JP2015117626A - Turbine rotor blade, turbine, and method of manufacturing turbine rotor blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a deterioration in quality and an increase in manufacturing time by reducing weight and securing strength.SOLUTION: A turbine rotor blade 10 according to an embodiment comprises: a back-side part 20 that has a blade back face 20a; a belly-side part 21 that has a blade belly face 21a and that forms a hollow part 22 between itself and the back-side part 20; and a beam part 23 that passes through the hollow part 22 and that connects the back-side part 20 and the belly-side part 21 together. The beam part 23 is seamlessly and integrally formed in the back-side part 20 and the belly-side part 21.

Description

  Embodiments described herein relate generally to a turbine blade, a turbine, and a method for manufacturing a turbine blade.

  A turbine installed in a power plant such as thermal power generation tends to make a turbine blade (hereinafter simply referred to as a blade) longer in order to improve power generation efficiency. In this case, since the centrifugal force of the moving blade at the time of rotation increases, a material having good strength characteristics is used for the material of the moving blade in order to withstand the centrifugal force.

  However, even when a material with good strength characteristics is used, it may be difficult to give the moving blade sufficient strength to withstand the increasing centrifugal force depending on the degree of the longer blades.

  As a prior art, there is known a moving blade which is provided with a mesh-like member (honeycomb skin) constituting a hollow structure at a tip portion to reduce the weight. In this case, the centrifugal force of the moving blades during rotation can be effectively reduced.

JP 2010-106833 A

  However, the mesh-like member described above is joined to the moving blade support structure by welding or the like. As a result, heat generated during welding may adversely affect the rotor blades.

  For example, since the moving blade is locally heated during welding, residual stress may be locally generated. When the residual stress is generated, the actual stress distribution of the moving blade is different from the stress distribution that can be assumed by analysis or the like, and there is a problem that deformation or breakage may occur at a location different from the assumption. There is also concern about stress corrosion cracking.

  On the other hand, the residual stress can be removed by performing a heat treatment. However, when the moving blade has a hollow structure, the internal structure of the moving blade is complicated, and it may be difficult to heat-treat a desired portion as intended. For this reason, even if it is a case where heat processing is performed, there exists a subject that it becomes difficult to remove a residual stress.

  Moreover, when welding the mesh-shaped member mentioned above to the support structure of a moving blade, welding work may become difficult because the structure of the said member is complicated. In this case, there is a problem that the quality of welding is deteriorated and a lot of time is spent on the welding work. Furthermore, when performing a weld inspection, the internal structure is complicated, so that it is difficult to detect welding defects.

  Thus, when the member for comprising a hollow structure is joined to a support structure by welding, the subject of the fall of quality and the increase in manufacturing time may arise.

  The problem to be solved by the present invention is to provide a turbine rotor blade, a turbine, and a method of manufacturing a turbine rotor blade that can reduce weight and ensure strength, and prevent deterioration in quality and increase in manufacturing time. is there.

  A turbine rotor blade according to an embodiment includes a back side portion having a blade back surface, a ventral portion having a blade abdominal surface and forming a hollow portion with the back side portion, and passing through the hollow portion. And a beam portion connecting the side portions. The beam portion is seamlessly and integrally formed on the back side portion and the ventral side portion.

It is a section construction diagram showing an example of a steam turbine in an embodiment. FIG. 2 is an external view showing an example of a turbine rotor blade in the steam turbine of FIG. 1. It is a figure which shows an example of the AA line cross-section of FIG. It is a figure for demonstrating an example of the manufacturing method of a turbine rotor blade.

  Hereinafter, a turbine blade, a turbine, and a method for manufacturing the turbine blade according to an embodiment of the present invention will be described with reference to the drawings.

  Here, first, a steam turbine will be described with reference to FIG. 1 as an example of a turbine. FIG. 1 shows an example of a low pressure steam turbine with a relatively low steam pressure.

  As shown in FIG. 1, the steam turbine 1 includes a casing 2, a turbine rotor 3 provided rotatably in the casing 2, and a plurality of blade cascades 4 attached to the turbine rotor 3. . The moving blade cascade 4 is composed of a plurality of turbine moving blades 10 (see FIG. 2, hereinafter simply referred to as moving blades) 10 arranged at a predetermined interval in the circumferential direction. On the other hand, a plurality of stationary blade cascades 5 arranged alternately with the moving blade cascades 4 are attached to the casing 2. The stationary blade cascade 5 includes a plurality of stationary blades (nozzles) arranged at a predetermined interval in the circumferential direction. Each moving blade cascade 4 and a corresponding stationary blade cascade 5 constitute a turbine stage. The turbine stage on the highest pressure side (upstream side) among the plurality of turbine stages is referred to as a first stage 6, and the turbine stage on the lowest pressure side (downstream side) is referred to as a final stage 7.

  Connected to the casing 2 is a steam pipe 8 for supplying steam generated in a boiler or the like (not shown) to the turbine stage as working steam. The steam supplied through the steam pipe 8 enters the first stage 6, flows downstream through each turbine stage, and exits from the final stage 7. During this time, the rotor blade 10 receives the expansion work of the steam and the turbine rotor 3 rotates. As a result, power is generated in a generator (not shown) connected to the turbine rotor 3. Further, the steam that has escaped from the final paragraph 7 is sent to a condenser (not shown) outside the casing 2 to generate condensed water, and the generated condensed water is supplied to the above-described boiler.

  In the present embodiment, as shown in FIG. 2, the above-described moving blade 10 has a hollow structure. For example, a plurality of moving blades 10 are provided from the first paragraph 6 to the final paragraph 7, but the moving blade 10 of the final paragraph 7 is the longest blade, and thus the moving blade 10 has a hollow structure. It is preferred that However, the present invention is not limited to this, and the moving blades 10 of other paragraphs may have a hollow structure, and the moving blades 10 of a plurality of paragraphs or all of the moving blades 10 may have a hollow structure. Also good. Further, the hollow structure may be provided in a part (preferably the tip) of the moving blade 10 or may be provided over the entire moving blade 10.

  Hereinafter, the moving blade 10 will be described in detail.

  As shown in FIG. 2, the moving blade 10 includes a moving blade main body 11 and an implanted portion 12 provided at one end of the moving blade main body 11. Among these, the implantation part 12 can be engaged with an implantation groove (both not shown) provided in the rotor disk of the turbine rotor 3, and the implantation part 12 engages with the implantation groove, so that the moving blade 10 Is attached to the turbine rotor 3.

  As shown in FIG. 3, the rotor blade main body 11 includes a back side portion 20 having a blade back surface 20a and a ventral side portion 21 having a blade abdominal surface 21a. A hollow portion 22 is formed between the back portion 20 and the ventral portion 21. Thus, the moving blade body 11 has a hollow structure and is lightened.

  The back portion 20 and the ventral portion 21 are connected by a beam portion 23 that passes through the hollow portion 22. This ensures the strength of the rotor blade body 11 having a hollow structure. Such a beam portion 23 is formed in a honeycomb mesh shape or a lattice mesh shape when viewed from the normal direction of the blade back surface 20a or the blade belly surface 21a (when viewed from a direction perpendicular to the paper surface of FIG. 2). Is preferable. Thus, the weight of the moving blade 10 can be reduced while effectively ensuring the strength of the moving blade body 11 in the hollow portion 22. In FIG. 2, the example currently formed in the lattice mesh shape is shown. The shape of the beam portion 23 is not limited to the honeycomb mesh shape or the lattice mesh shape. For example, a plurality of separate beam portions may connect the back portion 20 and the ventral portion 21. Moreover, the arrangement of the beam portions 23 may not be made uniform, and may be arranged at an appropriate location based on the result of stress analysis or the like. In this case, the strength of the rotor blade body 11 can be effectively ensured, and further weight reduction can be achieved. Moreover, the hollow part 22 and the beam part 23 mentioned above may be provided in a part of the moving blade main body 11, or may be provided over the whole region of the moving blade main body 11. In the latter case, the moving blade 10 can be further reduced in weight.

  As shown in FIG. 3, the beam portion 23 is formed seamlessly and integrally with the back portion 20 and the ventral portion 21. That is, in the present embodiment, the back side portion 20, the abdominal side portion 21 and the beam portion 23 are integrally formed as one part using a three-dimensional additive manufacturing technique. For example, when the back part 20, the ventral part 21, and the beam part 23 are formed as separate parts and joined by welding or the like, a seam (seam) can be formed at the boundary between the parts. Such a seam is not formed in the rotor blade body 11 according to the form. That is, the term “seamless” in the present embodiment is used in the sense that there is no seam formed when the back side portion 20, the ventral side portion 21 and the beam portion 23 are formed separately and joined together by welding or the like. Yes. Such a seamless moving blade main body 11 is produced by integrally forming the back side portion 20, the ventral side portion 21 and the beam portion 23 as one part using, for example, a three-dimensional additive manufacturing machine (3D printer). can do.

  In addition, it is preferable that the back side portion 20, the ventral side portion 21 and the beam portion 23 of the moving blade 10 according to the present embodiment are made of, for example, a titanium (Ti) alloy material. As a result, the moving blade 10 can be formed using a titanium alloy material generally used for the moving blade 10, and performance such as strength and heat resistance of the moving blade 10 can be ensured.

  Next, the operation of the present embodiment having such a configuration, that is, a method for manufacturing the moving blade 10 will be described with reference to FIG. The moving blade 10 according to the present embodiment is formed using a three-dimensional additive manufacturing technique.

  First, as the first layer, a metal powder such as a titanium alloy material is discharged from the nozzle 31 of the three-dimensional additive manufacturing apparatus 30, and a first metal layer 41 is formed on the stage 32 (see FIG. 4A).

  Subsequently, the first metal layer 41 is irradiated with laser light L (or electron beam) (see FIG. 4B). The laser beam L is applied to a region corresponding to the shape of the moving blade 10 in the first metal layer 41 based on the three-dimensional CAD data of the moving blade 10. The portion of the first metal layer 41 irradiated with the laser beam L is melted and solidified to form an integrated solidified portion 41a.

  Next, as the second layer, metal powder is discharged from the nozzle 31 to form the second metal layer 42 on the first metal layer 41 (see FIG. 4C).

  Subsequently, the second metal layer 42 is irradiated with a laser beam L in a region corresponding to the shape of the moving blade 10 in the second metal layer 42 (see FIG. 4D). As a result, the portion of the second metal layer 42 irradiated with the laser light L is melted and solidified to form an integrated solidified portion 42a. At this time, the solidified portion 42 a of the second metal layer 42 is also integrated with the solidified portion 41 a of the first metal layer 41.

  By repeating such a process, the solidified portions of the metal powder are laminated, and the solidified portions of the respective layers are integrated to form the moving blade 10 (see FIG. 4E). At this time, the non-solidified metal powder of each layer remains around the solidified portion.

  Thereafter, the non-solidified portion of the metal powder is removed to obtain the moving blade 10 (see FIG. 4 (f)).

  In the above-described processing, the solidified portion can be formed in a desired shape in accordance with the CAD data by reducing the thickness of each layer and laminating finely. 4 shows an example in which the stacking direction is the longitudinal direction of the moving blade 10 (the vertical direction in FIG. 4E), but the present invention is not limited to this, and the stacking direction is the moving blade 10. The direction perpendicular to the longitudinal direction may be used.

  The obtained moving blade 10 is attached to the turbine rotor 3, and the turbine rotor 3 is attached to the casing 2 to obtain the steam turbine 1 as shown in FIG. 1.

  Thus, according to this Embodiment, the hollow part 22 is formed between the back | dorsal part 20 which has the wing | blade back surface 20a, and the ventral | abdominal part 21 which has the wing | belly ventral surface 21a. Thereby, the moving blade 10 can be reduced in weight, and the centrifugal force at the time of rotation can be reduced. Further, the weighted moving blade 10 is advantageous during transportation and construction.

  Moreover, according to this Embodiment, the beam part 23 which passes along the hollow part 22 between the back part 20 and the ventral part 21 has connected the back part 20 and the ventral part 21. FIG. Thereby, the beam portion 23 can support the back side portion 20 and the ventral side portion 21, and can ensure the strength of the moving blade 10 having the hollow portion 22. In this case, it is possible to prevent the rotor blade 10 from being twisted or sagged during the operation of the steam turbine 1.

  Furthermore, according to the present embodiment, the moving blade 10 is formed using a three-dimensional additive manufacturing technique, and the beam portion 23 is formed seamlessly and integrally with the back side portion 20 and the ventral side portion 21. As a result, even if the moving blade 10 has a complicated structure having the hollow portion 22 and the beam portion 23, it is not necessary to join the respective portions by welding or the like. It can be formed easily. Further, since the beam portion 23 is formed seamlessly and integrally with the back side portion 20 and the ventral portion 21, between the beam portion 23 and the dorsal portion 20 and between the beam portion 23 and the ventral portion 21. It is possible to avoid the formation of a seam on the surface, and the strength of the beam portion 23 can be improved.

  Here, the rotor blade 10 having the hollow portion 22 and the beam portion 23 can be formed by forging or casting. However, in this case, there is a problem that it takes time to manufacture the mold and costs. . Moreover, if the structure of the hollow part 22 and the beam part 23 becomes complicated, it may become difficult to form the moving blade 10 by forging or casting. For example, the degree of complexity of the structure that can be formed by forging is limited. Even in the case of casting, it can be difficult to flow the molten metal depending on the degree of complexity. In addition, even when cutting is performed after forging or casting, there may be a problem that the cutting tool cannot reach the inside of a complicated structure and the processing becomes difficult.

  On the other hand, according to the present embodiment, since the moving blade 10 is formed by the three-dimensional additive manufacturing technique, the moving blade 10 can be formed with high quality in a short time. In addition, by using the three-dimensional additive manufacturing technique, the moving blade 10 having a more complicated shape can be easily formed in a short time compared to the case of forming by forging or casting. Furthermore, by using the three-dimensional additive manufacturing technology, a more complicated structure can be formed, and the shape and structure of the hollow portion 22 and the beam portion 23 are optimal as compared with the case of forming by forging or casting. Therefore, it is possible to form the moving blade 10 that is superior in terms of weight reduction and strength.

  According to the embodiment described above, the weight can be reduced and the strength can be secured, and the deterioration of quality and the increase of manufacturing time can be prevented.

  Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in the present embodiment described above, the example in which the hollow portion 22 and the beam portion 23 are provided in the moving blade body 11 of the moving blade 10 has been described. However, the present invention is not limited to this, and the hollow portion and the beam portion may also be provided in the implanted portion 12. In this case, the moving blade 10 can be further reduced in weight.

  Moreover, in embodiment mentioned above, the turbine rotor blade demonstrated the example applied to a low pressure steam turbine. However, the present invention is not limited to this, and the turbine blade according to the above embodiment can be applied to a high-pressure steam turbine, an intermediate-pressure steam turbine, and a gas turbine.

  Based on this Embodiment mentioned above, the reduction | decrease model of the moving blade 10 was produced using the three-dimensional additive manufacturing technique.

  Specifically, a one-third size moving blade 10 was manufactured by a three-dimensional additive manufacturing machine using a titanium alloy material powder. The rotor blade 10 is provided with a hollow portion 22 and a beam portion 23.

  No apparent defects were observed in the manufactured moving blade 10. Moreover, the mechanical property test of the back part 20, the ventral part 21, the beam part 23, and the implantation part 12 was conducted, and it was confirmed that each part satisfied a predetermined standard. As a result, it was confirmed that the moving blade 10 can be manufactured soundly using the three-dimensional additive manufacturing technique.

DESCRIPTION OF SYMBOLS 1 Steam turbine 10 Moving blade 20 Back side part 20a Blade back surface 21 Abdomen side part 21a Blade abdominal surface 22 Hollow part 23 Beam part

Claims (6)

A dorsal portion having a wing back;
A ventral portion having a wing belly surface and forming a hollow portion with the dorsal portion;
A beam portion that passes through the hollow portion and connects the dorsal portion and the ventral portion; and
The turbine blade according to claim 1, wherein the beam portion is formed seamlessly and integrally with the back portion and the ventral portion.   2. The turbine blade according to claim 1, wherein the beam portion is formed in a honeycomb mesh shape or a lattice mesh shape when viewed from the normal direction of the blade back surface or the blade belly surface.   The turbine blade according to claim 1, wherein the back side portion, the ventral side portion, and the beam portion are formed of a titanium alloy.   The turbine rotor blade according to claim 1 or 2, wherein the back portion, the ventral portion, and the beam portion are formed using a three-dimensional additive manufacturing technique.   A turbine comprising the turbine rotor blade according to claim 1. A turbine rotor blade manufacturing method for manufacturing the turbine rotor blade according to any one of claims 1 to 4,
A method for manufacturing a turbine rotor blade, which is formed using a three-dimensional additive manufacturing technique.

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