Method for manufacturing a turbine component and method for repairing a turbine component

Abstract

Provided is a turbine component production method, and the like, with which it is possible to obtain a single-crystal structure more simply and produce a favorable turbine component. In a seed crystal placement step, a seed crystal is placed on the surface of a base. In a molding layer formation step, powder of ingredients used to constitute a molding layer is first paved on the surface of the base so as to conceal the seed crystal, and then irradiating the powder paved on the base surface with an energetic beam in a scanning direction, thereby forming a molding layer. Here, the seed crystal is of single-crystal metal that has either a face-centered cubic crystal structure or a structure in which an L12 regular phase is coherently precipitated in a face-centered cubic crystal. In the seed crystal placement step, the seed crystal is placed on the surface of the base such that a first orientation running along <001> of the seed crystal forms an angle that falls within the absolute value of not more than 15° with respect to the direction of lamination. In the molding layer formation step, the scanning is performed such that the scanning direction forms an angle falling within the absolute value of not more than 20° with respect to a second orientation which is <001> that is orthogonal to the first orientation of the seed crystal.

Description

Technical Field

[0001] Embodiments of the present invention relate to a method for manufacturing a turbine component, a method for repairing the same, and a turbine component.

Background Art

[0002] In recent years, in order to reduce carbon dioxide emissions, the efficiency of power generation equipment has been improved. In gas turbines, the efficiency has been improved by increasing the combustion gas temperature. The increase in the combustion gas temperature can be achieved by improving the creep strength of the turbine blade material and the cooling performance.

[0003] As for the turbine blade material, from an ordinary casting alloy containing a large number of crystals with different orientations, to a material in which crystal grains are oriented in the longitudinal direction of the turbine blade where centrifugal stress is applied and creep strength is required, and the crystal grains are oriented and strengthened in the

[0001] orientation of the face-centered cubic lattice. Also, the improvement of strength has been achieved by using a single crystal alloy in which the

[0001] direction of the face-centered cubic lattice is oriented in the longitudinal direction of the turbine blade.

[0004] Regarding cooling, the cooling method has changed from a simple cooling method of making long holes in the centrifugal axis direction and flowing cooling air to a cooling method in which cooling air called return flow flows in a complex manner, and the cooling performance has been improved.

[0005] A complex cooling structure called return flow is manufactured by a method in which casting is performed with a ceramic component called a core inserted, and then the core is dissolved using an alkaline solution such as sodium hydroxide. However, the cooling structure is restricted by the strength of the core and the like.

[0006] In recent years, the development of a technique called additive manufacturing has advanced. Since additive manufacturing can manufacture structures that have been difficult to manufacture until now, proposals for cooling structures unique to additive manufacturing have also been made for turbine blades and the like.

[0007] In additive manufacturing methods, in general, since crystals are grown on a base such as a stainless steel plate having an equiaxed crystal structure, a large number of crystal grains with different orientations grow, and grain boundaries are generated. Grain boundaries affect mechanical properties, and it is known that high-temperature creep and fatigue strength decrease when grain boundaries are present.

[0008] In additive manufacturing methods, a method for manufacturing single crystals using a seed crystal has been proposed, and a shaped article without grain boundaries can be obtained. In this method, shaping is performed with the surface of the seed crystal at the same height as the base. Although there is a possibility of unevenness in the amount of powder during powder coating, and there is a risk that good crystals cannot be shaped in subsequent shaping, by polishing the surface of the seed crystal so that the direction of linear scratches due to polishing intersects the moving direction of powder particles by a recoater during the formation of the shaping layer, and arranging the seed crystal to make it easier for powder to remain, it is said that good single crystals can be obtained.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] However, with linear scratches due to polishing, there is also a possibility that the powder may shift during the movement of the recoater, and depending on the way the linear scratches due to polishing enter, there is also a possibility that the powder residue may become uneven.

[0011] Therefore, an object of the present invention is to provide a method for manufacturing a turbine component, a turbine component, a method for repairing a tip portion of a blade having a single crystal structure, etc., and a repair product, which can obtain a single crystal structure more simply than conventional methods and can manufacture good turbine components.

Means for Solving the Problems

[0012] The method for manufacturing a turbine component according to the embodiment includes a seed crystal placement step and a shaping layer formation step, and manufactures a turbine component by laminating a shaping layer in the lamination direction on the surface of a base. In the seed crystal placement step, a seed crystal is placed on the surface of the base. In the shaping layer formation step, after spreading a powder of a component constituting the shaping layer so as to hide the seed crystal on the surface of the base, an energy beam is scanned and irradiated in the scanning direction on the powder spread on the surface of the base, thereby forming a shaping layer. Here, the seed crystal is a single crystal and is a metal having a face-centered cubic crystal or a structure in which an L12 ordered phase is coherently precipitated in a face-centered cubic crystal. In the seed crystal placement step, the seed crystal is placed on the surface of the base so that a first orientation along <001> of the seed crystal forms an angle within 15° in absolute value with respect to the lamination direction. In the shaping layer formation step, scanning is performed so that the scanning direction forms an angle within 20° in absolute value with respect to a second orientation which is <001> orthogonal to the first orientation of the seed crystal.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0014] [A] Turbine Component FIG. 10 is a diagram schematically showing an example of a turbine component according to an embodiment.

[0015] As shown in FIG. 10, the turbine component 200 is, for example, a turbine blade. Although details will be described later, the turbine component 200 is manufactured by laminating a plurality of shaped layers L in the lamination direction LD by an additive manufacturing technique (three-dimensional lamination molding technique). Here, the lamination direction LD is along the longitudinal direction of the turbine component 200.

[0016] [B] Manufacturing Method of Turbine Component Hereinafter, the manufacturing method of the turbine component according to the embodiment will be described with reference to the drawings.

[0017] FIG. 1 is a diagram schematically showing the manufacturing method of the turbine component 200 of the embodiment. In FIG. 1, 101 is a base, 102 is a seed crystal, 103 is an energy beam (for example, a laser beam or an electron beam, etc.), and 104 is a recoater.

[0018] [B-1] Seed Crystal Arrangement Step When manufacturing the turbine component 200, first, as shown in FIG. 1, the seed crystal 102 is arranged on the surface of the base 101 (seed crystal arrangement step).

[0019] The seed crystal 102 is, for example, a single crystal metal having a face-centered cubic crystal structure. The seed crystal 102 may be a metal having a structure in which the L12 regular phase is coherently precipitated in the face-centered cubic crystal. Generally, in the cubic crystal system, it is known that the primary crystal orientation is <001> (=

[0100] ,

[0010] ,

[0001] , etc.).

[0020] The arrangement of the seed crystal 102 is carried out by embedding it in the base 101 such that the first orientation D1 along the <001> of the seed crystal 102 forms an angle within 15°, preferably within 5° in absolute value, with respect to the lamination direction LD (the direction perpendicular to the surface of the base 101). It is more preferable to arrange the seed crystal 102 such that the first orientation D1 along the <001> of the seed crystal 102 is parallel to the lamination direction LD. As this seed crystal 102, the same alloy as the alloy to be laminated (for example, a nickel-based alloy) can be used. That is, the material of the seed crystal 102 is, for example, the same as the components constituting the shaping layer L.

[0021] [B-2] Shaping layer formation step Next, after laying the powder (not shown) of the components constituting the shaping layer L (see FIG. 10) on the surface of the base 101 so as to hide the seed crystal 101, the energy beam 103 is scanned and irradiated in the scanning direction SD (the direction perpendicular to the lamination direction LD) on the powder laid on the surface of the base 101 (see FIG. 1), thereby forming the shaping layer L (see FIG. 10) (shaping layer formation step).

