Turbine rotor blade and contact surface manufacturing process

Abstract

Turbine rotor blade, featuring: a blade body (42); and a tip cover band (43) which is provided at a tip of the blade body (42), wherein the lace cover band (43) has a contact block (50, 60) which faces an adjacent lace cover band (43), where the contact block (50, 60) has: a base material (100); and a hard, wear-resistant coating (104); characterized by the fact that the contact block (50, 60) further comprises an oxidation-resistant coating (102) applied to a surface of the base material (100); wherein the hard wear-resistant coating (104) is applied to a surface of the oxidation-resistant coating (102); wherein, in the case of the hard wear-resistant coating (104) and the oxidation-resistant coating (102), the ratio of the thickness of the oxidation-resistant coating (102) to the thickness of the hard wear-resistant coating (104) is at least 0.7 and at most 1.3.

Description

field of technology

[0001] The present invention relates to a turbine rotor blade and a contact surface manufacturing process. State of the art

[0002] A gas turbine for power generation, which is a type of turbomachine, consists of, for example, a compressor, a combustion chamber, and a turbine. The compressor compresses the air collected through an air intake into high-temperature, high-pressure compressed air. The combustion chamber then feeds fuel into the compressed air and burns the mixture to produce high-temperature, high-pressure combustion gas (operating fluid). This gas drives the turbine, which in turn drives a coupled generator.

[0003] In a gas turbine, the rotor blades of the first or second stage, belonging to a pre-stage, are short in their vertical direction (radial to the rotating shaft), while the rotor blades of the third or fourth stage (last stage), belonging to a rear stage, are long in their vertical direction from a power output standpoint (long blades). Since turbine rotor blades that are long in the vertical direction tend to vibrate more, tip shrouds are applied to the tips of the rotor blades, and the tip shrouds of adjacent rotor blades are brought into contact with each other, forming an annular shroud. Coatings are applied to the surfaces of the contact sections where the rotor blade shrouds meet (JP 2010-255044A).

[0004] A turbine rotor blade with the features of the preamble of claim 1 is known from JP 2001-152803 A. Further relevant prior art is known from JP H09-196176 A and US 2010 / 0062173 A1. Brief description of the technical task

[0005] If the contact surface of a tip cover strip in the turbine rotor blade is damaged, maintenance tasks such as repair or replacement become necessary. Furthermore, such maintenance is impossible in some cases if the base material of the contact surface is damaged. Therefore, there is a need to improve the durability of the contact surface.

[0006] At least one embodiment of the present invention is intended to solve the previously described technical problem, and it is an object of the present invention to provide a turbine rotor blade and a contact surface manufacturing method that are able to improve the durability of the contact surface in order to improve the reliability of the blade. Solution to the task

[0007] This problem is solved by a turbine blade with the features of claim 1 and a contact surface manufacturing method with the features of claim 8. To solve the problem described above, a turbine blade has a blade body and a tip cover strip provided at a tip of the blade body. The tip cover strip has a contact block facing an adjacent tip cover strip. The contact block comprises a base material; an oxidation-resistant coating applied to a surface of the base material; and a hard, wear-resistant coating applied to a surface of the oxidation-resistant coating.

[0008] The oxidation-resistant coating is preferably made of an MCrAlY alloy.

[0009] The oxidation-resistant coating is preferably made of a CoNiCrAlY alloy.

[0010] The hard, wear-resistant coating preferably has a thickness of at least 0.02 mm and at most 0.30 mm, and the oxidation-resistant coating preferably has a thickness of at least 0.02 mm and at most 0.20 mm.

[0011] For the hard wear-resistant coating and the oxidation-resistant coating, the ratio of the thickness of the oxidation-resistant coating to the thickness of the hard wear-resistant coating is at least 0.7 and at most 1.3.

[0012] The oxidation-resistant coating is preferably applied, at least on an area that is unlikely to come into contact with an opposing contact block, to a surface of the contact block facing the adjacent tip cover band.

[0013] The hard, wear-resistant coating is preferably applied only to the contact block.

[0014] The blade body preferably has a thermal barrier coating applied to a surface of the blade.

[0015] To solve the previously described problem, the contact surface manufacturing process serves to form a contact surface on a contact block of a tip cover strip provided on a turbine rotor blade. The contact surface manufacturing process comprises a step of forming an oxidation-resistant coating on a surface of the base material and a step of forming a hard, wear-resistant coating on a surface of the oxidation-resistant coating.

