EP1886743A1 - High temperature forging die - Google Patents

Abstract

The die for high temperature mild intermetallic component for the production of aircraft engine or stationary gas turbines or its shovel, comprises upper and lower particle or fiber reinforced die parts (4), which are connected with a reinforcement ring (7) over a stop element. Each die part is assigned as the reinforcement ring surrounding with fixture by ambient temperature. The die parts are placed on the ring due to its thermal expansion during heating. A compressive stress is exerted on the die part by the reinforcement ring. The die part is ceramic or graphite. The die for high temperature mild intermetallic component for the production of aircraft engine or stationary gas turbines or its shovel, comprises upper and lower particle or fiber reinforced die parts (4), which are connected with a reinforcement ring (7) over a stop element. Each die part is assigned as the reinforcement ring surrounding with fixture by ambient temperature. The die parts are placed on the ring due to its thermal expansion during heating. A compressive stress is exerted on the die part by the reinforcement ring. The die part is ceramic or graphite and the reinforcement ring consists of a fiber reinforced composite with wrapped carbon fiber. The fixture is designed by ambient temperature under circumstances of the expansion behavior of the die part and the ring in such a way that the constructed compressive stress is implemented by a predetermined value of a mild temperature. The reinforcement ring has an internal bearer ring (9) on which the heated die part adjoins. The bearer ring has projections (11) serving the support of the inserted die part and is sectionally closed at a side. The projection is intended at rotating edge side around 180[deg]. The die parts are intended at forcible guidance cooperated with compatible place of the die part. The guidance has fiber reinforced bolts or plug that is interfered into the bolt- or plug reception at the opposite die part. The bolt or plug exists out of ceramic or graphite. The die parts have die part elements (5, 6) and gravures. The stop element is a peg that is received in corresponding sockets at the reinforced ring and at the die part or the die part element.

Description

The invention relates to a die for high-temperature forging metallic, in particular intermetallic components, comprising an upper and a lower die part.

In high-temperature forging, the forming of the blank takes place at temperatures above 1000 ° C, in the forming of components made of intermetallic compounds such. B. TiAl even at temperatures at the tool of about 1150 ° C. A forming method relating to such a component made of an intermetallic compound is, for example WO 02/48420 A2 known. From such materials usually lightweight and highly resilient components for conventional and aviation technology, for example, for aircraft engines or stationary gas turbines, where their blades manufactured. As a die a die of a molybdenum alloy is used, which has a sufficient hot strength up to a mold temperature of 1150 ° C. However, this hot strength is not sufficient to produce components with tight dimensional tolerances, that is, it could only be made forge forgings, which require subsequent machining and / or electrochemical finishing. A transformation in the temperature range above the eutectic in the α-γ phase region, ie at temperatures of 1200 - 1300 ° C or more, has proven to be advantageous. There can be made much more dimensionally accurate components. However, since a die of a molybdenum alloy can not be used in this temperature range, dies of ceramics of about carbon or silicon base are to be used in this case. The disadvantage here is that these die materials are extremely sensitive to tensile stresses that inevitably occur during drop forging, which is why the durability of such dies is limited.

The invention is therefore based on the problem of specifying a die, which can be used for high-temperature forging at temperatures from above 1200 ° C, to at least 1300 ° C, and that a sufficient stability the stresses occurring during drop forging, in particular tensile stresses.

To solve this problem is provided according to the invention in a die of the type mentioned that each die part is assigned at room temperature with play surrounding reinforcing ring to which the respective die part applies due to its thermal expansion during heating, and on a compressive stress on the respective die part is exercised.

