JPS6221963B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a method for manufacturing turbine stator blades. More specifically, the blade part and the shaft part are manufactured separately by casting and forging, and are integrated by welding using the enlarged part formed at the end of the shaft part, that is, the zabuton part. This is a characteristic feature. For example, exhaust gas from blast furnaces, etc. has a fairly high temperature and pressure, so it is economically problematic to discharge it into the air in that state, and methods of recovering the energy contained in this exhaust gas are being considered. One of the most effective ways to recover the energy of this exhaust gas is to drive a turbine with this exhaust gas, and use this turbine to drive a generator to recover the energy of the exhaust gas as electrical energy. be. By the way, since the exhaust gas discharged from the blast furnace contains a lot of dust and harmful components, it is subjected to dust removal treatment before being supplied to the turbine. The gas pretreated in this way is likely to be corrosive, and therefore the stator blades of the top pressure energy recovery turbine have traditionally been made using the following method to maintain corrosion resistance against humid gas containing salt. It is manufactured by That is, as shown in FIG. 2, a stationary blade having the shape shown in FIG. A method has been adopted in which the shaft portion 3B is manufactured by forming the joint portion 5 by welding. The manufacturing method for the stator blades of this turbine is to manufacture the blade part 1, the blade part 2, and the shaft part 3A with a complicated shape by casting, so heat treatment is performed after casting to remove casting defects. is being carried out. However, if this heat treatment is not sufficient, casting defects are likely to occur at the boundary portion 4 (or R portion 4) between the blade portion 1 and the blade portion 2, and between the blade portion 2 and the shaft portion 3A, making it difficult to manufacture a high-quality blade. This required advanced casting technology. In addition, when using TIG welding to manufacture turbine stator blades using this method, it is necessary to weld with low heat input to prevent defects due to welding. In this case, it was necessary to increase the number of welding layers to 20, which required a great deal of time and effort. The present invention was obtained in order to solve the problems of the conventional turbine stator blades, and its purpose is to prevent the occurrence of the problem in the R part (boundary part) on the shaft side of the stator blade G. The objective is to solve problems in casting technology to eliminate easy defects and to manufacture high-quality turbine blades with high efficiency. The configuration of the present invention to achieve the above object is to separate the wing section and the shaft section, manufacture the wing section by casting, manufacture the shaft section by forging, and integrate the two by welding. This is a stator vane for a turbine which has been modified to have a Zabuton part (enlarged part) at the end of the blade part, a Zabutton part is formed by expanding the end of the shaft part, and both Zabuton parts are welded together. This is a method of manufacturing a stator blade for a turbine. In particular, the present invention is characterized in that the shaft portion and the zabuton portion for fixing the shaft portion to the wing portion are integrally manufactured by a forged product of austenitic stainless steel, and the wing portion coupled to the shaft portion is cast. It is characterized by the fact that both parts are manufactured by welding and integrated by welding. More preferably, the method used for the welding is electron beam welding. As described above, the present invention is characterized in that the blade part is manufactured by a cast product and the shaft part is manufactured by a forged product, a zabuton part is formed at the matching part of both, and this zabuton part is welded. As a result of being configured in this way, it is possible to achieve the following effects. B. Reliability is further improved by manufacturing the R part (boundary part) of the shaft part with a forged product. (b) Since a Zabuton part (enlarged part) is formed in the shaft part and the wing part, and this Zabuton part is electron beam welded, welding can be performed automatically, and once the welding conditions are set on the control panel, the welding All stator blades can be manufactured with only a few adjustments, no special skills are required on the part of the operator, and the reliability of the welded parts is high.
Also, the time required for welding is the net amount per stationary blade.
It takes about 40 minutes, and it is possible to significantly reduce worker fatigue compared to TIG welding. C. When electron beam welding is used, the shaft diameter is 60 mm compared to conventional TIG welding because it is one-pass welding.
In the case of mmφ, it is possible to weld stationary blades with 2.5 to 3 times higher efficiency. d) Since the heat input is low and the bead width is narrow, there is little shrinkage due to welding, and there are fewer defects in the blades due to welding. E. Even if the stator vane has a different shaft diameter, it has the advantage of requiring fewer spare parts because only the shaft needs to be replaced. In addition, it is possible to immediately replace defective products during periodic inspections, thereby reducing costs for after-sales service. F) With low heat input welding, the cooling rate of the heat-affected zone is high, so no sensitization is observed in the heat-affected zone.Therefore, there is no need for solution heat treatment after welding, which reduces heat treatment costs and improves heat treatment efficiency. There is an advantage that extra material can be saved considering the accompanying deformation. (g) Since the reliability of the strength of the shaft portion is improved, the shaft diameter can be reduced and the weight of the stator vane can be reduced. Furthermore, as the shaft diameter becomes smaller, as shown in FIG.
0, lever 18, nut 19, etc. can be made smaller,
In addition, the cost of other parts can be reduced, such as by reducing the need for holes in the casing 16 to which these parts are attached. Next, embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a front view of a stator vane G for a turbine showing an embodiment of the present invention, in which the blade part 10 is manufactured by casting, and a part 11 of the Zabuton part is simultaneously attached to the upper end of this blade part 10. Cast it. Separately from this wing section 10, a part 12 of the zabuton section and a shaft section 13 are manufactured integrally by forging. The Zabuton parts 11 and 12 have substantially the same shape, and are welded together.
This welded portion is provided with a normally required predetermined bevel. The blade part 10 manufactured by casting as described above and the shaft part 13 manufactured by forging are combined with the double-sided parts 11 and 12 formed at the ends of both, and the combined parts are welded to integrate them. A material for the stator blade according to the present invention is prepared, and the stator blade G is completed by subjecting it to final finishing processes such as screw processing and shaft outer circumferential processing. FIG. 4 shows the cross-sectional shape of the bead portion, and the bead 14 is formed on the entire surface of the zabuton portions 11 and 12. When the shaft material was, for example, SUS316L, electron beam welding was performed under the welding conditions shown in Table 1.

