JPS6151124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas turbine cooling component, and more particularly to a gas turbine cooling component with a novel structure that has improved high temperature characteristics and can be made larger.

[Technical background of the invention and its problems]

Gas turbine power generation systems are widely adopted in various power generation technology plants. Here, FIGS. 1 and 2 show stationary blades that are representative examples of conventional gas turbine cooling components. 1 is a plan view, and FIG. 2 is a sectional view taken along line AA' in FIG. 1. In the figure, 1 and 1' are implanted parts, and 2 is a wing part having a leading edge 2' and a trailing edge 2''. A cooling passage portion 4 is formed at both ends of the wing portion 2.
1' and the whole becomes an integrated structure. When the stationary vane is in operation, air is introduced into the cooling passage section 4 from the implanted section to cool the vane section 2 . In such a stationary blade, a gas flow flows from the direction of arrow P in the figure to the leading edge 2' at a certain inlet temperature, the blade part 2 becomes a high temperature region, and the implanted parts 1 and 1' have a relatively low temperature region. It is formed.

Generally, increasing the gas turbine inlet temperature improves the thermal efficiency of the gas turbine. However, typically, the higher the temperature of a material, the lower its mechanical strength. Therefore, the inlet temperature of the gas flow must be determined in relation to the heat resistance of the material used for the stationary blades, and cannot be increased unrestrictedly.

Therefore, if the stationary blades could be made of a material that can be processed into the above-mentioned complex shape and has excellent heat resistance, it would be possible to increase the gas turbine inlet temperature and improve its thermal efficiency, making it possible to use it industrially. It is extremely useful.

Currently, stator vanes of the above-described structure are typically manufactured as an integral structure by precision casting of a gamma prime precipitation-strengthened nickel-based superalloy (eg, IN-939) with a ceramic core.

However, this γ′ precipitation-strengthened Ni-based superalloy has a heat resistance of 850 to 900°C even when used after air cooling.
is the limit, which restricts further increases in the gas turbine inlet temperature.

Therefore, research has recently progressed on maintaining and improving the mechanical strength at high temperatures by using materials consisting of unidirectionally solidified columnar crystals, single crystals, and unidirectionally solidified eutectics as the constituent materials of the wing portion 2. It is being

However, applying this technology to the production of large stator blades is extremely problematic due to the difficulty of uniformly growing crystals as mentioned above, and the need for large-scale equipment and equipment. .

On the other hand, dispersion-strengthened heat-resistant alloys (ODS alloys:
Oxide dispersion strengthening alloy) is known. This ODS alloy has a matrix of Ni, Fe, and Co-based alloys, and contains Y ₂ O ₃ , A ₂ O ₃ ,
It is a type of composite material that contains a predetermined amount of fine powder of metal oxide such as ThO ₂ as a dispersion. The heat resistance varies depending on its composition, but is generally around 1100°C or higher. Therefore, with this ODS alloy, the wing part 2
is configured, the gas turbine inlet temperature is set to ODS
Since the heat resistance can be raised to just below the heat resistance of the alloy, it is possible to improve the overall thermal efficiency. Moreover, at that time, the mechanical strength of the wing section does not decrease.

However, this ODS alloy cannot be manufactured by the precision casting method described above, and is usually manufactured by the forging method, and is either a block or a thin plate in that shape. For this reason, attempts have been made to apply this ODS alloy to solid rotor blades without a cooling section or stator blades with a thin plate-shaped brazed structure.
A complex shape with a hollow cooling part as described above.
Moreover, it is currently not being applied to large cooling parts of gas turbines for power generation, such as large stationary blades with a robust structure.

[Purpose of the invention]

An object of the present invention is to provide a cooling component for an industrial gas turbine or the like that has excellent high-temperature characteristics and thus enables high thermal efficiency, and can be made larger in size.

[Summary of the invention]

In the present invention, in a gas turbine cooling component, the high temperature (blade portion 2 in Figs. 1 and 2) is made of an ODS alloy, and in order to take advantage of the characteristics of the ODS alloy, the high temperature region is In addition, in the low temperature range (implanted parts 1 and 1' and their joints shown in Figures 1 and 2), it is necessary to create a split structure using a special alloy. The above-mentioned object is achieved by a metallurgical bond, in particular by applying a liquid phase diffusion bonding method, which allows a high resistance to thermal stress.

That is, the gas turbine cooling component of the present invention is
It is a gas turbine cooling component that operates while being cooled in a high-temperature gas flow and has a split structure in which each element is joined together as a whole, with the joints in the high-temperature region made up of mechanical joints, and the joints in the low-temperature region using metallurgical joints. It consists of
The present invention is also characterized in that the elements used in the joints in the high temperature range are made of a dispersion-strengthened heat-resistant alloy.

An example of the gas turbine cooling component of the present invention will be described in more detail with reference to FIGS. 3 to 7, including the method of manufacturing the stationary blade described above.

FIG. 3 is a diagram for explaining the structure of the wing portion according to the present invention, and is a longitudinal sectional view taken along line AA' in FIG. 1. In the figure, 1 is the implanted part, 2
is a two-part wing section consisting of an upper wing 2a and a lower wing 2b. 3 is an element constituting the partition wall;
3' is a cooling blow-off hole, and 4 is a cooling passage. 5
is an element of a fitting member for mechanically coupling the upper wing 2a, the lower wing 2b, and the partition wall 3. The perspective views of each of these elements, that is, the upper surface wing 2a, the partition wall 3, the lower surface wing 2b, and the fitting member 5 are shown in the fourth to fourth sections, respectively.
It is shown as Figure 7.

Now, in the present invention, the wing section 2 is the upper surface wing 2.
It is a divided structure consisting of the following elements: a, lower wing 2b, partition wall 3, and fitting member 5. This part becomes a high temperature area. Both of these elements are composed of ODS alloys. The ODS alloy used is 0.3 to 15% of Y ₂ O ₃ and ThO ₂ powder of 0.5 μm or less as metal oxides.
Y ₂ O ₃ powder containing % by weight and preferably 0.5 μm or less
It is preferable that the matrix contains 0.6 to 2% by weight, and the matrix contains Ni as a balance component and Cr, A, and Ti. At this time, the particle size of the fine metal oxide powder is
Affects the mechanical strength of ODS alloys at high temperatures. If the grain size exceeds 0.5 μm, sufficient high-temperature strength cannot be obtained, so it is preferable to use an ODS alloy whose grain size is controlled to 0.5 μm or less.

The wing section 2 of the present invention is constructed by mechanically coupling the elements shown in FIGS. 4 to 6 that have been previously formed and machined based on design specifications. That is, for example, the upper wing 2
a. Machining a groove extending in the blade span direction with a wedge-shaped cross section as shown in the figure at a predetermined position on the inner surface of the lower blade 2b,
These are placed opposite to each other with a partition wall 3 formed by forming similar grooves in the longitudinal direction interposed therebetween. Thus, as shown in FIG. 3, the cooling passage section 4 is formed to form the wing section. Next, the fitting member 5 shown in FIG. 7 is driven into the space of the wedge-shaped groove between the elements (butterfly-shaped cross section in the figure) in the wing length direction to assemble and integrate the whole. Finally, cooling blow-off holes 3' are processed and bored.

Such mechanical coupling is not limited to the exemplified fitting, but may also be achieved by other means such as screwing or screwing.

In addition, in order to maintain the airtightness of the above-mentioned joint portion sufficiently, a thin film of a low melting point metal such as A is formed on the surface of the fitting member by a commonly used thin film forming method (e.g. vacuum evaporation method). Then, if this member is driven into the space above and heat treated, A
This is a quasi-liquid phase diffusion bonding method for fillers, and it is possible to obtain not only good airtightness but also high bonding strength without impairing the properties of each element (ODS alloy).

Both ends of the wing section 2 manufactured as described above are
The cooling component of the present invention is obtained by joining the implanted portions 1, 1' made of a material such as IN-939 and previously machined into a predetermined shape.

The latter joint constitutes a low temperature region in the stator vane. Therefore, each element of the wing section 2 and the implanted sections 1 and 1' are metallurgically combined to form a stator vane.

That is, the assembled wing section 2 is joined by liquid phase diffusion bonding to a predetermined position of the implanted sections 1, 1' made of IN939 manufactured by precision casting. At this time, both ends of the wing portion 2 are joined with a reverse taper. The joint part does not reach as high a temperature as the wing part 2 during use, but
Since the thermal stress increases, ductility becomes important.
Also, since this part becomes large in terms of mass,
It is not necessary to use ODS alloy; in fact, IN939 is preferred.

In applying the liquid phase diffusion bonding method, the filler (solvent material) used is usually preferably an amorphous filler having a composition similar to that of the base alloy and containing B, Si, etc. At the time of joining, the ODS alloy of the wing portion 2 in the joint portion reacts with the molten metal, so that its dispersion strengthening properties are locally significantly impaired. However, this is not an inconvenient problem because, as mentioned above, it is desired to improve the ductility of the joint portion.

In addition, in the diffusion treatment of the liquid-phase diffusion bonding method in this case, the long-term heat treatment that was conventionally performed to uniformly diffuse B, Si, etc. and increase the bonding strength is no longer necessary; Processing conditions are determined from the viewpoint of ensuring hot corrosion and ductility.

In the present invention, since the wing portion and the implanted portion are joined over a wide area, sufficiently good rigidity can be ensured for the entire component.

Note that, for example, the fitting method applied to the assembly of the wing portion 2 can also be adopted for this joint portion.
At this time, it is preferable that the mechanically connected portion be located on the cooling side of the interior. Furthermore, the joint portion may be inclined or may have a stepped structure in order to maintain its airtightness.

Although the above description has been made regarding stator blades, the structure of the present invention can also be applied to moving blades and combustors. That is, in the case of a rotor blade, 1 is an implanted part like a Christmas tree, and the part corresponding to 1' can be changed to a type like a tip-jointed blade. Since the centrifugal force acting on this chip portion is small and it is sufficient to provide resistance to thermal fatigue, the above-mentioned liquid phase diffusion bonding method may be applied to bonding.

In addition, in the case of a combustor, the present invention allows the parts facing the cooling passage to be joined using the liquid phase diffusion bonding method, and the internal parts that come into contact with the flame to be joined using the mechanical bonding method. It is similar to

In the present invention, the implanted parts 1, 1', the element 2
Examples of materials for a, 2b, and 3 are shown, but these are Co alloy for 1 and 1', and material examples for 2a, 2b, and 3.
For example, Fe-based ferrite matrix
It is also possible to use a method that utilizes the difference in thermal expansion caused by a combination of Ni-based austenite matrices.

[Embodiments of the invention]

MA754 (A0.3wt%,
Ti0.5wt%, Y ₂ O ₃ 0.6wt%, Cr20wt%, BaNi;
(manufactured by INCO) was prepared. The upper wing, lower wing, bulkhead, and fitting members were fabricated from this ODS alloy as designed. Electrical discharge machining methods such as electrolytic machining and wire cutting were applied to create the grooves in the joints. By combining these, a fitting member whose surface was covered with an A layer of approximately 20 μm by ion plating was driven into the groove space of the joint portion in the blade length direction and wedged to manufacture a wing portion. At this time, layer A enabled an even firmer fit.

Next, use IN-939 (22.5Cr-
19.0Co―2.0W―1.0Nb―1.4Ta―3.7Ti―1.9A―
A precision cast product of 0.1Zr―0.01B―0.15C―BaNi (manufactured by INCO) was prepared.

16% in place between both ends of the wing and the implant.
A piece of amorphous filler having a composition of Cr-4%B-Ni and a thickness of 38 μm was interposed and fixed, and the whole was heated in a vacuum at 1100° C. for 30 minutes, and then cooled in air. Next, heat at 1150°C for 4 hours and air cool, heat at 1000°C for 6 hours and air cool, heat at 900°C for 4 hours and air cool,
Heat treatment was performed sequentially by heating at 700°C for 16 hours and cooling in air. A stator blade with an integrated structure was obtained.

This is then treated with plastic and applied to the wing surface.
After plasma spraying an alloy with a composition of Y0.4wt%, A6wt%, Cr16wt%, and BaNi,
A corrosion-resistant coating was obtained by applying A-Pack infiltration treatment for 1 hour. Finally, cooling holes were drilled at the trailing edge using electrical discharge machining.

In the obtained stationary blade, the temperature in the blade part could be increased by 70°C compared to the case of a Ni-based superalloy blade part made by conventional precision casting. Furthermore, the stator vane of the present invention is a solid vane with no internal cooling structure.
Compared to the case of ODS alloy wings, the wing temperature can be reduced by 170°C.
It was found that the temperature could be lowered by ℃. In other words, the inlet temperature of the gas stream could be increased by 170°C.

〔Effect of the invention〕

The gas turbine cooling component of the present invention has a structure with a complicated cooling passage, so its cooling efficiency is high, and since the high temperature is made of ODS alloy, the gas turbine inlet temperature can be raised, improving thermal efficiency. Since the high-temperature region is a divided structure with mechanical connection, the characteristics of ODS alloy can be utilized as they are.The ODS alloy used as the material does not need to be a large block material or a wide thin plate, so the overall cost can be reduced. Since the high temperature area is an assembly of each element, the whole can be assembled into a large size. Since it is possible to conduct internal inspections, cooling performance is stable, and advanced technologies such as turbine lens promoters can be applied.
It has advantages such as easy regeneration and repair of damaged blades after use, and its industrial value can be applied to industrial gas turbine cooling parts that require toughness, durability, and large size. is large.

[Brief explanation of the drawing]

Figure 1 is a plan view of the stator vane, Figure 2 is A- in Figure 1.
FIG. 3 is a vertical cross-sectional view taken along line A'. FIG. 3 is a longitudinal cross-sectional view showing an example of a stationary blade having the structure of the present invention, FIG. 4, and FIG.
6 and 7 are perspective views of the upper wing, partition wall, lower wing, and fitting member in FIG. 3, respectively. 1, 1'... Implanted part, 2... Wing part, 2'... Leading edge,
2″... trailing edge, 2a... upper surface wing, 2b... lower surface wing, 3...
Partition wall, 3'...Cooling outlet, 4...Cooling passage section, 5
...Fitting member, P...Inflow direction of gas flow.

Claims (1)

[Claims] 1. A gas turbine cooling component that is operated while being cooled in a high-temperature gas flow and has a split structure in which each element is joined as a whole, with the joint portion in the high-temperature region being constituted by mechanical connection, and the cooling component in the low-temperature region A gas turbine cooling component characterized in that the joint parts in the high temperature range are formed by metallurgical bonding, and the elements used in the joint parts in the high temperature range are made of a dispersion-strengthened heat-resistant alloy. 2. The gas turbine cooling component according to claim 1, wherein the dispersion-strengthened heat-resistant alloy contains 0.3 to 15% by weight of a metal oxide having a particle size of 0.5 μm or less dispersed therein. 3. The gas turbine cooling according to claim 1, wherein the mechanical connection is made by fitting, screwing, or screwing, and the metallurgical connection is made by liquid phase diffusion bonding. parts.