[0016] The contact surface manufacturing process preferably comprises a step of forming an oxidation-resistant coating on the blade surface of the turbine rotor blade after the step of forming the hard wear-resistant coating and further comprises a step of performing tip brazing, a stabilization treatment and a thermal diffusion treatment after the step of forming the oxidation-resistant coating on the blade surface.

[0017] The contact surface manufacturing process preferably comprises a step of forming a blade surface primer to form an oxidation-resistant coating on a blade surface of the turbine rotor blade prior to the step of forming the hard wear-resistant coating.

[0018] The turbine blade is preferably a used turbine blade, and the contact surface manufacturing process preferably comprises the step of removing a used contact surface formed on a surface of a contact block before the oxidation-resistant coating is formed. Advantages of the invention

[0019] According to one embodiment of the present invention, it is possible to improve the durability of a contact surface of a tip cover strip in order to reduce the risk of damage to the base material and to improve the reliability of the running blade. Brief description of the drawings Fig. Figure 1 is a general scheme illustrating a gas turbine that uses turbine blades according to the embodiment. Fig. Figure 2 is a general scheme illustrating an arrangement of turbine rotor blades according to one embodiment. Fig. Figure 3 is a schematic representation illustrating a general structure of tip cover bands provided on the turbine rotor blades. Fig. Figure 4 is a schematic representation showing an enlarged view of contact sections and nearby elements in the tip cover bands. Fig. Figure 5 is a front view showing a general structure of a suction-side contact section. Fig. Figure 6 is a sectional view illustrating a general structure of the suction-side contact section. Fig. Figure 7 is a flowchart illustrating an example of a contact surface manufacturing process. Fig. Figure 8 is a flowchart illustrating an example of the contact surface manufacturing process. Fig. Figure 9 is a flowchart illustrating an example of the contact surface manufacturing process. Description of embodiments.

[0020] A turbine rotor blade and a contact surface manufacturing process are subsequently explained in detail with reference to the accompanying drawings. However, this embodiment is not intended to limit the scope of the present invention in any way.

[0021] Fig. Figure 1 is a general scheme illustrating a gas turbine that uses turbine blades according to the embodiment. Fig. Figure 2 is a general diagram illustrating an arrangement of turbine blades according to the embodiment. The gas turbine according to the embodiment has a compressor 11, a combustion chamber 12, and a turbine 13, as shown in Figure 2. Fig. Figure 1 shows a generator (not shown) coupled to the gas turbine, which can generate electricity.

[0022] The compressor 11 has an air inlet 21 for collecting air, as well as several compressor guide vanes 23 and compressor blades 24, arranged alternately in the forward and reverse directions (the axial direction of a rotor 32, which is described below) within a compressor chamber 22 and a vent chamber 25 provided outside the compressor chamber 22. The combustion chamber 12 is capable of burning fuel by supplying the fuel to the compressed air in the compressor 11 and igniting the mixture. The turbine 13 has several guide vanes 27 and rotor blades 28, arranged alternately in the forward and reverse directions (the axial direction of the rotor 32, which is described below) within a turbine chamber 26. A suction hood 30 is arranged on the downstream side of the turbine chamber 26, with a suction hood 29 positioned between them.The extraction hood 30 has an exhaust gas diffuser 31 which is connected to the turbine 13.

[0023] A rotor (rotating shaft) 32 is arranged such that it passes through the centers of the compressor 11, the combustion chamber 12, the turbine 13, and the extraction hood 30. One end of the rotor 32 on the compressor 11 side is rotatably supported by a bearing 33, and the other end on the extraction hood 30 side is rotatably supported by a bearing 34.

[0024] In this gas turbine, feet 35 support the compressor chamber 22 of the compressor 11. Feet 36 support the turbine chamber 26 of the turbine 13 and feet 37 support the extraction hood 30.

[0025] Therefore, the air collected through the air inlet 21 in the compressor 11 flows through the compressor guide vanes 23 and the compressor blades 24 and is compressed into high-temperature, high-pressure compressed air. The combustion chamber 12 then feeds a supplied fuel into the compressed air and combusts it. This high-temperature, high-pressure combustion gas, which is the operating fluid generated in the combustion chamber 12, flows through the guide vanes 27 and the rotor blades 28 in the turbine 13 and sets the rotor 32 in rotation, thus coupling the generator to the rotor 32. The exhaust diffuser 31 in the exhaust hood 30 converts the energy of the flue gas (combustion gas) into pressure, slows down the flue gas, and releases it into the atmosphere.

