JPS6248902A - Complex radial turbine rotor - Google Patents

Abstract

PURPOSE:To ease detection of a defect on the fitting face by forming said face between a rotor shell, which has a radial blade group, and a solid rotor hub, into a paraboloid. CONSTITUTION:Grouping radial blades 3 are connected together by the rim 8 of a rotor shell 6. The fitting face between the inner face of the rim 8 and the outer face of a solid hub 9 innerly fitted to the rim is formed from a paraboloid 10. After fitting the rotor hub 9 to the inner face of the rim 8, these two are joined in one body through hot hydrostatic pressurization. Supersonic waves incident upon the fitting face from a supersonic waves oscillator 7 are reflected and entirely focussed upon a supersonic waves receiver 13 at the focus F. Thus, detection of a defect on the fitting face can be performed easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to the improvement of a composite radial turbine used in a small gas turbine or the like.

(Prior art) In the radial inflow turbine, as shown in Fig. 2,
High-temperature gas flows into the radial part 1 from the radial direction, expands in the exducer part 2, becomes low temperature, and is discharged in the axial direction. The large outer diameter of the radial portion 1 results in a high circumferential speed and generates high stress, so a forged material with excellent mechanical strength is required. On the other hand, for the exducer part 2, a cast material is suitable because the stress is not so great and the blade 3 is thin and twisted, making machining difficult. For this reason, conventionally, as shown in the figure, the radial part 1 is formed by cutting out a forged material, and the exducer part 2 is formed by precision casting, and the two are mechanically connected by a fastening means 4. According to this configuration, the hub 5 of the exducer section 2 must be hollow. In the one shown in FIG. 2, the radial part 1 and the exducer part are made of separate parts and made of different materials, and are integrated to form a rotor shell. There are also molded rotor shell types. That is, as seen in what was disclosed in Japanese Patent Application Laid-open No. 56-106005 (details are given to Kii of the same publication).
, consisting of a cast metal shell having a row of radial plates formed over the shell and connected by a rim, and a dense metal hub fitted within the bottom of the shell, the mating integralness of the two being integral. In this case, a cylindrical inner hole and a conical cavity form a continuous fitting inner surface on the shell rim side, and a rotor hub made of a dense metal material is integrated with the fitting inner surface by diffusion bonding. In other words, a block material made of high-strength superalloy powder is used as the hub material, and a hot isostatic pressing device (HIP device) is used to form the block and diffusion bond it to the fitting inner surface at the same time. It is integrated with the rotor hub.

(Problems to be Solved by the Invention) Among the above-mentioned conventional technologies, in the one shown in FIG. 2, the rotor hub is hollow, and when the rotor rotates at high speed, stress is generated on the circumferential surface of the inner hole of the hub. This method is unsuitable for high-speed turbines because of its high resistance, and requires mechanical fastening means. Furthermore, the integration of the rotor shell and rotor hub shown in Japanese Patent Application Laid-Open No. 56-106005 is advantageous in terms of integration by diffusion bonding of dissimilar metal materials using ultra-high pressure without using mechanical fastening means. However, this method also has the following problems. That is, a problem in integrating two types of metal materials by diffusion bonding is that it is difficult to inspect for defects on the bonded surface between the two.

In JP-A-56-106005 exemplified above,
In order to inspect the joint surface between the rotor hub using the superalloy powder block and the rim side of the rotor shell, if the rotor hub is a hollow hub, the ultrasonic transmitter of the known ultrasonic flaw detection device should be placed at the center of the hollow hub. The ultrasonic wave is applied to the conical cavity surface and the cylindrical inner hole surface, which are the joint surfaces of the two, and the presence or absence of a joint defect and its location can be determined from the reflected signal of the incomplete joint. can be detected, but
The disadvantage of having a hollow hub cannot be avoided. Furthermore, if the rotor hub is a solid body, it is impossible to insert an ultrasonic transmitter into the rotor hub, so it is impossible to completely inspect the joint surfaces. In an ultrasonic flaw detection device, for a conical block such as the conical part 5a shown in FIG. 3, if the apex angle θ of the conical part 5a is larger than 90 degrees, the conical part 5a is It is known that it is possible to perform flaw detection on a conical surface by disposing an ultrasonic transmitter 7 on the side of the rear end surface 5b perpendicular to the axis of the block, that is, to perform ultrasonic flaw detection from the outer surface of the block. Therefore, as shown in the figure, a solid rotor hub 5 is connected to a rotor shell 6 in which three groups of blades each consisting of a radial part 1 and an exducer part 2 are connected via a rim (not shown). In order to obtain an integrated product by diffusion bonding using high pressure, it would be good if the rotor hub 5 could be replaced with a solid body having a shape that allows ultrasonic flaw detection from the outside, that is, the conical portion 5a shown in the figure, but as mentioned above, As mentioned above, the conical portion 5a is required to have a conical apex angle of 90° or more, while the hub 5 occupies the axial center position of the rotor shell 6, and the overall length of the hub is longer than both axial end surfaces of the shell. Since the conical portion 5a has a protruding length, replacing the conical portion 5a with the apex angle of 90° or more so that the apex side thereof is located on the front end side of the hub 5 depends on the shape and height of the blade 3 on the rotor shell 6 side. Therefore, when incorporating such a conical portion 5a into the rotor hub 5, the length of the conical portion 5a is
There is a restriction that the length l) shown in the figure is about an odd length of the required total length. This is achieved by forming a solid rotor hub 5 using a high-strength metal material made of superalloy powder block-formed by super-pressure molding, and inspecting its diffusion bonded surface from the outside using ultrasonic flaw detection. Even if it is made into a conical block, it means that only the length between the required lengths of the rotor hub 5 can be replaced, so it is possible to form a solid rotor hub using a high-strength metal material. However, it is impossible to achieve the purpose of integrating this into the rotor shell side by diffusion bonding and performing an accurate inspection from the outside for the presence or absence of defects on the diffusion bonded surface.

(Means for Solving the Problems) In order to solve the problems, the present invention improves the shape of the fitting surfaces of the rotor shell and rotor hub, thereby creating a solid body that satisfies the required length using a superalloy powder block material. The rotor hub can be formed, and its diffusion bonding surface can be accurately inspected from the outside. Specifically, the rotor shell has a group of radial plates connected by a rim, and It consists of a solid rotor hub that is fitted inside the rim of a rotor shell, and the fitting surface between the rotor bubble and the rim is a paraboloid of revolution.

(Function) According to the technical means of the present invention, as shown in FIG.
A rotor shell 6 in which groups are connected by a rim 8 and a solid rotor hub 9 made of a superalloy powder block are assembled by fitting the rotor hub 9 into the rim 8 of the rotor shell 6, and applying a hot isostatic press (HIP). When the inner surface of the rim 8 and the outer surface of the hub 9 are integrally joined by diffusion bonding by applying pressure using The entire length of the hub can be formed as a solid body made of a high-strength metal material, and the diffusion bonded surface between the inner surface of the rim 8 and the outer surface of the hub 9 can be accurately and easily inspected for defects from the outside. That is, the paraboloid of revolution 10 is, needless to say, a quadratic curved surface obtained by rotating a parabola expressed by orthogonal coordinates y2=ax (a is a constant) around the X-axis, and the focal point F is placed on the X-axis. Therefore, in defect inspection on the diffusion bonded surface, as shown in the figure, the rear end surface 9a of the rotor hub 9, which is a flat surface perpendicular to the rotor axis, is
An ultrasonic transmitter 7 is movably disposed on the side, and the focus F
By using the through hole 11 and the recessed hole 12 provided at a position including
By making ultrasonic waves incident in the axial direction toward . Therefore, if there is an unbonded part on the bonded surface formed by the paraboloid of revolution 10 integrated by diffusion bonding, the ultrasonic receiver 13 placed at the focal point F will capture the reflected wave and detect the defect. The presence or absence of defects on the surface of the rotor hub 5, which is a solid body, and the rim 8 joined thereto, and its position can be detected extremely accurately by moving the ultrasonic transmitter 7 along the rear end surface 9a. And it can be easily detected. Furthermore, since the shape of the rotor hub 9 is a parabola with y2=ax, the apex angle is 90
Since the paraboloid of revolution 10 can have a relatively gentle slope compared to the conical shape described above, the rotor hub sufficiently satisfies the required length of the rotor hub 9 and can be smoothly integrated with the rotor shell 6 side. 9 can easily be formed as a completely solid body of strong metallic material such as a superalloy powder block.

EXAMPLE A suitable example of a rotor according to the invention will be described with reference to FIG. The rotor shell 6 can adopt various conventional structures. For example, the radial part 1 is made of a forged material and the exducer part 2 is made of precision casting, so that both parts are made of different materials, and the rim 8 is formed integrally with the exducer part 2 or the radial part 1. At this time, as shown in FIG. 1, the blade 3a of the radial part 1 and the blade 3b of the exducer part 2 are made into a continuous blade 3 with a slight gap S therebetween, and the electron beam welding 14 is made from the gap S. When the rim 8 is integrated with the exducer part 2, it is precision cast, and when it is integrated with the radial part 1, it is formed by machining a forged material. When diffusion bonding the rotor shell 6 and the rotor hub 5, the above-mentioned through hole 11 provided in the boss portion 8a of the rim 8 is used to degas the inside of the fitting portion between the hub 9 and the rim 8. Maintain the vacuum state and use a hot isostatic pressurizer (
By applying ultra-high pressure from the outside of the rotor shell 6 using a HIP device, the paraboloid of revolution 10, which is the fitting surface between the rim 8 and the hub 9, are integrally joined by diffusion bonding. In the same figure, a portion indicated by 15 is a portion of the rotor hub 9 that was cut and removed after inspection, and 16 is a portion of the rim 8 that was also cut and removed. Further, the rotor shell 6 including the rim 8 can be integrally molded by precision casting.

(Effects of the Invention) According to the present invention, as a composite radial turbine rotor,
In contrast to the rotor shell 6, the rotor hub 9 is made of a solid body, which is most advantageous in terms of strength, and its material is made of a high-strength metal material such as a superalloy powder block.
Moreover, it is extremely advantageous in that the presence or absence of defects on the bonded surface due to diffusion bonding can be precisely and easily detected from the outside over the entire surface. That is, by making the mating surfaces of both a paraboloid of revolution, it can be easily detected from the outside by ultrasonic flaw detection means, and the ultrasonic transmitter 7 and the ultrasonic receiver I
Although both of 3 are necessary, the receiver 13 only needs to be installed in the hole that includes the focal point F, and this does not need to be moved.
Since it is fixed and immovable at the focal point position, the defect detection is completely consistent and extremely reliable, and the detection work can be automated.Moreover, the shape of the rotor hub 9 is much gentler than the conical shape, so its slope is much gentler. With a sufficient length, a smooth fitting relationship with the rotor shell 6 side can be obtained without changing the blade shape or height, and manufacturing itself is facilitated.

[Brief explanation of drawings]

FIG. 1 is a half longitudinal sectional front view of an embodiment of the rotor of the present invention, FIG. 2 is a longitudinal sectional front view of a conventional rotor 1 side, and FIG. 3 is a structural explanatory diagram of a solid rotor hub. 1.-Radial part, 2-.Exducer part, 3-.
-Blade, 6-Rotor shell, 7-Ultrasonic transmitter, 8--Rim, 9--Solid rotor hub, 1o-paraboloid of rotation, 13-Ultrasonic receiver, F...- focus. Patent Applicant: Kobe Steel, Ltd. Procedural Amendment (Voluntary) October 3, 1985
Day 2 - Name of the invention (tentative name), 1 Relationship with the person making the amendment Patent applicant (119) Kabushikami Pl Steel Works 4 Agent Address: Osaka Prefecture Higashi Inu 1ii+7 #rf110131 Overturned P University 11 ((1617+12) Igjj: 5 Date of notice of reasons for refusal Showa year, month, day (voluntary)
Character deletion 6 Subject/application for amendment - Part 1, 7, Contents of amendment (1) Does it say "in radial section 1" on page 1, line 19 of specification strip grJ? The radial portion l is corrected as follows. (2) In the same book, on page 2, line 6, does it say “kiradashi”? Correct it by saying, "By cutting it out." i31 Same book, page 7, line 3: “The said rota pub”
a? Correct it to "the above Romehap". (4) Amend the attached drawing, “Figure 1” as shown in the attached sheet.

Claims (1)

[Claims] 1. Consisting of a rotor shell having a group of radial plates connected by a rim, and a solid rotor hub fitted into the rim of the rotor shell, the fitting surface between the rotor hub and the rim is a paraboloid of rotation. A composite radial turbine rotor characterized by: