JPS58124003A - Manufacture of ceramic turbine rotor - Google Patents

Abstract

PURPOSE:To enable to carry out combination firmly and easily, by sintering and combining a rotor part made of silicon carbide and a turbine disk part made of the silicon carbide and a carbon composite under existence of a silicon ingredient. CONSTITUTION:A rotor part 1 provided with a fitting hole 2 is manufactured by sintering from silicon carbide powder and a turbine disk part 4 is molded from a mixture of carbon powder and organic binder admixed with silicon carbide powder. Common foundations 2a and 4b whose composites are identical with a material of the turbine disk part 4 are sprayed on the inner surface of the fitting hole 2 or the outer periphery of a fitting shaft and touched by a brush. Green molds of the rotor part 1 and the turbine disk part 4 molded in this manner are made to react and sinter in a body under existence of a silicon ingredient.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a ceramic turbine rotor in which a rotor portion and a disk portion are integrally joined.

Turbine rotors have a very complex shape, and traditionally they have been manufactured using ceramic casting or injection molding methods. However, since the thickness of each part is different, cracks and deformation are likely to occur during the molding process, sharpening process, or firing process, making it extremely difficult to obtain an integrated molded body. In addition, the mold itself used is complicated.1. Ka, ah. Operation Ir1l techniques - 4 requests. It was not suitable for industrial use. Furthermore, the silicon nitride sintered body obtained by the reaction sintering method, which is suitable for molding into complex shapes, has low strength and is not suitable for the turbine disk portion, which is subject to large stress. Therefore, various methods have been proposed for joining the rotor portion and the turbine disk portion. For example, Tokuko Sho 53-387
The method of No. 21-3872/1 is one of them, and this method is related to manufacturing an axial flow turbine rotor, and involves making a rotor part by injection molding using a reactive sintered silicon nitride material.
This is a method of setting it in a carbon mold, molding the turbine disk part by hot pressing, and joining it to the rotor part. However, this method requires very strict hot press mold setting conditions and pressurizing conditions, making it difficult to manufacture turbine rotors with good productivity.

Therefore, the inventor of the present invention has conducted extensive research into a method of connecting the rotor part and the turbine disk part firmly, reliably, and easily. As a result, the present inventor has previously fired the complex-shaped rotor part made of silicon carbide, The present invention was completed by discovering that it is sufficient to sinter and C-bond a green molded body of a turbine disk portion made of a carbon composition and a green molded body of a turbine disk part in the presence of a silicon component.

That is, the gist of the present invention is a method of manufacturing a ceramic turbine rotor including the following a-CI step.

a. A rotor portion made of pressureless sintered silicon carbide or reaction sintered silicon carbide with a fitting hole provided in the shaft core is manufactured by molding and sintering.

b Silicon carbide powder, carbon powder, and a binder, or silicon carbide powder, carbon powder, and a mixed raw material that carbonizes at 1000°C or higher [11 substances and a binder, or silicon carbide powder, an organic substance that carbonizes at 1000°C or higher, and a binder, A green molded body of a turbine disk portion including a fitting shaft portion to be inserted into the fitting hole is molded.

C Insert the fitting shaft part of the green molded body of the turbine disk part obtained in the above step into the fitting hole of the rotor part obtained in step a above, and green mold the turbine disk part in the presence of a silicon component. The carbon content in the raw material composition of the body is reacted with silicon to form reactive sintered silicon carbide, thereby firmly integrating the rotor part and the Kubin disk part.

The present invention will be described in more detail below. First, in the present invention, a
As a process, a rotor part (blade part) 1 is manufactured. In the case of a radial rotor, as in the embodiment shown in FIG. 3, or as in another embodiment shown in FIG. The conical shape may be any airfoil shape in which the back plate 3 of the back plate portion is thinner than that in FIG. In addition, in the case shown in FIG. 2, the back plate 3 of the back plate part is thinner than that shown in FIG. This has the advantage of making the bond stronger. In order to manufacture such a rotor part 1, silicon carbide powder and a sintering aid are molded and sintered using a well-known injection molding method, a casting molding method, etc., or a pressureless sintering method is used, or a silicon carbide powder and a carbon Sintering is performed by a reaction sintering method in which a powder or the like is molded by a well-known injection molding method, a casting method, etc., and then sintered. At this time, as shown in FIG. 3, a material made of the same composition as the green molded body of the turbine disk portion 4 is applied to the inner circumferential surface of the fitting hole 2 or to the fitting shaft surface as shown in FIG. If the common base material 2a or 4b is formed, an interfacial reaction will occur at the joint surface between the fitting hole 2 of the rotor part 1 and the fitting shaft part 4a of the turbine disk part 4 during the sintering process, increasing the joint strength. That's preferable. Such a common substrate 2ak connects 4b to the fitting shaft 4a.
To form it on the surface, for example, spraying,
There are methods such as brush painting. Furthermore, if the entire inner circumferential surface of the fitting hole 2 is roughened in advance by etching or sandblasting after sintering, the connection between the turbine disk portion 4 and the fitting shaft 4a can be made stronger. becomes.