[0026] In the turbine 13 according to the embodiment described above, the rotor blades (turbine rotor blades) 28 in the rear stage are provided with tip trim bands. Examples of rear stage rotor blades include third-stage rotor blades. As in Fig. Figure 2 illustrates that each of the rotor blades 28 has a blade root 41 attached to a disk (the rotor 32), a blade body 42 whose base end is connected to the blade root 41, a tip trim band 43 connected to the tip of the blade body 42, and a sealing rib 44 provided on the outer surface of the tip trim band 43. The blade body 42 has a suction surface 42a and a pressure surface 42b. The suction surface 42a is a suction-side surface with a convex cross-section along which the flue gas flows. The pressure-side surface 42b is a pressure-side surface with a concave cross-section along which the flue gas flows. The blade body 42 is twisted at a specific angle.When the blade roots 41 of several of the rotor blades 28 engage with the outer circumference of the disk along the circumferential direction, the tip cover bands 43 are brought into contact with each other and joined together. By bringing the tip cover bands 43 of the rotor blades 28 into contact with each other, an annular cover band is formed on the outer circumferential side of the turbine 13.

[0027] A detailed structure of the lace cover band 43 is now presented using the Fig. 4, Fig. 5 to Fig. 6 in addition to Fig. 3 explained. Fig. Figure 4 is a schematic representation showing an enlarged view of contact sections and nearby elements in the tip cover bands. Fig. Figure 5 is a front view showing a general structure of a suction-side contact section. Fig. Figure 6 is a sectional view illustrating a general structure of the suction-side contact section.

[0028] The tip cover band 43 has a long plate-like shape extending in the circumferential direction of the cover band and is radially outward in a direction from the pressure surface (the pressure-side blade surface) towards the suction surface (the suction-side blade surface) in the axial direction (see Fig. 9 in patent literature 1). The tip trim band 43 has a suction-side tip trim band 46 extending on the side of the suction surface 42a of the blade body 42, and a pressure-side tip trim band 48 extending on the side of the pressure surface 42b of the blade body 42. In the turbine rotor blade 28, the radially outwardly extending rib 44 is provided on the outer upper surface of the suction-side tip trim band 46 and the pressure-side tip trim band 48 in the radial direction. The rib 44 is arranged in the circumferential direction in the center of the tip trim band 43 and extends in the circumferential direction of the rotor blade 28. The rib 44 has a radius 120 on the portion connected to the tip trim band 43.In other words, there is a region corresponding to the rounding 120 at an inner end of the rib 44 in the radial direction, which is located on the side of the tip cover band 32, and this region has a plate width that becomes wider towards the tip cover band 43.

[0029] The suction-side tip cover strip 46 has a suction-side contact block 50 and a suction-side cover plate 51 extending downstream of the rib 44 in the axial direction. The suction-side cover plate 51 has a downstream suction-side cover plate 52 and a downstream pressure-side cover plate 66. The downstream suction-side cover plate 52 is provided at the front end near the suction-side contact block 50 on the suction-side and downstream side of the rib 44 in the axial direction. The downstream pressure-side cover plate 66 is provided at the rear end near the pressure-side contact block 60. The rib 44, the contact block 50, and the suction-side cover plate 51 are formed integrally.The suction-side cover plate 51 is a plate extending in a direction that intersects the radial direction with respect to the blade body 42 and is coupled to the blade body 42 at the lower surface of an upstream end thereof in the axial direction. The suction-side cover plate 51 is coupled to the suction-side contact block 50 near the leading end at the upper surface of an upstream end of the suction-side cover plate 51 in the axial direction, and the remaining portion of the suction-side cover plate 51 is coupled to the rib 44.

[0030] The suction-side contact block 50 is provided at the front end of the suction-side tip cover strip 46. The suction-side contact block 50 has a suction-side contact surface (first surface) 110 facing the circumferential direction. The suction-side contact block 50 has a structure that is thick in one direction perpendicular to the suction-side contact surface 110, as shown in Fig. Figure 7 shows the suction-side contact block 50, and the end of the suction-side contact block 50 on the opposite side of the suction-side contact surface 110 is coupled to the downstream suction-side cover plate 52. A coating 101 is formed on one surface of the suction-side contact block 50. One end of the suction-side contact block 50 is connected to the rib 44, with the end located circumferentially on the opposite side of the suction-side contact surface 110 and axially on the upstream side. The downstream side of the suction-side contact block 50 in the axial direction is connected via an inclined surface 116 to the downstream suction-side cover plate 52 of the suction-side tip cover band 46.