[Table] The bead shape in this case has a penetration depth of 40
mm, and the bead width was 3.5 mm (center of melting). The turbine stator blade G manufactured in this way is
No defects occurred in either the bead portion 14 or the groove portions 11 and 12, making it possible to manufacture a sound and high-quality stationary blade. Also, the time required for electron beam welding of the wing is approximately
40 minutes, and the shaft diameter is 60 mm compared to the conventional method of welding the shaft part using TIG welding.
In the case of φ, the production efficiency was about 2.5 to 3 times higher. Furthermore, stator blades manufactured by this method are in practical use in furnace top pressure turbines that use exhaust gas from blast furnaces, but no problems have occurred, and it is clear that the present invention is superior. It goes without saying that the present invention is applicable not only to stator blades of furnace top pressure turbines but also to similar products such as axial flow compressors and turbine stator blades.

[Brief explanation of the drawing]

FIGS. 1 and 2 are front views of conventional turbine vanes. FIG. 3 is a front view of a stator vane of a turbine according to an embodiment of the present invention, FIG. 4 is an enlarged sectional view of the welded part in FIG. 3, and FIG. 5 is a diagram showing how the stator vane is installed. be. 1... Wing part, 2... Zabuton part, 3... Shaft part,
10... Wing section, 11, 12... Zabuton section, 13
...Shaft part, 14...Bead part, 15...Gas, 1
6...Casing, 17...Sleeve, 18...
Lever, 19... nut, 20... bearing.

Claims (1)

[Scope of Claims] 1. A stationary blade for a turbine in which a blade part and a shaft part are separated, the blade part is manufactured by casting, the shaft part is manufactured by forging, and both are integrated by welding. A stationary blade for a turbine, characterized in that a Zabuton part is formed at the end of the blade part, a Zabuton part is formed by widening the end of the shaft part, and both Zabuton parts are welded together. manufacturing method. 2. The invention as set forth in claim 1, characterized in that the Zabuton part formed at the end of the wing part and the Zabuton part formed at the end of the shaft part are welded and integrated by electron beam welding. A method of manufacturing turbine stator blades.