Each die part according to the invention has a special surrounding reinforcing ring, which at room temperature, ie when the die is not arranged in the press and heated to operating temperature, surrounds the die part with play. The game is for example a millimeter. This allows the separation of die and reinforcing ring at room temperature, which may be necessary when changing the die part against another die part with a different engraving. Now, if the Gesenkteil-Armierungsring combination heated so the die part expands during heating much stronger than the reinforcing ring, which, depending on which material or composite materials it is constructed, if necessary, even a negligible extent. The thermally induced expansion of the die part now causes the die part to bear firmly against the surrounding reinforcing ring. This in turn means that the reinforcing ring exerts compressive stresses on the respective die part, which counteract or counteract the tensile stress arising during forging. So here comes to a targeted stress relief, which has a much longer life of the die part result.

In this case, the game at room temperature in development of the invention is preferably designed taking into account the expansion behavior of the respective die part and possibly the reinforcing ring, so this shows a certain expansion behavior, that the built-up compressive stress at the forging temperature assumes a predetermined value. It can therefore by suitable dimensioning taking into account the specific material parameters of the Gesenkteilmaterials as well as the Armierungsringsmaterials a very Accurate adjustment of the height of the built-up compressive stress. After the tensile stresses occurring during forging can also be determined relatively accurately, as a result, a corresponding design of the die part as well as the reinforcing ring with respect to the game at room temperature, so that a substantial compensation of the tensile stresses built up during forging is possible.

The die parts themselves are made of ceramic or graphite, optionally particle or fiber reinforced. These materials readily withstand the high forging temperatures required for forging in the temperature range above the eutectic in the α-γ phase region, and can be used for high temperature forging due to the use of the reinforcing ring of this invention.

The reinforcing ring itself according to the invention consists of a fiber composite material, in particular carbon fibers, which are wound around a core during manufacture. Carbon fibers have an extremely small, possibly even negative thermal expansion coefficient in the fiber direction. With appropriate winding or orientation of the fiber layer around the core, a reinforcing ring can thus be produced as a wound reinforcing structure, which exhibits almost no expansion during heating. An advantageous development of the invention provides that the reinforcing ring is constructed hybrid and has an inner support ring on which rests the heated die part. That is, the reinforcing ring here consists of the outer Armierungsringabschnitt of wound carbon fibers and an inner support ring against which the heated die part. This inner support ring, which according to the invention consists of a textile structure wound around a core during manufacture, in particular a fabric or braid of synthetic fibers, permits a relatively high degree of shaping possibilities and freedom of design with regard to the structural design of the reinforcing ring. Because it is difficult to integrate into the outer Armierungsringabschnitt of coiled carbon fibers corresponding, deviating from the pure cylindrical shape geometries or form or form, for example in the form of holes or the like, after the strength or mechanical properties perpendicular to the fiber longitudinal direction or the winding structure are significantly worse. This is taken into account that the inner support ring is provided which has low Armierungs- or compressive stress generating properties, but primarily serves to enable constructive or geometric peculiarities. For this purpose, a textile structure in the form of a fabric or braid is wound around the core of the support ring during manufacture, ie there is no excellent fiber direction here. The use of this textile structure now makes it possible, for example, to carry out projections or undercuts or the like or to mount holes or the like on corresponding sections, which for whatever reason are required.

As described, the reinforcing ring surrounds the die part, which, as will be discussed below, surrounds one or more parts, at room temperature with a slight play. In order to avoid that the die part falls out of the reinforcing ring during transport of the Gesenkteil-Armierungsring combination, one or more of the holder of the inserted die part serving radially inwardly directed projections or is preferably provided on the inner support ring, preferably in the form of at least 180th ° circumferential edge. On this projection, the die part rests on and can not fall out of the reinforcing ring over the projection and, if appropriate, slight clearance tilting towards the inner support ring.