[0031] As in Fig. As shown in Figure 4, the suction-side contact surface 110 is a surface that faces a pressure-side contact surface 140 of the pressure-side contact block 60 in the circumferential direction, the pressure-side contact block 60 being enclosed in the tip cover band 43 of the adjacent rotor blade, as described below. The downstream suction-side cover plate 52 extends from the suction-side surface of the blade body 42 or from the suction-side contact surface 110 in a separate direction towards the downstream side in the axial direction in a manner that follows the inner circumferential surface 46b of the tip cover band 43, the inner being the radially inner position. The downstream suction-side cover plate 66 is axially connected to the downstream end of the pressure-side contact block 60 via a connecting section 68, which is described below.The connecting section 68 is a convexly curved surface that projects in the direction of the pressure surface of the blade body 42.

[0032] The pressure-side tip cover band 48 has the pressure-side contact block 60 and a pressure-side cover plate 61, which extends axially from the rib 44 to the upstream side. The pressure-side cover plate 61 has an upstream pressure-side cover plate 56 and an upstream pressure-side cover plate 62. The upstream pressure-side cover plate 56 is provided at the front end near the pressure-side contact block 50 on the pressure side and the upstream side of the rib 44 in the axial direction. The upstream pressure-side cover plate 62 is provided at the rear end near the pressure-side contact block 60. The rib 44, the pressure-side contact block 60, and the pressure-side cover plate 61 are formed integrally.

[0033] The pressure-side contact block 60 is located at the rear end of the pressure-side tip cover strip 48. The pressure-side contact block 60 has a pressure-side contact surface (contact surface) 140 facing the circumferential direction. The pressure-side contact surface 140 is a surface that faces the suction-side contact block 50 (suction-side contact surface 110) of the tip cover strip 43, which is provided circumferentially on an adjacent turbine rotor blade 28. In other words, the pressure-side contact surface 140 is arranged to face the suction-side contact surface 110 of the adjacent turbine rotor blade 28.The upstream pressure-side cover plate 62 is a plate extending in a direction intersecting the radial direction in which the blade body 42 is oriented. It extends from the edge of the suction-side blade surface of the blade body 42, or the suction-side contact surface 110, in a separate direction to the upstream side in the axial direction, following the inner circumferential surface 48b of the tip cover band 43. The upstream suction-side cover plate 56 is axially connected to an upstream end of the suction-side contact block 50 via a connecting section 58. The connecting section 58 is a convexly curved surface projecting towards the suction-side blade surface of the blade body 42.

[0034] The following section explains the structures of the suction-side contact surface (contact surface) 110 of the suction-side contact block 50 and the pressure-side contact surface (contact surface) 140 of the pressure-side contact block 60. As described in the Fig. 3 and Fig. As illustrated in Figure 4, the suction-side contact surface 110 faces the pressure-side contact surface 140 of an adjacent turbine rotor blade 28. Although the structure of the suction-side contact surface 110 is described below, the pressure-side contact surface 140 has the same structure.

[0035] A coating 102 is formed on a base material 100 on the pressure-side contact surface 140 of the pressure-side contact block 60. Since the turbine blade 28 in the gas turbine is exposed to a high temperature, the base material 100 from which the blade is made is a highly heat-resistant alloy material, such as a nickel-based alloy. Examples of Ni-based alloys include a Ni-based alloy with a composition containing at least 12.0% and at most 14.3% Cr, at least 8.5% and at most 11.0% Co, at least 1.0% and at most 3.5% Mo, at least 3.5% and at most 6.2% W, at least 3.0% and at most 5.5% Ta, at least 3.5% and at most 4.5% Al, at least 2.0% and at most 3.2% Ti, at least 0.04% and at most 0.12% C and at least 0.005% and at most 0.05% B, the remainder being Ni and random impurities.The nickel-based alloy with the composition described above may also contain at least 0.001 ppm and at most 5 ppm Zr. The nickel-based alloy with the composition described above may also contain one or both of Mg and Ca at at least 1 ppm and 100 ppm, respectively; one or both of at least 0.02% and at most 0.5% Pt; at least 0.02% and at most 0.5% Rh; at least 0.02% and at most 0.5% Re; or both.

[0036] The base material 100 is formed by casting or forging the material described above. If the base material is to be cast, a base material such as a conventional casting material (CC), a directional solidification material (DS), or a single crystal material (SC) can be used. An example using CC material as the base material 100 is explained below, but the embodiment is not limited to this, and the base material can be a DS material or an SC material.

[0037] The coating 101 is formed on the surface of the base material 100 and provides the contact surface 110. The coating 101 comprises a primer (oxidation-resistant coating) 102, which is applied to the surface of the base material 100, and a hard, wear-resistant coating (abrasion-resistant coating) 104, which is applied to the surface of the primer 102. The coating 101 is formed over the entire surface contact area 110.

[0038] Primer 102 is a coating made of a material that is more oxidation-resistant than base material 100. An alloy material such as MCrAlY can be used as the material for primer 102. An alloy material such as CoNiCrAlY is particularly preferred as the material for primer 102.

[0039] The hard wear-resistant coating 104 is a coating made of a material that is more abrasion-resistant than the primer 102. The material used for the hard wear-resistant coating 104 can be a cobalt-based abrasion-resistant material, such as Tribaloy (registered trademark).

[0040] In the turbine blade 28, it is possible to form the coating 101 as a coating comprising a layer of the abrasion-resistant coating on top of a layer of the oxidation-resistant coating. This is achieved by applying the primer (oxidation-resistant coating) 102 to the surface that is to become the contact surface 110, followed by applying the hard, wear-resistant coating 104 to the primer 102. In this way, it is possible to create a contact block in which the base material is protected by the oxidation-resistant coating even if the hard, wear-resistant coating 104 is damaged. For example, the oxidation-resistant coating can protect the base material even if the hard, wear-resistant coating is lost, no longer in contact with the contact surface facing it, and exposed to the atmosphere.In this way, it is possible to achieve a very durable contact surface. By providing a TBC film on the surface of the turbine blade 28, it becomes possible to use the turbine blade 28 in an environment where the temperature is even higher.

[0041] Preferably, the hard, wear-resistant coating 104 has a thickness of at least 0.02 mm and at most 0.30 mm, and the primer 102 has a thickness of at least 0.02 mm and at most 0.30 mm. By adjusting the thicknesses of the primer 102 and the hard, wear-resistant coating 104 to the range described above, it is possible to prevent the loss of the hard, wear-resistant coating 104 due to abrasion and to allow the primer 102 to prevent the surface of the base material 100 from losing its thickness. Furthermore, it is preferred, for example, to represent the thickness of the base material 100 as one, to set the thickness of the primer 102 to 0.1, and to set the thickness of the hard, wear-resistant coating 104 to 0.1. In other words, it is preferable to set the thickness of the primer 102 and that of the hard, wear-resistant coating 104 to approximately the same value.Since each of these films experiences a manufacturing defect of approximately 30%, it is further preferred to adjust the ratio of the thicknesses of the primer and the hard wear-resistant coating to at least 0.7 and at most 1.3.

[0042] Furthermore, the hard, wear-resistant coating 104, as in the embodiment, can be formed only on the contact block. In this way, it is possible to reduce the area on which the hard, wear-resistant coating 104 is formed, and therefore it becomes possible to form the hard, wear-resistant coating 104 efficiently.

[0043] In the turbine blade 28 according to the embodiment, the primer and the thermal barrier coating (TBC) are also applied to the surfaces of the blade body 42, i.e., to the surfaces corresponding to the suction surface 42a and the pressure surface 42b, on the base material. The primer is an oxidation-resistant coating corresponding to coating 101. The TBC is a ceramic film made of oxide ceramic, which is applied, for example, to the surface of the primer. The primer serves as an adhesion layer for the TBC. The ceramic film can have a ZrO2 base material, in particular yttrium oxide-stabilized zirconium oxide (YSZ), which is ZrO2, partially or completely stabilized with Y2O3. The TBC is thermally insulating and protects the base material.

[0044] Furthermore, in the turbine blade 28 according to the embodiment, the coating 101 is provided over the entire suction-side contact surface 110 and the pressure-side contact surface 140, but the embodiment is not limited to this. The oxidation-resistant coating 102 need not be provided over the entire contact surface and can be provided in areas that are unlikely to come into contact with the opposite contact surface. In other words, it is possible that the oxidation-resistant coating 102 is not provided on a portion of the area that comes into contact with the opposite contact surface. It is also possible not to provide the hard, wear-resistant coating 104 in areas that are unlikely to come into contact with the opposite contact surface.Furthermore, according to the embodiment with the two layers, the coating 101 can be provided only on the contact surface, as previously described, but it is also possible to provide the coating 101 on the other part of the tip cover strip, e.g., on the rib. In addition, according to the embodiment with two layers, the coating 101 can be provided on a part located on the radially inner side of the rib, or on a part located on the radially inner side of the rib and also on the inner side of a circumferential end in the axial direction. Alternatively, the coating 101 can be provided on a part of an end in the circumferential direction on the upstream or downstream side in the direction in which the gas flows.

[0045] Fig. Figure 7 is a flowchart illustrating an example of a contact surface manufacturing process. On a turbine rotor blade, the contact surface is formed by applying the coating 101 to the area corresponding to the contact surface of the contact block 50, 60 made of the base material 100. The contact surface can be manufactured by a worker performing a process or by equipment that automatically generates the contact surface. In the example described below, it is assumed that this task is performed by a worker.

[0046] The worker performs the machining of a blade (step S12). The worker fabricates a structure from the base material. An example of such a rotor blade is a shrouded rotor blade. A shrouded rotor blade is arranged multiple times along a predetermined direction, e.g., in the direction in which the turbine rotor rotates, and has a contact block on which the contact surface is formed. The blade is manufactured by casting or forging and machining. If the base material is to be cast, a base material such as a CC material, a DS material, or an SC material can be used. An example is described below in which CC material is used as the base material, but the embodiment is not limited to this, and the base material can be a DS material or an SC material.Furthermore, the shovel can be manufactured using three-dimensional additive manufacturing.

[0047] The worker then performs a surface treatment on the base material (step S14). In particular, the worker washes a part that will become the contact surface of the contact block made from the base material and blasts the part. The worker also masks the area different from the area to be treated.

[0048] The worker then forms a primer corresponding to a contact section on a part, which will become the contact surface of the contact block (step S16). On the surface that will become the contact surface of the base material, a primer is formed, which will become the oxidation-resistant coating. For the oxidation-resistant coating material, it is possible to use an alloy material, such as MCrAlY, which, as already mentioned, is more oxidation-resistant than the base material. For example, the primer is formed by heating the surface of the base material and thermally spraying the alloy material, or a similar process, onto the surface of the base material. The primer can be formed on the surface of the base material using a process such as atmospheric plasma spraying, high-velocity flame spraying, low-pressure plasma spraying, or atmospheric plasma spraying.

[0049] The worker then forms a contact surface (step S18). Specifically, the contact surface is formed by applying a hard, wear-resistant coating to the surface of the primer. A cobalt-based abrasion-resistant material, such as Tribaloy (registered trademark), can be used as the hard, wear-resistant coating. The hard, wear-resistant coating can be applied to the surface of the primer using a process such as atmospheric plasma spraying, high-velocity flame spraying, low-pressure plasma spraying, or atmospheric plasma spraying.

[0050] The worker then performs tip brazing and a stabilization treatment (step S20). Specifically, the worker brazes the base material, cools the base material slowly, and performs solution annealing of the base material as a stabilization treatment. Brazing is a process of melting a brazing alloy by heating the alloy while it is placed on the base material, followed by joining the alloy to the base material. For example, a brazing alloy such as Amdry (registered trademark) DF-6A is used. In this case, the liquidus temperature of the brazing alloy is, for example, about 1155 °C. The amount of brazing alloy used is determined in advance by conducting experiments or the like. During brazing, the base material can be thermally treated at a temperature at which the brazing alloy melts, for example, at a minimum of 1175 °C and a maximum of 1215 °C.

[0051] Stabilization (solution treatment) is a process of heating the base material to solution annealing and cultivating a gamma prime phase, which is an intermetallic compound within the base material. In solution treatment, the base material can be thermally treated at a lower temperature than in brazing, e.g., at a minimum of 1100 °C and a maximum of 1140 °C. This thermal treatment also serves to improve the adhesion between the base material, the primer, and the hard, wear-resistant coating.

[0052] The worker then performs a surface treatment and masking (step S22). In particular, the worker performs a surface treatment on the surface of the turbine rotor blade and a masking process to mask the area different from the blade surface.

[0053] The worker then applies the primer to the blade surface (step S24). Specifically, a primer is applied to the blade surface of the base material, which will become the oxidation-resistant coating. For the oxidation-resistant coating material, it is possible to use an alloy such as MCrAlY, which, as mentioned earlier, is more oxidation-resistant than the base material. For example, the primer is applied by heating the surface of the base material and thermally spraying the alloy material onto the surface of the base material, or by a similar process.

[0054] The worker then applies a topcoat to the bucket surface (step S26). This topcoat is a thermal barrier coating (TBC). The thermal barrier coating is applied by thermal spraying.

[0055] The operator then performs a thermal diffusion treatment (step S28). Specifically, by performing an aging treatment to heat the solution-annealed base material, the gamma prime phase grown in the base material during the solution treatment can be further cultivated, and a gamma prime phase with smaller grain diameters, smaller than those resulting from the solution treatment, can precipitate. This gamma prime phase with smaller grain diameters increases the strength of the base material. Therefore, the aging treatment serves to achieve a final adjustment of the strength and ductility of the base material by precipitating the gamma prime phase with smaller grain diameters and improving the strength of the base material. The temperature used in the aging treatment can, for example, be set within a range of at least 830 °C and at most 870 °C.After the base material has undergone aging treatment for a predetermined period, it is rapidly cooled (quenched) by stopping the heating device in the furnace and supplying cooling gas to the furnace at a temperature reduction rate of approximately 30 °C / min.