Next, separate from step a, the turbine disk portion 4 is formed from a sintered raw material containing silicon carbide powder as a main component. That is, for example, silicon carbide powder, for example, carbon powder or an organic binder, or carbon and an organic substance and binder, such as a phenolic resin, which is carbonized at a sintering temperature of 1000°C or higher, or a phenolic resin, which is carbonized at a sintering temperature of 1000°C or higher. A green molded body of the turbine disk portion 4 is formed by using a mixture of organic substances such as the above, a binder, etc. as a sintering raw material. Molding methods include injection molding, casting molding, and isostatic press molding. Next, in step C, the rotor section 1 and the turbine disk section 4 are integrated by sintering. That is, the fitting shaft 4a of the green molded body of the turbine disk part 4 is inserted into the fitting hole 2 of the rotor part 1, and placed into a carbon crucible for firing reactive sintered silicon carbide.
Reaction sintering is carried out at 1550 to 2000° C. for 1 to 6 hours under reduced pressure in the presence of silicon components. Note that the silicon component is generated by heating metal silicon, or is present by impregnating heated and molten metal silicon. In this way, the green molded body composition of the turbine disk portion 4 becomes a reaction-sintered silicon carbide sintered body, and both are integrated at the joint between the fitting hole 2 and the fitting shaft portion 4a, as shown in FIG. 5 or 6. A strong turbine rotor can be obtained. Furthermore, as mentioned above, the fitting hole 2
An even stronger joint can be achieved by roughening the inner circumferential surface of the inner peripheral surface or the surface of the mating shaft portion 4a by etching or sandblasting, or by providing a common base material of the same quality as the turbine disk portion 4 at the joint portion. is obtained. Further, FIG. 7 shows an example in which the present invention is applied to an axial flow turbine rotor, in which a rotor part 20 made of a silicon carbide sintered body pre-injected into a ring shape and a turbine disk part 21 made of silicon carbide are green. An example will be shown in which molded bodies are fitted at the fitting portion 22 and integrated by reaction sintering using the same method as described above.

As described above, the present invention comprises a rotor portion made of a silicon carbide sintered body provided with a previously prepared fitting hole, and a silicon carbide and carbon-containing component provided with a fitting shaft inserted into the fitting hole. A ceramic turbine rotor made of reaction-sintered silicon carbide in which the green molded body of the turbine disk portion is joined between the fitting hole and the fitting shaft, and the two are integrated by reaction-sintering in the presence of a silicon component. This method has the advantage that a turbine rotor with a complicated structure can be produced with industrially simple operations without causing cracks, deformation, etc. Furthermore, the method of the present invention can be applied not only to turbine rotors but also to ceramic high-temperature parts (4) where ceramics are subjected to high stress and require bonding between ceramics.

Next, the present invention will be described with reference to examples, but the present invention is not limited to the following examples unless the gist of the invention is exceeded.

EXAMPLE A mixed raw material containing silicon carbide powder and a sintering aid was molded and sintered by an injection molding method to produce a rotor portion 1 as shown in FIG.

