JP3040680B2 - Gas turbine vane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine stationary blade applied to a gas turbine.

[0002]

2. Description of the Related Art Most gas turbine stationary blades used in conventional gas turbines use a Co-based heat-resistant alloy, and a Ni-based heat-resistant alloy is used as an extremely small part thereof. It is manufactured by precision casting.

That is, as shown in FIG. 3, an inner shroud portion 02 provided on the inner peripheral side of the wing portion 01 and the wing portion 1 and an outer shroud portion 0 provided on the outer peripheral side of the wing portion 01.
Reference numeral 3 is made of a Co-base heat-resistant alloy or the like, and is manufactured by precision casting.

On the other hand, in a jet engine which is used by increasing the inlet gas temperature to that of a gas turbine in order to improve the performance, in order to cope with the increase in the inlet gas temperature, the cooling performance of high-temperature parts and the material Improvements have been made. As one of the remedies for this material, a high-temperature component is manufactured using a unidirectional solidified material in which columnar crystals are arranged in one direction.

That is, in a unidirectionally solidified material in which columnar crystals are arranged in one direction, the crystal grain (columnar crystal) growth direction ｛approximately (00
1) Since the Young's modulus in the direction｝ is small, the generated thermal stress when operating in a high-temperature atmosphere is reduced, and the thermal fatigue life of a high-temperature component can be improved by about one digit. In applying the one-way solidified material to a turbine rotor blade or a stationary blade, which is a high-temperature component, for example, as shown in FIG. 4, the blade height direction of the blade portion 01 of the turbine stationary blade grows crystal grains (columnar crystals). The direction {(001) direction} is set so as to improve the thermal fatigue life of the root portions of the wing portion 01 and the shroud portions 02 and 03. In the turbine rotor blade, the blade height direction is set to the crystal grain (columnar crystal) growth direction to improve the thermal fatigue life of the joint between the blade part and the platform part.

However, turbine rotor blades and stationary blades used for gas turbines are larger than turbine rotor blades and stationary blades used for jet engines, and are particularly used for large gas turbines having a single-unit output of 100 MW class or more. Turbine blades and stationary blades are very large, generally 200 mm or more. In particular, in the production of gas turbine stationary blades with shrouds on the inner and outer circumferences, In addition, a high level of manufacturing technology is required, the manufacturing yield is deteriorated, and the cost is increased.

(1) That is, when a unidirectional solidified material is applied to a turbine stationary blade of a gas turbine, the blade height direction is set to the crystal grain growth direction {(001)}, and the blade portion 01 and the shroud portions 02 and 03 are used. Although it is conceivable to improve the thermal fatigue life at the root of the blade, as shown in FIG. It has a surface perpendicular to the part 01 and has a larger Young's modulus than the {001} direction.
10) The direction｝ is included. For this reason, improvement in the thermal fatigue life of the shroud portions 02 and 03 cannot be expected, and the shroud portions 02 and 03 are almost the same as those of the equiaxed precision casting.

(2) In addition, the turbine vanes of a large gas turbine become large, and the crystal grains of the shroud portions 02 and 03 inevitably become large. Since the chemical components do not change depending on the size of the product and are the same, the increase in the crystal grain means that the total grain boundary area becomes relatively small and the amount of grain boundary segregation becomes relatively large. Therefore, the segregation of impurity elements at the grain boundaries is large and the solidification rate is low, so that the grain boundary carbides are coarsened. For this reason, the grain boundaries are weak, and cracks are likely to occur during casting or during actual use.

(3) Further, since the gas turbine stationary blade manufactured by using the unidirectional solidified material of the large gas turbine becomes a large blade, the unit price increases. That is, even if a small defect occurs only in the wing portion 01 or the shroud portions 02 and 03, since it is manufactured by integral molding, all of the components must be discarded, and the yield becomes worse. Leads to increased costs.

[0010]

SUMMARY OF THE INVENTION The present invention can be applied to a large wing in order to solve the above-mentioned problems, and can reduce the generated thermal stress and remarkably improve the material strength characteristics of the wing and the shroud. It is an object of the present invention to provide a gas turbine vane which can be manufactured easily, can improve the yield, and can reduce the cost.

[0011]

Therefore, the gas turbine stationary blade of the present invention has the following means.

(1) A blade portion was formed from a unidirectional solidified material in which columnar crystals were grown in the blade height direction.

(2) From the results of the thermal stress analysis at the design stage, it is found that when the blades are arranged and operated on the outer peripheral side and the inner peripheral side, the direction in which thermal fatigue cracks are liable to occur due to the generated thermal stress. At right angles, a shroud portion was formed from a unidirectionally solidified material obtained by growing columnar crystals.

(3) The individually formed blades and the shroud are combined and joined to form a gas turbine stationary blade.
Further, another gas turbine stationary blade according to the present invention includes the above (1) to (4).
(3) In addition to the following means.

(4) The joining of the blade portion and the shroud portion in combination is performed by brazing or welding to form a gas turbine stationary blade.

[0016]

According to the present invention, the gas turbine stationary blade of the present invention has the above (1)
By means of (3), (1) the wing portion is formed of a unidirectional solidified material in which the wing height direction is a crystal grain (columnar crystal) growth direction, so that the Young's modulus is small {(001) direction}. And the thermal fatigue life becomes long.

(2) The unidirectional solidified material forming the shroud portion grows columnar crystals so as to be substantially perpendicular to the direction in which the highest thermal stress is likely to occur, that is, the ｛(001) direction having a small Young's modulus. Since the shroud portion is formed as｝, the thermal fatigue life of the shroud portion can be significantly improved.

(3) Since the blade portion and the shroud portion are separately manufactured and joined to form a gas turbine stationary blade, the casting weight is reduced and the solidification speed of the one-way solidified material is increased. This makes it possible to obtain a unidirectional solidified material having a more uniform metal structure and good material strength characteristics, and to facilitate casting. In the case of integral casting, for example, even if the wing portion is sound, if a defect occurs in the shroud portion, this product will be discarded, but if manufactured separately, at least one of the products will be a passed product.
Therefore, the yield is improved and the cost is reduced.

Further, another gas turbine stationary blade according to the present invention comprises:
In addition to the above (1) to (3), by means of the above (4), (4) assembling of the gas turbine stationary blade is facilitated,
The assembly structure of a large gas turbine vane can be made strong. Furthermore, since the joining is performed in a small range and heating is not performed at a high heat that damages the crystal structure, the wings and the columnar crystals grown in the shroud are not damaged,
The thermal fatigue life at the root of the wing and the shroud can be improved.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a gas turbine stationary blade according to an embodiment of the present invention. FIG. 1 is a perspective view showing a blade portion and a shroud portion constituting an embodiment of the gas turbine stationary blade of the present invention.

As shown in FIG. 1A, N for unidirectional solidification
The wing portion 1 is cast using an i-base alloy. At this time, crystal grains (columnar crystals) are grown in the blade height direction indicated by the arrow, and the blade height direction is made to coincide with the (001) direction in which the Young's modulus of the one-way solidified material is small.

Further, as shown in FIG. 1 (B), the inner shroud portion 2 mounted on the inner peripheral side of the wing portion 1 is made of an Ni-based alloy for unidirectional solidification, and the inner shroud portion 2 is in an operating state. When it is perpendicular to the direction where the thermal stress is maximum,
Crystal grains (columnar crystals) are grown in the direction indicated by the arrow, and are manufactured in accordance with the {001 (001) direction} having a small Young's modulus.

Further, as shown in FIG.
The outer shroud portion 3 mounted on the outer peripheral side of the outer shroud portion is made, similarly to the inner shroud portion, perpendicular to the direction in which the thermal stress becomes maximum when the outer shroud portion 3 is in the operating state by the Ni-based alloy for unidirectional solidification. Crystals (columnar crystals) are grown in the direction, and are manufactured from a unidirectionally solidified material that matches the {001} direction with a small Young's modulus.

The direction in which the thermal stress of the inner shroud 2 and the outer shroud 3 becomes maximum can be grasped by thermal stress analysis at the design stage.

The wing portion 1, the inner shroud portion 2, and the outer shroud portion 3 manufactured as described above are assembled as shown in FIG. Joint 4 'of the part 1 and the outer shroud part 3
Are joined by a Ni—Cr brazing material to produce a gas turbine stationary blade of an assembly structure type. At this time, welding may be performed by welding instead of the brazing material.

As described above, the gas turbine stationary blade of the present embodiment is manufactured by separately manufacturing the blade portion 1, the inner shroud portion 2, and the outer shroud portion 3, and joining these by brazing material or welding. Since the wings 1 are formed, the wings 1 grow crystal grains (columnar crystals) in the wing height direction, and can match the (001) direction with a small Young's modulus.
The inner and outer shrouds 2 and 3 are also capable of growing crystal grains (columnar crystals) in a direction perpendicular to the direction in which the thermal stress is maximized, so as to match the (001) direction in which the Young's modulus is small. As a result, the material strength characteristics of the wing portion 1 and the inner and outer shroud portions 2 and 3 can be significantly improved.

Further, the wing portion 1 and the inner and outer shroud portions 2 and 3
By separately producing, the castability was improved, thereby improving the yield and contributing to cost reduction.

[0028]

As described above, according to the gas turbine stationary blade of the present invention, the configuration shown in claim 1 (1) significantly improves the thermal fatigue life of the blade portion, the inner and outer shroud portions. be able to.

(2) In addition, the casting weight can be reduced, the metal structure can be made more uniform, the material having good material properties can be obtained, and the casting operation can be facilitated.

(3) The production yield is improved, and it is easy to achieve cost reduction.

According to the second aspect of the present invention, (4) the assembly of the gas turbine vane is facilitated, and the assembly structure of the large turbine vane can be made stronger.

(5) The thermal fatigue life of the connecting portion between the blade portion where a large thermal stress is generated and the shroud portion can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a view showing a blade portion, an inner peripheral shroud portion, and an outer peripheral shroud portion which constitute one embodiment of a gas turbine vane of the present invention. FIG. 1 (A) is a perspective view of the blade portion, and FIG. 1 (B) is a perspective view of an inner shroud portion, FIG. 1 (C) is a perspective view of an outer shroud portion,

FIG. 2 is an assembled perspective view of the embodiment shown in FIG. 1;

FIG. 3 is a perspective view showing a conventional integrated precision casting vane (equiaxial crystal material);

FIG. 4 is a perspective view showing a conventional integrated precision casting vane (one-way solidified material).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wing part 2 Inner peripheral shroud 3 Outer peripheral shroud 4, 4 'Joint

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisakataka Kawai 2-1-1, Shinhama, Arai-machi, Takasago-shi, Hyogo In-house Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. No. 1 Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Eiji Akita 2-1-1, Shinhama, Araimachi, Takasago City, Hyogo Prefecture Inside the Takasago Works, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-4-284102 (JP, A (58) Fields surveyed (Int. Cl. ⁷ , DB name) F01D 9/02 F01D 5/28

Claims (2)

(57) [Claims] 1. A wing formed of a unidirectional solidified material in which columnar crystals are grown in a wing height direction, and a direction in which thermal stress generated when the wing is mounted and operated when operated is substantially perpendicular to the wing. 1. A gas turbine vane comprising a shroud portion formed of a unidirectionally solidified material having columnar crystals grown thereon and joined thereto. 2. The gas turbine vane according to claim 1, wherein the blade portion and the shroud portion are joined by brazing or welding.