[0056] The worker then performs an inspection and a finishing process (step S30). For example, the worker performs a visual inspection and finishes the contact surface.

[0057] As in Fig. As illustrated in Figure 7, it is possible to form a hard, wear-resistant coating (abrasion-resistant coating) on ​​top of the oxidation-resistant coating by applying a primer (oxidation-resistant coating) to the surface that will become the contact surface, followed by the hard, wear-resistant coating on top of the primer. In this way, it is possible to form a contact block where the base material is protected by the oxidation-resistant coating even if the hard, wear-resistant coating is damaged. For example, even if the hard, wear-resistant coating is lost, and contact with the opposing contact surface is lost, and the surface is exposed to the atmosphere, the base material can be protected by the oxidation-resistant coating. In this way, it is possible to achieve a very durable contact surface.

[0058] Another example of the contact surface manufacturing process will be explained below. Fig. Figure 8 is a flowchart illustrating an example of the contact surface fabrication process. If the in Fig. The 8 illustrated steps are the same as in the one described in Fig. The detailed explanations of the 7 illustrated contact surface manufacturing processes are omitted.

[0059] The worker performs the machining of a shovel (step S12). The worker then carries out a surface treatment on the base material (step S14). The worker then forms a primer corresponding to a contact section on a part that will become the contact surface of the contact block (step S16).

[0060] The worker then forms a contact surface (step S18). The worker then performs a surface treatment and masking (step S42). Specifically, the worker performs a surface treatment on the surface of the turbine rotor blade and a masking process to mask the area different from the blade surface. The worker then forms a primer on the blade surface (step S44).

[0061] The worker then performs tip soldering, stabilization treatment, and a thermal diffusion treatment (step S46). Specifically, the treatment in step S28 follows the treatment in step S20. Fig. 7. Performed as previously explained.

[0062] The worker then applies a top coating to the bucket surface (step S26). The worker then performs an inspection and a finishing process (step S30).

[0063] As in Fig. As illustrated in Figure 8, by forming the primer (oxidation-resistant coating) on ​​the contact surface and the blade surface before performing tip brazing and the stabilization treatment, and by performing the thermal diffusion treatment together with the tip brazing and the stabilization treatment, these heat treatments can be carried out sequentially. In this way, it is possible to form the primer on the contact surface while improving process efficiency.

[0064] Another example of the contact surface manufacturing process will be explained below. Fig. Figure 9 is a flowchart illustrating an example of the contact surface manufacturing process. If the in Fig. The 9 illustrated steps are the same as in the one described in Fig. For the 8 illustrated contact surface manufacturing processes, the respective detailed explanations are omitted.

[0065] The worker performs the machining of a shovel (step S12). The worker then carries out a surface treatment on the base material (step S14). In particular, the worker washes a part that will become the contact surface of the contact block made from the base material and blasts the part. The worker also masks the area different from the area to be treated (i.e., the area that will become the contact surface).

[0066] The worker forms a primer corresponding to a contact section on a part that will become the contact surface of the contact block (step S16). The worker then forms the primer on the blade surface (step S52). The same treatment equipment can be used to successively form the primer on the contact section and the primer on the blade surface.

[0067] The worker then forms the contact surface (step S18). The worker then performs tip brazing, stabilization treatment, and thermal diffusion treatment (step S46). The worker then forms a top coating on the blade surface (step S26). The worker then performs an inspection and finishing process (step S30).

[0068] As in Fig. As illustrated in Figure 9, by successively forming the primers on the contact surface and the blade surface, the primers can be applied in a single process. This eliminates the need to apply a surface treatment to the blade surface and to mask the blade surface. Furthermore, by forming the primer (oxidation-resistant coating) on ​​the contact surface and the blade surface before performing the tip brazing and stabilization treatment, and by performing the thermal diffusion treatment together with the tip brazing and stabilization treatment, these heat treatments can be carried out sequentially in the same manner as in the [reference to figure]. Fig. The 8 described methods are carried out. In this way, it is possible to form the primer on the contact surface while improving process efficiency.