[0022] Specifically, by horizontally moving the recoater 104, powder of the substance constituting the desired alloy to be laminated (for example, a nickel-based alloy) is laid so as to hide the upper surface of the seed crystal 102. Then, in a vacuum atmosphere or an inert gas atmosphere, the energy beam 105 is scanned in the scanning direction SD. The energy beam 105 has energy capable of melting the powder, is irradiated according to the shape of the shaped object, and the powder laid on the surface of the base 101 is selectively melted and bonded. The scanning direction SD in which the energy beam 105 is scanned forms an angle within 20°, preferably within 10° in absolute value, with respect to the second orientation D2 which is <001> perpendicular to the first orientation D1 of the seed crystal (when the first orientation D1 is the

[0001] orientation, the second orientation D2 is, for example, the

[0010] direction or the

[0100] direction). It is more preferable that the second orientation D2 (D2 in the figure) of the seed crystal 102 is parallel to the scanning direction SD.

[0023] As shown in Fig. 1, in the embodiment, the seed crystal 102 is embedded in the base 101, and the second orientation D2 (for example, the

[0010] orientation or the

[0100] orientation) of the embedded seed crystal 102 is made substantially parallel to the scanning direction SD of the energy beam 103, thereby promoting the epitaxial growth property of the laminated forming material.

[0024] [C] Summary By such a method, a formed material having a single crystal structure can be obtained without making the surface of the seed crystal 102 flush with the base 101. Further, by aligning the scanning direction of the energy beam 103 with the installation orientation of the seed crystal 102, the productivity of manufacturing single crystals can be improved.

[0025] Therefore, by forming a laminated forming material in a state where the second orientation D2 (for example, the

[0010] orientation or the

[0100] orientation) of the seed crystal 102 and the scanning direction SD of the energy beam 103 are substantially parallel, and manufacturing a turbine component 200 having a predetermined shape, a single crystal structure can be obtained more simply than in the prior art, and it is possible to manufacture a good turbine component 200.

[0026] In addition, the above method is similarly applicable when repairing the turbine component 200. Specifically, instead of the base 101, after performing a seed crystal placement step of placing the seed crystal 102 on the surface of the portion to be repaired in the turbine component 200, the shaping layer formation step is performed in the same manner as above, whereby the turbine component 200 can be repaired.

[0027] [D] Examples (Example 1) In Example 1, as the forming powder, a material having the metal composition shown in Table 1 was used. And as the seed crystal, a single crystal material having the same composition as the forming powder was used.

Table 1

[0028] Here, the orientation of the seed crystal 102 was measured in advance by the back Laue method. Then, as schematically shown in FIG. 2, the first orientation D1 (for example, the

[0001] orientation) along <001> of the seed crystal 102 becomes the lamination direction LD, and the second orientation D2 which is <001> orthogonal to the first orientation D1 of the seed crystal 102 (for example, the

[0010] orientation or the

[0100] orientation) becomes parallel to the scanning direction SD of the energy beam 103, and the seed crystal 102 was embedded on the base 101. When embedding the seed crystal 102, the upper surface of the seed crystal 102 was set to be parallel to the plane of the base 101 and 100 μm lower than the surface of the base 101.

[0029] After setting, lamination was performed on the seed crystal 102 by the selective laser melting (SLM) method. FIG. 3 shows the cross-sectional structure of the formed object and the seed crystal interface obtained in Example 1. As shown in FIG. 3, the seed crystal and the formed product are crystals of the same orientation. Thus, as shown in FIG. 2, it became clear that even if the surface of the seed crystal 102 is not set to the same height as the base 101, by controlling the scanning direction SD of the energy beam 103 and the orientation of the seed crystal 102, a formed object following the orientation of the seed crystal 102 can be obtained.

[0030] (Example 2) In Example 2, similar to Example 1, as the forming powder, a material having the metal composition shown in Table 1 was used. And as the seed crystal, a single crystal material having the same composition as the forming powder was used.

[0031] Here, the orientation of the seed crystal 102 was measured in advance by the back Laue method. Then, as schematically shown in FIG. 4, the first orientation D1 (for example, the

[0001] orientation) along <001> of the seed crystal 102 becomes the lamination direction LD, and the second orientation D2 which is <001> orthogonal to the first orientation D1 of the seed crystal (for example, the

[0010] orientation or the

[0100] orientation) becomes parallel to the scanning direction SD of the energy beam 103, and the seed crystal 102 was embedded on the base 101. When embedding the seed crystal 102, the upper surface of the seed crystal 102 was set to be parallel to the plane of the base 101 and 100 μm higher from the surface of the base 101.

[0032] After setting, lamination was performed on the seed crystal by the selective laser melting (SLM) method. FIG. 5 shows the cross-sectional structure of the interface between the shaped article and the seed crystal obtained in Example 2. As shown in FIG. 5, the seed crystal and the shaped article are crystals of the same orientation. Thus, as shown in FIG. 4, it became clear that a shaped article following the orientation of the seed crystal 102 can be obtained by controlling the scanning direction of the energy beam 103 and the orientation of the seed crystal 102 without making the surface of the seed crystal 102 the same height as the base 101.

[0033] (Example 3) In Example 3, similar to Example 1, a material having the metal composition shown in Table 1 was used as the shaping powder. And as the seed crystal, a single crystal material having the same composition as the shaping powder was used.

[0034] Here, the orientation of the seed crystal 102 was measured in advance by the back Laue method. Then, as schematically shown in FIG. 6, the first orientation D1 (for example, the

[0001] orientation) along <001> of the seed crystal 102 becomes the stacking direction LD, and the second orientation D2 which is <001> orthogonal to the first orientation D1 of the seed crystal 102 (for example, the

[0010] orientation or the

[0100] orientation) is parallel to the scanning direction SD of the energy beam 103, and the seed crystal 102 was embedded on the base 101. When embedding the seed crystal 102, the upper surface of the seed crystal 102 was set to be parallel to the plane of the base 101 and 20 μm lower than the surface of the base 101.

[0035] After setting, a layer was stacked on the seed crystal by the selective laser melting (SLM) method. FIG. 7 shows an EBSP-IPF map representing the crystal orientation of the fabricated object and the seed crystal interface obtained in Example 3. As shown in FIG. 7, the seed crystal and the fabricated product have crystals of the same orientation. Thus, as shown in FIG. 6, it became clear that even if the surface of the seed crystal 102 is not set to the same height as the base 101, by controlling the scanning direction of the energy beam 103 and the orientation of the seed crystal 102, a fabricated object following the orientation of the seed crystal 102 can be obtained.

[0036] (Comparative Example) In the comparative example, as in Examples 1 - 3, a material having the metal composition shown in Table 1 was used as the modeling powder, and a single crystal material having the same composition as the modeling powder was used as the seed crystal.

[0037] Here, the orientation of the seed crystal 102 was measured in advance by the back Laue method. Then, as schematically shown in FIG. 8, the first orientation D1 (for example, the

[0001] direction) along <001> of the seed crystal 102 is set to be the lamination direction LD, and the second orientation D2 which is <001> orthogonal to the first orientation D1 of the seed crystal 102 (for example, the

[0010] orientation or the

[0100] orientation) is set to be at a 45-degree angle to the scanning direction SD of the energy beam 103, and the seed crystal 102 was embedded on the base 101. When embedding the seed crystal 102, the upper surface of the seed crystal 102 was set to be parallel to the plane of the base 101 and 20 μm lower than the surface of the base 101.

[0038] After setting, lamination was performed on the seed crystal by the Selective laser melting (SLM) method. FIG. 9 shows an EBSP-IPF map representing the crystal orientation of the fabricated object and the seed crystal interface obtained in the comparative example. As shown in FIG. 9, although there are regions that are single crystals, the generation of polycrystals is recognized. Thus, it was found that in the comparative example, the crystal growth property is inferior to that of Examples 1-3.