If the die is intended for use in a cold-hot-process technology, in which the die is taken out of the press and loaded, after which it is transported back into the press and heated and removed from the press after completion of the pressing operation, is also the inner support ring of its basic shape cylindrical. It is open on both sides, so that the die part with its opposite side of the respective engraving rests flat and directly on the respective punch. However, a die according to the invention can also be used for use in the context of a pure hot-process technology. Here, the die remains in the press, that is, the two individual die parts are fixed to the respective press stamp connected. In order to enable a connection, the support ring according to the invention is at least partially closed on one side in a suitable for such an insert die. The support ring thus has on the side on which the die part abuts with its engraving-free side, an at least partially closed surface in which corresponding holes or the like may be provided, via which the fixation of the support ring and on this of the reinforcing ring together with the swaging part at the respective Press stamp bottom is possible.

So that the die parts can be moved in the correct relative position to each other in the pressing position, co-operating positive guides are provided on both die parts when placing the die parts cooperating positive, which preferably comprise one or more bolts or pins, or in the respective pin or pin shots on engage opposite die part. In this case, for example, when using two bolts or pins both pins or pins may not necessarily be provided on the same die part. It is also conceivable to provide a respective receptacle on each die part, a bolt and this each opposite to the other die part. These bolts or pins are preferably made of graphite or ceramic, optionally also fiber or textile reinforced, primarily using carbon fibers produced.

As already described, it is possible to carry out a die part in one piece or to assemble it from two or more individual die part elements. This is necessary if undercuts or the like must be formed on the forging part in order to open the die part and to be able to form the forged part. The two or more die parts are, when they are inserted into the reinforcing ring, introduced so that each Gesenkteilelement rests on one or the serving to its support projection on the respective inner ring, including optionally on the die part or die part a corresponding undercut into which the projection engages, can be trained. The die-part elements also have a certain clearance relative to each other at room temperature, so that the individual die-part elements can be readily arranged or fitted within the reinforcing ring.

It is also expedient if the die part, optionally the die part elements are connected via at least one retaining element with the reinforcing ring. This holding element, which as well as the one or more protrusions plays a certain fixing function, also serves as a guide of the components relative to each other during the thermally induced radial expansion movement. Such a holding element is preferably a retaining pin, which is received in corresponding plug-in receptacles on the reinforcing ring and the die part or a Gesenkteilelement.

Finally, each die part can either have a single engraving or else several engravings, depending on the type and size of the forged part to be produced.

Fig. 1

eine Schnittansicht durch ein erfindungsgemäßes Obergesenk einer ersten Ausführungsform,

Fig. 2

eine Schnittansicht durch das zugehörige Untergesenk,

Fig. 3

eine Schnittansicht durch ein Obergesenk einer erfindungsgemäßen zweiten Ausführungsform,

Fig. 4

eine Aufsicht auf das Obergesenk aus Fig. 3 mit Blick auf die Gravurseite,

Fig. 5

das zugehörige Untergesenk, und

Fig. 6

eine Aufsicht auf ein Gesenk einer dritten Ausführungsform mit mehreren Gravuren.

Further advantages, features and details of the invention will become apparent from the embodiments described below and with reference to the drawings. Showing:

Fig. 1

a sectional view through an inventive upper die of a first embodiment,

Fig. 2

a sectional view through the associated lower die,

Fig. 3

a sectional view through an upper die of a second embodiment according to the invention,

Fig. 4

a top view of the upper die of Figure 3 with a view of the engraving side,

Fig. 5

the associated lower cast, and

Fig. 6

a plan view of a die of a third embodiment with multiple engravings.

Fig. 1 shows the upper part 1 of a Gesenk 2 according to the invention, while Fig. 2 shows the lower part 3. The upper part 2 consists of a die part 4, here consisting of two die part elements 5, 6. The upper part 2 further comprises a reinforcing ring 7, consisting of the outer Armierungsringteil 8 and an inner support ring 9. The die part 4 consisting of the two Gesenkteilelementen 5, 6 has on its pressing side a mold cavity 10, which serves for the shaping of a molded part to be produced in high temperature forging. Fig. 1 shows the upper die 2 at room temperature, while Fig. 3 shows the lower die at an operating temperature of 1200 ° C or more.

As can be seen from Fig. 1, the die 4 has a slight clearance to the reinforcing ring 7, here the cylindrical inner wall of the support ring 9, represented by the narrow gap of width d, where d ≤ 1 mm. The two Gesenkteilelemente 5, 6 have a slight play each other, as also represented by the indicated distance d, the game does not have to be equal to the game to support ring. In any case, the die part elements 5, 6 sit loosely in the reinforcing ring 7 when this combination is at room temperature.

So that the die-part elements 4 inserted into the support ring 7 do not fall downwardly out of the reinforcing ring 7 during handling of the upper part, the inner support ring 9 has an inwardly directed projection 11 in the form of a retaining flange which either rotates 360 ° or at least turns it around at least 180 °. On it the die part elements 5, 6 are on the edge, they have corresponding undercuts 12, 13, in which the edge-side projection 11 engages. Furthermore, a guide pin 14 is provided, which passes through a bore 15 through the support ring 7 and in a insertion bore 16 of a Gesenkteilelements, here the Gesenkteilelement 6, engages. This guide pin, which also has a certain holding or supporting function, serves primarily the radial guidance of the Gesenkteilelements during the expansion process, which will be discussed below.

The die part elements 5, 6 are preferably made of ceramic or a ceramic matrix composite material of any kind, which is chosen such that it can be used at forging temperatures above 1200 ° C, wherein a die according to the invention certainly at temperatures of 1500 - 2000 ° C can be used.

The reinforcing ring 7 itself is constructed as described hybrid of the outer Armierungsringteil 8 and the inner support ring 9. The outer Armierungsringteil 9 consists of a ring made of carbon fiber composite material. The fibers are aligned with their fiber longitudinal direction to generate compressive stresses in the heated shell 2, which are exerted on the die part 4, to counteract any tensile stresses built up in the die part 4 during forging, which are primarily directed radially. The Armierungsringteil 8 has an extremely low, possibly depending on the used carbon fiber material even negative thermal expansion coefficient in the fiber longitudinal direction, which means that it shows almost no thermal expansion during heating.

The inner ring 9, however, also consists of a ring of carbon fiber composite material having a reinforcing structure, preferably a woven fabric or braid of carbon fibers, so that a textile support structure results, unlike the all of exactly the same aligned winding fibers on Armierungsringteil 8. The use of a fiber fabric or - braid makes it possible to perform different geometric shapes, for example, on the inner ring to form the inwardly projecting flange or projection 11. This is not possible with the use of individual laid fibers, as they are wound on the outer ring part 8, without sacrificing mechanical properties. The inner ring 9 has therefore the function of providing any geometrical shapes and designs available, which - as here - for example, for supporting the Die part elements are required.

If the upper part 2 is then heated using an induction heater 17, in which the upper part 2 according to FIG. 1 is located, then the die part 4 or the die part elements 5, 6 expands thermally depending on the given thermal expansion coefficient of the graphite or graphite Ceramic material primarily radially out. As a result, with increasing expansion, the gaps between the die part elements 5, 6 and the support ring 9 are closed. The stronger the expansion, the stronger the die part 4 abuts radially on the reinforcing ring 7. After the reinforcing ring 7 or the outer Armierungsringteil 8 despite the extremely high temperature shows no or only a reducible expansion, but the die part 4 is strongly pressed due to its own extent against the reinforcing ring 7, 7 high compressive stresses in the die 4 induced. These compressive stresses now counteract the tensile stresses occurring during forging. The design of the gap or of the clearance d takes place taking into account the coefficients of expansion of the materials used for the die part as well as the reinforcing ring 7, here in particular the Armierungsringteils 8, so that at the working temperature, the induced compressive stresses take a predetermined value. After it is possible to determine the tensile stresses occurring during forging in the die part 4 as well as their direction, so an interpretation of the game with respect to the operating temperature can be such that the compressive stresses generated substantially compensate for the tensile stresses caused by the press.

Fig. 2 shows the lower part 3, the die part 4 also consists of two die part elements 5, 6, which are received in a reinforcing ring 7 consisting of the outer Armierungsringteil 8 and the inner support ring 9. Here, however, the lower part 3 is heated by the induction heater 17 already at operating temperature or only slightly below. Obviously, the gaps d still given at room temperature (see Fig. 1) are all closed.

The die 1 according to FIGS. 1 and 2 is primarily intended for cold-hot process technology. The die thus has no fixed connection to the forming machine.

It is cold assembled outside the machine, so assembled at room temperature and provided with an inserted into the engraving 10 blank, which may be cold or preheated. Subsequently, the two die elements, so the upper part 2 and the lower part 3 in the press room, which is to avoid oxidation under vacuum or inert gas, introduced through a suitable lock. The upper part 2 and the lower part 3 are heated in the press room to the required forming temperature of for example 1200 - 1300 ° C, either inductively (as shown in the figures) or by radiant heating. After reaching the forging temperature, the die 1 is placed between the also located at this temperature press plates of the forming press and carried out the forming process with the required low speed for forming the blank. Subsequently, the die with the formed component cools under protective gas after removal from the forming press and is discharged again via the lock, after which the component is removed and a new component is inserted.

In order to ensure that the upper part 2 and the lower part 3 are also moved correctly relative to one another, a forced guidance is provided in the example shown, in the example shown consisting of two bolts 18, which are received here at the lower part in corresponding bolt receptacles. On the upper part corresponding bolt guides 19 are provided, in which the bolts 18 are immersed in the merging of the dies and guided. The bolts 18 are preferably also made of graphite or a suitable ceramic material, they may also be textile or fiber reinforced.

3 to 5 show a further embodiment of a die 1 according to the invention, likewise consisting of a top part 2 shown in FIG. 3 and a bottom part 3 shown in FIG. 5. Both each have a die part 4 consisting of two die part elements 5, 6 which in a reinforcing ring 7 also consisting of an outer Armierungsringteil 8 and an inner support ring 9 are added. Again, all elements are arranged at room temperature with play each other, as in this regard Fig. 1 has been described. For the sake of simplicity, however, the two die tools are shown in FIGS. 3 and 5, as if they were already heated, thus therefore the respective die part 4 has completely expanded, firmly rests against the reinforcing ring 7 and be induced in the die part 4 via these compressive stresses.

In the embodiment described therein, however, the inner support ring 9 is designed differently than the support ring 9 in the embodiment of FIGS. 1 and 2. While here on the one support ring side of the radially inwardly directed projection 11 is provided, the other side of the support ring 9 completely closed, so it is an upper (in Fig. 3) and lower (in Fig. 5) bottom plate 20 is provided. About this bottom plate 20, the entire upper part 2 or lower part 3 can now be attached to the corresponding press plate. For this purpose, although not shown in detail, corresponding apertures for receiving connecting screws or the like are provided on the respective base plate 20, which allow a fixation. The die shown in Figs. 3, 4, 5 is a die designed for a hot-process technology, that is, the top and bottom parts 2, 3 always remain in the forming press and will not removed, only the reshaped compact is removed. That is, the upper and lower parts 2, 3 remain continuously at the working temperature. For the shaping is here - unlike the engraving 10 of FIG. 2 - the engraving 10 on the lower part in a section provided with a Ausformschräge 24 which is at a slight angle α to the vertical, unlike the engraving 10 of FIG that runs vertically in this section. When removing the forcibly guided over the positive guidance on the bolt 18 and the pin guides 19 tool parts forged remains the forged component in the upper part 2. To remove the pressed part from the upper part of this is cooled so far that the gap between the die-part elements 5, 6 easily opens and the forging falls out of the shell due to its own weight and can be taken with the help of a simple manipulator from the die.

Fig. 4 shows a plan view of the underside with the engraving 10 of the upper part of Fig. 3. It can be seen that the projection 11 of the inner support ring 8 of the reinforcing ring 7 only by about 240 °. This allows the two die part elements 5, 6 in the closed on the other side, quasi pot-like support ring 9. Nevertheless, the two die part elements 5, 6, although they have as shown at room temperature to each other as well as to the reinforcing ring a game, safely and captive out. Shown in Fig. 4 further, that in this embodiment, a total of four bolt holes 19 are provided, and therefore four bolts 18 are also provided on the lower part, although only two are shown in Fig. 5.

Finally, FIG. 6 shows a further exemplary embodiment of a die 1, wherein only the upper part 2 is shown here. This upper part 2 consists - in a corresponding manner, of course, the lower part - from a total of eight individual Gesenkteilelementen, the Gesenkteilelemente 21 are all made the same, only the two Gesenkteilelemente 22 and 23 are executed differently in their shape and in terms of existing engraving. In any case, a total of seven engravings 10 are realized here, unlike the previously described embodiments, which have only one engraving. Here, too, the dividing lines between the individual die part elements 21, 22, 23 are such that the respective engraving is opened when the die part elements are detached from one another, as is the case with the die part elements 5, 6 of the exemplary embodiments according to FIGS. 1 and 2 or 3. 5 is the case. That is, when the die part is opened, the engraving automatically opens.

Claims (17)

Die for high-temperature forging metallic, in particular intermetallic components, comprising an upper and a lower die part, characterized in that each die part (4) is associated with a surrounding at room temperature with play reinforcing ring (7) to which the respective die part (4) due its thermal expansion during heating applies and over which a compressive stress on the respective die part (4) is applied, wherein the die parts (4) made of ceramic or graphite and the reinforcing ring (7) consists of a fiber composite material with wound fibers. Die according to claim 1, characterized in that the clearance at room temperature, taking into account the expansion behavior of the respective die part (4) and optionally of the reinforcing ring (7) is designed such that the built-up compressive stress at the forging temperature assumes a predetermined value. Die according to claim 1 or 2, characterized in that the die parts are particle or fiber reinforced. A die according to any one of the preceding claims, wherein the reinforcing ring (7) consists of wound carbon fibers. Die according to claim 4, characterized in that the reinforcing ring (7) has an inner support ring (9) on which the heated die part (4) rests. Die according to claim 5, characterized in that the inner support ring (9) consists of a wound textile structure, in particular a woven fabric or braid of carbon fibers. Die according to claim 5 or 6, characterized in that on the inner support ring (9) one or more of the holder of the inserted die part (4) serving projections (11). Die according to claim 7, characterized in that an at least 180 ° circumferential edge-side projection (11) is provided. Die according to one of claims 5 to 8, characterized in that the support ring (9) on one side (20) is closed at least in sections. Die according to one of the preceding claims, characterized in that cooperating positive guides are provided on both die parts (4) when the die parts (4) are placed on one another. Die according to claim 10, characterized in that the positive guides comprise one or more bolts (18) or pins which engage in respective pin or pin receivers (19) on the opposite die part. Die according to claim 11, characterized in that the one or more bolts (18) or pins made of graphite or ceramic, optionally fiber or textile reinforced, are. Die according to one of the preceding claims, characterized in that a die part (4) consists of two or more individual die part elements (5, 6, 21, 22, 23). Die according to claim 13, characterized in that the die part elements (5, 6, 21, 22, 23) at room temperature have a game to each other. Die according to one of the preceding claims, characterized in that the die part (4), optionally the die part elements (5, 6, 21, 22, 23) via at least one holding element with the reinforcing ring (7) are connected. Die according to claim 15, characterized in that a holding element is a retaining pin (14) which is received in corresponding plug-in receptacles on the reinforcing ring (7) and the die part (4) or a Gesenkteilelement (5, 6, 21, 22, 23). Die according to one of the preceding claims, characterized in that each die part (4) has a plurality of engravings (10).

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