DE2519154A1 - TURBINE IMPELLER AND METHOD OF MANUFACTURING IT - Google Patents

Description

Turbine impeller and process for its manufacture

The invention relates to a turbine runner with a hub disk and blades that are integral with one another are made potted.

Cast turbine runners are usually cast statically in a vacuum using the lost wax method. Because the area of the hub disk and the blades are very different when the gas turbine is in operation heated, and the blade root must absorb the highest tensile and bending loads, is used as the material for the cast turbine impeller of highly heat-resistant material adapted to the load on the turbine blades. Such impellers meet the technical requirements placed on them, but are very expensive because a material is used for the hub disk that is thermally oversized and at low temperatures does not have the optimal strength possible, whereby it must be assumed that the material price increases according to the high temperature strength.

609846/0473

Klöckner-Humboldt-Deutz AG Z ^ emBaU ac l Λ CfI ^

The object of the present invention is to remedy these disadvantages and to create a turbine runner, that meets all mechanical and thermal requirements and is also inexpensive to manufacture is. This object of the invention is achieved in that the blade area is made of highly heat-resistant and the area the hub disc is made of a different material that is high-strength at low temperatures. The material for the hub area can now be selected so that it is in the temperature range in question for the disc, which is much lower than the temperature range for those exposed to the hot gas Blades, has high strength to absorb the mechanical forces, with high strength at higher Temperatures is not required. In contrast to this, the blade area is made of a material that is at high temperature still has high strength.

To produce such a turbine runner suggested that a preferably after the wax

609846/0473

Klöckner-Humboldt-Deutz AG ÄIVHU -j 5 4 1975

Melting process rotationally symmetrical shape, which is coaxial to the turbine runner axis, preferably is rotatably mounted about a vertical axis, is possibly set in rotation in a vacuum and that through a pouring funnel arranged coaxially to the axis of rotation from successively melted material high-temperature and then high-strength material is shed. The material that flows into the mold first is due to the centrifugal force pressed into the cavities provided for the blades or the blade area and remains there until to freeze. If a sufficient amount of highly heat-resistant material has been introduced, then, depending on Material also with a time lag, molten material that is at low temperatures is high strength, cast so that this connects to the material of the blade area. Depending on the state of solidification of the material filled in first forms between the hub disk and the blade area a Miechzonei that creates a good connection between the two materials. To the strength of the

609846/0473

Klöckner-Humboldt-Deutz AG with% HU 16. A. 1975

D 75/27

To influence both materials, the speed of the casting mold can be changed during the casting process and so that the centrifugal force can be varied.

To further explain the invention, reference is made to the drawing, in which an exemplary embodiment the invention is shown in simplified form. Show it:

Fig. 1 is a view with a partial section through a turbine runner, in which the hub disk from is cast in a different material than the blade area.

2 shows a section through a casting mold by means of which the method according to the invention is carried out can be.

The turbine runner according to FIG. 1 has a blade area denoted by 1, the blades 2 and one Has ring 3 in the area of the blade roots. The blades and the ring are cast in one piece and consist of one

9646/0473

Klöckner-Humboldt-Deutz AG /> Λ I% H U April 16, 1975

D 75/27

Material that has great strength even at high temperatures. Within the ring 3 closes a hub disk 4, which thickens to form a hub and with this on a not shown Shaft is attached. The hub disk 4 is also cast and made of a material that in particular has high strength at low temperatures. In the area of lower temperatures is the Strength of the material of the hub disk higher than that of the material of the blade area. Between the ring and the hub disk 4 is an annular mixing zone area, denoted by 5, its creation the description of the manufacturing process according to FIG. 2 can be found.

In Fig. 2, 6 denotes a weft-shaped casting mold, which is attached centrally to a shaft 7. The shaft 7 is rotatably mounted about a vertical axis. the bowl-shaped casting mold 6 is filled with filling material 8 and contains central, coaxial to the axis of rotation Shaft 7 arranged, one produced by a wax model

809846/0473

KHD ₁₆

D 75/27

Kiöckner-Humboldt-Deutz AG Ζ / λ \ r% n W ^ -JA / ^ 1975

Provided cavity, which corresponds to the outer shape of a desired turbine runner. The wax model had a coating which forms the inner wall 9 of the casting mold after the wax has melted. On the opposite On the side of the shaft, a pouring funnel 10 is centrally incorporated through which the casting material can be fed. The entire mold according to FIG. 2 is preferably in during casting housed in a vacuum chamber.

Before the start of the casting process, the bowl-shaped casting mold 6 with its contents is set to a certain speed brought, which is matched to the density of the material to be poured first. If this speed is reached, material is poured in through the pouring funnel, which after cooling at high temperatures is highly heat resistant. This material fills the blade area 1 and is in recorded in this area. Depending on the choice of material, the mold can be rotated for a while, by one to achieve partial solidification of the blade area *

609846/0473

Kiöckner-Humboldt-Deutz AG A ^ ItM LP -j £ _# / ^ 1975

This can depend on the density of the material to be potted be important, as otherwise the subsequent casting material could penetrate into the shovel area. Afterward liquid material is poured through the pouring funnel 10, which the space of the hub disk 4 fills out. The latter material is a metallic material, which in the low temperature range a

has higher strength than the first cast material. The one between the blade area 1 and the hub disk 4 resulting mixing area 5 is formed by the fact that the first cast material is not yet is completely cold when the material of the hub disc hits it. This mixing zone is This is an advantage, as this ensures good interlocking and connection between the two cast workpieces will.

609846/0473

Claims (4)

P a t e. η t ans ρ r ü c h e 1. . Turbine impeller with a hub disk Ί and blades j ;: which are manufactured as one-piece cast with one another, characterized in that the blade area; (j ) from high temperature resistant? and; <ierr area of the hub disc; {4); from, .Another and «r ^ n, j ^ ei low temperature high-strength factory ^ tc ^ fb; it; teht. 2. A method for producing a Tur.hinenlauf- - _{: v} wheel according to claim 1, characterized in that a, preferably rotationally symmetrically produced by the lost wax process (6, 8, 9), which is coaxial to the turbine axis, preferably rotatable about a vertical axis is stored, possibly set in rotation in a vacuum and that successively melted material made of high-temperature and then high-strength material is poured through a pouring funnel (10) arranged coaxially to the axis of rotation. Klöckner + lumboldt-Deirtz AG ÄKHD ^ 5 _# / ^ 1975 D 75/27 3. The method according to claim 2, characterized in that the casting of the material of the hub disc (4) compared to that of the blade area (1) takes place with a time delay that the first cast material is at least partially or partially solidified. 4. The method according to any one of claims 2 or 3 »characterized in that the materials for the Hub disk (4) and the blade area (1) at different speeds of the casting mold (6, 8, 9) to be shed. 609846/0473 A ₀ Blank page