Next, raw material silicon carbide having the following composition: GC940070 parts by weight Carbon black 30 parts Phenol resin 20 parts by weight Polyethylene glycol 2
0 parts by weight was placed in a stainless steel pot of cemented carbide ore, acetone was added thereto, the mixture was ground and mixed for 24 hours, and then dried and granulated to prepare a sintered raw material for the turbine disk part 4. Put this into a rubber mold and make it 800! A turbine disk having a fitting shaft portion 4a that can be formed by isostatic press molding at a pressure of +/Cil, degreased, and then processed using a lathe to fit snugly into the fitting hole 2 of the rotor portion 1 as shown in FIG. A green molded body of Section 4 was made. Next ('', the fitting shaft part 4a of the green molded body of the turbine disk part 4 is inserted into the fitting hole 2 of the rotor part 1, placed in a carbon crucible for reaction-sintered silicon carbide firing, and the silicon component is The composition of the turbine disk part 4 becomes a silicon carbide sintered body, and the composition of the rotor part 1 becomes the same as that of the rotor part 1, so that the turbine disk part 4 has the same composition as the rotor part 1, and the two parts are firmly bonded together. was gotten.

Next, we cut out the joint part of the integrated turbine disk, created a 4 x 8 x 25 mm test piece, set it so that stress was applied to the joint part, and measured the 3-point bending strength at Span 20111. -Yugori is the reaction sintered ash IL Kei JF! In the case of a solid body, the bending strength is 11 [38,5
k<1/Ij! : In the case of F12 silicon sintered body under normal pressure, it was 29.3 kg/mj. It should be noted that all the fractures occurred at the joint surface during the measurement. The bending strength of a single reaction-sintered silicon carbide sintered body is approximately b Ok(]/m ton. The bending strength of a single normal-pressure sintered silicon carbide sintered body is 48 kg/1I.
However, in practical use, the bending strength of the F joint has no problem at the above value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a rotor part used in the present invention,
Fig. 2 is a sectional view of another example, Fig. 3 is a sectional view of still another example, Fig. 4 is a sectional view of an example of the fitting shaft, and Fig. 5 is a sectional view of the rotor section and the turbine disk section. FIG. 6 is a cross-sectional view showing a joined state in another example, and FIG. 7 is a cross-sectional view showing a joined state in the case of an axial flow turbine rotor. 1... Rotor section (blade section) 2...
Fitting hole 2a...Silicon carbide base material 3...Back plate part 4...Turbine armrest part 4a...Fitting shaft part 20...Rotor part ( Blade part) 21... Turbine disk part 22... Fitting part agent Tsutomu Adachi, patent attorney Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] A sesmic turbine 11-II & ih characterized in that it includes four culms of first order a.-C1. a. A rotor part made of 1,1 sintered silicon carbide or reaction sintered silicon carbide with a fitting hole installed in the shaft core is molded and sintered yh
′! I. b Silicon carbide powder, carbon powder, and binder, or silicon carbide powder, carbon powder, organic matter that carbonizes at 1000°C or higher, and binder, 1 cL carbonized! Carbonize at 1000° C. or higher with lA powder A: 1. From a mixed raw material consisting of a material and a binder, mold a green molded body of a turbine disk portion equipped with a fitting shaft portion to be inserted into a fitting hole. C above a] "Insert the fitting shaft of the green molded body of the rotor part obtained in [note] X into the fitting hole of the rotor part, and insert the The carbon content in the raw material composition of the clean molded body of the turbine disk part is reacted with silicon (to form reaction sintered carbide,
To firmly integrate a rotor part and a turbine disk part. 2 The inner diameter of the fitting hole provided in the axis of the rotor part is formed into a tapered shape from the back plate part toward the tip, and the green molded body of the turbine disk part to be inserted into this hole fits. 2. The ceramic turbine rotor according to claim 1, wherein the outer diameter of the shaft portion is formed into a tapered shape from the back plate portion toward the tip so as to fit tightly into the fitting hole. 3 C in the presence of silicon vapor generated by heating metal silicon, or by impregnation with liquid silicon melted by heating
A method for manufacturing a ceramic turbine rotor according to claim 1 or 2, wherein sintering is performed. 4. Claims 1 to 4, in which a material of the same quality as the raw material for the green molded body of the turbine disk part is applied in advance to the inner periphery of the fitting hole provided in the axis of the rotor part, and then sintered. 3
A method for manufacturing a ceramic turbine rotor according to any one of paragraphs. 5. According to any one of claims 1 to 4, in which a rough surface is formed in advance on the inner periphery of a fitting hole provided in the axis of the rotor part by a T-tuching method or a sandblasting method, and then sintered. Ceramic turbine low evening! Il construction method.