JPH07208103A - Compound construction disk and manufacture thereof - Google Patents

Abstract

PURPOSE:To facilitate manufacture of a complex shaped outer side disk outer circumference so as to adapt high speed rotation and a high load at a high temperature by providing with a ring shaped outer side disk made of cast member and an inner side disk which is brought in contact with the inner circumferential surface of the outer side disk and made of cast member. CONSTITUTION:A gear a and the rim part 1 of an impeller b are manufactured by cast member, and complex shaped gear and the implanted part of a blade 5 are manufactured easily. A web part 2 and a bore part 3 are manufactured integratedly with each other by cast member, a joining part 4 is joined by expansion joining, and the outer circumferential surface of the web part 2 is joined with the inner circumferential surface of the rim part 1. Cast member constituting the rim part 1 can be manufactured in a complex shape, and the cast member has sufficient fatigue strength which is demanded to the rim part 1. Cast member constituting the web part 2 and the bore part 3 has sufficient creep strength, and manufacture is facilitated by cast since the shape of the parts thereof is a simple. It is thus possible to manufacture the complex shaped rim part 1 easily, and also it is possible to obtain a disk which is resistant to a high load at a high temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear such as a turbine and a jet engine, and a disk such as an impeller having a blade attached to the outer circumference of the disk, and particularly to a composite structure formed by joining a cast material and a forged material. Regarding the disc.

[0002]

2. Description of the Related Art Gears and impellers are often used in gas turbines and aircraft gent engines. As shown in FIG. 1, teeth and blades forming a gear are provided on the rim portion on the outer periphery of the disk, and they are composed of a bore portion that is connected to the rotating shaft and a web portion that connects the bore portion and the rim portion. These gears and impellers rotate at high speed at high temperature,
It is used under severe conditions such as high load.

Conventionally, these gears and impellers are integrally manufactured by forging or casting. Since the outer side of the rim has a complicated shape such as teeth and blade implants, the disc is made of a forged material and machined, or the whole is made of a cast material. In terms of strength, the rim portion is required to have high fatigue strength at high temperature, and the web portion and the bore portion are required to have creep strength.

[0004]

Conventionally, in order to satisfy the creep strength requirements of the web portion and the bore portion, it has been often the case that the rim portion is manufactured by forging and machined into a complicated shape of the rim portion. Further, when it is made of a cast material to facilitate the production of the rim portion, it has been used where the creep strength of the web portion and the bore portion is not so high. Therefore, the advantage of the creep strength of the forged material was offset by the drawback of machining. In addition, the cast material is suitable for manufacturing products with complicated shapes,
Although it has an advantage of being strong in fatigue strength required for the rim portion, it was offset by the drawback that creep strength was not large. For this reason, there is a problem in that forged materials and cast materials do not fully utilize their respective advantages in high temperature, high speed rotation, and high load members such as jet engines and gas turbines.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a composite structural disk and a method for manufacturing the same, which make the most of the advantages of the forged material and the cast material.

[0006]

In order to achieve the above object, a ring-shaped outer disc made of a cast material and an inner disc made of a forged material joined to the inner peripheral surface of the outer disc are provided. is there.

Further, the inner peripheral surface of the ring-shaped outer disk made of a cast material and the outer peripheral surface of the inner disk made of a forged material are joined by diffusion bonding.

The inner peripheral surface of the outer disk is inclined at a predetermined angle with respect to the rotation axis of the composite structure disk, and the outer peripheral surface of the inner disk is also inclined at the predetermined angle with respect to the rotation axis. It is a thing.

[0009]

[Function] Casting material and forging material can be manufactured by forming the outer surface of the disk with a casting material that is suitable for manufacturing complicated shapes and having high fatigue strength, and by forming the inner surface of the disk with a forging material that is strong in creep strength and suitable for simple shapes. It is possible to construct a disk that uses only the advantages of both.

Further, by diffusion-bonding the outer disc made of a cast material and the inner disc made of a forged material, sufficient joining strength can be obtained, and cracks do not occur unlike welding, and strength like brazing does not occur. Do not run short.

In the case of diffusion bonding, it is necessary to press the both at a high temperature, but the inner peripheral surface of the outer disk made of cast material and the outer peripheral surface of the inner disk made of forged material should be at the same angle with respect to the rotation axes of both disks. By inclining and pressing both disks from the direction of the rotation axis along the inclined surface, a sufficient pressing force acts on the contact surface, and it becomes possible to reliably perform diffusion bonding.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a composite structure disk of this embodiment, (a) shows a gear (b) shows an impeller. These are used as high performance disks for cogeneration gas turbines and aircraft jet engines. In both (a) and (b), the rim portion 1 is made of a cast material, which facilitates the production of a complex shape of the tooth and the implantation portion of the blade 5. The web portion 2 and the bore portion 3 are integrally manufactured by a forging material, and the joint portion 4 is joined by diffusion joining to join the outer peripheral surface of the web portion 2 and the inner peripheral surface of the rim portion 1.

FIG. 2 is a view showing each component of FIG. 1 (b). The bore portion 3 is in the range of a, the web portion 2 is in the range of b, and the rim portion 1 is in the range of c. The joint portion 4 is a boundary portion between b and c. The cast material forming the rim portion 1 is suitable for manufacturing a complicated shape, and has sufficient fatigue strength required for the rim portion 1. The forged material forming the web portion 2 and the bore portion 3 has sufficient creep strength required for the web portion 2 and the bore portion 3, and since these portions have a simple shape, they can be easily manufactured by forging. . In this way, it is possible to realize a composite structure disk which utilizes the respective advantages of the cast material and the forged material and compensates for each other's defects.

Diffusion bonding involves placing members to be bonded in a vacuum,
As an example, it is a method of joining by heating at a high temperature of about 1000 ° C. and pressing the joining surfaces for a predetermined time. FIG. 3 is a view for explaining a method of pressing the inner surface of the link such as the rim portion 1 and the outer peripheral surface of the disc such as the web portion 2. The inner peripheral surface of the rim portion 1 and the outer peripheral surface of the web portion 2 are inclined surfaces that are angled with respect to the rotation axis 6, and the web portion 2 is formed from the direction indicated by the arrow.
By pressing against the rim portion 1, a vertical force perpendicular to the surface and a shearing force along the surface act on the contact surface. For the diffusion bonding, not only the vertical force but also the shearing force is applied to complete the bonding. As shown in the drawing, when the inclination angle from the direction perpendicular to the rotating shaft 6 is θ, when θ is about 60 °, the joining is sufficiently performed.

FIG. 4 shows the result of diffusion bonding using the test piece having the shape shown in FIG. In the figure, the vertical axis represents the tensile strength, A is a cast material, B is a forged material, and C is a diffusion bonded portion.
(A) has a tensile strength of about 1000 MPa and a temperature of about 1010 ° C.
It is shown that, as a result of diffusion bonding for 2 hours, a joint C1 having a tensile strength of about 900 MPa was obtained. (B) is a cast material A2 having a tensile strength of about 1000 MPa and a tensile strength of about 1400 MP.
In the case of the joint Ca2, the forging material B2 of a has a surface pressure of 46M.
This is the result of diffusion bonding at Pa at a temperature of 950 ° C. for 2 hours, and in the case of the bonding portion Cb2 at a surface pressure of 15 MPa and at a temperature of 1050 ° C. for 2 hours.
And that a joint Cb2 of about 800 MPa was obtained. If the strength of the joint is 70% or more of that of the weaker cast material, there is no problem in the strength of the disc, but in the case of (a), the joint C
1 is 90% of the cast material A1, and in the case of (b), the joint Cb2
Is 80% of the cast material A2 and has sufficient bonding strength. The cast material A1 is used for the rim portion 1 of FIG. 1A, the forged material B1 is used for the web portion 2 and the bore portion 3, and the cast material A2 is used.
Is a material used for the rim portion 1 of FIG. 1B, and the forged material B2 is a material used for the web portion 2 and the bore portion 3.

[0016]

As is apparent from the above description, according to the present invention, since the composite disc is formed by using the cast material for the outer disc and the forged material for the inner disc, it becomes easy to manufacture a complicated shape of the outer periphery of the outer disc. It is possible to obtain a disc suitable for high speed rotation and high load at high temperature. Further, by diffusion-bonding the inner peripheral surface of the outer disk and the outer peripheral surface of the inner disk, sufficient bonding strength can be obtained without causing cracks or the like. Moreover, by providing the joint surface with an inclination, it becomes easy to apply an appropriate surface pressure.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, in which (a) is a gear,
(B) shows an impeller.

FIG. 2 is a diagram illustrating the configuration of FIG. 1 (b).

FIG. 3 is a diagram illustrating a shape of a bonding surface and a pressing method in diffusion bonding.

FIG. 4 is a diagram showing test results by diffusion bonding.

[Explanation of symbols]

 1 rim part (outer disk) 2 web part (inner disk) 3 bore part (inner disk) 4 joining part 5 blade 6 rotating shaft

Claims (3)

[Claims] 1. A composite structure disc comprising: a ring-shaped outer disc made of a cast material; and an inner disc made of a forged material, which is joined to an inner peripheral surface of the outer disc. 2. A method for manufacturing a composite structure disk, comprising: joining an inner peripheral surface of a ring-shaped outer disk made of a cast material and an outer peripheral surface of an inner disk made of a forged material by diffusion bonding. 3. The inner peripheral surface of the outer disk is inclined at a predetermined angle with respect to the rotation axis of the composite structure disk, and the outer peripheral surface of the inner disk is also inclined at the predetermined angle with respect to the rotation axis. 3. The method for manufacturing a composite structure disc according to claim 2, wherein: