DE1060224B - Process for the production of internally cooled metal blades for turbines and compressors - Google Patents

Description

It is known to produce internally cooled metal blades for turbines and compressors in such a way that that one starts from a molding, which is arranged according to the position of the cooling channels, one deformable and later removable filler containing 5., holding longitudinal bores is provided, and these Shaped molding by extrusion to the blade, but leaves a pressed residue from which then the blade root is carved out. With this method you have the choice of the width of the cooling channels bound by the shape and dimensions of the blade root. If the method z. B. for the production of blades, their. Vane flow has a relatively narrow rear, · like it applies to the well-known pine cone foot, and the channels should open on der.Hinterseite, then must the diameter of the channels must be smaller than the width of the area available there. Then you can the diameter of the cooling channels often do not make as large as the cross-section of the root on the blade would allow, and arrives at a poorly cooled shovel; because with decreasing diameter the cooling surface decreases, while at the same time the wall thickness between the cooling surface and the outer surface and the flow resistance for the cooling air increases.

The invention has for its object to redesign the known method so that one of the Binding of the diameter of the cooling channels to the shape and dimensions of the foot is released. According to the Invention, the longitudinal holes in the molding are only drilled so deep that they are still within the Later blade root end, and they are after extrusion either by at least one Cross hole with a lateral blade root surface or through longitudinal holes in the rear blade root surface tied together. With this method, the diameter of the cooling channels in the sheet can be unlimited choose what is most favorable for cooling. Only when dimensioning the cross hole or the longitudinal bores in the blade root one is bound to its dimensions and shape. These holes however, they are short and, moreover, have practically no effect on cooling. The one in extrusion unavoidable displacement of the bores, which makes their position indeterminate, is thereby rendered harmless, that the longitudinal bores end within the later blade root. That’s the inner ends of these bores removed from the action of extrusion and there is no uncertainty about theirs Position, so that the holes made later in the foot with certainty hit the channels. ..

It is known, in the manufacture of valves for internal combustion engines with a copper core, a bag

COPY _BAD method of manufacture

of internally cooled metal blades for turbines and compressors

. Applicant:

Henry Wiggin & Company Limited, London

Representative: Dr.-Ing. G. Eichenberg, patent attorney, Düsseldorf, Cecilienallee 76

Claimed priority: Great Britain October 26, 1955 and September 24, 1

Alexander Barbour Graham, Thornliebank, Glasgo and Philip George Turner, Inkberrow, Worcestersr

(Great Britain) have been named as inventors

To drill a hole in a molding, to put a copper core in this L <and then to subject the whole thing to 1 extrusion, whereby the valve disk remains as a pressed residue. This procedure results in the use of a Sackioc! directly from the fact that the copper core is supposed to be completely enclosed around the body of the valve. On the other hand, it is the other way around with blades 1 cooling channels, because the channels d should pass from one end to the other. Furthermore, there are two further steps, namely the stretching of the holes drilled in the molding in the later blade root and production \ Boreholes in the blade root after the Straugpress in the known method of manufacturing ν valves nothing comparable.

The method according to the invention can be designed expediently that the removal of the filler, which happens in particular by Säurebehai treatment, after the production of the Querbt tion or the longitudinal bores carried out wi This measure is used to accelerate, because 1 Dissolving acid can also penetrate through the bore or B (stanchions in the blade root and thus τ can attack two sides.

ORIGINAL. ^909i5S

Claims (2)

The method according to the invention is explained in detail below in conjunction with the illustrated embodiment. In the drawing, FIG. 1 shows a molding which forms the starting workpiece of the method, FIG. 2 shows the same. Molding according to the extrusion: n, Fig. 3 the foot brought to the shape of a pine cone according to Fig. 2 and Fig. 4 a blade base of a slightly modified type. that it coincides with the opening of the foot of the shovel to be manufactured, apart from the last machining that gives the foot its exact shape, four blind holes 2 are drilled in this molding so deep that they extend into that area of the molding, which later forms the foot and lies within the dashed line 3. The holes 2 'are then filled with a filler. The molding is then placed in the receptacle of an extrusion press, the shape of which is precisely matched to the cross-section of the molding, while the opening of the die through which the molding is torn essentially corresponds in its cross-section to that of the blade. The molding is only pressed over part of its length by this die, and the pressing is interrupted at the moment when there is still as much material inside the receiver as is necessary for the foot. The result of this step is shown in FIG. The workpiece now consists of a shaft 4 forming the blade and a foot 5. Inside the shaft 4, the originally circular holes 2 assume the shape of channels 6 with an elliptical cross-section. Within the foot 5, however, nothing has changed in terms of the shape and position of the holes 2. The 'uß 5 is then brought by forging to the roof-5 -rmig tapering shape 7 according to FIG. 3, odann steps 8 are milled in the side surfaces, 3 that the known pine cone shape is created. Connection holes 9 of a relatively small diameter are then drilled so deep from the narrow end face 10 of the pine cone foot that they open into holes 2. You can drill from the front of the foot at any angle. All that matters is that they flow into the, öcher 2. In the modification according to FIG. 4, a single larger hole 12 is drilled from the side of the foot 11 in such a way that it connects all the blind holes 2 to one another at the same time. The foot can then be milled into the shape of a pine cone, as indicated in dash-dotted lines. The process steps described are followed by the removal of the filler. If the blade is made of an alloy that contains predominantly nickel and chromium, possibly also cobalt and also aluminum and titanium, i.e. an alloy with a low tendency to creep, an iron-manganese-titanium alloy is expediently used as the filler. The filler can then be removed by dissolving in acid. This is best done after drilling the holes 9 or 12 so that the acid can pass through these holes and also dissolve the filler by attack from the blade root. In general, it is advisable to drill the blind holes in the molding. However, it is also possible to use a strand produced by extrusion as the molding, which had already been provided with filled holes before the extrusion. Patent claims: 1. Process for the production of internally cooled metal blades for turbines and compressors by extrusion of a molding with arranged according to the position of the cooling channels, a deformable and later removable filler containing longitudinal bores to the airfoil except for a pressed residue from which the blade root is then worked out, characterized in that, that the longitudinal bores (2) in the molding (1) are only drilled so deep that they still end within the later blade root (5), and that they either after extrusion through at least one transverse bore (12) with a lateral or longitudinal bore (9) be connected to the rear blade root surface. 2. \ "experienced according to claim 1, characterized in that the removal of the filler, in particular by acid treatment, after the production of the transverse bore (12) or the Longitudinal bores (9) is made. Considered publications:
U.S. Patent No. 2,093,776;
Metal Industry, June 25, 1954, p. 55. 1 sheet of drawings COPY