[0069] The contact surface fabrication process described above can be used to produce the contact surface of a newly manufactured turbine blade, although the embodiment is not limited to this. The contact surface fabrication process described above can also be applied to a situation where a coating is to be applied to repair a used turbine blade. When the contact surface of the turbine blade is to be repaired, the machining in step S12 is replaced by a step of removing a used contact surface from the contact block of the used turbine blade. With this step, the process is modified to a contact surface fabrication process in which the used contact surface is removed and a new contact surface is produced in the previously described step. List of reference symbols 11 Compressor 12 Combustion chamber 13 Turbine 27 Guide vane 28 Running blade (turbine running blade) 32 Rotor (rotating shaft) 41 Shovel foot 42 blade bodies 42a Suction surface (suction-side surface) 42b Printing area (print-side surface) 43 Lace Cover Tape 44 Sealing rib (rib) 46 absorbent-side lace cover tape 47 suction-side end area 49 print-side end area 48 print-side lace cover tape 50, 60 contact block 51 suction-side cover plate 52 downstream suction-side cover plate 56 Upstream suction-side cover plate 54 Front surface of the pressure-side cover 64 Front surface of the suction-side cover 58, 68 connecting section 61 pressure-side cover plate 62 Upstream pressure-side cover plate 66 downstream pressure-side cover plate 100 basic materials 101 Coating 102 Primer (oxidation-resistant coating) 104 hard wear-resistant coating (abrasion-resistant coating) 110 contact surface 140 contact surfaces

Claims

[1] Turbine rotor blade, comprising: a blade body (42); and a tip cover band (43) which is provided at a tip of the blade body (42), wherein the lace cover band (43) has a contact block (50, 60) which faces an adjacent lace cover band (43), where the contact block (50, 60) has: a base material (100); and a hard, wear-resistant coating (104); characterized by , that the contact block (50, 60) further comprises an oxidation-resistant coating (102) applied to a surface of the base material (100); wherein the hard wear-resistant coating (104) is applied to a surface of the oxidation-resistant coating (102); wherein, in the case of the hard wear-resistant coating (104) and the oxidation-resistant coating (102), the ratio of the thickness of the oxidation-resistant coating (102) to the thickness of the hard wear-resistant coating (104) is at least 0.7 and at most 1.

3. [2] Turbine rotor blade according to claim 1, wherein the oxidation-resistant coating (102) is formed from an MCrAlY alloy. [3] Turbine blade according to claim 2, wherein the oxidation-resistant coating (102) is formed from a CoNiCrAlY alloy. [4] Turbine blade according to any one of claims 1 to 3, wherein the hard wear-resistant coating (104) has a thickness of at least 0.02 mm and at most 0.30 mm, and the oxidation-resistant coating (102) has a thickness of at least 0.02 mm and at most 0.20 mm. [5] Turbine blade according to one of claims 1 to 4, wherein the oxidation-resistant coating (102) is applied at least on an area which is unlikely to come into contact with an opposing contact block, on a surface of the contact block (50, 60) which faces the adjacent tip cover band (43). [6] Turbine rotor blade according to one of claims 1 to 5, wherein the hard wear-resistant coating (104) is applied only to the contact block (50, 60). [7] Turbine rotor blade according to any one of claims 1 to 6, wherein the blade body (42) has a thermal barrier coating applied to a surface of a blade surface (42a, 42b). [8] Contact surface manufacturing process for forming a contact surface on a contact block (50, 60) of a tip cover strip (43) provided on a turbine rotor blade (28), wherein the contact surface manufacturing process comprises the following steps: Forming an oxidation-resistant coating (102) on a surface of a base material (100); and Forming a hard wear-resistant coating (104) on a surface of the oxidation-resistant coating (102); wherein, in the case of the hard wear-resistant coating (104) and the oxidation-resistant coating (102), the ratio of the thickness of the oxidation-resistant coating (102) to the thickness of the hard wear-resistant coating (104) is at least 0.7 and at most 1.

3. [9] Contact surface manufacturing process according to claim 8, further comprising the following steps: Forming the oxidation-resistant coating (102) on a blade surface (42a, 42b) of the turbine rotor blade (28) after the step of forming the hard wear-resistant coating (104); Performing tip brazing, a stabilization treatment and a thermal diffusion treatment after the step of forming the oxidation-resistant coating (102) on the blade surface (42a, 42b). [10] Contact surface manufacturing method according to claim 8, further comprising the step of forming the oxidation-resistant coating (102) on a blade surface (42a, 42b) of the turbine rotor blade (28) prior to the step of forming the hard wear-resistant coating (104). [11] Contact surface manufacturing method according to any one of claims 8 to 10, wherein the turbine rotor blade (28) is a used turbine rotor blade and The contact surface manufacturing process further comprises the step of removing a used contact surface formed on a surface of a contact block (50, 60) prior to the step of forming the oxidation-resistant coating (102).

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