the start of operation at room temperature to the steady operation, so that the efficiency of the plant can be improved.

  A seventh embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the presence or absence of buttering and the others are the same, the description is omitted.

When the thermal deformation cannot be made equal only by the shape of the rotor disk shown in the first embodiment, buttering 39 is applied to the end face of the rotor blade ring 35 with the same material as the rotor. At that time, the coefficient of thermal expansion of the blade ring 35 can be adjusted by applying a large amount of buttering 39 to the steam inlet side surface of the blade ring 35. FIG. 10 shows a schematic diagram of the vicinity of the weld according to the present embodiment. This is particularly effective when the thermal expansion coefficient of the rotor disk 36 is smaller than that of the rotor blade ring 35 (α _R <α _B ). This means that the third term on the right side in Equation (6) shown in Example 1 changes as in Equation (15).

α _B L ⁱ _B → α _R L _BU + α _B (L ⁱ _R− L _BU ) (15)

Because it is L _BU> 0, since the equation (16) holds, equation (6) is easily satisfied.

α _B L ⁱ _B > α _R L _BU + α _B (L ⁱ _B− L _BU ) (16)

  Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained from the start of operation at room temperature to the steady operation, so that the efficiency of the plant can be improved.

  An eighth embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the presence or absence of an intermediate ring and the other is the same, the description is omitted.

  In the case where thermal deformation cannot be made equal only by the shape of the rotor disk shown in the first embodiment, an intermediate ring 47 made of the same material as that of the rotor blade is incorporated in the rotor disk 36 and welded. Thereafter, the blade ring 35 is assembled and welded. Thereby, compared with Example 6, it is possible to adjust the thermal expansion coefficient of the rotor over a wider range.

  Thus, according to the present embodiment, the gap between the moving blade and the stationary blade can be maintained, so that the efficiency of the plant can be improved.

  A ninth embodiment of the present invention will be described with reference to FIG. The present embodiment is different from the first embodiment only in the number of target rotor disks, and the others are the same, so the description is omitted.

In Example 1, although it showed with respect to one rotor disk, in this Example, the case where a moving blade ring is welded with respect to several rotor disks is shown. This is because, when the steam temperature is higher or the temperature of the steam that has passed through the preceding rotor blade is higher, the rotor blade ring is also welded to the latter rotor disk. FIG. 12 is a schematic diagram in the case of welding a rotor blade ring to a plurality of rotor disks. D _R ¹ is the maximum outer diameter of the front rotor disk, and D _B ² is the maximum inner diameter of the rear rotor ring. The moving blade ring 35 incorporated in the latter rotor disk 41 needs to pass through the former rotor disk. Therefore, the maximum outer diameter D _R ¹ of the preceding stage of the rotor disc, needs to be smaller than the maximum inner diameter D _B ² in the subsequent stage of the rotor blade ring ^{_{(D R 1 <D B 2}} ). This condition is similarly established for a plurality of subsequent rotor disks.

  Thus, according to the present embodiment, the moving blade ring can be welded to a plurality of rotors, and the gap between the moving blade and the stationary blade can be maintained, so that the efficiency of the plant can be improved.

  A tenth embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the diameter of the rotor disk in the previous stage and the other is the same, the description is omitted.

In the first embodiment, the turbine in which the steam flows in one direction is shown. However, in this embodiment, the double-flow turbine in which the steam flows in a plurality of directions is shown. This is a system in which the pressure distribution of the rotor is symmetric as the steam flows separately from the center of the rotor in both end directions as in the high-medium pressure integrated rotor. The rotor disk diameter is larger on the low pressure side at the end than on the high pressure side at the center. If the maximum outer diameter of the rotor disk on the high-pressure side upstream is D _R ¹ and the maximum outer diameter of the rotor disk on the low-pressure side downstream is D _R ² , then D _R ¹ <D _R ² is satisfied. Therefore, the moving blade ring 35 cannot be incorporated from the end. In this case, the rotor blade 35 is incorporated into the rotor disk with respect to the rotor divided by the shaft portion that satisfies D _R ¹ <D _B ² , and then the shaft portion is welded with the weld metal 42. That is, when the rotor blade ring is welded to the rotor disk with respect to the double-flow turbine rotor, at least one welded portion is included in the rotor shaft portion.

  Thus, according to the present embodiment, even in a double-flow turbine rotor, a moving blade ring can be welded to a plurality of rotors, and a gap between the moving blade and the stationary blade can be maintained. Can be made more efficient.

  An eleventh embodiment of the present invention will be described with reference to FIG. Since the present embodiment is different from the first embodiment only in the diameter of the rotor disk in the previous stage and the other is the same, the description is omitted.

  In the ninth embodiment, a welded portion is included in the shaft portion of the rotor, but in this embodiment, a welded portion extending in the radial direction is included in the rotor blade ring 35. As described in the ninth embodiment, in the double-flow turbine rotor, the rotor blade ring 35 cannot be incorporated from the end. Therefore, by dividing the blade ring 35 into at least two parts in advance, each can be incorporated into the rotor disk. Thereafter, the blade ring 35 is integrated by welding in the radial direction.

  Thus, according to the present embodiment, even in a double-flow turbine rotor, a moving blade ring can be welded to a plurality of rotors, and a gap between the moving blade and the stationary blade can be maintained. Can be made more efficient.

  A twelfth embodiment of the present invention will be described. Since the present embodiment is different from the first embodiment only in the material of the rotor blade ring 35 and the rotor disk 36 and the other parts are the same, the description thereof is omitted.

  Since the moving blade ring 35 has more locations that directly contact the steam as compared with the rotor disk 35, the ultimate temperature is also increased. As a result, the rotor blade ring 35 requires a higher service temperature than the rotor disk 35. Therefore, in Example 1, the rotor blade ring 35 is a high chromium steel system, and the rotor disk 36 is a low alloy steel system. In this embodiment, assuming a higher steam temperature, the rotor blade ring 35 employs a Ni-based superalloy system, and the rotor disk 36 employs a high chromium steel system.

  Thus, according to this embodiment, even in a plant at a higher steam temperature, the rotor blade ring can be welded to the rotor, and the gap between the rotor blade and the stationary blade can be maintained. High efficiency can be achieved.

  A thirteenth embodiment of the present invention will be described. Since the present embodiment is different from Embodiment 1 only in the width of the weld metal and the other portions are the same, description thereof will be omitted.

  The actual blade ring 35 is not solid, but includes a root portion that is welded to the rotor disk 36, a blade portion through which steam passes, and an outer peripheral portion that supports the blade portion. Therefore, thermal deformation is not uniform. From this, in consideration of the shape conditions such as the actual moving blade ring 35, the operating conditions such as the steam temperature on the inlet side and the outlet side, and the construction conditions such as the shape of the torch 10 to be put into the groove 30, Numerical analysis on thermal deformation was performed. As a result, it has been clarified that the width of the weld metal is desirably 9 to 30 mm on the steam inlet side and 4 to 12 on the steam outlet side. The lower limit values of these numerical values were calculated from conditions for appropriately scanning the torch 10 even when the inside of the groove 30 contracted due to thermal deformation during welding. Further, the upper limit value of the numerical value was calculated in consideration of the heat shrinkage of the groove 30 due to welding heat input and the thermal deformation due to the difference in steam temperature between the inlet side and the outlet side.

  As described above, according to the present embodiment, a condition for properly welding the moving blade ring 35 to the rotor disk 26 can be obtained, and the gap between the moving blade and the stationary blade can be maintained, so that the efficiency of the plant can be improved.

DESCRIPTION OF SYMBOLS 1, 2 Turbine rotor 6 Welding part 8 Turbine rotor welding apparatus 9 Electrode 10 Torch 11, 37 Weld metal 12 Arm 13 Welding power supply 14 Gas cylinder 15 Turbine rotor rotating apparatus 16 Welding wire feeding apparatus 17 Power transmission line 18 Gas hose 19 Electric line 20 Rotation Signal line 21 Feed signal line 30 Welding groove 31 Outer contact surface 32 extending in the radial direction Contact surface 33 extending in the axial direction Inner contact surface 34 extending in the radial direction Notch 35 Blade ring 36 Rotor disk 38 Depending on the blade material Buttering 39 Battering with rotor material 40 Front rotor disk 41 Rear rotor disk 42 Welded metal 43 of shaft portion 43 Welded portion 44 in the blade radial direction Intermediate ring

Claims (15)

A rotor shaft, at least one stage of a blade ring integrally formed with a plurality of blades, and a rotor disk integrated with the rotor shaft and fixing the blade ring to the rotor shaft;
A rotor for a steam turbine in which a base portion of the blade ring and an outer peripheral portion of the rotor disk are welded and fastened via a weld metal portion;
The rotor for steam turbines characterized in that an outer diameter on the steam inlet side of the rotor disk is smaller than an outer diameter on the steam outlet side.   The steam turbine rotor according to claim 1, wherein an inner diameter of the moving blade ring on a steam inlet side is larger than an inner diameter on a steam outlet side.   3. The steam turbine rotor according to claim 1, wherein a width of the weld metal portion on a steam inlet side is larger than a width on a steam outlet side. 4. A rotor shaft, at least one stage of a blade ring integrally formed with a plurality of blades, and a rotor disk for fixing the blade ring to the rotor shaft;
A rotor for a steam turbine in which a base portion of the blade ring and an outer peripheral portion of the rotor disk are welded and fastened via a weld metal portion;
The steam turbine rotor, wherein an inner diameter of the moving blade ring on a steam inlet side is larger than an inner diameter of a steam outlet side. A rotor shaft, at least one stage of a blade ring integrally formed with a plurality of blades, and a rotor disk for fixing the blade ring to the rotor shaft;
A rotor for a steam turbine in which a base portion of the blade ring and an outer peripheral portion of the rotor disk are welded and fastened via a weld metal portion;
The steam turbine rotor, wherein a width of the weld metal part on a steam inlet side is larger than a width on a steam outlet side. A steam turbine rotor according to any one of claims 1 to 5,
A rotor for a steam turbine, wherein the rotor disk is buttered with an alloy having the same composition as the rotor blade ring. A steam turbine rotor according to any one of claims 1 to 5,
The rotor blade for a steam turbine, wherein the blade ring is buttered with an alloy having the same component as the rotor disk. A steam turbine rotor according to any one of claims 1 to 7,
The rotor for a steam turbine, wherein the blade ring is welded to the rotor disk via an intermediate ring. A steam turbine rotor according to any one of claims 1 to 8,
A plurality of stages of blade rings, each of which is fixed to a corresponding rotor disk;
A rotor for a steam turbine, wherein an outer diameter of a rotor disk corresponding to a moving blade ring on a steam inlet side is smaller than an outer diameter of a rotor disk corresponding to a moving blade ring on a steam outlet side. A steam turbine rotor according to any one of claims 1 to 9,
The rotor shaft is composed of a plurality of members welded at least at one place by a shaft welded portion in the circumferential direction of the rotor, and the shaft welded portion is on the high-pressure side of the rotor disk welded with the rotor ring, A rotor for a steam turbine, which is used as a rotor for a turbine. A steam turbine rotor according to any one of claims 1 to 9,
The blade ring is composed of at least two members welded in the radial direction of the ring,
A rotor for a steam turbine, which is used as a rotor for a double-flow steam turbine. A steam turbine rotor according to any one of claims 1 to 11, comprising:
The rotor blade for steam turbines, wherein the rotor ring is made of high chromium steel containing 9 to 12% chromium, and the rotor shaft is made of low alloy steel. A steam turbine rotor according to any one of claims 1 to 11, comprising:
The rotor blade for steam turbines, wherein the rotor ring is made of a Ni-based alloy, and the rotor shaft is made of high chromium steel containing 9 to 12% chromium. A steam turbine rotor according to any one of claims 1 to 13,
The width of the weld metal part provided between the rotor disk and the rotor blade ring is such that the steam inlet side is 9 to 30 mm, the steam outlet side is 4 to 12 mm, and the steam inlet side is larger than the steam outlet side. A rotor for a steam turbine.   A steam turbine using the steam turbine rotor according to any one of claims 1 to 14.

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