[0039] In addition, in Examples 1 to 3, the case where the first orientation D1 of the seed crystal 102 is parallel to the lamination direction LD and the second orientation D2 of the seed crystal 102 is parallel to the scanning direction SD of the energy beam 103 was described. However, even when the first orientation D1 of the seed crystal 102 is inclined at an angle within 15° (that is, within +15° and -15°) with respect to the lamination direction LD and the second orientation D2 of the seed crystal 102 is inclined at an angle within 20° (that is, within +20° and -20°) with respect to the scanning direction SD of the energy beam 103, results similar to those of Examples 1 to 3 can be obtained.

[0040] As described above, several embodiments of the present invention have been explained. However, 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 gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0041] 101... base, 102... seed crystal, 103... energy beam (laser beam), 104... re-coater, D1... first orientation, LD... stacking direction, D2... second orientation, SD... scanning direction

Claims

1. A method for manufacturing a turbine component by laminating a shaped layer in a lamination direction on a surface of a base, the method comprising: a seed crystal placement step of placing a seed crystal on the surface of the base; a shaped layer forming step of laying a powder of a component constituting the shaped layer on the surface of the base so as to cover the seed crystal, and then scanning and irradiating the powder laid on the surface of the base with an energy beam in a scanning direction to form the shaped layer; characterized by The seed crystal is a single crystal, which is a metal having a face-centered cubic crystal or a structure in which an L1 ２ regular phase is coherently precipitated in a face-centered cubic crystal, ２ and has a structure in which an L1 ２ regular phase is coherently precipitated in a face-centered cubic crystal, in the seed crystal placement step, the seed crystal is placed on the surface of the base such that a first orientation along <001> of the seed crystal forms an angle within an absolute value of 15° with respect to the lamination direction; in the shaped layer forming step, the energy beam is scanned such that the scanning direction forms an angle within an absolute value of 20° with respect to a second orientation which is <001> orthogonal to the first orientation of the seed crystal; A method for manufacturing a turbine component.

2. in the seed crystal placement step, the seed crystal is placed on the surface of the base such that the first orientation forms an angle within an absolute value of 5° with respect to the lamination direction; The method for manufacturing a turbine component according to claim 1.

3. in the shaped layer forming step, the scanning is performed such that the scanning direction forms an angle within an absolute value of 10° with respect to the second orientation; The method for manufacturing a turbine component according to claim 1 or 2.

4. The powder is formed of a nickel-based alloy. The method for manufacturing a turbine component according to any one of claims 1 to 3.

5. The material of the seed crystal is a nickel-based alloy. The method for manufacturing a turbine component according to any one of claims 1 to 4.

6. placing the seed crystal on the base such that an upper surface of the seed crystal is lower than the surface of the base, and obtaining a shaped article that inherits the crystal orientation of the seed crystal; The method for manufacturing a turbine component according to any one of claims 1 to 5.

7. The energy beam is a laser beam. The method for manufacturing a turbine component according to any one of claims 1 to 6.

8. A method for repairing a turbine component by laminating a shaped layer in a lamination direction on a surface of the turbine component, the method comprising: a seed crystal placement step of placing a seed crystal on a surface of a portion to be repaired in the turbine component; A shaping layer forming step of forming the shaping layer by laying a powder of a component constituting the shaping layer on the surface so as to hide the seed crystal and then scanning and irradiating the powder laid on the surface with an energy beam in a scanning direction which comprises The seed crystal is a single crystal and is a metal having a face-centered cubic crystal or a structure in which an L1 ２ regular phase is coherently precipitated in a face-centered cubic crystal. ２ ​ In the seed crystal arranging step, the seed crystal is arranged on the surface of the turbine component such that a first orientation along <001> of the seed crystal forms an angle within an absolute value of 15° with respect to the lamination direction. In the shaping layer forming step, the energy beam is scanned such that the scanning direction forms an angle within an absolute value of 20° with respect to a second orientation which is <001> orthogonal to the first orientation of the seed crystal. A method for repairing a turbine component.

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